Computer Hardware Terminology
64 Bit

64 bit processor parallel data bus processing

64 bit parallel data bus processing

How many bits make up a quadruple word or eight bytes data bus?
You got it . . . 64!

64 bit first and foremost refers to the number of bits that can be processed or transmitted in parallel, that basically means at the same time as one.

As well as being the number of bits that can be used for single element in a data format, for example eight Bytes (sometimes called double Octets) or quadruple word.

A Byte is eight bits wide and a word is sixteen bits wide. You could compare a byte to eight swimmers in swimming lanes swimming at same time side by side. Or an eight lane motorway with a car in each lane side by side.

  • The term ’64 bit’ is also applied to the following within:
    • Microprocessors, indicating the width of the registers. A 64-bit microprocessor can process data and memory addresses that are represented by 64-bits.
    • Data bus, indicating the physical number of wires in a data bus line. A 64-bit bus transmits 64-bits in parallel.
    • Graphical device, such as a scanner or digital camera, specifying the number of bits used to represent each pixel. Typically 24 bits are used for true colour and the remaining 8 bits are used for control information.
    • Operating system: refers primarily to the number of bits used to represent memory addresses.

Within computer architecture, 64-bit whole numbers (integers), memory addresses, or other data units are those that are at most 64-bits (four bytes or octets) wide.

The range of which whole number (integer values) can be stored in 64-bits is 0 to 18,446,744,073,709,551,615 or −9,223,372,036,854,775,808 to +9,223,372,036,854,775,807, using two's complement encoding.

Because of this, a processor with 64-bit memory address data lines can directly read/write 18,000,000 terabytes (18,000,000,000,000,000,000 bytes) of byte addressable memory.

Also, 64-bit CPU and ALU architectures are those that are based on registers, address buses, or data buses of that size. 64-bit is also a term given to a generation of computers in which 64-bit processors are the norm. It had taken on the new gold standard for computing very recently.

The external address and data buses can be wider than 64-bits but both of these are stored and manipulated internally in the processor as 32-bit quantities. The Pentium Pro processor, for example, is a 32-bit processor machine, even so the external address bus lines are 36 bits wide, the external data bus lines are 64-bits wide.

Other prominent 64-bit processors also include the Intel 64-bit Xeon, Pentium dual core series, Athlon 64, Opteron, Sempron, Turion 64 and Phenom processors. Intel's Intel 64 extensions (used in newer Celeron, Pentium 4, Pentium D, Xeon, and Core 2 processors. VIA's 64-bit extensions, used in the VIA Nano processorsis and is compatible with all 32-bit application software.

In images, 32-bit refers to 24-bit true colour images with an 8-bit alpha channel.

In 64 bits file format, a binary file format in which each elementary information is defined on 64 bits (or 8 Bytes).

Hopefully that's cleared the mud a bit, pardon the pun.

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