Unit
of Measurements in Computer
1.
Storage measurements:
The basic unit used in computer
data storage is called a bit (binary digit). Computers use these little bits,
which are composed of ones and zeros, to do things and talk to other computers.
All your files, for instance, are kept in the computer as binary files and
translated into words and pictures by the software (which is also ones and
zeros). This two-number system, is called a “binary number system” since it has
only two numbers in it. The decimal number system in contrast has ten unique
digits, zero through nine.
2.
Speed measurement:
The speed of Central Processing
Unit (CPU) is measured by Hertz (Hz), Which represent a CPU cycle. The speed of
CPU is known as Computer Speed.
Clock speed is measured in units of
cycles per second, which is called a Hertz (Hz).
Computer boards and CPUs run at rates of millions and billions of Hertz, megahertz (MHz)
and gigahertz (GHz).
CPU SPEED MEASURES
1 hertz or Hz 1
cycle per second
1 MHz 1 million
cycles per second or 1000 Hz
1 GHz 1 billion
cycles per second or 1000 MHz
3.
Clock Speed:
An
internal system clock synchronizes the machine cycle. On each clock tick, the
CPU executes another instruction. Clock speed is the rate at which the CPU
carries out its basic instructions. Computers execute instructions very
rapidly, at speeds measured in hertz. One hertz is one cycle per second.
Microcomputer clock speed is measured in megahertz (MHz, millions of
cycles/second) or gigahertz (GHz, billions of cycles/ second). Newer chip set
designs combined with faster electronic storage are making it difficult to rate
CPU performance solely on clock speed. Increasing internal clock speed is just
one method of improving the performance of a CPU. Other performance features
must also be optimized to take full advantage of the processor’s power.
4.
Word Size:
One
important factor that contributes to CPU power is the amount of data or
instructions that are moved through a processor in one machine cycle. Word size
refers to the group of bits that a processor can manipulate as a unit in one
machine cycle. A 64-bit processor can manipulate 64 bits (or 8 bytes) of data
at one time, clearly an advantage over a 32-bit (4 bytes) processor.
5.
Bus Width:
Another
performance factor is the width of the system bus between the processor and
memory. A bus is an electronic path for the flow of data. The system bus is an
electronic pathway between the CPU, memory, and other system components.
The processor has two bus
connections to memory:
1. Data
Bus
2. Address
Bus.
1. Data
Bus:
The data bus is the set of pathways that carries the actual data between memory
and the CPU. A 64-bit data bus can move 8 bytes of data to the processor in the
same machine cycle. The data bus width should be matched to the word size of
the CPU for optimum performance.
2. Address
Bus: The address bus is the electronic pathway that carries
information about the memory locations of data. The width of the address bus
determines how much potential memory a processor can recognize. Larger address
buses mean the processor can address more memory. Processors that use a 64-bit
address bus can access a potential of 16 GB of memory (264). The processor’s
ability to access a large address space is important for multimedia
applications. Digital video, sound, and images produce large data files. Larger
address buses support faster multimedia processing by allowing these files to
be moved from hard drives, CD-ROMs, DVDs, and other peripheral storage devices
to the computer’s electronic memory where they can be processed and displayed
faster.
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