Parts of a Computer:
(Central Processing Unit) or Microprocessor
Access Memory RAM
Input/output system BIOS
Disk or secondary memory
What happens when you turn a computer on?
runs it checks memory and for the existence of I/O devices
loads in the operating system (Windows 2000)
system lets you run programs and sends output to correct devices.
What does a microprocessor do?
math (add, subtract, multiply and divide
of data from one memory location to another
of values (<, >, =)
from one set of instructions to another
wires that move data between the CPU and memory
temporary data locations within the CPU
logic circuitry that performs the math and comparisons
Unit logic that moves data in and out of the CPU
Performance is measured by
gigahertz (clock speed) in a Pentium 4
billion instructions per second
How does memory work?
- Random Access Memory (DRAM) is a
capacitor which needs to be recharged.
If charge level is high, it is a 1. If it is low, it is a 0.
is necessary to keep bringing capacitors up to charge. If refreshing stops (like when you turn
the computer off), all memory goes to 0.
memory is kept more permanently either by magnetizing pieces of plastic
(your floppy disk) or marking up an optical disk (CD)
is measured in bytes the memory needed to store one letter of the
alphabet. Good computers will have
at least 64 million (mega) bytes RAM, and 5-10 billion (giga) bytes of
hard disk storage