Architecture of CPU

ALU – Arithmetic logic unit

FPU – Floating point unit

Cache – Cache memory

1.   ALU: Co- Processor inside the CPU which performs the arithmetical logical operations.

Arithmetical operations: - ,+,*,/ etc.

Logical operations: =, >, > etc.

2.   FPU: Co-processor inside the CPU which process the floating (decimal value).

Eg. 10/4, 6/5 etc.

Resister:  These are the high speed memory circuit located inside the CPU that holds the data for temporary period.

Modern processors are 64 and 128 bits registers.

Cache memory: It is also a memory inside the CPU which stores the data for temporary period.

It has 3 types:

Level 1 (L3), Level 2(2) and Level 3 (L3)

Level 1 : It is built director into the processor.

It's capacity is 8 to 64 kB.

Also called on-board or primary cache.

Level 2: It is positioned between CPU and RAM.

Also called external or secondary Cache,

Size is 64 kB to 2MB.

 Level 3: It is only on Zeon and Itanium processors.

Size is 8 MB.

Bus: It is a group of parallel wires which refers to the path between the components of a computer. These are two types of bus:

1.   Internal bus or system bus

2.   External or expansion bus.

1.      Internal or system bus: These are two types of internal or system bus:

I)                   Front side bus II) Back side bus. 

II)                Front side bus: It is the collective term for the physical pathways connecting the CPU, north bridge chipset and RAM.

It consists of two types. A) Data bus and B) Address bus.

A)    data bus: It is the channel that the CPU uses to access data in the RAM.

B)    Address Bus: It is the pathway that the CPU uses to communicate with the north bridge chipset.

II)                Backside Bus: It refers to pathway that connects the CPU and the L2 cache memory.

Clock: The maximum no. of clock cycles that a CPU can handle in a given period of time is called to as its clock speed. It is CPU's speed which have two types:

Internal (main) speed and External speed:

1.      Internal Speed: Main speed of CPU, at which it process the raw input data.

2.      External speed: This is the speed at which it transfers the processed data.

NOTE: Internal speed is higher than external speed.

NOTE: Pentium processors and their equivalents have a 64 bits data bus and a 82 bits address bus. 

INTEL PENTIUM FAMILY

CPU                                        speed                           type                             socket

8088                                        4.77 Mgz                     DIPP                           DIPP

80286                                      12                                QIPP                           QIPP

80386                                      16-40                           QIPP                           QIPP

80486                                      25-120                         QIPP/PGA                 QIPP,socket,1,2,3

80586                                      60                                PGA                           Socket 4

Pentium I                                75-166 MHz                PGA                            Socket 5,6

Pentium MMX                        166-233                       PGA                             socket 7

(Multimedia extension)

Pentium II                               233-450 MHz              SECC/SEC                 Slot – 1

Pentium III                             450-600                       SEC/SEC                    slot - 1

Pentium III                             500-1300                     PGA                            socket 370      

Pentium 4                                1300MHz                    mpGA,                      mpGA 423, 478and LGA775  

INTEL CELERON FAMILY

Pentium II based Celeron:

Speed: 266-700 MHz

Package: SEPP (single edge processor package)

 Socket: slot 1 socket 370

Pentium III based Celeron:

Speed – 533-700 MHz

Package – PGA

Socket- Socket 370

Pentium 4 based Celeron:

Speed – 850 MHz

Package – SECC, PGA

Socket – Slot 1, socket 370.