Inside a PC

Tom Kelliher, CS14A

Feb. 21, 1997

Announcements:

1. First paper is due in two weeks.

2. Video on Monday.

3. Keep up with the assigned readings.

4. We'll start MS Word on Wednesday, so bring the Word Essentials book with you.

Important Terminology

You are responsible for being familiar with all these terms.

1. Serial port --- used for connecting external modems and older mice. A serial port has a programmable baud rate for transferring data.

2. Serial data --- data that is transferred one bit at a time.

3. Baud rate --- the rate at which data is transferred; bits per second. Typical modem baud rates are 14.4K, 28.8K, and 33.6K.

4. Parallel port --- used for connecting a printer. A parallel port has a fixed rate for data transfer. Data is transferred eight bits at a time.

5. Parallel data --- data that is transferred several bits at a time.

6. Motherboard --- the PC's main circuit board.

7. Memory SIMM --- a small circuit board which holds the PC's RAM. Plugs into the motherboard.

8. Ethernet --- Another name for the cable connecting computers into a network. Physically, we saw two types: thinwire (like cable TV cable) and 10BaseT (like a telephone cable).

9. Static discharge --- a single static discharge can destroy computer components.

10. CPU --- central processor unit. The Pentium, Pentium Pro, 486, 386, etc. chip. It controls the PC.

11. Heat sink --- a metallic device which draws heat away from the CPU.

12. Cache --- a type of very fast RAM which is connected between the CPU and the main RAM. Its purpose is to prevent the CPU from being slowed by the main RAM.

13. Bus --- a set of wires that permit data to be transferred from one device to another.

14. ISA expansion bus --- the slower of the two expansion buses. Expansion cards (internal modem, network, sound, etc.) plug into slots on the bus.

15. PCI/VL expansion bus --- two faster expansion buses. A computer will have one of these. New computers all use the PCI bus. Expansion cards (video adapters, hard disk controllers, etc.) plug into slots on the bus.

16. Die --- a silicon wafer holding the transistors that make-up an integrated circuit.

17. ROM BIOS --- the integrated circuit (chip) that contains the PC's start-up program.

18. Video adapter --- the expansion card which controls the PC's monitor.

19. Sound card --- the expansion card which provides multi-media. It controls the PC's stereo speakers (not the simple one which ``beeps'' at us all the time) and will be connected to the CD-ROM drive.

20. Hard drive --- the PC's main disk drive.

21. Platter --- a disk with a iron oxide (rust) coating. The bits and bytes of which files are composed are stored here. The platter is rigid for a hard drive and flexible for a floppy drive.

22. Read/Write head --- an arm with a sensor at the end which reads and writes data from/to the platter. On a hard drive, the head flies above the platter. On a floppy drive, the head contacts the platter.

23. Transistor --- the simple switch from which all computer chips are constructed. It has two states: on and off. This is why all computers use the binary (0 and 1) number system.