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Computer Chips:

Computer Chips are constructed out of silicon which is a semi conductor.  A semi conductor does not allow electrons to flow through the semi conductor but does allow the storage of electrons in the semi conductor.  This is possible with Silicon because of the atomic structure of Silicon.

ROM - Read Only Memory Chips

The first computer chips developed were called Read Only Memory - ROM.  These chips came with an instruction set (program) when purchased.    When the computer is turned on the data is transferred in to main memory.  When the computer is turned off the data remains in the chip.  The data can not be modified on the chip. 

PROM - Programmable Read Only Memory Chips

 Industry, like the car makers and others, told the chip builders that they wanted a chip that could be developed for specific purposes. The Programmable ROM chip was developed.  This chip had a glass window on the top that allowed a laser beam to program the chip once after it was built.  This way industry could get a chip to plug into their computer for a specific job.

EPROM - Erasable Programmable Read Only Memory Chips

Industry after a while said to the manufactures of chips "we don't want to continue buying a new chip each time we change our program how about a chip that can be erased and reprogrammed." The outcome of this request was the Erasable Prom.  EPROM chips also had a glass window by which a laser beam could program the chip, erase the program, and reprogram it many times. Industry still had to send the chip back to the company for the erasing and reprogramming. 

EEROM - Electronically Erasable Read Only Memory Chips

Industry then said "we don't like having to pay you all of the time to erase and reprogram our chip, especially when it takes so long".  In 1991 Sycor and MIT developed the Electronically Erasable ROM chip.  EEROM technology currently replaces disk drives and cd drives in the 2001 digital cameras. Often it is referred to as Flash Memory, Stick Memory, USB Memory, Chip Memory, and etc. When power is on the chip can be programmed.  When power is turned off the data remains in the chip.  Power can be put back on, the data transferred and the chip can be electronically erased. Eventually EEROM chips will replace HD, FD, and CD's on our PC's and Digital Cameras. 

RAM - Random Access Memory Chips

Random Access Memory chips are fully addressable.  Each and every byte of data is stored at a specific hexadecimal address in the chip and can be retrieved from that address. RAM is a term for all memory that can be read from or written to in a nonlinear fashion. The chip comes with no instructions in the chip.  When power is turned on the data can be moved in and out of the chip.  When power is turned off the chip loses all of its data.  The RAM chip is Volatile and that is the reason that we always have to save our data to an auxiliary storage device such as a floppy drive, hard drive, CD or EEROM.

RAM chips are used to temporally store data and  make up main memory. In human brains this is referred to as short term memory.  When some one says my computer has 512 Mega Bytes of RAM they are talking about main memory. All main memory is comprised of RAM chips.

Main Memory

There are numerous types of RAM
    1) SIMM - single in line memory module
    2) DIMM - dual in line memory module
    3) DRAM - dynamic RAM
    4) FPM RAM - fast page mode RAM
    5) EDO RAM - extended - data out RAM
    6) BEDO RAM - burst extended data out RAM
    7) SDRAM - synchronous dynamic RAM
    8) SRAM - static random access memory
    9) Async SRAM - asynchronous SRAM
    10) PB SRAM - pipeline burst SRAM
    11) VRAM - video RAM
    12) WRAM - windows RAM
    13) SGRAM - synchronous graphics RAM

CMOS RAM Composite Metal Oxide Silicon Chip

Another type of specialized RAM chip is the Composite Metal Oxide Silicon chip.  This chip was first used with the 80286 CPU (IBM AT-1984) computer.  This chip has a battery attached so that when power is turned off the data on the chip will remain.  The cmos chip contains the set up data.  When you turn your computer on you will see instructions that say enter Alt-F10 or something similar to enter the set up program.

CPU - Central Processing Unit Chip

The CPU is the brains of the computer.  The CPU is responsible for all Input/Output I/O, Arithmetic, and Logic.

I/O - All input from devices such as keyboard, CD, HD, FD, touch screen, touch pad, writing pad, mouse, modem, network cable, video camera,  EEROM, tape drive, credit cards, etc. is controlled by the CPU. All output from the computer to printers, modems, monitor, disk drives, cd's, EEROM, tape drives, etc is controlled by the CPU.

Arithmetic  

Logic 

Relational operators.

Boolean Operators
AND, OR, XOR, NOT

    AND

 OR

XOR

Not   

Operator Precedence used in evaluating expressions

Intel's web site http://www.intel.com/museum/index.htm?iid=about_intel+cr_museum
 will give you a history of the development of CPU's.