Types Of Computers

Types of Computers

Mainframes

Mainframes

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:

File maintenance:

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.

Emulations:

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.

General purpose:

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.

Minicomputers:

Minicomputers

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:

Plant control:

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.

Network control:

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.