Central Processing Unit (CPU):



Figure 3. Intel Pentium Processor. (Courtesy Intel)


The brains of the computer is referred to as the Central Processing Unit (CPU). There is some comparison of the CPU to the human brain. Here are some things that are similar to both the CPU and the Human brain.




An example is as follows.

Figure 4. Human Brain and Computer Comparison

All info goes through the CPU to be processed. IBM compatibles use CPUs from Intel (and others) with names like 8086, 80286, 80386, 80486, and Pentium (80586). Apple computers use CPUs from Motorola with names like 6502, 68000, 68020, 68030. The latest CPUs execute many millions of instructions per second.


The types of operations that the CPU can do include:

a)    Retrieving data from memory

b)    Outputting data to memory or ports

c)     Logical operations such as AND, OR, NOT

d)    Math operations such as add, subtract, multiply, and divide

e)    Comparisons such as equal to, greater than, and less than

f)      Program control operations such as jump to a new spot, skip the next instruction, and "if..then.." statements

g)    Response to special external impulses ("interrupts").


A CPU doesn’t have to run a whole computer. There are specialized CPU’s made that are explicitly geared to do specific tasks, such as run the electronics in a car, or a VCR, or microwave oven. If fact, inside the computer itself are a number of these "imbedded" CPU’s that run the keyboard, the video controller, the serial ports, the network card, and the disk controller.