Class Summary 10/3/07: Computer Hardware

State:
Inside of a computer, there are three major subsystems: the Central Processor Unit (AKA the CPU), memory, and input/output.

Elaborate
When we run a Java program, the program actually executes in the hardware of the computer. The program uses the CPU, memory, and input/out subsystems. When we use JCreator or BlueJ, the Java program is stored on the hard drive, which is part of the input/output subsystem, when we save it. When we run a Java program, the program is copied from the hard drive into memory where the CPU actually executes each instruction.


Exemplify:
The CPU is the "brain" of the computer. In a PC, it consists of a microprocessor like an Intel Pentium or Duo Core chip.

The memory is similar to our own memory. When a software program runs, the program is copied into memory.

The input/output is similar to our senses. Information flows into and goes out of the computer through input and output devices. Input devices include a mouse, a keyboard, web cam, or microphone. Output devices include printers, speakers, and monitors. Devices that perform both input and output functions include hard drives, touch screens, digital cameras, floppy drives, and flash disks.

Illustrate
The three major hardware subsystems are often compared to a human body where the CPU is the brain, the memory is similar to human memory, and the input/output is like the senses.