COMPUTER ARCHITECTURE

Computer: of today are complex devices. Each computer contains hundreds of individual components and these components work together to perform specific function inside the computer.

1^st   A vacuum Tube

Small voltage at one pole switchers Larger voltage at other poles either On Or Off .

2^nd   Transistors

They use sandwich of silicon instead of tubes filled with gas.

3^rd   Resistors

Resist electricity which is dissipated in the form of heat, types of resistors.

·        Fixed reduce current by a certain amount.

·        Variable used for volume control or brightness control.

4^th   Capacitors

They are able to store electrical charge.

5^th   Integrated circuits (ICs)

This is made a possible to put all these components together into circuits that perform certain function.

Types of ICs

·        Dual Inline package.

·        Quad small outline package.

·        Single Inline Package.

·        Pin grid Array Package.

NUMBERING SYSEM

Computers have often been called number crunchers “but what numbers do they actually “crunch”? There are several different types’ of numbering system in use in the computer industry today. The three major ones used by computers are Decimal (base 10) binary (base 2) hexadecimal (base 16).

 Decimal numbers are. Count number. 0, 1, 2,3,-9

Binary number.

Binary numbers are place holders and can be categorized by.

·        A single digit 0 or 1 which is a bit.

·        8 bit which is byte

·        Multiple bytes which is word

System board: this is the spine of the computer known as motherboard it is the most important component that connects all other component

E.g.

• CPU
• Circuitry
• Expansion slots
• Memory Slots
• Other Chip

System Board Component

• Expansion slots
• Memory slots
• Processor slots or socket
• Power connectors
• On board disk drive connectors
• Keyboard connectors
• Peripheral port connectors
• Bios chip
• CMOS Battery
• Jumper and Dip Switchers 

Types of System Board.

Integrated: Because most of the component will be installed as expansion cards are integrated into the Motherboard for circuitry simplicity.

None-integrated: they have major assembly installed in the computer as expansion cards.

Eg: video circuitry, disk controllers and accessories.

Motherboard form Factors

None-integrated are classified by their form factors such as AX, ATX, and NLX BABYAT.

• In AT the processor, memory slots and expansion slots are inline with each Other.
• Baby AT it is at compressed into the smaller area but it has it’s disadvantage in the processor and memory Were inline with expansion slots only one are full length card could be used also the processor is placed far from the cooling fan and this is leading form over head.
• AXT it has the processor and memory slots at right angle to the expansion card
• NLX this form factor is used in the low profile cases expansion slot are placed sideway as special riser card.

Memory

Memory gives the computer its work area the computer use this work area to store a program instructions and data that it is working with.

Types of memory

• Physical Memory
• Logical Memory

Physical Memory: is a collection of integrated circuits that store data and program information as patterns of 0s and 1s in the chip.

Logical Memory: is a way of the physical memory is put together. (Arranged together.)

PHYSICAL MEMORY TYPES.

SRAM a type of computer memory that retains its contents as long as power is supplied it doesn’t need constant refreshment like dynamic chip.

DRAM was an improvement over SRAM DRAM stores the information as charges of very small capacitors it needs to use constant refresh signal to keep the information in memory.

Let us a brief look at some of the different types of DRAM

• Fast Page Mode (FPM)
• Extended Data Out (EDO)
• Synchronous DRAM (SDRAM)
• Double Data Rate SDRAM (DDR SDRAM)
• Direct Rambus (RIMM)

Fast Page Mode (FPM)

DRAM chip at the time of 486 Pentium transition was the most common type DRAM.

Extend Data out (EDO)

1995 A new type of Ram becomes a Popular EDO Ram increases Performance 10 to 15 percent over FPM Dram by eliminating Memory wait states. It is usually more expensive than regular DRAM.

Synchronous DRAM (SDRAM)

In final 1996 a new type of memory was introduced SDRAM Was developed to march the ever-increasing processing speeds of Pentium System.

Double Data Rate SDRAM (DDR SDRAM)

DDR SDRAM is Clock doubled SDRAM the memory chip can perform reads and writes on both sides of any clock cycle the “UP” or s Start “Down “thus Doubling effective memory execution per second.

Direct Rambus (RIMM)

It is relatively new and extremely fast up to 800 MHz.