Types of Computers
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 ...view middle of the document...
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...