Central
Processing Unit: Parts, Definition & Function
Central Processing Unit (CPU)
The Central Processing
Unit (CPU) is the brain of the computer. It performs all the calculations and
computations necessary for performing basic arithmetic, logical, control and
input/output (I/O) operations.
Computer Organization
Computer Organization provides
a logical explanation using block diagrams and arrows to describe how a
computer works i.e. how the various parts of the CPU interact and how it works
with the input and output devices to make the computer work.
The block diagram above
represents a uni-processor CPU computer. Black lines indicate data flow,
whereas red lines indicate control flow; arrows indicate flow directions.
Computer Processor/Microprocessor
Computer Processor
Traditionally, the term
“CPU” refers to a processor, more specifically to its processing unit and
control unit (CU), distinguishing these core elements of a computer from
external components such as main memory and I/O circuitry. A central processing
unit (CPU) is the electronic circuitry within a computer that carries out the
instructions of a computer program by performing the basic arithmetic, logical,
control and input/output (I/O) operations specified by the instructions.
Microprocessor
Most modern processors
are microprocessors, meaning, several components (Arithmetic Logic Unit,
Control Unit, etc.,) contained on a single integrated circuit (IC) chip. An IC
that contains a CPU may also contain memory, peripheral interfaces, and other
components of a computer; such integrated devices are variously called micro
controllers or systems on a chip (SoC). Some computers employ a multi-core
processor, which is a single chip containing two or more CPUs called “cores”.
Parts of a Processor/Central Processing Unit(CPU)
Control Unit
The control unit (CU) is
a component of a computer’s central processing unit (CPU) that directs
operation of the processor. It tells the computer’s memory, arithmetic/logic
unit and input and output devices how to respond to a program’s instructions.
Arithmetic Logic Unit
An arithmetic logic unit
(ALU) is a digital circuit used to perform arithmetic and logic operations. It
represents the fundamental building block of the central processing unit (CPU)
of a computer.
Memory Unit
This unit can store
instructions, data and intermediate results. This unit supplies information to
the other units of the computer when needed.
Registers
In a computer, a register
is one of a small set of data holding places that are part of a computer
processor. A register may hold a computer instruction, a storage address, or
any kind of data. Some instructions specify registers as part of the
instruction.
Processor Cores
Single Core
A chip with one CPU (one
processing unit).
Multi-Core Processor
A multi-core processor is
a single computing component with two or more independent actual processing
units (called “cores”), which are the units that read and execute program
instructions.
Instruction Pipe-Lining
A pipeline is a set of
data processing elements connected in series, where the output of one element
is the input of the next one. The elements of a pipeline are often executed in
parallel or in time-sliced fashion. By using the concept of pipe lining the CPU
processes instructions at a faster rate.
FLOPS (Floating-Point Operations Per Second)
FLOPS or flops (an
acronym for floating-point operations per second) is a measure of computer
performance, useful in fields of scientific calculations that make heavy use of
floating-point calculations. For such cases it is a more accurate measure than
the generic instructions per second.
Processor/Memory Speed Measurement in Clock Cycles
1. Hz: Hertz (equal to one cycle per
second)
2. KHz: Kilo Hertz (1000 cycles per
second)
3. MHz: Mega Hertz (1 Million cycles
per second)
4. GHz: Giga Hertz (1000 Million/1
Billion cycles per second)
Processor Speed Measurement in terms of Operations Per Second
1. FLOPS: Floating Point Operations Per
Second
2. MFLOPS: Million Floating point
Operations Per Second
3. MIPS: Millions of Instruction Per
Second
4. TFLOPS: Tera Floating-Point Operations
Per Second
Acronyms of the Logical Units of a Computer
1. CPU: Central Processing Unit
2. ALU: Arithmetic Logic Unit
3. MCB: Memory Control Block
4. CU: Control Unit
5. DMA: Direct Memory Access
Abbreviations in Integrated Circuits
1. IC: Integrated Circuit
2. SSI: Small Scale Integrated Circuit
3. MSI: Medium Scale Integrated Circuit
4. LSI: Large Scale Integrated Circuit
5. VLSI: Very Large Scale Integrated
Circuit
