Word (computer architecture)

Computer simulation, one of the main cross-computing methodologies.

Natural unit of data used by a particular processor design.

- Word (computer architecture)
Computer simulation, one of the main cross-computing methodologies.

245 related topics

Relevance

Some of the different types of data.

Integer (computer science)

Integer is a datum of integral data type, a data type that represents some range of mathematical integers.

Integer is a datum of integral data type, a data type that represents some range of mathematical integers.

Some of the different types of data.

Computer hardware nearly always provides a way to represent a processor register or memory address as an integer.

Block diagram of a basic computer with uniprocessor CPU. Black lines indicate data flow, whereas red lines indicate control flow. Arrows indicate the direction of flow.

Computer architecture

Set of rules and methods that describe the functionality, organization, and implementation of computer systems.

Set of rules and methods that describe the functionality, organization, and implementation of computer systems.

Block diagram of a basic computer with uniprocessor CPU. Black lines indicate data flow, whereas red lines indicate control flow. Arrows indicate the direction of flow.

Instruction set architecture (ISA): defines the machine code that a processor reads and acts upon as well as the word size, memory address modes, processor registers, and data type.

Modern DDR4 SDRAM module, usually found in desktop computers.

Computer memory

Device or system that is used to store information for immediate use in a computer or related computer hardware and digital electronic devices.

Device or system that is used to store information for immediate use in a computer or related computer hardware and digital electronic devices.

Modern DDR4 SDRAM module, usually found in desktop computers.
Detail of the back of a section of ENIAC, showing vacuum tubes.
8GB microSDHC card on top of 8bytes of magnetic-core memory (1core is 1bit).
Various memory modules containing different types of DRAM (from top to bottom): DDR SDRAM, SDRAM, EDO DRAM, and FPM DRAM

The memory cells are grouped into words of fixed word length, for example, 1, 2, 4, 8, 16, 32, 64 or 128 bits.

Percentage difference between decimal and binary interpretations of the unit prefixes grows with increasing storage size

Byte

Unit of digital information that most commonly consists of eight bits.

Unit of digital information that most commonly consists of eight bits.

Percentage difference between decimal and binary interpretations of the unit prefixes grows with increasing storage size

These systems often had memory words of 12, 18, 24, 30, 36, 48, or 60 bits, corresponding to 2, 3, 4, 5, 6, 8, or 10 six-bit bytes.

In a computer using virtual memory, accessing the location corresponding to a memory address may involve many levels.

Memory address

Reference to a specific memory location used at various levels by software and hardware.

Reference to a specific memory location used at various levels by software and hardware.

In a computer using virtual memory, accessing the location corresponding to a memory address may involve many levels.

There exist word-addressable computers, where the minimal addressable storage unit is exactly the processor's word.

Working DEC KI-10 System at Living Computers: Museum + Labs

PDP-10

Mainframe computer family manufactured beginning in 1966 and discontinued in 1983.

Mainframe computer family manufactured beginning in 1966 and discontinued in 1983.

Working DEC KI-10 System at Living Computers: Museum + Labs
Working DEC KI-10 System at Living Computers: Museum + Labs
PDP-10 systems on the ARPANET highlighted in yellow
Flip Chip from a DEC KA10, containing 9 transistors, 1971
Quick Latch Memory Bus Terminator, used on KI10, 1973
KL10 Wire-Wrap CPU Backplane
KL10-DA 1090 CPU and 6 Memory Modules
KL10 frontend PDP-11/40
KS10
MF10 Light Panel with LED lamps

The PDP-10's architecture is almost identical to that of DEC's earlier PDP-6, sharing the same 36-bit word length and slightly extending the instruction set (but with improved hardware implementation).

Bitwise AND of 4-bit integers

Bitwise operation

In computer programming, a bitwise operation operates on a bit string, a bit array or a binary numeral (considered as a bit string) at the level of its individual bits.

In computer programming, a bitwise operation operates on a bit string, a bit array or a binary numeral (considered as a bit string) at the level of its individual bits.

Bitwise AND of 4-bit integers
Bitwise OR of 4-bit integers
Bitwise XOR of 4-bit integers
Left arithmetic shift
Right arithmetic shift

If the set of bit strings of fixed length n (i.e. machine words) is thought of as an n-dimensional vector space ]], then vector addition corresponds to the bitwise XOR.

A PDP-11/40 CPU is at the bottom, with a TU56 dual DECtape drive installed above it.

PDP-11

Series of 16-bit minicomputers sold by Digital Equipment Corporation from 1970 into the 1990s, one of a set of products in the Programmed Data Processor (PDP) series.

Series of 16-bit minicomputers sold by Digital Equipment Corporation from 1970 into the 1990s, one of a set of products in the Programmed Data Processor (PDP) series.

A PDP-11/40 CPU is at the bottom, with a TU56 dual DECtape drive installed above it.
A PDP-11/40 CPU is at the bottom, with a TU56 dual DECtape drive installed above it.
PDP-11/03 (top right)
Original PDP-11/20 front panel
Original PDP-11/70 front panel
Later PDP-11/70 with disks and tape
PDP-11/03, cover removed to show the CPU board, with memory board beneath (two of the CPU chipset's four 40-pin packages have been removed, and the optional FPU is also missing)
The PDT-11/150 smart terminal system had two 8-inch floppy disc drives
DEC GT40 running Moonlander
MINC-23 laboratory computer
This Unimation robot arm controller used DEC LSI-11 series hardware
The DEC TU10 9-track tape drive was also offered on other DEC computer series
Q-Bus board with LSI-11/2 CPU
DEC "Fonz-11" (F11) Chipset
DEC "Jaws-11" (J11) Chipset

During this period, the computer market was moving from computer word lengths based on units of 6 bits to units of 8 bits, following the introduction of the 7-bit ASCII standard.

An early electromechanical programmable computer, the Z3, included floating-point arithmetic (replica on display at Deutsches Museum in Munich).

Floating-point arithmetic

Arithmetic using formulaic representation of real numbers as an approximation to support a trade-off between range and precision.

Arithmetic using formulaic representation of real numbers as an approximation to support a trade-off between range and precision.

An early electromechanical programmable computer, the Z3, included floating-point arithmetic (replica on display at Deutsches Museum in Munich).
Single-precision floating point numbers on a number line: the green lines mark representable values.
Augmented version above showing both signs of representable values
Leonardo Torres y Quevedo, who proposed a form of floating point in 1914
William Kahan. A primary architect of the Intel 80x87 floating-point coprocessor and IEEE 754 floating-point standard.

Floating-point compatibility across multiple computing systems was in desperate need of standardization by the early 1980s, leading to the creation of the IEEE 754 standard once the 32-bit (or 64-bit) word had become commonplace.

Four PCI Express bus card slots (from top to 2nd bottom: ×4, ×16, ×1 and ×16), compared to a 32-bit conventional PCI bus card slot (very bottom)

Bus (computing)

Communication system that transfers data between components inside a computer, or between computers.

Communication system that transfers data between components inside a computer, or between computers.

Four PCI Express bus card slots (from top to 2nd bottom: ×4, ×16, ×1 and ×16), compared to a 32-bit conventional PCI bus card slot (very bottom)
Single system bus

Buses can be parallel buses, which carry data words in parallel on multiple wires, or serial buses, which carry data in bit-serial form.