Computer Hardware

Tom Kelliher, CS14F

Sept. 17, 1996

Data Representation

1. Computers use the binary system. Why?

2. Bits, bytes, words.

3. Converting between binary and decimal.

4. ASCII and EBCDIC.
   1. A: 01000001

   2. 4: 00110100

5. Even and odd parity; error detection.

The CPU

1. Control unit
   1. Coordinates all activity in system.

   2. Fetches, decodes instructions.

2. ALU
   1. Executes instructions.

   2. Bus width.

   3. Multiple functional units --- superscalar.

   4. Pipelining.

   5. Branch prediction.

3. Different machine languages.

4. RISC vs. CISC.

5. Downward compatibility.

6. Data bus --- widths for various x86's. Internal vs. external.

7. Address bus --- limits addressable memory.

Memory

1. RAM:
   1. Primary memory.

   2. Volatile.

   3. How much for various OSs.

2. Virtual Memory.

3. Cache memory.

4. ROM
   1. BIOS, POST.

   2. Not volatile.

5. Secondary storage

   Capacities?

   1. Magnetic disks
      1. DASD.

      2. Sectors, tracks, cylinders.

      3. Read/write head.

      4. Access times.

      5. Data storage.

      6. Flopppy disk.

      7. Hard disk.

      8. IDE, SCSI.

   2. Magnetic Tape
      1. Sequential access.

      2. Inexpensive backup medium.

   3. Optical disk.
      1. CD-ROM; 660MB

      2. Access speeds: double, quad, etc.

      3. CD-R --- write once, read many.