The PC construction

[top]

The PC consists of a central unit (referred to as the computer) and various peripherals. The computer is a box, which contains most of the working electronics. It is connected with cables to the peripherals.

On these pages, I will show you the computer and its components. Here is a picture of the computer:

Here is a list of the PC components. Read it and ask yourself what the words mean. Do you recognize all these components? They will be covered in the following pages.

Components in the central unit - the computer	Peripherals
The motherboard: CPU, RAM, cache, ROM chips with BIOS and start-up programs. Chip sets (controllers). Ports, buses and expansion slots. Drives: Hard disk(s), floppy drive(s), CD-ROM, etc. Expansion cards: Graphics card (video adapter), network controller, SCSI controller. Sound card, video and TV card. Internal modem and ISDN card.	Keyboard and mouse. Joystick Monitor Printer Scanner Loudspeakers External drives External tape station External modem

So, how are the components connected. What are their functions, and how are they tied together to form a PC? That is the subject of Click and Learn. So, please continue reading...

---

The von Neumann Model of the PC

[top]

Computers have their roots 300 years back in history. Mathematicians and philosophers like Pascal, Leibnitz, Babbage and Boole made the foundation with their theoretical works. Only in the second half of this century was electronic science sufficiently developed to make practical use of their theories.

The modern PC has roots that go back to the USA in the 1940s. Among the many scientists, I like to remember John von Neumann (1903-57). He was a mathematician, born in Hungary. We can still use his computer design today. He broke computer hardware down in five primary parts:

CPU

Input

Output

Working memory

Permanent memory

Actually, von Neumann was the first to design a computer with a working memory (what we today call RAM). If we apply his model to current PCs, it will look like this:

All these subjects will be covered.

---

Data exchange - the motherboard

[top]

The ROM chips contain instructions, which are specific for that particular motherboard. Those programs and instructions will remain in the PC throughout its life; usually they are not altered.

Primarily the ROM code holds start-up instructions. In fact there are several different programs inside the start-up instructions, but for most users, they are all woven together. You can differentiate between:

POST (Power On Self Test)

The Setup instructions, which connect with the CMOS instructions

BIOS instructions, which connect with the various hardware peripherals

The Boot instructions, which call the operating system (DOS, OS/2, or Windows )

All these instructions are in ROM chips, and they are activated one by one during start-up. Let us look at each part.

---

The suppliers of system software

[top]

All PCs have instructions in ROM chips on the motherboard. The ROM chips are supplied by specialty software manufacturers, who make BIOS chips. The primary suppliers are:

Phoenix

AMI ( American Megatrends )

Award

You can read the name of your BIOS chip during start-up. You can also see the chip on the system board. Here is a picture (slightly blurred) of an Award ROM chip:

Here is an AMI chip with BIOS and start-up instructions: