Types Of Computers
Length: 1046 words (3 double-spaced pages)
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Was the dominant form of computing before microcomputers. They are usually very expensive, powerful and operate specialist software
Mainframes are typically used by large companies, public authorities and universities for their data handling tasks. These tasks are typically:
This is perhaps the most common use of mainframes. Maintaining records is a huge task for institutions. Records can contain information on sales, credit card status, payroll details, social security details, health records, stock inventory, etc. These either need to be accessed by different people in real-time (for instance a travel agent booking an airline ticket) or updated in batches (for instance warehouse stock levels at the end of each day). It is necessary in such cases to have the data stored centrally and then accessible by those who need it. A lot of minicomputers are now capable of performing these tasks in medium-sized companies.
Many physical and engineering problems cannot be solved without the help of complex computer simulations. These require intensive mathematical work, and so take advantage of a mainframe's computational power. Examples include weather forecasting, or calculating the position of astronomical bodies with extreme accuracy. Many minicomputers or workstations are now used for this type of problem.
Many universities used a mainframe to act as a general purpose computing facility. Each user can then be given their own area on the mainframe to store files, and different departments can use its resources to perform different tasks, e.g. predicting bird populations in the Biology department and calculating metal stress in the Engineering Department. PCs are now used to perform many of these tasks.
Are powerful, special-purpose computers. They were originally viewed as small mainframes - hence the prefix 'mini'. However, they have become increasingly powerful and have replaced mainframes for many functions. Examples include Digital Equipment's VAX machines and IBM's AS/400s. They typically cost in the $100,000s.
Tasks minicomputers might be used for include:
Many industrial plants require a central computing facility to collect data from various sensors and then to act accordingly. For example, in a chemical engineering plant, as the pressure in one vat increases the computer registers this, and opens a release valve slightly while also adjusting the boiler temperature.
Many computer networks need a central computer which provides storage space and controls the network using special network software. This is known as a server. The other computers which access the server are called clients.
Such machines can also act as the interface to the Internet, accepting Internet messages and hosting e-mail and World Wide Web facilities. Powerful PCs can also be used to perform these functions.
As mentioned above, the role of mainframes in file maintenance is increasingly being taken by minicomputers. Minicomputers can hold databases of records which appropriate people can access.
For the general public it is PCs which tend to symbolize computers. However, most 'heavy duty' computing is performed not by PCs but by minicomputers. With the growth in networking computers in most institutions the role of minicomputers has grown. It is in this market that some of the largest software companies, such as Novell who provide networking software and Oracle who supply database software, do most of their business.
Are based on specialized microprocessors and can be thought of as powerful PCs. They are typically used for specialist engineering tasks. Workstations use a special type of microprocessor known as a RISC chip (Reduced Instruction Set Computing). This technology, developed at IBM, removes many of the complex instructions from a microprocessor and has instead a set of basic instructions, which perform their tasks very quickly. This approach increases the speed and the power of the microprocessor, particularly when dealing with numerical problems. The workstation market is dominated by SUN Microsystems.
Tasks workstations might be used for include:
Computer Aided Design and Computer Aided Manufacturing have been growth industries since the mid-1980s. These technologies allow engineers to design complex machine parts without having to produce an actual physical model. The necessary complex, 3-D graphics require a lot of computing power and good quality video capabilities.
Similarly to CAD/CAM, animations require a lot of processing power which must be performed quickly, and are ideally suited to the RISC technology.
Performing simulations of processes, such as the behavior of an industrial plant, require considerable computing power.
Any complex programming which is deemed to require more power than is offered by a PC, and which needs to perform more than one task at a time (called multi-tasking), is often performed on a workstation. Recent PC operating systems such as Windows NT can also perform multi-tasking.
Microcomputers are based on a microprocessor and are intended for individual use; hence they are called personal computers, or PCs. They were initially stand-alone machines, but are increasingly connected to a network. They typically cost around $1,500. They are ideal for tasks such as those listed below where the user requires individual computing power.
Word processing programs allow a user to produce professional-looking documents, with different fonts, styles and pictures. The production of complex and attractive documents is much easier with the use of word processing software than it was in the days of the typewriter.
Spreadsheets allow a user to create mathematical models. These are particularly useful in financial planning.
This allows people to create drawings, manipulate images and combine them with text to produce professional graphic design work, for instance magazine layouts, posters, book covers, etc.
Although this may seem a non-serious use of computers, games represent a large market. By making use of the PC's computing power very good quality graphics and complex game play can be achieved.
As mentioned above, many powerful PCs are now being used as servers to control a network.
Generally the tasks performed by the mainframes have been taken over by minicomputers. PCs initially created a new type of usage for the computer; for instance, spreadsheets and desktop publishing took over from activities previously performed by hand. As PCs have increased in power they have begun to be used for some of the tasks that required minicomputers and even mainframes in the past.