What is the definition of word in computer

In computing, a word is the natural unit of data used by a particular processor design. A word is a fixed-sized datum handled as a unit by the instruction set or the hardware of the processor. The number of bits or digits^[a] in a word (the word size, word width, or word length) is an important characteristic of any specific processor design or computer architecture.

The size of a word is reflected in many aspects of a computer’s structure and operation; the majority of the registers in a processor are usually word-sized and the largest datum that can be transferred to and from the working memory in a single operation is a word in many (not all) architectures. The largest possible address size, used to designate a location in memory, is typically a hardware word (here, «hardware word» means the full-sized natural word of the processor, as opposed to any other definition used).

Documentation for older computers with fixed word size commonly states memory sizes in words rather than bytes or characters. The documentation sometimes uses metric prefixes correctly, sometimes with rounding, e.g., 65 kilowords (KW) meaning for 65536 words, and sometimes uses them incorrectly, with kilowords (KW) meaning 1024 words (2¹⁰) and megawords (MW) meaning 1,048,576 words (2²⁰). With standardization on 8-bit bytes and byte addressability, stating memory sizes in bytes, kilobytes, and megabytes with powers of 1024 rather than 1000 has become the norm, although there is some use of the IEC binary prefixes.

Several of the earliest computers (and a few modern as well) use binary-coded decimal rather than plain binary, typically having a word size of 10 or 12 decimal digits, and some early decimal computers have no fixed word length at all. Early binary systems tended to use word lengths that were some multiple of 6-bits, with the 36-bit word being especially common on mainframe computers. The introduction of ASCII led to the move to systems with word lengths that were a multiple of 8-bits, with 16-bit machines being popular in the 1970s before the move to modern processors with 32 or 64 bits.^[1] Special-purpose designs like digital signal processors, may have any word length from 4 to 80 bits.^[1]

The size of a word can sometimes differ from the expected due to backward compatibility with earlier computers. If multiple compatible variations or a family of processors share a common architecture and instruction set but differ in their word sizes, their documentation and software may become notationally complex to accommodate the difference (see Size families below).

Uses of wordsEdit

Depending on how a computer is organized, word-size units may be used for:

Fixed-point numbers

Holders for fixed point, usually integer, numerical values may be available in one or in several different sizes, but one of the sizes available will almost always be the word. The other sizes, if any, are likely to be multiples or fractions of the word size. The smaller sizes are normally used only for efficient use of memory; when loaded into the processor, their values usually go into a larger, word sized holder.

Floating-point numbers

Holders for floating-point numerical values are typically either a word or a multiple of a word.

Addresses

Holders for memory addresses must be of a size capable of expressing the needed range of values but not be excessively large, so often the size used is the word though it can also be a multiple or fraction of the word size.

Registers

Processor registers are designed with a size appropriate for the type of data they hold, e.g. integers, floating-point numbers, or addresses. Many computer architectures use general-purpose registers that are capable of storing data in multiple representations.

Memory–processor transfer

When the processor reads from the memory subsystem into a register or writes a register’s value to memory, the amount of data transferred is often a word. Historically, this amount of bits which could be transferred in one cycle was also called a catena in some environments (such as the Bull GAMMA 60 [fr]).^[2][3] In simple memory subsystems, the word is transferred over the memory data bus, which typically has a width of a word or half-word. In memory subsystems that use caches, the word-sized transfer is the one between the processor and the first level of cache; at lower levels of the memory hierarchy larger transfers (which are a multiple of the word size) are normally used.

Unit of address resolution

In a given architecture, successive address values designate successive units of memory; this unit is the unit of address resolution. In most computers, the unit is either a character (e.g. a byte) or a word. (A few computers have used bit resolution.) If the unit is a word, then a larger amount of memory can be accessed using an address of a given size at the cost of added complexity to access individual characters. On the other hand, if the unit is a byte, then individual characters can be addressed (i.e. selected during the memory operation).

Instructions

Machine instructions are normally the size of the architecture’s word, such as in RISC architectures, or a multiple of the «char» size that is a fraction of it. This is a natural choice since instructions and data usually share the same memory subsystem. In Harvard architectures the word sizes of instructions and data need not be related, as instructions and data are stored in different memories; for example, the processor in the 1ESS electronic telephone switch has 37-bit instructions and 23-bit data words.

Word size choiceEdit

When a computer architecture is designed, the choice of a word size is of substantial importance. There are design considerations which encourage particular bit-group sizes for particular uses (e.g. for addresses), and these considerations point to different sizes for different uses. However, considerations of economy in design strongly push for one size, or a very few sizes related by multiples or fractions (submultiples) to a primary size. That preferred size becomes the word size of the architecture.

Character size was in the past (pre-variable-sized character encoding) one of the influences on unit of address resolution and the choice of word size. Before the mid-1960s, characters were most often stored in six bits; this allowed no more than 64 characters, so the alphabet was limited to upper case. Since it is efficient in time and space to have the word size be a multiple of the character size, word sizes in this period were usually multiples of 6 bits (in binary machines). A common choice then was the 36-bit word, which is also a good size for the numeric properties of a floating point format.

After the introduction of the IBM System/360 design, which uses eight-bit characters and supports lower-case letters, the standard size of a character (or more accurately, a byte) becomes eight bits. Word sizes thereafter are naturally multiples of eight bits, with 16, 32, and 64 bits being commonly used.

Variable-word architecturesEdit

Early machine designs included some that used what is often termed a variable word length. In this type of organization, an operand has no fixed length. Depending on the machine and the instruction, the length might be denoted by a count field, by a delimiting character, or by an additional bit called, e.g., flag, or word mark. Such machines often use binary-coded decimal in 4-bit digits, or in 6-bit characters, for numbers. This class of machines includes the IBM 702, IBM 705, IBM 7080, IBM 7010, UNIVAC 1050, IBM 1401, IBM 1620, and RCA 301.

Most of these machines work on one unit of memory at a time and since each instruction or datum is several units long, each instruction takes several cycles just to access memory. These machines are often quite slow because of this. For example, instruction fetches on an IBM 1620 Model I take 8 cycles (160 μs) just to read the 12 digits of the instruction (the Model II reduced this to 6 cycles, or 4 cycles if the instruction did not need both address fields). Instruction execution takes a variable number of cycles, depending on the size of the operands.

Word, bit and byte addressingEdit

The memory model of an architecture is strongly influenced by the word size. In particular, the resolution of a memory address, that is, the smallest unit that can be designated by an address, has often been chosen to be the word. In this approach, the word-addressable machine approach, address values which differ by one designate adjacent memory words. This is natural in machines which deal almost always in word (or multiple-word) units, and has the advantage of allowing instructions to use minimally sized fields to contain addresses, which can permit a smaller instruction size or a larger variety of instructions.

When byte processing is to be a significant part of the workload, it is usually more advantageous to use the byte, rather than the word, as the unit of address resolution. Address values which differ by one designate adjacent bytes in memory. This allows an arbitrary character within a character string to be addressed straightforwardly. A word can still be addressed, but the address to be used requires a few more bits than the word-resolution alternative. The word size needs to be an integer multiple of the character size in this organization. This addressing approach was used in the IBM 360, and has been the most common approach in machines designed since then.

When the workload involves processing fields of different sizes, it can be advantageous to address to the bit. Machines with bit addressing may have some instructions that use a programmer-defined byte size and other instructions that operate on fixed data sizes. As an example, on the IBM 7030^[4] («Stretch»), a floating point instruction can only address words while an integer arithmetic instruction can specify a field length of 1-64 bits, a byte size of 1-8 bits and an accumulator offset of 0-127 bits.

In a byte-addressable machine with storage-to-storage (SS) instructions, there are typically move instructions to copy one or multiple bytes from one arbitrary location to another. In a byte-oriented (byte-addressable) machine without SS instructions, moving a single byte from one arbitrary location to another is typically:

1. LOAD the source byte
2. STORE the result back in the target byte

Individual bytes can be accessed on a word-oriented machine in one of two ways. Bytes can be manipulated by a combination of shift and mask operations in registers. Moving a single byte from one arbitrary location to another may require the equivalent of the following:

1. LOAD the word containing the source byte
2. SHIFT the source word to align the desired byte to the correct position in the target word
3. AND the source word with a mask to zero out all but the desired bits
4. LOAD the word containing the target byte
5. AND the target word with a mask to zero out the target byte
6. OR the registers containing the source and target words to insert the source byte
7. STORE the result back in the target location

Alternatively many word-oriented machines implement byte operations with instructions using special byte pointers in registers or memory. For example, the PDP-10 byte pointer contained the size of the byte in bits (allowing different-sized bytes to be accessed), the bit position of the byte within the word, and the word address of the data. Instructions could automatically adjust the pointer to the next byte on, for example, load and deposit (store) operations.

Powers of twoEdit

Different amounts of memory are used to store data values with different degrees of precision. The commonly used sizes are usually a power of two multiple of the unit of address resolution (byte or word). Converting the index of an item in an array into the memory address offset of the item then requires only a shift operation rather than a multiplication. In some cases this relationship can also avoid the use of division operations. As a result, most modern computer designs have word sizes (and other operand sizes) that are a power of two times the size of a byte.

Size familiesEdit

As computer designs have grown more complex, the central importance of a single word size to an architecture has decreased. Although more capable hardware can use a wider variety of sizes of data, market forces exert pressure to maintain backward compatibility while extending processor capability. As a result, what might have been the central word size in a fresh design has to coexist as an alternative size to the original word size in a backward compatible design. The original word size remains available in future designs, forming the basis of a size family.

In the mid-1970s, DEC designed the VAX to be a 32-bit successor of the 16-bit PDP-11. They used word for a 16-bit quantity, while longword referred to a 32-bit quantity; this terminology is the same as the terminology used for the PDP-11. This was in contrast to earlier machines, where the natural unit of addressing memory would be called a word, while a quantity that is one half a word would be called a halfword. In fitting with this scheme, a VAX quadword is 64 bits. They continued this 16-bit word/32-bit longword/64-bit quadword terminology with the 64-bit Alpha.

Another example is the x86 family, of which processors of three different word lengths (16-bit, later 32- and 64-bit) have been released, while word continues to designate a 16-bit quantity. As software is routinely ported from one word-length to the next, some APIs and documentation define or refer to an older (and thus shorter) word-length than the full word length on the CPU that software may be compiled for. Also, similar to how bytes are used for small numbers in many programs, a shorter word (16 or 32 bits) may be used in contexts where the range of a wider word is not needed (especially where this can save considerable stack space or cache memory space). For example, Microsoft’s Windows API maintains the programming language definition of WORD as 16 bits, despite the fact that the API may be used on a 32- or 64-bit x86 processor, where the standard word size would be 32 or 64 bits, respectively. Data structures containing such different sized words refer to them as:

• WORD (16 bits/2 bytes)
• DWORD (32 bits/4 bytes)
• QWORD (64 bits/8 bytes)

A similar phenomenon has developed in Intel’s x86 assembly language – because of the support for various sizes (and backward compatibility) in the instruction set, some instruction mnemonics carry «d» or «q» identifiers denoting «double-«, «quad-» or «double-quad-«, which are in terms of the architecture’s original 16-bit word size.

An example with a different word size is the IBM System/360 family. In the System/360 architecture, System/370 architecture and System/390 architecture, there are 8-bit bytes, 16-bit halfwords, 32-bit words and 64-bit doublewords. The z/Architecture, which is the 64-bit member of that architecture family, continues to refer to 16-bit halfwords, 32-bit words, and 64-bit doublewords, and additionally features 128-bit quadwords.

In general, new processors must use the same data word lengths and virtual address widths as an older processor to have binary compatibility with that older processor.

Often carefully written source code – written with source-code compatibility and software portability in mind – can be recompiled to run on a variety of processors, even ones with different data word lengths or different address widths or both.

Table of word sizesEdit

key: bit: bits, c: characters, d: decimal digits, w: word size of architecture, n: variable size, wm: Word mark
Year	Computer architecture	Word size w	Integer sizes	Floating­point sizes	Instruction sizes	Unit of address resolution	Char size
1837	Babbage Analytical engine	50 d	w	—	Five different cards were used for different functions, exact size of cards not known.	w	—
1941	Zuse Z3	22 bit	—	w	8 bit	w	—
1942	ABC	50 bit	w	—	—	—	—
1944	Harvard Mark I	23 d	w	—	24 bit	—	—
1946 (1948) {1953}	ENIAC (w/Panel #16[5]) {w/Panel #26[6]}	10 d	w, 2w (w) {w}	—	— (2 d, 4 d, 6 d, 8 d) {2 d, 4 d, 6 d, 8 d}	— — {w}	—
1948	Manchester Baby	32 bit	w	—	w	w	—
1951	UNIVAC I	12 d	w	—	1⁄2w	w	1 d
1952	IAS machine	40 bit	w	—	1⁄2w	w	5 bit
1952	Fast Universal Digital Computer M-2	34 bit	w?	w	34 bit = 4-bit opcode plus 3×10 bit address	10 bit	—
1952	IBM 701	36 bit	1⁄2w, w	—	1⁄2w	1⁄2w, w	6 bit
1952	UNIVAC 60	n d	1 d, … 10 d	—	—	—	2 d, 3 d
1952	ARRA I	30 bit	w	—	w	w	5 bit
1953	IBM 702	n c	0 c, … 511 c	—	5 c	c	6 bit
1953	UNIVAC 120	n d	1 d, … 10 d	—	—	—	2 d, 3 d
1953	ARRA II	30 bit	w	2w	1⁄2w	w	5 bit
1954 (1955)	IBM 650 (w/IBM 653)	10 d	w	— (w)	w	w	2 d
1954	IBM 704	36 bit	w	w	w	w	6 bit
1954	IBM 705	n c	0 c, … 255 c	—	5 c	c	6 bit
1954	IBM NORC	16 d	w	w, 2w	w	w	—
1956	IBM 305	n d	1 d, … 100 d	—	10 d	d	1 d
1956	ARMAC	34 bit	w	w	1⁄2w	w	5 bit, 6 bit
1956	LGP-30	31 bit	w	—	16 bit	w	6 bit
1957	Autonetics Recomp I	40 bit	w, 79 bit, 8 d, 15 d	—	1⁄2w	1⁄2w, w	5 bit
1958	UNIVAC II	12 d	w	—	1⁄2w	w	1 d
1958	SAGE	32 bit	1⁄2w	—	w	w	6 bit
1958	Autonetics Recomp II	40 bit	w, 79 bit, 8 d, 15 d	2w	1⁄2w	1⁄2w, w	5 bit
1958	Setun	6 trit (~9.5 bits)[b]	up to 6 tryte		up to 3 trytes		4 trit?
1958	Electrologica X1	27 bit	w	2w	w	w	5 bit, 6 bit
1959	IBM 1401	n c	1 c, …	—	1 c, 2 c, 4 c, 5 c, 7 c, 8 c	c	6 bit + wm
1959 (TBD)	IBM 1620	n d	2 d, …	— (4 d, … 102 d)	12 d	d	2 d
1960	LARC	12 d	w, 2w	w, 2w	w	w	2 d
1960	CDC 1604	48 bit	w	w	1⁄2w	w	6 bit
1960	IBM 1410	n c	1 c, …	—	1 c, 2 c, 6 c, 7 c, 11 c, 12 c	c	6 bit + wm
1960	IBM 7070	10 d[c]	w, 1-9 d	w	w	w, d	2 d
1960	PDP-1	18 bit	w	—	w	w	6 bit
1960	Elliott 803	39 bit
1961	IBM 7030 (Stretch)	64 bit	1 bit, … 64 bit, 1 d, … 16 d	w	1⁄2w, w	bit (integer), 1⁄2w (branch), w (float)	1 bit, … 8 bit
1961	IBM 7080	n c	0 c, … 255 c	—	5 c	c	6 bit
1962	GE-6xx	36 bit	w, 2 w	w, 2 w, 80 bit	w	w	6 bit, 9 bit
1962	UNIVAC III	25 bit	w, 2w, 3w, 4w, 6 d, 12 d	—	w	w	6 bit
1962	Autonetics D-17B Minuteman I Guidance Computer	27 bit	11 bit, 24 bit	—	24 bit	w	—
1962	UNIVAC 1107	36 bit	1⁄6w, 1⁄3w, 1⁄2w, w	w	w	w	6 bit
1962	IBM 7010	n c	1 c, …	—	1 c, 2 c, 6 c, 7 c, 11 c, 12 c	c	6 b + wm
1962	IBM 7094	36 bit	w	w, 2w	w	w	6 bit
1962	SDS 9 Series	24 bit	w	2w	w	w
1963 (1966)	Apollo Guidance Computer	15 bit	w	—	w, 2w	w	—
1963	Saturn Launch Vehicle Digital Computer	26 bit	w	—	13 bit	w	—
1964/1966	PDP-6/PDP-10	36 bit	w	w, 2 w	w	w	6 bit 7 bit (typical) 9 bit
1964	Titan	48 bit	w	w	w	w	w
1964	CDC 6600	60 bit	w	w	1⁄4w, 1⁄2w	w	6 bit
1964	Autonetics D-37C Minuteman II Guidance Computer	27 bit	11 bit, 24 bit	—	24 bit	w	4 bit, 5 bit
1965	Gemini Guidance Computer	39 bit	26 bit	—	13 bit	13 bit, 26	—bit
1965	IBM 1130	16 bit	w, 2w	2w, 3w	w, 2w	w	8 bit
1965	IBM System/360	32 bit	1⁄2w, w, 1 d, … 16 d	w, 2w	1⁄2w, w, 11⁄2w	8 bit	8 bit
1965	UNIVAC 1108	36 bit	1⁄6w, 1⁄4w, 1⁄3w, 1⁄2w, w, 2w	w, 2w	w	w	6 bit, 9 bit
1965	PDP-8	12 bit	w	—	w	w	8 bit
1965	Electrologica X8	27 bit	w	2w	w	w	6 bit, 7 bit
1966	SDS Sigma 7	32 bit	1⁄2w, w	w, 2w	w	8 bit	8 bit
1969	Four-Phase Systems AL1	8 bit	w	—	?	?	?
1970	MP944	20 bit	w	—	?	?	?
1970	PDP-11	16 bit	w	2w, 4w	w, 2w, 3w	8 bit	8 bit
1971	CDC STAR-100	64 bit	1⁄2w, w	1⁄2w, w	1⁄2w, w	bit	8 bit
1971	TMS1802NC	4 bit	w	—	?	?	—
1971	Intel 4004	4 bit	w, d	—	2w, 4w	w	—
1972	Intel 8008	8 bit	w, 2 d	—	w, 2w, 3w	w	8 bit
1972	Calcomp 900	9 bit	w	—	w, 2w	w	8 bit
1974	Intel 8080	8 bit	w, 2w, 2 d	—	w, 2w, 3w	w	8 bit
1975	ILLIAC IV	64 bit	w	w, 1⁄2w	w	w	—
1975	Motorola 6800	8 bit	w, 2 d	—	w, 2w, 3w	w	8 bit
1975	MOS Tech. 6501 MOS Tech. 6502	8 bit	w, 2 d	—	w, 2w, 3w	w	8 bit
1976	Cray-1	64 bit	24 bit, w	w	1⁄4w, 1⁄2w	w	8 bit
1976	Zilog Z80	8 bit	w, 2w, 2 d	—	w, 2w, 3w, 4w, 5w	w	8 bit
1978 (1980)	16-bit x86 (Intel 8086) (w/floating point: Intel 8087)	16 bit	1⁄2w, w, 2 d	— (2w, 4w, 5w, 17 d)	1⁄2w, w, … 7w	8 bit	8 bit
1978	VAX	32 bit	1⁄4w, 1⁄2w, w, 1 d, … 31 d, 1 bit, … 32 bit	w, 2w	1⁄4w, … 141⁄4w	8 bit	8 bit
1979 (1984)	Motorola 68000 series (w/floating point)	32 bit	1⁄4w, 1⁄2w, w, 2 d	— (w, 2w, 21⁄2w)	1⁄2w, w, … 71⁄2w	8 bit	8 bit
1985	IA-32 (Intel 80386) (w/floating point)	32 bit	1⁄4w, 1⁄2w, w	— (w, 2w, 80 bit)	8 bit, … 120 bit 1⁄4w … 33⁄4w	8 bit	8 bit
1985	ARMv1	32 bit	1⁄4w, w	—	w	8 bit	8 bit
1985	MIPS I	32 bit	1⁄4w, 1⁄2w, w	w, 2w	w	8 bit	8 bit
1991	Cray C90	64 bit	32 bit, w	w	1⁄4w, 1⁄2w, 48 bit	w	8 bit
1992	Alpha	64 bit	8 bit, 1⁄4w, 1⁄2w, w	1⁄2w, w	1⁄2w	8 bit	8 bit
1992	PowerPC	32 bit	1⁄4w, 1⁄2w, w	w, 2w	w	8 bit	8 bit
1996	ARMv4 (w/Thumb)	32 bit	1⁄4w, 1⁄2w, w	—	w (1⁄2w, w)	8 bit	8 bit
2000	IBM z/Architecture (w/vector facility)	64 bit	1⁄4w, 1⁄2w, w 1 d, … 31 d	1⁄2w, w, 2w	1⁄4w, 1⁄2w, 3⁄4w	8 bit	8 bit, UTF-16, UTF-32
2001	IA-64	64 bit	8 bit, 1⁄4w, 1⁄2w, w	1⁄2w, w	41 bit (in 128-bit bundles)[7]	8 bit	8 bit
2001	ARMv6 (w/VFP)	32 bit	8 bit, 1⁄2w, w	— (w, 2w)	1⁄2w, w	8 bit	8 bit
2003	x86-64	64 bit	8 bit, 1⁄4w, 1⁄2w, w	1⁄2w, w, 80 bit	8 bit, … 120 bit	8 bit	8 bit
2013	ARMv8-A and ARMv9-A	64 bit	8 bit, 1⁄4w, 1⁄2w, w	1⁄2w, w	1⁄2w	8 bit	8 bit
Year	Computer architecture	Word size w	Integer sizes	Floating­point sizes	Instruction sizes	Unit of address resolution	Char size
key: bit: bits, d: decimal digits, w: word size of architecture, n: variable size

^[8][9]

See alsoEdit

• Integer (computer science)

NotesEdit

ReferencesEdit

In computing, a word is the natural unit of data used by a particular processor design.The number of bits in a word (the word size, word width, or word length) is an important characteristic of any specific processor design or computer architecture.

What is word in memory?

A group of memory bits in a RAM or ROM block.In Verilog HDL, a memory word is a register in a memory (that is, RAM or ROM) block that contains the same range of bits as the other registers in the memory. For example, the memory reg [5:0] EXAMPLE [0:2] defines 3 memory words, each containing a bit range of 5 to 0 .

A computer is an electronic device that manipulates information, or data. It has the ability to store, retrieve, and process data. You may already know that you can use a computer to type documents, send email, play games, and browse the Web.

What is a word in binary?

Quick Reference. A binary word of length n is a string of n binary digits, or bits. For example, there are 8 binary words of length 3, namely, 000, 100, 010, 001, 110, 101, 011 and 111.

How many bits make a word?

16 bits
Fundamental Data Types
A byte is eight bits, a word is 2 bytes (16 bits), a doubleword is 4 bytes (32 bits), and a quadword is 8 bytes (64 bits).

What is word in PLC?

A word refers to the size of data the processor handles. This will vary by PLC model. If the PLC uses a 16 bit processor a word refers to 16 contiguous bits (2bytes). A 32 bit processor uses a 32 bit word. Older PLCs used 8 bit words, there are still alot of these out there.

How are words stored in a computer?

Text is stored on a computer by first converting each character to an integer and then storing the integer. For example, to store the letter `A’, we will actually store the number 65; `B’ is 66, `C’ is 67, and so on. The conversion of letters to numbers is called an encoding.

What are the 4 types of computer?

The four basic types of computers are as under: Supercomputer. Mainframe Computer. Minicomputer.

• Analog Computer.
• Digital Computer.
• Hybrid Computer.

What are the 7 types of computers?

Types of computers

• Supercomputer.
• Mainframe.
• Server Computer.
• Workstation Computer.
• Personal Computer or PC.
• Microcontroller.
• Smartphone. 8 References.

What is a computer for kids?

A computer is a. device for working with information. The information can be numbers, words, pictures, movies, or sounds. Computer information is also called data. Computers can process huge amounts of data very quickly.

Why is a word 2 bytes?

If a character is 8 bits, or 1 byte, then a WORD must be at least 2 characters, so 16 bits or 2 bytes.

What is word length in computer?

The word length of the processor in a computer refers to the maximum number of bits it can take as input. It is the number of bits processed by a computer CPU in a single pass. The computer further takes this input for process and gives the output.

What is opposite word?

The word which is a pronoun that means what one? It may also be used to introduce restrictive and nonrestrictive clauses. There are no categorical antonyms for this word.

What is a bit word?

A bit (short for binary digit) is the smallest unit of data in a computer. A bit has a single binary value, either 0 or 1.In many systems, four eight-bit bytes or octets form a 32-bit word. In such systems, instruction lengths are sometimes expressed as full-word (32 bits in length) or half-word (16 bits in length).

What is the name of 4 bit data?

From there, a group of 4 bits is called a nibble, and 8-bits makes a byte. Bytes are a pretty common buzzword when working in binary.

What are 4 bits called?

nibble
In computing, a nibble (occasionally nybble or nyble to match the spelling of byte) is a four-bit aggregation, or half an octet. It is also known as half-byte or tetrade. In a networking or telecommunication context, the nibble is often called a semi-octet, quadbit, or quartet.

Is a word 16 or 32 bits?

In x86 assembly language WORD , DOUBLEWORD ( DWORD ) and QUADWORD ( QWORD ) are used for 2, 4 and 8 byte sizes, regardless of the machine word size. A word is typically the “native” data size of the CPU. That is, on a 16-bit CPU, a word is 16 bits, on a 32-bit CPU, it’s 32 and so on.

What is difference between word and integer?

Integer is a signed value 16-bit (+32767 to -32768 range), WORD is an unsigned 16-bit value (0 to +65535 range).

How many words are in a PLC?

Most PLCs use 16-bit words. a 16-bit unsigned integer (0 to 65,535). a 16-bit signed integer (-32,768 to 32,767). 16 individual bits (such as a group of boolean values).

Which is word addressable RAM?

A memory word is certain bytes that bidirectional data bus can carry at a time.And such memory are called word addressable memory. In a 32 bit machine, size of the data bus is 32 bits or 4 bytes. So, a 32 bit machine has word size of 4 bytes.

What is digital word?

1 : relating to or using calculation directly with digits rather than through measurable physical quantities. 2 : of or relating to data in the form of numerical digits digital images digital broadcasting. 3 : providing displayed or recorded information in numerical digits from an automatic device a digital watch.

What is a word in computing?

In computer architecture, a word is a unit of data of a defined bit length that can be addressed and moved between storage and the computer processor. Usually, the defined bit length of a word is equivalent to the width of the computer’s data bus so that a word can be moved in a single operation from storage to a processor register. For any computer architecture with an 8-bit byte, the word size is some multiple of 8 bits. In IBM’s System/360 mainframe architecture, a word is 32 bits, or four contiguous 8-bit bytes. In Intel’s PC processor architecture, a word is 16 bits, or two contiguous 8-bit bytes.

In general, the longer the architected word length, the more the computer system processor can do in a single operation.

Word sizes in computer architectures

Some computer processor architectures support a half word, which is half the number of bits in a word, and a double word, which is two contiguous words. Intel’s processor architecture also supports a quad word, or two contiguous double words, and a double quad word, or two contiguous quad words. Figure 1 depicts examples of an 8-bit byte, 8-bit word and 16-bit double word.

Functions of a computer word

A word can contain a computer instruction, a storage address or application data that is manipulated — for example, added to the data in another word space. In some architectures, a double word or larger unit is required to contain an instruction, address or application data. Typically, an instruction is a word in length, but some architectures support half word- and double word-length instructions.

A computer’s word size is typically a function of the computer’s design and how it moves data bits within the various system elements. For example, registers are important holders for various system functions, such as addressing, and the word size is likely to be the size accepted by the computer.

Here’s how words are used in a system:

• Fixed-point numbers. These are numerical values that typically include a standard word and can have different bit counts for various activities.
• Floating-point numbers. These are numerical values that have a minimum size of one word and can also have multiple word sizes using the basic word.
• Addresses. Used for memory, addresses can be a single word or multiples/fractions of that word.
• Registers. These are used to hold data in preparation for processing and can support data sizes ranging from standard words to fixed- and floating-point numbers, as well as other combinations.
• Memory-processor transfer. The movement of data from memory to central processing units (CPUs) typically uses registers that support the word size used by memory, usually a single word. However, depending on the system, variable word sizes may also be used.
• Instructions. Computing functions are executed using a variety of instructions that are typically formatted in the same size as the word used in the computer’s architecture.

Importance of word size

The word size is an important design decision that is made during the design phase of a computing system. It becomes the foundation upon which the computer’s capabilities are based. Once the word size has been decided, the architecture can be designed to accommodate multiple word sizes, such as double words, as part of the overall processing environment.

For example, Microsoft’s Windows operating system uses a 16-bit word as its foundation. Multiples of the 16-bit word size can be accommodated based on the type of Intel processor being used. An Intel x86 processor can support 32-bit or 64-bit words, which are then used to support Microsoft (and other vendor) applications (e.g., Word), various programming languages and application programming interfaces.

By contrast, traditional IBM mainframe platforms, such as System/360, System/370 and System/390, use 8-bit bytes, 16-bit half words, 32-bit words and 64-bit double words.

While they both execute some of the same computer tasks, their functions differ slightly. Learn how CPUs and microprocessors differ.

This was last updated in April 2023

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Updated: 01/18/2023 by

Word may refer to any of the following:

1. When referring to a word processor, Word is short for Microsoft Word.

2. In general, a word is a single element of verbal communication with a unique meaning or use. For example, this sentence contains seven words. The English language contains several hundred thousand different words and Computer Hope lists over 15,000 computer-related words in its computer dictionary.

What are word classes?

Word classes or parts of speech are categories of English words that help you construct good sentences. These categories are noun, verb, adjective, adverb, determiner, pronoun, preposition, conjunction, and interjection.

3. In computing, a word is a single unit of measurement that is assumed to be a 16-bits in length value. However, it can be any set value, common word size values included: 16, 18, 24, 32, 36, 40, 48, and 64.

Bit, Buzzword, Character, Computer abbreviations, Desktop publishing, Double Word, Editor, Google Docs, Software terms, Synonym, Typography terms, Word count, WordPad, Word processor, Word processor terms, WOTD

In computing, «word» is a term for the natural unit of data used by a particular computer design. A word is simply a fixed-sized group of bits that are handled together by the machine. The number of bits in a word (the word size or word length) is an important characteristic of a computer architecture.

The size of a word is reflected in many aspects of a computer’s structure and operation. The majority of the registers in the computer are usually word-sized. The typical numeric value manipulated by the computer is probably word sized. The amount of data transferred between the processing part of the computer and the memory system is most often a word. An address used to designate a location in memory often fits in a word.

Modern computers usually have a word size of 16, 32, or 64 bits. Many other sizes have been used in the past, including 8, 9, 12, 18, 24, 36, 39, 40, 48, and 60 bits; the slab is an example of an early word size. Some of the earliest computers were decimal rather than binary, typically having a word size of 10 or 12 decimal digits, and some early computers had no fixed word length at all.

Sometimes the size of a word is defined to be a particular value for compatibility with earlier computers. The most common microprocessors used in personal computers (for instance, the Intel Pentiums and AMD Athlons) are an example of this. Their IA-32 architecture is an extension of the original Intel 8086 design which had a word size of 16 bits. The IA-32 processors still support 8086 (x86) programs, so the meaning of «word» in the IA-32 context was kept the same, and is still said to be 16 bits, despite the fact that they at times (especially when the default operand size is 32-bit) operate largely like a machine with a 32 bit word size. Similarly in the newer x86-64 architecture, a «word» is still 16 bits, although 64-bit («quadruple word») operands may be more common.

Uses of words

Depending on how a computer is organized, units of the word size may be used for:

*Integer numbers – Holders for integer numerical values may be available in one or in several different sizes, but one of the sizes available will almost always be the word. The other sizes, if any, are likely to be multiples or fractions of the word size. The smaller sizes are normally used only for efficient use of memory; when loaded into the processor, their values usually go into a larger, word-sized holder.

*Floating point numbers – Holders for floating point numerical values are typically either a word or a multiple of a word.

*Addresses – Holders for memory addresses must be of a size capable of expressing the needed range of values, but not be excessively large. Often the size used is that of the word, but it can also be a multiple or fraction of the word size.

*Registers – Processor registers are designed with a size appropriate for the type of data they hold, e.g. integers, floating point numbers, or addresses. Many computer architectures use «general purpose» registers that can hold any of several types of data; those registers are sized to allow the largest of any of those types, and typically that size is the word size of the architecture.

*Memory-processor transfer – When the processor reads from the memory subsystem into a register, or writes a register’s value to memory, the amount of data transferred is often a word. In simple memory subsystems, the word is transferred over the memory data bus, which typically has a width of a word or half word. In memory subsystems that use caches, the word-sized transfer is the one between the processor and the first level of cache; at lower levels of the memory hierarchy larger transfers (which are a multiple of the word size) are normally used.

*Unit of address resolution – In a given architecture, successive address values designate successive units of memory; this unit is the unit of address resolution. In most computers, the unit is either a character (e.g. a byte) or a word. (A few computers have used bit resolution.) If the unit is a word, then a larger amount of memory can be accessed using an address of a given size. On the other hand, if the unit is a byte, then individual characters can be addressed (i.e. selected during the memory operation).

*Instructions – Machine instructions are normally fractions or multiples of the architecture’s word size. This is a natural choice since instructions and data usually share the same memory subsystem. In Harvard architectures the word sizes of instructions and data need not be related.

Word size choice

When a computer architecture is designed, the choice of a word size is of substantial importance. There are design considerations which encourage particular bit-group sizes for particular uses (e.g. for addresses), and these considerations point to different sizes for different uses. However, considerations of economy in design strongly push for one size, or a very few sizes related by multiples or fractions (submultiples) to a primary size. That preferred size becomes the word size of the architecture.

Character size is one of the influences on a choice of word size. Before the mid-1960s, characters were most often stored in six bits; this allowed no more than 64 characters, so alphabetics were limited to upper case. Since it is efficient in time and space to have the word size be a multiple of the character size, word sizes in this period were usually multiples of 6 bits (in binary machines). A common choice then was the 36-bit word, which is also a good size for the numeric properties of a floating point format.

After the introduction of the IBM System/360 design which used eight-bit characters and supported lower-case letters, the standard size of a character (or more accurately, a byte) became eight bits. Word sizes thereafter were naturally multiples of eight bits, with 16, 32, and 64 bits being commonly used.

Variable word architectures

Early machine designs included some that used what is often termed a «variable word length». In this type of organization, a numeric operand had no fixed length but rather its end was detected when a character with a special marking was encountered. Such machines often used binary coded decimal for numbers. This class of machines included the IBM 702, IBM 705, IBM 7080, IBM 7010, UNIVAC 1050, IBM 1401, and IBM 1620.

Most of these machines work on one unit of memory at a time and since each instruction or datum is several units long, each instruction takes several cycles just to access memory. These machines are often quite slow because of this. For example, instruction fetches on an IBM 1620 Model I take 8 cycles just to read the 12 digits of the instruction (the Model II reduced this to 6 cycles, but reduced the fetch times to 4 cycles if both address fields were not needed by the instruction). Instruction execution took a completely variable number of cycles, depending on the size of the operands.

Word and byte addressing

The memory model of an architecture is strongly influenced by the word size. In particular, the resolution of a memory address, that is, the smallest unit that can be designated by an address, has often been chosen to be the word. In this approach, address values which differ by one designate adjacent memory words. This is natural in machines which deal almost always in word (or multiple-word) units, and has the advantage of allowing instructions to use minimally-sized fields to contain addresses, which can permit a smaller instruction size or a larger variety of instructions.

When byte processing is to be a significant part of the workload, it is usually more advantageous to use the byte, rather than the word, as the unit of address resolution. This allows an arbitrary character within a character string to be addressed straightforwardly. A word can still be addressed, but the address to be used requires a few more bits than the word-resolution alternative. The word size needs to be an integral multiple of the character size in this organization. This addressing approach was used in the IBM 360, and has been the most common approach in machines designed since then.

The power of 2

Data values may occupy differing sizes of memory, because, for instance, some numbers need to be capable of having greater precision than others. The commonly used sizes are usually chosen to be a power of 2 multiple of the unit of address resolution (byte or word). This is convenient because converting the index of an item in an array into the address of the item then requires only a shift operation (which is just a conductor routing in hardware) rather than a multiplication. In some cases this relationship can also avoid the use of division operations. As a result, most modern computer designs have word sizes (and other operand sizes) that are a power of 2 times the size of a byte.

Size families

As computer designs have grown more complex, the central importance of a single word size to an architecture has decreased. Although more capable hardware can use a wider variety of sizes of data, market forces exert pressure to maintain backward compatibility while extending processor capability. As a result, what might have been the central word size in a fresh design has to coexist as an alternative size to the original word size in a backward compatible design. The original word size remains available in future designs, forming the basis of a size family.

In the mid-1970s, DEC designed the VAX to be a successor of the PDP-11. Perhaps for conceptual compatibility, they used «word» for a 16-bit quantity while they used the term «longword» to refer to a 32-bit quantity. This is in contrast to earlier machines, where something that is one word would be called a «word», while a quantity that is one half a word would be called, if anything, a «halfword». This is a terminological quirk, since the VAX is clearly a 32-bit machine in all important respects. As well, a «quadword» is 64 bits.

A major example of this can be seen in the x86 designs. The original 8086 architecture clearly used a word size of 16 bits. The significantly-enhanced design of the 80386 added to the 8086 base an organization which was based around units of 32 bits. If it were an unencumbered design, it would have had a 32-bit «word», but as an extension of the 8086, its «word» continued to be considered to be 16 bits.

Part of the confusion, the 8086 has methods to access more than 64 KiB with a 16-bit address, while the 286 extended it to some byzantine methods. The 386extended it more. More important, the 386 provided a mode where one can have a «flat» 32-bit address space. The segmented addressing was always, at best, troublesome, while mixing 16- and 32-bit was more or less a nightmare. Programmers desired to move to 32-bit addressing as quickly as possible. This took a long time because of 286 compatibility issues. But that’s what happened. Therefore, the 386 (et seq) «as used» is no different from the earlier VAX and machines at the same time such as the 68K and SPARC.

This same situation has recently recurred in the same line, as the AMD64 architectural extensions bring the 64-bit size into a major position without dropping any of the 16- and 32-bit support.

Thus one sees that today a computer architecture is based on a family of closely related sizes more than on a single omnipresent word size. The sizes are intimately related to one another by integral factors, usually a power of two. Calling any one of them the architecture’s word size may be somewhat arbitrary, and a size may be so designated due to the history of the architecture’s evolution rather than the properties of the size itself in a recent design.

Dword, Qword, and Oword

In computer science, a dword (double word) is a unit of data that is twice the size of a word. On the x86 platforms, which have a word size of 16 bits, a dword unit of data is 32 bits long.

A qword (or quadword, or quadruple word) is a unit of data that is four times the size of a word. On the common x86 platforms, this unit of data is 64 bits because the size of a word on an x86 system is defined to be 16 bits (whether the particular machine works primarily with 16, 32, or 64 bit items).

Finally, Intel uses the term double quadruple word, or DQWord, to denote a 128-bit datum, found in the implementation of Streaming SIMD Extensions and its ancestors. Microsoft Macro Assembler uses oword (octuple word) for the same data size.

Table of word sizes

ee also

*Byte
* 32-bit
* 32-bit applications
* 64-bit
* 128-bit

References

* Gerrit A. Blaauw & Frederick P. Brooks, «Computer Architecture: Concepts and Evolution» (Addison-Wesley, 1997, ISBN 0-201-10557-8)
* Anthony Ralston & Edwin D. Reilly, «Encyclopedia of Computer Science Third Edition» (Van Nostrand Reinhold, 1993, ISBN 0-442-27679-6)

(1) See Microsoft Word.

(2) The computer’s internal processing unit. Word «size» refers to the amount of data a CPU’s internal data registers can hold and process at one time. Modern desktop computers have 64-bit words. Computers embedded in appliances and consumer products have word sizes of 8, 16 or 32 bits. See bit and byte.

The larger the word, the faster the computer calculates and compares (processes). However, the speed increase also depends on the size of the data being calculated. Given the same clock rate, adding a 16-bit number will not be faster in a computer with 32-bit registers than one with 16 bits, but a 24-bit number will be. The 16-bit computer requires additional steps (16 bits first, then the remaining 8), whereas all 24 bits of the number can fit in the 32-bit register. See MHz.

x86 Architecture

In the x86 PC (Intel, AMD, etc.), although the architecture has long supported 32-bit and 64-bit registers, its native word size stems back to its 16-bit origins, and a «single» word is 16 bits. A «double» word is 32 bits. See 32-bit computer and 64-bit computer.

Many Word Sizes

Since the advent of computers starting in the 1940s, machines have been designed with a variety of word sizes, including 10, 12, 20, 24, 36, 48 and 60 bits.

A 36-Bit Computer


These are 36-bit PDP computers from Digital Equipment Corporation (DEC). In 1971, they were used to send the first email over the Internet (see email for more detail). Both machines barely totaled 500K of memory. (Image courtesy of Dan Murphy, www.opost.com/dlm)

Read this article. As it explains:

«In computing, a word is the natural unit of data used by a particular processor design. A word is a fixed-sized piece of data handled as a unit by the instruction set or the hardware of the processor. The number of bits in a word (the word size, word width, or word length) is an important characteristic of any specific processor design or computer architecture.»

In computing, a word is the natural unit of data used by a particular processor design. A word is a fixed-sized piece of data handled as a unit by the instruction set or the hardware of the processor. The number of bits in a word (the word size, word width, or word length) is an important characteristic of any specific processor design or computer architecture.

The size of a word is reflected in many aspects of a computer’s structure and operation; the majority of the registers in a processor are usually word sized and the largest piece of data that can be transferred to and from the working memory in a single operation is a word in many (not all) architectures. The largest possible address size, used to designate a location in memory, is typically a hardware word (here, «hardware word» means the full-sized natural word of the processor, as opposed to any other definition used).

Modern processors, including embedded systems, usually have a word size of 8, 16, 24, 32, or 64 bits, while modern general purpose computers usually use 32 or 64 bits. Special purpose digital processors, such as DSPs for instance, may use other sizes, and many other sizes have been used historically, including 9, 12, 18, 24, 26, 36, 39, 40, 48, and 60 bits. The slab is an example of a system with an earlier word size. Several of the earliest computers (and a few modern as well) used BCD rather than plain binary, typically having a word size of 10 or 12 decimal digits, and some early decimal computers had no fixed word length at all.

The size of a word can sometimes differ from the expected due to backward compatibility with earlier computers. If multiple compatible variations or a family of processors share a common architecture and instruction set but differ in their word sizes, their documentation and software may become notationally complex to accommodate the difference (see Size families below).

Uses of words

Depending on how a computer is organized, word-size units may be used for:

Fixed point numbers

Holders for fixed point, usually integer, numerical values may be available in one or in several different sizes, but one of the sizes available will almost always be the word. The other sizes, if any, are likely to be multiples or fractions of the word size. The smaller sizes are normally used only for efficient use of memory; when loaded into the processor, their values usually go into a larger, word sized holder.

Floating point numbers

Holders for floating point numerical values are typically either a word or a multiple of a word.

Addresses

Holders for memory addresses must be of a size capable of expressing the needed range of values but not be excessively large, so often the size used is the word though it can also be a multiple or fraction of the word size.

Registers

Processor registers are designed with a size appropriate for the type of data they hold, e.g. integers, floating point numbers or addresses. Many computer architectures use «general purpose registers» that can hold any of several types of data, these registers must be sized to hold the largest of the types, historically this is the word size of the architecture though increasingly special purpose, larger, registers have been added to deal with newer types.

Memory-processor transfer

When the processor reads from the memory subsystem into a register or writes a register’s value to memory, the amount of data transferred is often a word. Historically, this amount of bits which could be transferred in one cycle was also called a catena in some environments (such as the Bull GAMMA 60 (fr)). In simple memory subsystems, the word is transferred over the memory data bus, which typically has a width of a word or half-word. In memory subsystems that use caches, the word-sized transfer is the one between the processor and the first level of cache; at lower levels of the memory hierarchy larger transfers (which are a multiple of the word size) are normally used.

Unit of address resolution

In a given architecture, successive address values designate successive units of memory; this unit is the unit of address resolution. In most computers, the unit is either a character (e.g. a byte) or a word. (A few computers have used bit resolution.) If the unit is a word, then a larger amount of memory can be accessed using an address of a given size at the cost of added complexity to access individual characters. On the other hand, if the unit is a byte, then individual characters can be addressed (i.e. selected during the memory operation).

Instructions

Machine instructions are normally the size of the architecture’s word, such as in RISC architectures, or a multiple of the «char» size that is a fraction of it. This is a natural choice since instructions and data usually share the same memory subsystem. In Harvard architectures the word sizes of instructions and data need not be related, as instructions and data are stored in different memories; for example, the processor in the 1ESS electronic telephone switch had 37-bit instructions and 23-bit data words.

Word size choice

When a computer architecture is designed, the choice of a word size is of substantial importance. There are design considerations which encourage particular bit-group sizes for particular uses (e.g. for addresses), and these considerations point to different sizes for different uses. However, considerations of economy in design strongly push for one size, or a very few sizes related by multiples or fractions (submultiples) to a primary size. That preferred size becomes the word size of the architecture.

Character size was in the past (pre-variable-sized character encoding) one of the influences on unit of address resolution and the choice of word size. Before the mid-1960s, characters were most often stored in six bits; this allowed no more than 64 characters, so the alphabet was limited to upper case. Since it is efficient in time and space to have the word size be a multiple of the character size, word sizes in this period were usually multiples of 6 bits (in binary machines). A common choice then was the 36-bit word, which is also a good size for the numeric properties of a floating point format.

After the introduction of the IBM System/360 design, which used eight-bit characters and supported lower-case letters, the standard size of a character (or more accurately, a byte) became eight bits. Word sizes thereafter were naturally multiples of eight bits, with 16, 32, and 64 bits being commonly used.

Variable word architectures

Early machine designs included some that used what is often termed a variable word length. In this type of organization, a numeric operand had no fixed length but rather its end was detected when a character with a special marking, often called word mark, was encountered. Such machines often used binary coded decimal for numbers. This class of machines included the IBM 702, IBM 705, IBM 7080, IBM 7010, UNIVAC 1050, IBM 1401, and IBM 1620.

Most of these machines work on one unit of memory at a time and since each instruction or datum is several units long, each instruction takes several cycles just to access memory. These machines are often quite slow because of this. For example, instruction fetches on an IBM 1620 Model I take 8 cycles just to read the 12 digits of the instruction (the Model II reduced this to 6 cycles, or 4 cycles if the instruction did not need both address fields). Instruction execution took a completely variable number of cycles, depending on the size of the operands.

Word and byte addressing

The memory model of an architecture is strongly influenced by the word size. In particular, the resolution of a memory address, that is, the smallest unit that can be designated by an address, has often been chosen to be the word. In this approach, address values which differ by one designate adjacent memory words. This is natural in machines which deal almost always in word (or multiple-word) units, and has the advantage of allowing instructions to use minimally sized fields to contain addresses, which can permit a smaller instruction size or a larger variety of instructions.

When byte processing is to be a significant part of the workload, it is usually more advantageous to use the byte, rather than the word, as the unit of address resolution. This allows an arbitrary character within a character string to be addressed straightforwardly. A word can still be addressed, but the address to be used requires a few more bits than the word-resolution alternative. The word size needs to be an integer multiple of the character size in this organization. This addressing approach was used in the IBM 360, and has been the most common approach in machines designed since then.

Individual bytes can be accessed on a word-oriented machine in one of two ways. Bytes can be manipulated by a combination of shift and mask operations in registers. Moving a single byte from one arbitrary location to another may require the equivalent of the following:

• LOAD the word containing the source byte
• SHIFT the source word to align the desired byte to the correct position in the target word
• AND the source word with a mask to zero out all but the desired bits
• LOAD the word containing the target byte
• AND the target word with a mask to zero out the target byte
• OR the registers containing the source and target words to insert the source byte
• STORE the result back in the target location

Alternatively many word-oriented machines implement byte operations with instructions using special byte pointers in registers or memory. For an example the PDP-10 byte pointer contained the size of the byte in bits (allowing different-sized bytes to be accessed), the bit position of the byte within the word, and the word address of the data. Instructions could automatically adjust the pointer to the next byte on, for example, load and deposit (store) operations.

Powers of two

Different amounts of memory are used to store data values with different degrees of precision. The commonly used sizes are usually a power of two multiple of the unit of address resolution (byte or word). Converting the index of an item in an array into the address of the item then requires only a shift operation rather than a multiplication. In some cases this relationship can also avoid the use of division operations. As a result, most modern computer designs have word sizes (and other operand sizes) that are a power of two times the size of a byte.

Size families

As computer designs have grown more complex, the central importance of a single word size to an architecture has decreased. Although more capable hardware can use a wider variety of sizes of data, market forces exert pressure to maintain backward compatibility while extending processor capability. As a result, what might have been the central word size in a fresh design has to coexist as an alternative size to the original word size in a backward compatible design. The original word size remains available in future designs, forming the basis of a size family.

In the mid-1970s, DEC designed the VAX to be a successor of the PDP-11. They used word for a 16-bit quantity, while longword referred to a 32-bit quantity. This was in contrast to earlier machines, where the natural unit of addressing memory would be called a word, while a quantity that is one half a word would be called a halfword. In fitting with this scheme, a VAX quadword is 64 bits.

Another example is the x86 family, of which processors of three different word lengths (16-bit, later 32- and 64-bit) have been released. As software is routinely ported from one word-length to the next, some APIs and documentation define or refer to an older (and thus shorter) word-length than the full word length on the CPU that software may be compiled for. Also, similar to how bytes are used for small numbers in many programs, a shorter word (16 or 32 bits) may be used in contexts where the range of a wider word is not needed (especially where this can save considerable stack space or cache memory space). For example, Microsoft’s Windows API maintains the programming language definition of WORD as 16 bits, despite the fact that the API may be used on a 32- or 64-bit x86 processor, where the standard word size would be 32 or 64 bits, respectively. Data structures containing such different sized words refer to them as WORD (16 bits/2 bytes), DWORD (32 bits/4 bytes) and QWORD (64 bits/8 bytes) respectively. A similar phenomenon has developed in Intel’s x86 assembly language – because of the support for various sizes (and backward compatibility) in the instruction set, some instruction mnemonics carry «d» or «q» identifiers denoting «double-«, «quad-» or «double-quad-«, which are in terms of the architecture’s original 16-bit word size.

In general, new processors must use the same data word lengths and virtual address widths as an older processor to have binary compatibility with that older processor.

Often carefully written source code – written with source code compatibility and software portability in mind – can be recompiled to run on a variety of processors, even ones with different data word lengths or different address widths or both.

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Source: Wikipedia, https://en.wikipedia.org/wiki/Word_(computer_architecture)
 This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 License.

In this tutorial, you’ll learn all about MS Word. You’ll discover what it’s used for. You’ll explore some of the features of Microsoft Word. Plus, we’ll show you how to get started and share some helpful resources.

What Is Microsoft Word?

You may be wondering: what type of program is Microsoft Word? A good definition is that it’s a word processor. That’s an application you use to “process”— format, manipulate, save, print, share — a text-based document. 

Microsoft Word is arguably the most popular word processor on the planet. That’s because it’s part of Microsoft’s Office Suite, which is installed in 1 billion devices in the world (according to groovyPost). 

When Word 1.0 for Windows was released in 1989, it was one of the first word processors that offered a WYSIWYG (what you see is what you get) interface. 

This combination of ease of use and robust features makes it the go-to word processor in both homes and offices today. It’s now also available for the Mac operating system as well as a web-based version through an Office 365 subscription.

What Is Microsoft Word Used For?

Now you’re ready to learn how to use MS Word. Use it to create many kinds of business and person documents. Here’s just a sampling of how to use it:

For Business or School

Microsoft Office’s Word is a great tool for creating business documents. Of course, you could design business and school documents from scratch. Or you could get a head start using a professionally designed template.

You can also find templates to help you create the following:

• letter
• report or paper
• proposal
• newsletter 
• brochure
• catalog 
• poster
• flyer
• postcard
• sign 
• banner 
• resume
• business card
• invoice
• receipt
• product packaging
• mailing label

For Personal Purposes

There are also many personal uses of MS Word. Here are just a few:

• invitation
• card
• gift tag
• recipe card
• place card
• certificates

As you can see, Microsoft Word comes in very handy for both your personal and professional lives!

How to Get Started Using Microsoft Word (+Top MS Word Features)

Microsoft Word has become more intuitive through the years. Even if you’re just starting to use it, you can easily figure things out and navigate your way through the simplest tasks. 

That said, it’s got a ton of features for the more advanced user. And you’re not aware of those features and how to use them, you can miss out on things that can make your workflow much easier.

1. Make Your Way Around: The Microsoft Word User Interface

Whichever version you’re using, the user interface is very similar:

The main menu gives you access to the major command groups:

• file
• edit
• view
• insert
• format
• tools
• table
• window
• help

Click on any of these items to reveal more detailed commands. For example, when you click on File, you get the following options.

Next, you see the Quick Access Toolbar lets complete frequently used tasks in Word with a single click. These include:

• save
• undo
• redo
• print
• search

This is also where you see the title of the document you’re working on.

You can customize which buttons appear on your Quick Access Toolbar. 

1. Go to Word > Preferences….

The Word Preferences dialog opens. 

2. Click on the Ribbon & Toolbar button.

The Ribbon & Toolbar dialog pops up. 

3. Click on the Quick Access Toolbar button.

4. Add, remove, or reorder the command buttons.

To add a button to your Quick Access Toolbar, find the command you wish to add from the left box. Click to select it, then click the right arrow. This moves it to the box on the right.

To remove a command from your Quick Access Toolbar, click on a command on the right. Then, click the left arrow.

You can also drag and drop the commands in your Quick Access Toolbar to change the order in which they appear.

5. When you’re done, click Save.

Next, you’ll find the tab and ribbon. Each tab displays a different ribbon of buttons for various related commands. For example, the Home tab displays this ribbon:

Follow the same steps above to customize the ribbon for each tab. Instead of selecting Quick Access Toolbar in the Ribbon & Toolbar dialog, click on the Ribbon button.

Let’s look at just some of the things you can do.

2. Create a New Document

You could fire up Microsoft Word and create a document from scratch. The interface is intuitive enough to figure out. But if you need it, here’s a quick guide to creating, opening, and saving files:

Earlier versions of Word create files in the DOC file format, a proprietary format. This means only Microsoft Word officially supported files with the DOC extension. But with some reverse engineering, other applications were able to open and save DOC files. That said, they may not fully support all its formatting and features.

Since 2007, Word started saving files as DOCX by default. The X stands for XML standard or Open Office Extensible Markup Language. 

DOCX makes for smaller files that are less prone to corruption. It can also be read by any robust word processor, like Google Docs. DOCX is now the standard file format of Word documents. Although, Word can save to DOC and other file formats as well (see Exporting to Other File Formats below).

3. Work With Text in MS Word

Microsoft Word shines when it comes to manipulating and formatting text. You can create the most basic, plain text-based documents to extremely creative layouts that previously required graphic design software.

Below are a few tutorials on the basics of working with text:

4. Go Beyond Text

Almost any document can benefit from the added impact of visuals. Read these articles to learn how to add and format pictures, as well as go beyond the basics with your layouts. 

And if you find yourself using Microsoft Word more and more, you’ll appreciate learning the keyboard shortcuts for your frequently used commands. Find out more below:

5. Print in Microsoft Word

You can print to standard-sized paper as well as custom sizes. Print on matte, glossy, or photo paper. You can even print large documents, such as a banner, by printing them on separate sheets that you then piece together.

To print a document:

1. Go to File > Print….

The Print dialog opens.

Select your printer. Then choose the printer settings you want to use, including which pages to print, how many, and print quality.

2. Click Print.

6. Export to Other File Formats

Microsoft Word isn’t just for making printed documents! 

Thanks to the exporting feature, you can export your document to other file formats. The most common one is a PDF, which you can upload to a website, email, or share in other ways.

Follow these steps to export your document:

1. Go to File > Save As….

The Save As dialog appears.

2. Choose a file format.

Give your document a name. Then, click on the File Format drop-down menu to display all the different formats you can export to. Select the format you want to use, then click Save.

Go to the Next Level With Word Templates

If you want to take your documents to the next level without getting a graphic design degree yourself, then use a template.

The best templates are created by professional designers who make the biggest design decisions for you: fonts, colors, formatting, image placement, and more. All you’ve got to do is to add your own text and images, customize the formatting elements as you see fit, and you have a professional-looking document. Read this article on how to use Microsoft Word templates:

For best results, use a premium Word template. These are specifically designed to be customizable. They often come with after-sales support from the designers. 

A great source of premium templates is Envato Elements. For one small monthly subscription, get unlimited downloads of templates and other design pieces you need, such as fonts, photos, and more.

For one-off projects, consider the Word templates from GraphicRiver. Here, you can access thousands of templates and other design tools, but on a pay-per-use basis.

5 Top Microsoft Word Templates from Envato Elements in 2021

Envato Elements has most of the templates you’ll need for any project in MS Word. Here are five different types of premium templates that can be used in Microsoft Word:

1. Word Resume

Edit this resume in Microsoft Word and in Adobe InDesign. The design of this template is minimal and modern. This template comes with a picture placeholder where you can add your image. Everything can be easily edited as needed.

2.  Product Catalog

If you’re looking for a product catalog, consider this one. Here are some features of this MS Word template:

• US letter size (8.5″ x 11″)
• 12 pages to add information on
• can be edited in Microsoft Word and Adobe InDesign

This template comes with a customer feedback page, membership information page, terms & policies page, and a bestsellers page.

3. Flower Word Wedding Invitation

Another use for templates in Microsoft Word is an invitation template. The Flower Word Wedding Invitation is a premium invitation template. This template has a simple and elegant design. The size of this template is A4 paper size, which can be folded and put in an envelope or passed out like a flyer. 

4. Business Brochure

Another template useful in Microsoft Word is a brochure that can be used to give any type of information. Here are some highlights of this templates:

• both US letter size (8.5″ x 11″) and A4 size (8.27″ x 11.69″)
• 16 pages you can add information on
• edit it in Microsoft Word and Adobe InDesign

You can easily edit everything in this template to fit the project you’re working on.

5. Clean and Minimal Business Invoice

The Clean and Minimal Business Invoice can be edited in Adobe InDesign and Microsoft Word. This template has a professional and clean look. The size of this template is US letter size (8.5″ x 11″), meaning it can be easily mailed in an envelope. This template comes with some icons at the bottom of the page.  

5 Ways You Can Customize Your Premium Template 

Customizing your template is a way to add a personal touch to your template. In this tutorial, we’ll use the CV Resume Word Template.

Here’s what the template looks like without any edits made:

Let’s get started on some customizations:

1. Insert a Headshot Image

There’s an image area that you can add your image to in this template. Add an image by clicking on the Insert tab in the top left corner of your window. Next, click on the Insert Picture button located below the toolbar.

When you click on Insert Picture, a menu drops down. Select the correct option for you depending on where your image is located. Once you’ve located your image, double click. You can resize and move the image as needed.

2. Add Your Information

To add your information, you need to delete the text that is already there. To delete text, highlight the text that you want to get rid of.

After the text is highlighted, press Delete on your keyboard. Next, click on the Insert tab in the top left corner of your window. Then, click on the Draw a Textbox button below the toolbar in the right side of your window.

Finally, click on where you want to add the textbox and draw a diagonal line to add the text box. Now, click in the text box and start typing.

3. Use the Spelling and Grammar Check

Bad spelling and grammar can cause an employer not to hire you. Microsoft Word has a helpful feature that’ll check spelling and grammar for you. 

To begin using the spelling and grammar check, highlight all the text that you want to check for errors. Next, click on the Review tab. The first button on the left side of the window under the toolbar is the Spelling & Grammar button. Click on the Spelling & Grammar button.

When you click on the Spelling & Grammar button, it’ll check the highlighted text for errors. When it’s done, a pop-up window pops up. Click on the correct spelling of the word and click on the Add button.

Keep repeating the previous step until every error is fixed. Then click on the Close button.

4. Change the Font 

Changing the font is the easiest way to customize your Microsoft Word template.

First, highlight the text that you want to change the font of. Next, click on the Home tab in the toolbar. The Home tab is the first option in the toolbar on the left side of your window.

Then click on the arrow next to the font menu. Clicking on the arrow next to the font menu causes a menu of fonts to drop down. Choose the font that you want from the drop-down menu. 

5. Delete an Object

Deleting an object that you don’t want can help you open up your Microsoft Word template layout. To get rid of an object, click on the object that you want to delete. When the object is collected, click the Delete key.

How to Get Microsoft Word Help and Support

Microsoft Word brings powerful word processing tools at your fingertips. But more features also mean more complexity. Fortunately for us, Microsoft provides a Help & Learning page. Here, you’ll find training, access to a community of other users, and a way to get support.

Good-Looking, High-Impact Documents at Your Fingertips

For beginners and advanced users alike, Word continues to be the top word processor in the world. Its intuitive features allow you to create visually attractive and effective documents.

You can create a document from scratch or shortcut the process by using a template. For unlimited downloads of templates and other design ingredients, subscribe to Envato Elements. But if you need a template for a single use, then GraphicRiver may be a better source for you. Why not download your favorite template today and get started?

Editorial Note: This post was originally published in April of 2020 It’s been updated with contributions from Sarah Joy. Sarah is a freelance instructor for Envato Tuts+.

What Does Microsoft Word Mean?

Microsoft Word is a widely used commercial word processor designed by Microsoft. Microsoft Word is a component of the Microsoft Office suite of productivity software, but can also be purchased as a stand-alone product.

Microsoft Word was initially launched in 1983, and has since been revised numerous times. It is available for both Windows and Apple operating systems.

Microsoft Word is often called simply Word or MS Word.

Techopedia Explains Microsoft Word

In 1981, Microsoft hired Charles Simonyi to develop a word-processing application. The first version was released in 1983.

Initially, MS Word was not very popular, owing to its radically different look compared to WordPerfect, the leading word processor at that time. However, Microsoft improved Word continually over the years, including a 1985 version that could run on a Mac. The second major release of Word, in 1987, included an upgrade of major features, in addition to new functionalities such as support for rich text format (RTF).

In 1995, Microsoft increased its market share in the word processor business with the release of Windows 95 and Office 95, which offered a bundled set of office productivity software.

Some features that have made MS Word useful include a WYSIWYG (what-you-see-is-what-you-get) display: this design ensures that everything displayed on screen appears the same way when printed or moved to another format or program. The ability of users to copy and paste MS Word content into many other platforms without significant formatting loss is one reason the software has stayed so popular in the last two decades.

In addition, MS Word has a built-in dictionary for spell checking; misspelled words are marked with a red squiggly underline. MS Word offers text-level features such as bold, underline, italic and strike-through, and page-level features such as indentation, paragraphing and justification. Word is compatible with many other programs, the most common being the other members of the Office suite.

In 2007, .docx became the default file format, replacing the “.doc” extension.

As Microsoft Word modernized over time, so did Microsoft operating systems. Since the Microsoft Office suite is inherently tied to the Microsoft operating system, its use featured in user frustrations around end-of-life for Microsoft XP and the successive Vista and Windows 7, 8 and 10 additions.

At the same time, Microsoft was getting on the cloud bandwagon. Its new offering, Microsoft Office 365, replaces old out of the box or single machine licensing methods with a cloud-delivered set of software applications that users can access from anywhere.

With subscription pricing, many customers are now accessing Microsoft Word and Office suites through office 365 instead of buying it through downloads with license keys. Theoretically, the cloud-delivered method allows for more versatile use on multiple devices, although some users have reported trouble trying to get new devices authorized.

One other popular aspect of the cloud-delivered software is that there’s no need to load it onto the local hard drive, leaving the end device less cluttered by drivers and other types of software infrastructure. At the same time, Microsoft has added other complementary cloud applications like OneNote, OneDrive and SharePoint for enterprise users, and a mobile Office suite for Apple and Android.

[Master the most popular Word Processing tool in no time, with this A-Z Microsoft Word Course from Udemy]

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In computing, word is a term for the natural unit of data used by a particular computer design. A word is simply a fixed sized group of bits that are handled together by the system. The number of bits in a word (the word size or word length) is an important characteristic of a computer architecture.

The size of a word is reflected in many aspects of a computer’s structure and operation; the majority of the registers in the computer are usually word sized and the amount of data transferred between the processing part computer and the memory system, in a single operation, is most often a word. The largest possible address size, used to designate a location in memory, is typically a hardware word (in other words, the full sized natural word of the processor, as opposed to any other definition used on the platform).

Modern computers usually have a word size of 16, 32 or 64 bits but many other sizes have been used, including 8, 9, 12, 18, 24, 36, 39, 40, 48 and 60 bits. The slab is an example of a system with an earlier word size. Several of the earliest computers used the decimal base rather than binary, typically having a word size of 10 or 12 decimal digits and some early computers had no fixed word length at all.

The size of a word is sometimes defined to be a particular value for compatibility with earlier computers. The most common microprocessors used in personal computers (for instance, the Intel Pentiums and AMD Athlons) are an example of this; their IA-32 architecture is an extension of the original Intel 8086 design which had a word size of 16 bits. The IA-32 processors still support 8086 (x86) programs, so the meaning of word in the IA-32 context was kept the same, and is still said to be 16 bits despite the fact that they at times (especially when the default operand size is 32 bits) operate largely like a machine with a 32 bit word size, similarly in the newer x86-64 architecture a word is still 16 bits, although 64 bit (quadruple word) operands may be more common.

Uses of words

Depending on how a computer is organized, units of the word size may be used for:

• Integer numbers: Holders for integer numerical values may be available in one or in several different sizes, but one of the sizes available will almost always be the word. The other sizes, if any, are likely to be multiples or fractions of the word size. The smaller sizes are normally used only for efficient use of memory; when loaded into the processor, their values usually go into a larger, word sized holder.

• Floating point numbers: Holders for floating point numerical values are typically either a word or a multiple of a word.

• Addresses: Holders for memory addresses must be of a size capable of expressing the needed range of values but not be excessively large, so often the size used is the word though it can also be a multiple or fraction of the word size.

• Registers: Processor registers are designed with a size appropriate for the type of data they hold, e.g. integers, floating point numbers or addresses. Many computer architectures use «general purpose» registers that can hold any of several types of data, these registers must be sized to hold the largest of the types, historically this is the word size of the architecture though increasingly special purpose, larger, registers have been added to deal with newer types.

• Memory-processor transfer: When the processor reads from the memory subsystem into a register or writes a register’s value to memory, the amount of data transferred is often a word. In simple memory subsystems, the word is transferred over the memory data bus, which typically has a width of a word or half word. In memory subsystems that use caches, the word-sized transfer is the one between the processor and the first level of cache; at lower levels of the memory hierarchy larger transfers (which are a multiple of the word size) are normally used.

• Unit of address resolution: In a given architecture, successive address values designate successive units of memory; this unit is the unit of address resolution. In most computers, the unit is either a character (e.g. a byte) or a word. (A few computers have used bit resolution.) If the unit is a word, then a larger amount of memory can be accessed using an address of a given size. On the other hand, if the unit is a byte, then individual characters can be addressed (i.e. selected during the memory operation).

• Instructions: Machine instructions are normally fractions or multiples of the architecture’s word size. This is a natural choice since instructions and data usually share the same memory subsystem. In Harvard architectures the word sizes of instructions and data need not be related.

Word size choice

When a computer architecture is designed, the choice of a word size is of substantial importance. There are design considerations which encourage particular bit-group sizes for particular uses (e.g. for addresses), and these considerations point to different sizes for different uses. However, considerations of economy in design strongly push for one size, or a very few sizes related by multiples or fractions (submultiples) to a primary size. That preferred size becomes the word size of the architecture.

Character size is one of the influences on a choice of word size. Before the mid-1960s, characters were most often stored in six bits; this allowed no more than 64 characters, so alphabetics were limited to upper case. Since it is efficient in time and space to have the word size be a multiple of the character size, word sizes in this period were usually multiples of 6 bits (in binary machines). A common choice then was the 36-bit word, which is also a good size for the numeric properties of a floating point format.

After the introduction of the IBM System/360 design which used eight-bit characters and supported lower-case letters, the standard size of a character (or more accurately, a byte) became eight bits. Word sizes thereafter were naturally multiples of eight bits, with 16, 32, and 64 bits being commonly used.

Variable word architectures

Early machine designs included some that used what is often termed a variable word length. In this type of organization, a numeric operand had no fixed length but rather its end was detected when a character with a special marking was encountered. Such machines often used binary coded decimal for numbers. This class of machines included the IBM 702, IBM 705, IBM 7080, IBM 7010, UNIVAC 1050, IBM 1401, and IBM 1620.

Most of these machines work on one unit of memory at a time and since each instruction or datum is several units long, each instruction takes several cycles just to access memory. These machines are often quite slow because of this. For example, instruction fetches on an IBM 1620 Model I take 8 cycles just to read the 12 digits of the instruction (the Model II reduced this to 6 cycles, but reduced the fetch times to 4 cycles if both address fields were not needed by the instruction). Instruction execution took a completely variable number of cycles, depending on the size of the operands.

Word and byte addressing

The memory model of an architecture is strongly influenced by the word size. In particular, the resolution of a memory address, that is, the smallest unit that can be designated by an address, has often been chosen to be the word. In this approach, address values which differ by one designate adjacent memory words. This is natural in machines which deal almost always in word (or multiple-word) units, and has the advantage of allowing instructions to use minimally-sized fields to contain addresses, which can permit a smaller instruction size or a larger variety of instructions.

When byte processing is to be a significant part of the workload, it is usually more advantageous to use the byte, rather than the word, as the unit of address resolution. This allows an arbitrary character within a character string to be addressed straightforwardly. A word can still be addressed, but the address to be used requires a few more bits than the word-resolution alternative. The word size needs to be an integral multiple of the character size in this organization. This addressing approach was used in the IBM 360, and has been the most common approach in machines designed since then.

The power of 2

v • d • e Multiples of bits
SI decimal prefixes	IEC binary prefixes
Name (Symbol)	Standard SI	Binary usage	Name (Symbol)	Value
kilobit (kbit)	103	210	kibibit (Kibit)	210
megabit (Mbit)	106	220	mebibit (Mibit)	220
gigabit (Gbit)	109	230	gibibit (Gibit)	230
terabit (Tbit)	1012	240	tebibit (Tibit)	240
petabit (Pbit)	1015	250	pebibit (Pibit)	250
exabit (Ebit)	1018	260	exbibit (Eibit)	260
zettabit (Zbit)	1021	270	zebibit (Zibit)	270
yottabit (Ybit)	1024	280	yobibit (Yibit)	280
See also: Nibble · Byte · Multiples of bytes Orders of magnitude of data

Different amounts of memory are used to store data values with different degrees of precision. The commonly used sizes are usually a power of 2 multiple of the unit of address resolution (byte or word). Converting the index of an item in an array into the address of the item then requires only a shift operation rather than a multiplication. In some cases this relationship can also avoid the use of division operations. As a result, most modern computer designs have word sizes (and other operand sizes) that are a power of 2 times the size of a byte.

Size families

As computer designs have grown more complex, the central importance of a single word size to an architecture has decreased. Although more capable hardware can use a wider variety of sizes of data, market forces exert pressure to maintain backward compatibility while extending processor capability. As a result, what might have been the central word size in a fresh design has to coexist as an alternative size to the original word size in a backward compatible design. The original word size remains available in future designs, forming the basis of a size family.

In the mid-1970s, DEC designed the VAX to be a successor of the PDP-11. They used «word» for a 16-bit quantity while they used the term «longword» to refer to a 32-bit quantity. This is in contrast to earlier machines, where the natural unit of addressing memory would be called a word, while a quantity that is one half a word would be called, if anything, a halfword. As well, a VAX «quadword» is 64 bits.

Another example is the x86 family. The original 8086 architecture used a word size of 16 bits. The 80386 was based around units of 32 bits. If it were an unencumbered design, it would have had a 32-bit «word», but as an extension of the 8086, its «word» continued to be considered as 16 bits. The AMD64 architectural extensions bring the 64-bit size into a major position without dropping any of the 16- and 32-bit support.

Thus one sees that today a computer architecture is based on a family of closely related sizes more than on a single omnipresent word size. The sizes are related by integral factors. Calling any one of them the architecture’s word size may be somewhat arbitrary, and a word size may be designated for historical reasons.

Dword, qword, and oword

Some computer architectures define the term dword (double word) to be a unit of data that is twice the size of a word. The x86 platform originally had a word size of 16 bits (2 bytes) and that usage of the term is confusingly retained even though the actual processor word size is now 32 bits or even 64 bits. In that platform, a dword designates a 32 bit (4 byte) unit.

Similarly qword (quadruple word) is a unit of data that is four times the size of a word. On the x86 platform, this unit of data is 64 bits long because the definition of word on an x86 system is 16 bits, as discussed above.

Finally, Intel uses the term double quadruple word, or dqword, to denote 128 bits, found in the implementation of Streaming SIMD Extensions, whereas Microsoft Macro Assembler uses oword (octuple word) for the same data size.

Table of word sizes

key: b: bits, d: decimal digits, w: word size of architecture, n: variable size
Year	Computer Architecture	Word Size w	Integer Sizes	Floating Point Sizes	Instruction Sizes	Unit of Address Resolution	Char Size
«1837»	Babbage Analytical engine	50 d	w	—	5 different cards were used for different functions, exact size of cards not known	w	—
1941	Zuse Z3	22 b	—	w	8 b	w	—
1942	ABC	50 b	w	—	—	—	—
1944	Harvard Mark I	23 d	w	—	24 b	—	—
1946 (1948) {1953}	ENIAC (w/Panel #16) {w/Panel #26}	10 d	w, 2w (w) {w}	—	— (2d, 4d, 6d, 8d) {2d, 4d, 6d, 8d}	— — {w}	—
1951	UNIVAC I	12 d	w	—	½w	w	1 d
1952	IAS machine	40 b	w	—	½w	w	5 b
1952	Fast Universal Digital Computer M-2	34 b	w?	w	34 b = 4 b opcode plus 3x 10b address	10 b	—
1952	IBM 701	36 b	½w, w	—	½w	½w, w	6 b
1952	UNIVAC 60	n d	1d, … 10d	—	—	—	2d, 3d
1953	IBM 702	n d	0d, … 511d	—	5d	d	1 d
1953	UNIVAC 120	n d	1d, … 10d	—	—	—	2d, 3d
1954 (1955)	IBM 650 (w/IBM 653)	10 d	w	— (w)	w	w	2 d
1954	IBM 704	36 b	w	w	w	w	6 b
1954	IBM 705	n d	0d, … 255d	—	5d	d	1 d
1954	IBM NORC	16 d	w	w, 2w	w	w	—
1956	IBM 305	n d	1d, … 100d	—	10d	d	1 d
1957	Autonetics Recomp I	40 b	w, 79 b, 8d, 15d	—	½w	½w, w	5 b
1958	UNIVAC II	12 d	w	—	½w	w	1 d
1958	SAGE	32 b	½w	—	w	w	6 b
1958	Autonetics Recomp II	40 b	w, 79 b, 8d, 15d	2w	½w	½w, w	5 b
1959	IBM 1401	n d	1d, …	—	d, 2d, 4d, 5d, 7d, 8d	d	1 d
1959 (TBD)	IBM 1620	n d	2d, …	— (4d, … 102d)	12d	d	2 d
1960	LARC	12 d	w, 2w	w, 2w	w	w	2 d
1960	CDC 1604	48 b	w	w	½w	w	6 b
1960	IBM 1410	n d	1d, …	—	d, 2d, 6d, 7d, 11d, 12d	d	1 d
1960	IBM 7070	10 d	w	w	w	w, d	2 d
1960	PDP-1	18 b	w	—	w	w	6 b
1961	IBM 7030 (Stretch)	64 b	1b, … 64b, 1d, … 16d	w	½w, w	b, ½w, w	1 b, … 8 b
1961	IBM 7080	n d	0d, … 255d	—	5d	d	1 d
1962	UNIVAC III	25 b, 6 d	w, 2w, 3w, 4w	—	w	w	6 b
1962	Autonetics D-17B Minuteman I Guidance Computer	27 b	11 b, 24 b	—	24 b	w	—
1962	UNIVAC 1107	36 b	1/6w, ⅓w, ½w, w	w	w	w	6 b
1962	IBM 7010	n d	1d, …	—	d, 2d, 6d, 7d, 11d, 12d	d	1 d
1962	IBM 7094	36 b	w	w, 2w	w	w	6 b
1963	Gemini Guidance Computer	39 b	26 b	—	13 b	13 b, 26 b	—
1963 (1966)	Apollo Guidance Computer	15 b	w	—	w, 2w	w	—
1963	Saturn Launch Vehicle Digital Computer	26 b	w	—	13 b	w	—
1964	CDC 6600	60 b	w	w	¼w, ½w	w	6 b
1964	Autonetics D-37C Minuteman II Guidance Computer	27 b	11 b, 24 b	—	24 b	w	4 b, 5 b
1965	IBM 360	32 b	½w, w, 1d, … 16d	w, 2w	½w, w, 1½w	8 b	8 b
1965	UNIVAC 1108	36 b	1/6w, ¼w, ⅓w, ½w, w, 2w	w, 2w	w	w	6 b, 9 b
1965	PDP-8	12 b	w	—	w	w	8 b
1970	PDP-11	16 b	w	2w, 4w	w, 2w, 3w	8 b	8 b
1971	Intel 4004	4 b	w, d	—	2w, 4w	w	—
1972	Intel 8008	8 b	w, 2d	—	w, 2w, 3w	w	8 b
1972	Calcomp 900	9 b	w	—	w, 2w	w	8 b
1974	Intel 8080	8 b	w, 2w, 2d	—	w, 2w, 3w	w	8 b
1975	ILLIAC IV	64 b	w	w, ½w	w	w	—
1975	Motorola 6800	8 b	w, 2d	—	w, 2w, 3w	w	8 b
1975	MOS Tech. 6501 MOS Tech. 6502	8 b	w, 2d	—	w, 2w, 3w	w	8 b
1976	Cray-1	64 b	24 b, w	w	¼w, ½w	w	8 b
1976	Zilog Z80	8 b	w, 2w, 2d	—	w, 2w, 3w, 4w, 5w	w	8 b
1978 (1980)	Intel 8086 (w/Intel 8087)	16 b	½w, w, 2d (w, 2w, 4w)	— (2w, 4w, 5w, 17d)	½w, w, … 7w	8 b	8 b
1978	VAX-11/780	32 b	¼w, ½w, w, 1d, … 31d, 1b, … 32b	w, 2w	¼w, … 14¼w	8 b	8 b
1979	Motorola 68000	32 b	¼w, ½w, w, 2d	—	½w, w, … 7½w	8 b	8 b
1982 (1983)	Motorola 68020 (w/Motorola 68881)	32 b	¼w, ½w, w, 2d	— (w, 2w, 2½w)	½w, w, … 7½w	8 b	8 b
1985	ARM1	32 b	w	—	w	8 b	8 b
1985	MIPS	32 b	¼w, ½w, w	w, 2w	w	8 b	8 b
1989	Intel 80486	16 b	½w, w, 2d w, 2w, 4w	2w, 4w, 5w, 17d	½w, w, … 7w	8 b	8 b
1989	Motorola 68040	32 b	¼w, ½w, w, 2d	w, 2w, 2½w	½w, w, … 7½w	8 b	8 b
1991	Alpha	64 b	¼w, ½w, w	w, 2w	½w	8 b	8 b
1991	Cray C90	64 b	32 b, w	w	¼w, ½w, 48b	w	8 b
1991	PowerPC	32-64 b	¼w, ½w, w	w, 2w	w	8 b	8 b
2000	IA-64	64 b	8 b, ¼w, ½w, w	½w, w	41 b	8 b	8 b
2002	XScale	32 b	w	w, 2w	½w, w	8 b	8 b
key: b: bits, d: decimal digits, w: word size of architecture, n: variable size

See also

• 32-bit
• 32-bit applications
• 64-bit
• 128-bit

References

• Gerrit A. Blaauw & Frederick P. Brooks, Computer Architecture: Concepts and Evolution (Addison-Wesley, 1997, ISBN 0-201-10557-8)
• Anthony Ralston & Edwin D. Reilly, Encyclopedia of Computer Science Third Edition (Van Nostrand Reinhold, 1993, ISBN 0-442-27679-6)