04/08/2021 STU96831 Computer Technology
Computer Technology – Lesson 1 – 10
Lesson 1 – Introductions & Types of Computer
Different types of computer
Classification of Different Types of Computer:
• No easy boundaries, but useful from a general perspective.
• Supercomputers
• Mainframe
• Server
• Workstation
• Desktop
• Personal computer
• Laptop
• Netbook
• Tablet
• Personal Digital Assistant (PDA)
• Smartphone
• Wearable computers
• Embedded systems
This slide lists the various types of computer that exist in the world today. As you can see,
the list is quite long. The problem, however, is that the boundaries between them are not
particularly well defined. For instance, the terms desktop and personal computer could
actually mean the same thing. Also, a supercomputer and mainframe could also mean the
same thing. The trick here is to familiarise yourself with the types of computer that exist,
but be aware of the ‘fuzzy boundaries’ in the descriptions. We shall start by trying to classify
computers into different types. However, the classification gives a useful overall guide to the
relative power of systems from the same era. Each of the classifications above is now
described in greater detail.
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Supercomputers & Mainframes:
• Supercomputer
• Powerful computer which performs complex, time-consuming calculations.
• Google search for an Economist article called the ‘The Data Deluge’.
• Mainframe
• Used as servers which gather and store data, process data into information and present
information to users?
• Note – this could also define a supercomputer
Supercomputers are used to perform hugely complicated calculations and are ideal for
specific domains such as molecular theory and fields where simulations are needed, as in
weather forecasting and astronomy. Their benefit is their parallel processing as well as a
highly hierarchical memory structure. They are often implemented as arrays of CPUs, often
with many processors running in parallel. Various e-Science projects have implemented
‘parallelised’ or grid networks to deal with the problem of the ‘data deluge’. (Google search
‘the data deluge’ to read an interesting Economist article on society’s attempt to manage
increasing digital data production.) Supercomputers have been used for Grand Challenge
programs and simulation of nuclear weapons. More recently, they have been applied to
evaluate in real time the risk of jet engine failure during flight, predicting for the flight
captain when engines should be shut down prior to failure. The distinction between
mainframe computers and supercomputers can be large or small, although the term
‘mainframe’ is infrequently used these days. Originally, this term was used to describe large
computers used by businesses for mass data processing. These days, mainframes tend to
provide back-end server functions (e.g. providing information to users) supporting large
databases and providing storage and data-sharing functions to large organisations. A more
recent development is to use these computers to replace several servers in order to host
virtual machines and multiple operating systems – this is termed virtualisation. You’ll
certainly come across this term again as your studies progress. Mainframes go back to the
days where size was such that a mainframe would fill an entire room. An example of a very
early mainframe was the Colossus computer that was used to crack encrypted German
codes during World War II. A more recent example of a mainframe is the 2007 IBM Blue-
Gene/P.
Server:
• Serves data and information to other computers and users.
• Web pages are served from servers when you click on a hyperlink.
• Can be as basic as a single computer or as large and complex as a mainframe.
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• Classification does not indicate size, only function.
A server is a computer that provides services to other computers or directly to users, usually
via a network such as a Local Area Network (LAN) within a company or via the Internet. For
example, a server ‘serves’ web pages to web users. In fact, every web page is contained on a
server of some description. Many other computer-related technologies are hosted on
servers and include intranets, extranets and management information systems. A server
may be little more than a normal PC or it may be a large mainframe, or anything in between.
This classification does not give indication of size, but of function. The image to the left is a
typical server called a blade. It may contain one or more processors, just like a personal
computer. Blades are installed into racks, much like that shown on the right-hand side of the
slide.
Workstation:
• This term is very vague.
• Can describe a very basic computer system connecting to a mainframe or server.
• Can also describe a place where a person sits down to work.
The term ‘workstation’ is very vague. In some contexts, when special tasks require enhanced
displays or access to complex or sensitive data (e.g. customer accounts), more memory and
powerful processor, a workstation is identified as a more powerful version of a personal
computer. This is because the workstations link directly into a mainframe or server and
share their computing power. Back in the ‘old days’, workers would have been provided
‘dumb terminals’, which are linked directly into the mainframe and contain no processor.
The dumb terminal was the workstation. In other cases, workstation may just refer to the
place you sit to work, including your desk, chair and your computer.
Minicomputers:
• Sit between microcomputers and mainframes.
• Term is rarely used these days.
• As technology developed, microcomputers have increased power to rival mainframe
capabilities.
• In fact, we call these devices personal computers.
Another term that is not used much these days, these were between microcomputers and
mainframes as far as physical size is concerned. These were also called midi computers or
workstations and they provided additional capabilities over a microcomputer, with more
affordable value and infrastructure (e.g. memory or processing power) than a mainframe. As
technology has developed, microcomputers have increased in power to rival
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minicomputers, and minicomputers have increased in power to rival mainframes. The
distinction was never that clear, and is now effectively obsolete.
Desktops & Personal Computers
Desktop:
• Built in a tower case or similar
• Called a Personal Computer (PC)
Personal Computer (PC)
• The same as a desktop, but can also be a laptop or netbook.
The desktop, as the name suggests, denotes a computer that is built in a tower case which
sits on or around the area where the person works. Often called a Personal Computer (PC)
and after the original IBM PC, this is now perceived to be the traditional computer with a
processing case (the tower shown in the left-hand image is the classic example of the
desktop) including all core components, a separate display and input peripheral devices
such as keyboard and mouse.
The PC is not necessarily a different computer type but a perception of what functionalities
a computer could offer to the average user. The term was used for IBM-compatible
computers, like the top image presented above, but these days Apple computers as
represented by the Mac Pro in the lower image are identical in the functionality they have
to offer, and are also termed PCs. There is little, if any, distinction between a PC and a
desktop, so the term desktop PC is used as well. For most people, this is just ‘the computer’.
Laptops and netbooks
Laptop:
• Provides normal functions of desktops.
• All components (keyboard and screen) are built in.
Netbook:
• Cutback version of the laptop.
• May have reduced capability due to miniaturisation.
Laptops and netbooks are also personal computers.
A laptop provides all the normal functions of a desktop computer but in a single device that
has built-in screen, keyboard and pointing device (e.g. trackpad) as well as built-in battery