Supercomputers
A supercomputer is a computer that performs at or near the currently highest
operational rate for computers. A supercomputer is typically used for scientific and
engineering applications that must handle very large databases or do a great amount of
computation (or both). At any given time, there are usually a few well-publicized
supercomputers that operate at the very latest and always incredible speeds.
Perhaps the best-known builder of supercomputers has been Cray Research, now a part
of Silicon Graphics. Some supercomputers are at "supercomputer center," usually
university research centers, some of which, in the United States, are interconnected on
an Internet backbone (A backbone is a larger transmission line that carries data gathered
from smaller lines that interconnect with it) known as vBNS or NSFNet.
At the high end of supercomputing are computers like IBM's "Blue Pacific," announced
on October 29, 1998. Built in partnership with Lawrence Livermore National Laboratory
in California, Blue Pacific is reported to operated at 3.9 teraflop (trillion floating point
operations per second), 15,000 times faster than the average personal computer. It
consists of 5,800 processors containing a total of 2.6 trillion bytes of memory and
interconnected with five miles of cable.
Mainframe Computers
thousands, of users simultaneously. In the hierarchy that starts with a simple
microprocessor (in watches, for example) at the bottom and moves to supercomputers at
the top, mainframes are just below supercomputers. In some ways, mainframes are more
powerful than supercomputers because they support more simultaneous programs. But
supercomputers can execute a single program faster than a mainframe. The distinction
between small mainframes and minicomputers is vague (not clearly expressed),
depending really on how the manufacturer wants to market its machines.
Servers / Minicomputers
A midsized computer. In size and power, minicomputers lie between workstations and
mainframes. In the past decade, the distinction between large minicomputers and small
mainframes has blurred, however, as has the distinction between small minicomputers
and workstations. But in general, a minicomputer is a multiprocessing system capable of
supporting from 4 to about 200 users simultaneously.
Desktops
These are also called microcomputers. Low-end desktops are called PC’s and high-end
ones “Workstations”. These are generally consisting of a single processor only, some
times 2, along with MB’s of memory, and GB’s of storage. PC’s are used for running
productivity applications, Web surfing, messaging. Workstations are used for more
demanding tasks like low-end 3-D simulations and other engineering & scientific apps.
These are not as reliable and fault-tolerant as servers. Workstations cost a few thousand
dollars; PC around a $1000.
Portables
Portable computer is a personal computer that is designed to be easily transported and
relocated, but is larger and less convenient to transport than a notebook computer. The
earliest PCs designed for easy transport were called portables. As the size and weight of
most portables decreased, they became known as laptop computer and later as notebook
computer. Today, larger transportable computers continue to be called portable computers.
Most of these are special-purpose computers - for example, those for use in industrial
environments where they need to be moved about frequently.PDA (personal digital assistant) is a term for any small mobile hand-held device that
provides computing and information storage and retrieval capabilities for personal or
business use, often for keeping schedule calendars and address book information handy.
The term handheld is a synonym. Many people use the name of one of the popular PDA
products as a generic term. These include Hewlett-Packard's Palmtop and 3Com's
PalmPilot.
Most PDAs have a small keyboard. Some PDAs have an electronically sensitive pad on
which handwriting can be received. Apple's Newton, which has been withdrawn from
the market, was the first widely-sold PDA that accepted handwriting. Typical uses
include schedule and address book storage and retrieval and note-entering. However,
many applications have been written for PDAs. Increasingly, PDAs are combined with
telephones and paging systems.
Some PDAs offer a variation of the Microsoft Windows operating system called
Windows CE. Other products have their own or another operating system.
