The computer has passed through many stages of evolution from the days of the mainframe computers to the era of microcomputers. Computers have been classified based on different criteria. In this post, we shall classify computers based on four popular methods.
Based
on configuration or size or capacity [multi-user]
In
the past, the capacity of computers was measured in terms of physical size.
Today, however, the physical size is not a good measure of capacity because the
modern technology has made it possible to achieve compactness.
A
better measure of capacity today is the volume of work that computer can
handle. The volume of work that a given computer handles is closely tied to the
cost and to the memory size of computer. Therefore, most authorities today
accept the price of rental price as the standard for ranking computers.
Here,
both memory size and cost shall be used to rank (classify) computer into four
main categories as follows:
Micro
computer
Microcomputers,
also known as single board computers, are the cheapest class of computers.
In
the microcomputer, we do not have a Central Processing Unit (CPU) as we have in
the larger computers rather we have a microprocessor chip as the main data
processing unit. They are the cheapest smallest and can operate under normal
office condition. Examples are IBM, APPLE, COMPAQ, Hewlett Packard (HP), Dell
Toshiba, etc.
Different
Types of Personal Computers (Micro Computers)
Normally,
personal computers are placed on table desk hence they are referred to as
desktop personal computers. Still other types are available under the
categories of personal computers.
They
are:
Laptop
Computers are small size types that are battery-operated. The screen is used to
cover the system while the keyboard is installed flatly on the system unit.
They could be carried about like a box when closed after operation and can be
operated in vehicles while on a journey.
Microcomputers
are generally referred to as Personal Computers (PCs). They have Smallest
memory and less power. They are widely used in day to day applications like
office automation, and professional applications, ex. PCAT, Pentium etc.
Notebook Computer
This
is like laptop computers but smaller in size. Though small, it comprises all
the components of a full system.
Palmtop Computer
Palmtop
computer is far smaller in size. All the components are complete as any of the
above but made smaller so that it can be held on the palm.
These
are the smallest range of computers. They were introduced in the early 70’s
having less storing space and processing speed. Microcomputers of todays are
equivalent to the mini computers of yesterday in terms of performing and
processing. They are also called “computer of a chip” because its entire
circuitry is contained in one tiny chip. The micro computers have a wide range
of applications including uses as portable computer that can be plugged into
any wall.
l A
microcomputer uses a microprocessor as its central processing unit.
Microcomputers are tiny computers that can vary in size from a single chip to
the size of a desktop model.
l
They are designed to be used by only one person at a time.
l
Small to medium data storage capacities 500MB – 2GB or more
The
common examples of microcomputers are chips used in washing machines, TVs,
cars, note book and personal computers.
E.g.:
IBMPC, PS/2 and Apple Macintosh
Applications:
Used in the field of desktop publishing, accounting, statistical analysis,
graphic designing, investment analysis, project management, teaching,
entertainment etc. The different models of microcomputers are given below:
l
Personal computers : The name PC was given by the IBM for its microcomputers.
PCs are used for word processing, spreadsheet calculations, database management
etc.
l
Note book or Laptop : It is small in terms of size and can be folded and
carried around. Its monitor is made up of LCD and the keyboard and system units
are contained in a single box. It has all the facilities of a personal computer
(HDD, CDD, Sound card, N/W card, Modem etc) and a special connection to connect
to the desktop PC which can be used to transfer data.
l
Palm Top : Smaller model of the microcomputer. Its size is similar to that of a
pocket size calculator. It has a processor, memory and a special connection to
connect to the desktop PC which can be used to transfer data.
l
Personal Digital Assistance : A personal digital assistant is a small
palm-sized hand-held computer which has a small colour touch screen with audio
and video features. They are used as smart phones, web-enabled palmtop
computers, portable media players or gaming devices. Most PDAs today have a
touch screen for data entry, a memory card, Bluetooth, Wi-Fi or an infra-red
connectivity and can be used to access the Internet and other networks.
Figure:
Micro Computer
Microcomputers
are the smallest type of computers available and are popularly known as
personal computers. Personal computers are small relatively inexpensive
computers that are designed for individual users. In terms of cost, they can
range anywhere from a few hundred dollars to over few thousand dollars.
Personal computers are designed for word processing, accounting, desktop
publishing and database management applications.
Personal
computers first appeared in the late stage of 1970. One of the first and most
popular computers was Apple 2, which was first introduced in 1977 by Apple
Computer. During the late 1970s and early 1980s different new models and
different operating systems started appearing daily. Then in 1981,
International Business Machine (IBM) entered in the fray with the first
personal computer called IBM PC. It became an overnight success and was the
people's choice for personal computer. One of the few companies, which survive
IBM's onslaught, is Apple Computer.
Today
the world of personal computers is divided between Macintosh and Personal
Computers. The principal characteristics of PC's are that they are single-user
systems. But they can be linked together to form a network. In terms of power
there is a great variation. At the high-end, the distinction between personal
computers and workstations has faded where high-end models of Macintosh and
Personal Computer offer the same computing power and graphics capability.
Microcomputers
are the smallest type of computers available and are popularly known as
personal computers. Personal computers are small relatively inexpensive
computers that are designed for individual users. In terms of cost, they can
range anywhere from a few hundred dollars to over few thousand dollars.
Personal computers are designed for word processing, accounting, desktop
publishing and database management applications. Personal computers first
appeared in the late stage of 1970. One of the first and most popular computers
was Apple 2, which was first introduced in 1977 by Apple Computer. During the
late 1970s and early 1980s different new models and different operating systems
started appearing daily. Then in 1981, International Business Machine (IBM)
entered in the fray with the first personal computer called IBM PC. It became
an overnight success and was the people's choice for personal computer. One of
the few companies, which survive IBM's onslaught, is Apple Computer.
Today
the world of personal computers is divided between Macintosh and Personal
Computers. The principal characteristics of PC's are that they are single-user
systems. But they can be linked together to form a network. In terms of power
there is a great variation. At the high-end, the distinction between personal
computers and workstations has faded where high-end models of Macintosh and
Personal Computer offer the same computing power and graphics capability.
Microcomputers
are small, low-cost and single-user digital computer. They consist of CPU,
input unit, output unit, storage unit and the software. Although microcomputers
are stand-alone machines, they can be connected together to create a network of
computers that can serve more than one user. IBM PC based on Pentium
microprocessor and Apple Macintosh are some examples of microcomputers.
Microcomputers include desktop computers, notebook computers or laptop, tablet
computer, handheld computer, smart phones and netbook, as shown in Figure.
Mini-computer
The
Mini Computers have memory capacity in the range 128K bytes to 256 Kbytes and
are also not expensive but reliable and smaller in size compare to mainframe.
It was first introduced in 1965; when DEC (Digital Equipment Corporation) built
the PDP – 8. Other Mini Computer includes WANG VS.
Mini
computers are smaller than mainframes, both in size and other facilities such
as speed, storage capacity and other services. They are versatile that they can
be fitted where ever they are needed. Their speeds are rated between one and
fifty million instructions per second (MIPS). They have primary storage in
hundred to three hundred megabytes range with direct access storage device.
l
Perform better than micros
l
Large in size and costlier than micros
l
Designed to support more than one user at a time
l
Possess large storage capacities and operate at higher speed
l
Support faster peripheral devices like high speed printers
l
Can also communicate with main frames
Applications:
l
These computers are used when the volume of processing is large. For example,
data processing for a medium sized organization
l
Used to control and monitor production processes
l
Used to analyze results of experiments in laboratories
l
Used as servers in LANs (Local Area Networks)
Examples
of mini computers are - Digital Equipments PDP 11/45 and VAX 11 etc.
When
Digital Equipment Corporation (DEC) began shipping its PDP series computers in
the early 1960s, the press dubbed these machines minicomputers because of their
small size compared to other computers of the day. Much to DEC’s chagrin, the
name stuck.
The best
way to explain the capabilities of a minicomputers is to say that they lie
somewhere between those of mainframes and those of personal computers.
Like
mainframes, minicomputers can handle a great deal more input and output than
personal computers can. Although some minis and designed for a single user,
many can handle dozens or even hundreds of terminals.
A
company that needs the power of a mainframe but cannot afford such a large
machine may find that a minicomputer suits its needs nicely. The major
minicomputer manufacturers include DEC, Date General, IBM, and Hewlett-Packard.
Mini
Computer is a midsize multi-processing system capable of supporting up to 250
users simultaneously. These were designed for specific tasks but have now lost
popularity due to the advent of PCs. Some of the Popular Minicomputers are
given below:
IBM
Midrange computers
Texas
Instrument TI-990
Mini
computers are more powerful than the microcomputers. They have higher memory
capacity and more storage capacity with higher speeds. These computers are
mainly used in process control systems. They are mainly used in applications
like payrolls, financial accounting, Computer aided design etc.
ex.
VAX, PDP-11
A
midsized computer. In size and power, minicomputers lie between workstations
and mainframes.
In
the past decade, the distinction between large minicomputers and small
mainframes has blurred, however, as has the distinction between small
minicomputers and workstations. But in general, a minicomputer is a
multiprocessing system capable of supporting from 4 to about 200 users
simultaneously. Generally, servers are comes in this category.
Minicomputers
(Figure) are digital computers, generally used in multi-user systems. They have
high processing speed and high storage capacity than the microcomputers.
Minicomputers can support 4–200 users simultaneously. The users can access the
minicomputer through their PCs or terminal. They are used for real-time
applications in industries, research centers, etc. PDP 11, IBM (8000 series)
are some of the widely used minicomputers.
Figure:
Minicomputer
It
is a multi-user computer system which is capable of supporting hundreds of
users simultaneously.
Mini
computers provide more power than microcomputers in terms of speed and storage
capacity. They are also less expensive. Their performance is also lower than
that of mainframes.
Mainframe
computer
The
Main Frame Computers often called number crunches have memory capacity of the
order of 4 Kbytes and they are very expensive. They can execute up to 100MIPS
(Meanwhile Instructions Per Second). They have large systems and are used by
many people for a variety of purpose.
A
very large and expensive computer capable of supporting hundreds, or even
thousands, of users simultaneously. In the hierarchy that starts with a simple
microprocessor (in watches, for example) at the bottom and moves to
supercomputers at the top, mainframes are just below supercomputers. In some
ways, mainframes are more powerful than supercomputers because they support
more simultaneous programs. But supercomputers can execute a single program
faster than a mainframe.
l
Are able to process large amount of data at a very high speed
l
Support multi-user facility
l
Number of processors varies from one to six.
l
Cost: 3500 to many million dollars
l
Are to be kept in air conditioned room to keep them cool
l
Support many I/O and auxiliary storage devices
l
Support network of terminals
Applications:
l
Mainframe computers are used to process large amount of data at a very high
speed such as in the case of banks insurance companies hospitals railways which
need online processing of large number of transactions and requires massive
data storage and processing capabilities
l
Used as controlling nodes in WANs (Wide Area Networks)
l
Used to manage large centralized databases
Examples
of main frame computers are– IBM 370, IBM 3081, IBM 3000 series, Univac 1180,
DEC IBM 3000 series, CDC Cyber - 2000V etc.
The
largest type of computer in common use is the mainframe. Mainframe computers
are used where many people in a large organization need frequent access to the
same information, which is usually organized into one or more huge databases.
For example, consider the Texas Department of Public Safety, where people get
their drivers’ licenses. This state agency maintains offices in every major
city in Texas, each of which has many employees who work at computer terminals.
A terminal is a keyboard and screen wired to the mainframe. It does not have
its own CPU or storage; it is just an input/output (I/O) device that functions
as a window into a computer located somewhere else. The terminals at the Public
Safety offices are all connected to a common database on a mainframe in the
state capital. A mainframe computer controls the database that handles the
input and output needs of all the terminals connected to it. Each used has
continuous access to the driving records and administrative information for
every licensed driver and vehicle in the state literally, millions of records.
On smaller systems, handling this volume of user access to a central database
would be difficult and more time consuming.
No
one really knows where the term mainframe originated. Early IBM documents
explicitly define the term frame as an integral part of a computer: “the
housing… hardware support structures… and all the parts and components
therein.” It may be that when computers of all sizes and shapes began to appear
in computer environments, the big computer was referred to as the main frame,
as in the main computer, and that eventually the term was shortened to one
word, mainframe.
Note:
- The main difference between a super computer and a mainframe is that a super
computer channels all its power into executing a few programs as fast as
possible whereas a mainframe uses its power to execute many programs concurrently.
Mainframe
is very large in size and is an expensive computer capable of supporting
hundreds or even thousands of users simultaneously. Mainframe executes many
programs concurrently and supports many simultaneous executions of programs.
Main
frame computers are very large computers which process data at very high speeds
of the order of several million instructions per second.
They
can be linked into a network with smaller computers, microcomputers and with
each other. They are typically used in large organizations, government
departments etc.
ex.
IBM4381, CDC
A
very large and expensive computer capable of supporting hundreds, or even
thousands, of users simultaneously. In the hierarchy that starts with a simple
microprocessor (in watches, for example) at the bottom and moves to
supercomputers at the top, mainframes are just below supercomputers. In some
ways, mainframes are more powerful than supercomputers because they support
more simultaneous programs. But supercomputers can execute a single program
faster than a mainframe.
Figure:
Mainframe computer
The
largest type of computer in common use is the mainframe. Mainframe computers
are used where many people in a large organization need frequent access to the
same information, which is usually organized into one or more huge databases.
For example, consider the Texas Department of Public Safety, where people get
their drivers‘ licenses. This state agency maintains offices in every major city
in Texas, each of which has many employees who work at computer terminals. A
terminal is a keyboard and screen wired to the mainframe. It does not have its
own CPU or storage; it is just an input/output (I/O) device that functions as a
window into a computer located somewhere else. The terminals at the Public Safety
offices are all connected to a common database on a mainframe in the state
capital. A mainframe computer controls the database that handles the input and
output needs of all the terminals connected to it. Each used has continuous
access to the driving records and administrative information for every licensed
driver and vehicle in the state literally, millions of records. On smaller
systems, handling this volume of user access to a central database would be
difficult and more time consuming.
No
one really knows where the term mainframe originated. Early IBM documents
explicitly define the term frame as a integral part of a computer: ―the
housing,… hardware support structures,… and all the parts and components
therein.‖ It may be that when computers of all sizes and shapes began to appear
in computer environments, the big computer was referred to as the main frame,
as in the main computer, and that eventually the term was shortened to one
word, mainframe.
Note:
- The main difference between a super computer and a mainframe is that a super
computer channels all its power into executing a few programs as fast as
possible whereas a mainframe uses its power to execute many programs
concurrently.
Mainframe
computers (Figure) are multi-user, multi-programming and high performance
computers. They operate at a very high speed, have very large storage capacity
and can handle the workload of many users. Mainframe computers are large and
powerful systems generally used in centralized databases. The user accesses the
mainframe computer via a terminal that may be a dumb terminal, an intelligent
terminal or a PC. A dumb terminal cannot store data or do processing of its
own. It has the input and output device only. An intelligent terminal has the
input and output device, can do processing, but, cannot store data of its own.
The dumb and the intelligent terminal use the processing power and the storage
facility of the mainframe computer.
Mainframe
computers are used in organizations like banks or companies, where many people
require frequent access to the same data. Some examples of mainframes are CDC
6600 and IBM ES000 series.
It
is a multi-user computer system which is capable of supporting hundreds of
users simultaneously. Software technology is different from minicomputer.
Mainframe
computers can also process data at very high speeds, but less than that of
super computers. Normally, they are used in banking, airlines and railways etc.
for their applications.
Super
computer
Large
scientific and research laboratories as well as the government organizations
have extra ordinary demand for processing data which required tremendous
processing speed, memory and other services which may not be provided with any
other category to meet their needs. Therefore very large computers used are
called Super Computers. These computers are extremely expensive and the speed
is measured in billions of instructions per seconds.
Supercomputer
is a broad term for one of the fastest computers currently available. The main
characteristics of a super computer are:
l
Most powerful Computer system -it needs a large room
l
Minimum world length is 64 bits
l
CPU speed: 100 MIPS (Million instruction per second)
l
Equivalent to 4000 computers
l
High cost: 4 – 5 millions
l
Able to handle large amount of data
l
High power consumption
l
High precision
Figure:
PARAM 1000 Series Super Computer
Applications:
l In
petroleum industry - to analyze volumes of seismic data which are gathered
during oil seeking explorations to identify areas where there is possibility of
getting petroleum products inside the earth.
l In
Aerospace industry - to simulate airflow around an aircraft at different speeds
and altitude. This helps in producing an effective aerodynamic design for
superior performance.
l In
Automobile industry – to do crash simulation of the design of an automobile
before it is released for manufacturing – for better automobile design.
l In
structural mechanics – to solve complex structural engineering problems to
ensure safety, reliability and cost effectiveness. For example the designer of
a large bridge has to ensure that the bridge must be proper in various atmospheric
conditions and pressures from wind, velocity etc and under load conditions.
l
Meteorological centers use super computers for weather forecasting.
l In
Biomedical research – atomic nuclear and plasma analysis – to study the
structure of viruses. l In structural mechanics – to solve complex structural
engineering problems to ensure safety, reliability and cost effectiveness. For
example the designer of a large bridge has to ensure that the bridge must be
proper in various atmospheric conditions and pressures from wind, velocity etc.
and under load conditions.
l
Meteorological centers use super computers for weather forecasting.
l In
Biomedical research – atomic nuclear and plasma analysis – to study the
structure of viruses.
l
For weapons research and development, sending rockets to space etc.
Examples
of supercomputers are: Cray-1(1976), Cray-2(1985), Cray T3D (1993), NEC’s
SX-S/44(1991), Fujitsu VP 2600/10(1991), Hitachi 820/80(1987), C-DAC’s PARAM
Series of supercomputers etc.APARAM10000 series super computer of IIT Guwahati
is shown in figure 1.5.
Supercomputers
are the most powerful computers made. They are built to process huge amounts of
data. For example, scientists build models of complex processes and simulate
the processes on a supercomputer. One such process is nuclear fission. As a
fissionable material approaches a critical mass, the researchers want to know
exactly what will happen during every nanosecond of a nuclear chain reaction. A
supercomputer can model the actions and reactions of literally millions of
atoms as they interact.
Because
computer technology changes so quickly the advanced capabilities of a
supercomputer today may become the standard features of a PC a few years from
now, and next year’s supercomputer will be vastly more powerful than today’s.
A
supercomputer is a computer with great speed and memory. This kind of computer
can do jobs faster than any other computer of its generation. They are usually
thousands of times faster than ordinary personal computers made at that time.
The
first Atlas was officially commissioned on 7 December 1962, nearly three years
after the Cray CDC6600 Supercomputer was introduced, as one of the world's
first supercomputers. Seymour Cray is called as father of super computer. A
supercomputer is a computer with great speed and memory. This kind of computer
can do jobs faster than any other computer of its generation. They are usually
thousands of times faster than ordinary personal computers made at that time.
The
first Atlas was officially commissioned on 7 December 1962, nearly three years
after the Cray CDC6600 Supercomputer was introduced, as one of the world's
first supercomputers. Seymour Cray is called as father of super computer.
A
super computer is the fastest, most powerful and most expensive computer which
is used for complex tasks that require a lot of computational power.
Super
computers have multiple processors which process multiple instructions at the
same time. This is known as parallel processing. These computers are widely
used in very advanced applications like weather forecasting, processing
geological data etc.
ex.
CRAY-2, NEC - 500, PARAM.
The
fastest type of computer. Super Computers are very expensive and are employed
for specialized applications that require immense amounts of mathematical
calculations. For example, weather forecasting requires a supercomputer. Other
uses of supercomputers include animated graphics, fluid dynamic calculations,
nuclear energy research, and petroleum exploration. PARAM, Pace & Flosolver
are the supercomputer made in India.
Figure:
Super computer
Supercomputers
are the most powerful computers made. They are built to process huge amounts of
data. For example, scientists build models of complex processes and simulate
the processes on a supercomputer. One such process is nuclear fission. As a
fissionable material approaches a critical mass, the researchers want to know
exactly what will happen during every nanosecond of a nuclear chain reaction. A
supercomputer can model the actions and reactions of literally millions of
atoms as they interact.
Because
computer technology changes so quickly the advanced capabilities of a
supercomputer today may become the standard features of a PC a few years from
now, and next year‘s supercomputer will be vastly more powerful than today‘s.
Supercomputers
(Figure) are the fastest and the most expensive machines. They have high
processing speed compared to other computers. The speed of a supercomputer is
generally measured in FLOPS (FLoating point Operations Per Second). Some of the
faster supercomputers can perform trillions of calculations per second.
Supercomputers are built by interconnecting thousands of processors that can
work in parallel.
Supercomputers
are used for highly calculation-intensive tasks, such as, weather forecasting,
climate research (global warming), molecular research, biological research,
nuclear research and aircraft design. They are also used in major universities,
military agencies and scientific research laboratories. Some examples of
supercomputers are IBM Roadrunner, IBM Blue gene and Intel ASCI red. PARAM is a
series of supercomputer assembled in India by C-DAC (Center for Development of
Advanced Computing), in Pune. PARAM Padma is the latest machine in this series.
The peak computing power of PARAM Padma is 1 Tera FLOP (TFLOP).
It
is an extremely fast computer which can execute hundreds of millions of
instructions per second.
Post activity:
In
this post we covered types or classification of computer in detail. The topic
is very tricky so repetition of sentences is observed but trust me they are
there for some purpose [they convey other aspects of the topic with same
sentence structure].
If
more detailed information is needed please browse or search the internet for above
terms. All images are from Google search.
Keywords:
Computer, type or classification of computer.
…till next post, bye-bye and take
care.
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