several MIPS and can support 5-20 users. CAD usage throughout the 1960's used
minicomputers due to their low cost and high performance. Examples of minicomputers
are: DEC PDP, VAX 11.
Microcomputers were invented in the 1970's and were generally used for home
computing and dedicated data processing workstations. Advances in technology have
improved microcomputer capabilities, resulting in the explosive growth of personal
computers in industry. In the 1980's many medium and small design firms were finally
introduced to CAD as a direct result of the low cost and availability of microcomputers.
Examples are: IBM, Compaq, Dell, Gateway, and Apple Macintosh.
The average computer user today uses a microcomputer. These types of computers
include PC's, laptops, notebooks, and hand-held computers such as Palm Pilots. Larger
computers fall into a mini-or mainframe category. A mini-computer is 3-25 times faster than
a micro. It is physically larger and has a greater storage capacity.
A mainframe is a larger type of computer and is typically 10-100 times faster than
the micro. These computers require a controlled environment both for temperature and
humidity. Both the mini and mainframe computers will support more workstations than will
a micro. They also cost a great deal more than the micro running into several hundred
thousand dollars for the mainframes.
The term processor is a sub-system of a data processing system which processes
received information after it has been encoded into data by the input sub-system. These
data are then processed by the processing sub-system before being sent to the output subsystem where they are decoded back into information. However, in common parlance
processor is usually referred to the microprocessor, the brains of the modern day computers.
There are two main types of processors: CISC and RISC
CISC: A Complex Instruction Set Computer (CISC) is a microprocessor Instruction Set
Architecture (ISA) in which each instruction can indicate several low-level operations, such as
a load from memory, an arithmetic operation, and a memory store, all in a single instruction.
The term was coined in contrast to Reduced Instruction Set Computer (RISC).
Examples of CISC processors are the VAX, PDP-11, Motorola 68000 family and the
Intel x86/Pentium CPUs.
RISC: Reduced Instruction Set Computing (RISC), is a microprocessor CPU design
philosophy that favors a smaller and simpler set of instructions that all take about the same
amount of time to execute. Most types of modern microprocessors are RISCs, for instance
ARM, DEC Alpha, SPARC, MIPS, and PowerPC.
The microprocessor contains the CPU which is made up of three components--the