- Supercomputers
- Mainframes
- Minicomputers
- Microcomputers
- Portable computers
- Palmtops and handhelds
- Embedded systems
- Nanocomputers
Supercomputers are the heavyweights in the computing world. These systems perform heavy calculations using hardware and software that is on the cutting edge of technology. These systems often require special liquid or gas cooling to keep them running, incorporate hundreds or thousands of processors, frequently require a large ammount of physical space and a dedicated team of professionals to keep the system running. The thousands of processors are all designed to work in parallel and/or as part of a neural network within the computer or a cluster of computers. Only government agencies, the U.S. military and a select few corporations and universities own supercomputers because they are exceedingly expensive. These systems are often custom designed to perform specific types of tasks such as graphics rendering, image enhancement (NASA JPL), or mathematical analysis. Supercomputers push the limits of current computer and electronic circuit design and are frequently so huge that they occupy a whole building or series of rooms.
Keep in mind that this is only a general definition, that technology is constantly advancing and that all of this is subject to change. When I was in college in the 80's, a supercomputer was defined as any device capable of 1million floating point calculations or megaflops (mega=million, flop=floating point operations) per second or more. Today's desktop computers have this much power, so supercomputers today claim hundreds of gigaflops or billions of calculations per second.
The last time I looked, Cray was building 40 teraflop systems... (trillions of floating point operations per second).
Mainframe is an older term used to refer to a large, powerful computer which performs the bulk of the data processing within an organization and is accessed using dumb terminals as the user interface. Mainframes are a single computer usually containing less than one hundred processors. Users access a mainframe by using a terminal or a terminal emulation application. Today, most mainframes are general-purpose systems designed to perform any data processing function needed by an organization. Most mainframes are housed in a single data center (one large room). IBM (International Business Machines) and DEC (Digital Equipment Corporation) were to of the bigger mainframe manufacturers. DEC is now a division of Compaq, which is owned by Hewlett-Packard who also toyed with the minicomputer before focusing on printing technologies.
Most of these systems were built before 1987 and are slightly more powerful than mainframes of the same era. These systems were physically smaller than the 'big iron' systems from IBM but had more computing power than their rivals. Many of these were manufactured by Digital Equipment Corporation (DEC) before they were bought out by Compaq. The PDP-1 was the first of these DEC computers, the last was the PDP-11 on which portions of the operating system Unix was developed.
Microcomputers are physically the smallest computers and fit on top of or underneath a desk and are therefore often referred to as desktops, towers or even personal computers. They are general-purpose machines and frequently have networking capability. These systems run a mix of operating systems, running the gamut from Microsoft, Mac OS, Linux and Unix.
Portable computers are called (in order of size) laptops, notebooks and tablet PC's. These are complete, full-blown systems using much of the same hardware and software used on other microcomputer systems.
The Palm Pilot, Journada, iPaq and Handspring devices all count as palmtop or handheld devices. These devices contain considerable computing power and are small enough to be held in the palm of one hand. They often come with a mini operating system, synchronization software (for transferring data between the palmtop and a microcomputer (desktop).
These are the chips and systems built into your favorite electronics, your house, your car, and even your appliances. Chips and software are embedded in the product to add functions that would otherwise not be possible without them. Today's cars use dozens of embedded computers to control fuel consumption, exhaust emissions, braking, acceleration, climate control and many other basic functions that once were purely mechanical. Houses use embedded chips in the thermostats of the hot water heater, the heating system and in the security system if you have one.
These computers don't exist yet. Though researchers have created simple molecular machines, this type of computer has not yet been developed. Nanocomputers will be smaller than the human eye can detect, will use molecular technology to perform computational functions and have a wide variety of functions not currently ascribed to computers today.