Computer History & Parts
Introduction to Personal Computer History, Parts and Repair Concepts

Personal Computer History
Bits - Short for “Binary Digits”
In 1959 Texas Instruments invented the IC (Integrated Circuit)
In 1973 MITS introduced the “Altair” featuring an 8080 processor and 256 Bytes of memory for $395.

Personal Computer History
In 1975 IBM introduced the”Model 5100” with 16 Kilobytes of memory for $9,000.
In 1976 Apple introduced the “Apple I” for $666.
In the 1980’s, Apple was the primary dominating force behind PCs.

The IBM Personal Computer
Wednesday, August 12th, 1981, IBM changed the face of computing by releasing the “IBM PC”
Digital Research was originally contacted to write the OS (Operating System) but balked. A small, fledgling company named Microsoft eagerly took up the task

What is a PC?
The definition of “IBM Compatible” or “Clone”
Who controls Hardware and Software?
Microsoft was free to sell their OS (DOS) to anyone, making IBM clones seemingly identical to their competition

System Types
8 Bit
16 Bit
32 Bit
64 Bit
PC/XT systems
AT systems

System Components
Motherboard
Processor
Memory (RAM)
Case
Power Supply
Disk Drives
Keyboard and Mouse

The Motherboard
Processor Socket
Chipset
Level 2 cache
Memory Sockets
ROM BIOS
Bus Slots

Processor
CPU “Central Processing Unit”
The “Brain” or “Engine” of the Computer
Reads Instructions (commands) from memory then executes them
One of the most expensive, yet smallest components

Memory
RAM (Random Access Memory)
Requires power to maintain storage
ROM (Read Only Memory)
Doesn’t require power to maintain storage
SIMM (Single Inline Memory Module)
DIMM (Dual Inline Memory Module”

Case and Power Supply
The shell of your computer
Protects and directs air flow
Different “Form Factors”
Power Supply converts AC into DC
Important yet often over looked

Disk Drives
Hard Disk (Fixed Disk) - primary storage area for computer. Analogous to a filing cabinet
Floppy Disk- used for storing and exchanging small files
CD-ROM Drives- Holds greater amounts of data and are faster than floppies, yet slower than hard disks

System Components
Video Card
Sound Card
Monitor (Display)
Must be matched to the Video Card Used
Speakers
Internal PC Speaker…beeps
External Powered Speakers using the sound card
Other Devices, e.g. Modems, SCSCI, etc.

I/O Ports and Devices
Devices which allow data to be put in or taken out of the PC
Video, Sound, Keyboard, Printer Port, Serial Port, USB, Firewire

Keyboard and Mouse
Many kinds of keyboards
Only input device available prior to the invention of the GUI (graphical user interface)
After the GUI, mice followed
“Point and Click”

Video Card
Early PC’s had Mono, Color, EGA cards and monitors.
Now Standard on VGA, but many resolutions and speeds
Can be separate card, but frequently on the Motherboard
Chipset
Video Ram
DAC (Digital to Analog Converter)
BIOS
Popular upgrade component, especially for gaming

Sound card and Speakers
Also popular upgrade components
Popular for home recording
Game Port
Many high quality home PC speaker systems. Can rival home stereos

Monitor
Similar to a high quality television
Digital vs Analogue..
Video card send its memory contents to monitor
DAC chip