1. Classification of computers according to size, features and latest versions of operatingsystems of computers.
Generations Of Computers
FIRST GENERATION COMPUTERS USED VACUUM TUBES AS SWITCHING DEVICE AND MAGNETIC DRUM FOR MEMORY. THESE COMPUTERS WERE OFTEN HUGE, OCCUPYING AN ENTIRE HALL.
The image on the left shows different vacuum tubes.
Because first generation of computers used vacuum tubes, they consumed a lot of electricity and produced excessive heat. You require cooling facilities to operate computers. This was the major problem of this generation of computers. Moreover, these tubes burned out because of too much heating and need to be replaced more frequent.
The operation cost of these computers were too expensive.
In first generation computers, the operating instructions or programs were specifically built for the task for which computer was manufactured. The Machine language was the only way to tell these machines to perform the operations. There was great difficulty to program these computers ,and more when there were some malfunctions.
Because first generation of computers used vacuum tubes, they consumed a lot of electricity and produced excessive heat. You require cooling facilities to operate computers. This was the major problem of this generation of computers. Moreover, these tubes burned out because of too much heating and need to be replaced more frequent.
SINCE WHEN THE FIRST GENERATION COMPUTERS STARTED?
There are two different views regarding from when the first generation began. Some believe that it started from 1946 when the first computer using valve – ENIAC – was developed. Do you remember how many vacuum tubes ENIAC used? (If no, go check the previous lesson – History of computers)
Some other argue that we should consider EDSAC be the first computer of first generation because it is the first computer to use stored procedure – a true computer in modern sense. ENIAC was just a calculator! If you consider EDSAC is the first computer of first generation, then 1949 should be the starting of first generation.
More generally the duration of first generation computers is 1946 to 1954
EXAMPLES OF FIRST GENERATION COMPUTERS
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| ENIAC |
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| UNIVAC |
VACUUM TUBES
The vacuum tube was an extremely important step in the advancement of computers. Vacuum tubes were invented the same time the light bulb was invented by Thomas Edison and worked very similar to light bulbs. It’s purpose was to act like an amplifier and a switch. Without any moving parts, vacuum tubes could take very weak signals and make the signal stronger (amplify it). Vacuum tubes could also stop and start the flow of electricity instantly (switch).
SECOND GENERATIONS OF COMPUTER!
TRANSISTORS
In 1947 the three Americal Physists - John Bardeen, William Shockley, and Walter Brattain - at Bell Telephone Laboratories invented transistors. They recieved the 1956 Nobel Prize jointly for this awesome invention.Transistors proved to be a much better alternative to the vacuum tubes. They were much smaller, produce low heat and were very reliable. This made it possible to develop computers more smaller and more reliable.
The two minutes video below talks about the history of transistors:
And this is the replica of the first transistor Bardeen & Brattain built. The video discusses how it worked.
SECOND GENERATION OF COMPUTERS (1955 TO 1964)
By 1948, the invention of the transistor greatly changed the computer’s development. Coupled with early advances in magnetic-core memory, transistors led to second generation computers that were smaller, faster, more reliable and more energy-efficient than their predecessors.
The first large-scale machines to take advantage of this transistor technology were early supercomputers,Stretch by IBM and LARC by Sperry-Rand. These machines were costly, however, and tended to be too powerful for the business sector’s computing needs, thereby limiting their attractiveness.
A remarkable improvement realized in this generation was the development of assembly language. Assembly language was abbreviated programming codes to replace the machine language – the difficult binary codes.
Towards the early 1960′s, there were a number of commercially successful second generation computers used in businesses, universities, and government. They contained all the components we associate with the modern day computer: printers, tape storage, disk storage, memory, and stored programs.
One important example was the IBM 1401, which was universally accepted throughout industry. This is the first computer to enter into Nepal as well. Nepal brought this computer for the census of 2028 BS.
It was the stored program and programming language that gave computers the flexibility to finally be cost effective and productive for business use.
More sophisticated high-level languages such as COBOL (Common Business-Oriented Language) and FORTRAN (Formula Translator) came into common use during this time, and have expanded to the current day.
EXAMPLES OF SECOND GENERATION COMPUTERS
IBM 7030 Stretch IBM 1401
INTEGRATED CIRCUITS
Integrated Circuit (IC) is a small electronic device made out of a semiconductor material. The first integrated circuit was developed in the 1950s by Jack Kilby of Texas Instruments and Robert Noyce of Fairchild Semiconductor.
It is amusing to know that two people thought about the same solution but independently. Here is the interesting story about how Robert Noyce got the patent. Please visit the Invention of the integrated circuitat PBS Online. I strongly recommend to go through the page. Its just about 450 words article.
Please check R.C. Khanal’s ‘Computer Concept‘ book. He has nicely explained how these IC Chips are manufactured in ‘Computer Generations’ chapter. Notice the terms silicon, wafers, photolityography.
So, after the invention of IC Chips, it is possible to integrate thousands of registers, diodes, capacitors and many other electronic components and circuitry in a tiny chip.
Integrated circuits are referred with different names like Chips, ICs, microchip and so on.
Types of Integrated Circuits
Up to 100 electronic components per chip
From 100 to 3,000 electronic components per chip
From 3,000 to 100,000 electronic components per chip
From 100,000 to 1,000,000 electronic components per chip
More than 1 million electronic components per chip
THIRD GENERATION COMPUTERS (1964-1971)
The computers using small scale integration circuits and medium scale integration circuits are under this class. The invention of IC Chips made it possible to greatly reduce the size of computers with improvement in operation speed (nanoseconds) and reliability.
One of the most noticeable achievement of third generation computers is the development of operating systems. The operating systems allowed the machines to run many different applications. These applications were monitored and coordinated by the computer’s memory.
In 1969 AT&T Bell Laboratories programmers Kenneth Thompson and Dennis Ritchie developed the UNIXoperating system on a spare DEC minicomputer. UNIX was the first modern operating system that provided a sound intermediary between software and hardware. UNIX provided the user with the means to allocate resources on the fly, rather than requiring the resources be allocated in the design stages. The UNIX operating system quickly secured a wide following, particularly among engineers and scientists at universities and other computer science organizations.
HP2115
FOURTH GENERATION COMPUTERS
Fourth generation for the computers is the era of blooming in multiple dimensions rather than invention of electronic components. Fourth generation computers use ICs as in third generation. But third generation computers used Small Scale and Medium Scale ICs where as in fourth generation Large Scale ICs (LSI), Very Large Scale ICs (VLSI) and the Ultra Large Scale ICs (ULSI) are used.
As millions of electronic components got integrated in a tiny chip, the size of computers are greatly reduced with increased speed, reliability and reduction in cost.
The size of computer reduced to mini computers and micro computers. Today, we have laptops, palm tops and pocket PCs.
Probably the most important development in this generation is microprocessor. The Intel 4004 chip, developed in 1971, took the integrated circuit one step further by locating all the components of a computer (central processing unit, memory, and input and output controls) on a minute chip. Whereas previously the integrated circuit had had to be manufactured to fit a special purpose, now one microprocessor could be manufactured and then programmed to meet any number of demands. Soon everyday household items such as microwave ovens, television sets, and automobiles with electronic fuel injection incorporated microprocessors (Source).
In this generation mini computers were built that had more user friendly software packages like word-processor and spreadsheet calculation.
In 1981, IBM introduced its personal computer (PC) for use in the home, office and schools. Other companies made the clones of IBM PCs to make the personal computers more affordable.
In 1984 Apple developed its Macintosh line. Notable for its user-friendly design, the Macintosh offered an operating system that allowed users to move screen icons instead of typing instructions. Users controlled the screen cursor using a mouse.
Fourth generation is the duration when we saw the tremendous improvement in operating systems and high level programming language.
As the small computers become powerful, it was possible to link and work in cooperative environment. This led to the invention of networking. WAN, MAN, LAN and PAN networks came into existence.
FIFTH GENERATION COMPUTERS
Well, up to fourth generation we saw the how computers evolved as the switching devices improved. Fifth generation computers are future computers.
In 1982 Japan started a project named Fifth Generation Computer Systems Project (FGCS) initiated to create a “fifth generation computer” which was supposed to perform much calculation using massive parallel processing. The project was to create the computer over a ten year period, after which it was considered ended and investment in a new, Sixth Generation project, began. Opinions about its outcome are divided: Either it was a failure, or it was ahead of its time. Anyway, its out of our context for the moment. I just wished to make you aware you of this fact.
Fifth generation computers are anticipated new type of computer based on emerging microelectronic technologies with high computing speeds and parallel processing. Other major expectations out of this generation is the ability to use natural language and acquire artificial intelligence (AI). Computers will be able to learn by its experience. These computers are being made using ULSI (Ultra Large Scale IC) and Bio-Chips.
We can see some development in achieving these features already. Parallel processing, voice recognition systems and some level of intelligence is been already realized.
CLASSIFICATION OF COMPUTERS BASED ON APPLICATION
We can identify three different classes if we look upon how a computer works or what they are applied for – Analog, Digital and Hybrid computers.
Analog Computer
An analog computer is a form of computer that uses the continuously-changeable aspects of physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved. These computers are used in Hospitals, Air-crafts and so on.
An analog computer can be mechanical analog computer or electronic analog computer. (There can be a confusion that electronic computers are digital but note that there are electronic analog computers too!)
Mechanical analog computers have existed for thousands of years, with the oldest known example being theAntikythera. This is a Greek machine, thought to have been made around 100 BC, designed for calculating astronomical positions. A more recent and common mechanical analog computer is the slide rule.
User interface devices such as Keyboards & Monitors started from this generation. This is another important development of third generation.
GUI was started from third generation.
The 5 minutes video below shows how Antikythera worked. Enjoy the video.
Digital Computer
Digital computers are the most common class of computers for us because we are using them everyday. Digital Computers can be defined as a computer that performs calculations and logical operations with quantities represented as digits, usually in the binary number system.
In digital computers, mathematical expressions are represented as binary digits (0 and 1) and all operations are done using these digits at a very high rate. It means that the computer operates on electrical inputs that have only two states, ON and OFF. These computers are widely used in commercial and control systems. Now a days when we use the word computer, we mostly refer to a digital computer.
Hybrid Computers
Analog computers worked purely measuring the physical quantities whereas digital computers counted and manipulated the numbers to produce results. There is another class of computers that can take benefit of features of both these two classes, so, known as hybrid computers.
Hybrid computers are computers with combined features of both digital and analog type. Desirable features of analog and digital machines can be combined to create a Hybrid Computer. This type of computer operates by counting as well as by measuring. In other words, the output can be either in the form of numbers or required units of measurement, e.g., an analog device measures patient’s heart beat (ECG). These measures will be converted into digital form and a digital device checks for any abnormality. Further, we can also input digital data like your marks and get digital results like the result of your class. Another example is a Modem. (which converts the digital signals into analog, carry it along the line and at the
receiving end again changes it back into digital signal).
receiving end again changes it back into digital signal).
If you are interested about the differences in analog, digital and hybrid computers, you are encouraged to visithttp://www.answerbag.com/q_view/1602745.
CLASSIFICATION OF COMPUTERS BASED ON SIZE
As we’ve already talked how large a computer was and we are using very small computers, even some embedded in wrist watch. So, based on size can be another interesting aspect to classify computers. If we look at the computers from this perspective, we can group them into three major classes – Mainframe, Mini and Micro computers.
Mainframe Computers
Well, these are very huge computers. It is interesting how the word ‘mainframe’ came into use. In fact, because the different units of computer were installed in a frame, it started to be called a computer in main frame and today a class of computers are called Mainframe computers.
Mainframe computers are very powerful computers with large memory and processing capabilities. It can support hundreds of users simultaneously.
Please visit Mainframe Introduction and features of mainframe (find the link at the bottom of Mainframe Introduction page)
Mini Computers
Mini computers are medium sized computers – much larger than the personal computers we are using and smaller compared to the mainframe computers. These computers can support multiple users simultaneously and is less powerful than mainframe computers.
A Minicomputer was typically a stand alone device that was ideal for use by small and mid-sized businesses who needed more power and memory than could be obtained with microcomputers, but did not have a need for the resources provided by mainframes. More recently, a minicomputer is thought of in terms of being a server that is part of a larger network.
You can dig for further information about mini computers by visiting here.
Micro Computers
A class of computers that use microprocessor as their central processing unit and are the smallest of the types are the micro computers. Microcomputers are often called personal computers (PCs) because they are intended to be used by a single person at a time. While mainframe and mini computers can support multiple users simultaneously, it can support only one user at a time.
Micro computers can further be classified into desktop computers (that can fit within the top of a desk), laptops (portable computers that can be operated on your lap) and palmtops (hand held computers).
Read more on micro computers in WiseGeek – click here.
Super Computers
Oh! There is this another class of computers too! But I always feel it uncomfortable to list it as a class based on size. Oh! it does not fit anywhere, but there are a group of powerful computers known as Super Computers.
Super Computers are the fastest type of computer. Supercomputers 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.
The chief difference between a supercomputer and a mainframe is that a supercomputer channels all its power into executing a few programs as fast as possible, whereas a mainframe uses its power to execute many programs concurrently.
Configuration of my laptop
System Information
------------------
Time of this report: 9/4/2012, 21:52:19
Machine name: XPSP3-WBB
Operating System: Windows XP Professional (5.1, Build 2600) Service Pack 3 (2600.xpsp.080413-2111)
Language: English (Regional Setting: English)
System Manufacturer: INTEL
System Model: P4I45Gx_PE,
BIOS: Version 1.00
Processor: Intel(R) Pentium(R) 4 CPU 1.70GHz
Memory: 760MB RAM
Page File: 1082MB used, 1076MB available
Windows Dir: C:\WINDOWS
DirectX Version: DirectX 9.0c (4.09.0000.0904)
DX Setup Parameters: Not found
DxDiag Version: 5.03.2600.5512 32bit Unicode
Time of this report: 9/4/2012, 21:52:19
Machine name: XPSP3-WBB
Operating System: Windows XP Professional (5.1, Build 2600) Service Pack 3 (2600.xpsp.080413-2111)
Language: English (Regional Setting: English)
System Manufacturer: INTEL
System Model: P4I45Gx_PE,
BIOS: Version 1.00
Processor: Intel(R) Pentium(R) 4 CPU 1.70GHz
Memory: 760MB RAM
Page File: 1082MB used, 1076MB available
Windows Dir: C:\WINDOWS
DirectX Version: DirectX 9.0c (4.09.0000.0904)
DX Setup Parameters: Not found
DxDiag Version: 5.03.2600.5512 32bit Unicode
Display Devices---------------
Card name: Intel(R) 82845G/GL/GE/PE/GV Graphics Controller
Manufacturer: Intel Corporation
Chip type: Intel(R) 82845G Graphics Controller
DAC type: Internal
Device Key: Enum\PCI\VEN_8086&DEV_2562&SUBSYS_25621849&REV_03
Display Memory: 64.0 MB
Current Mode: 1024 x 768 (32 bit) (75Hz)
Monitor: Plug and Play Monitor
Monitor Max Res: 1600,1200
Driver Name: ialmrnt5.dll
Driver Version: 6.14.0010.3943 (English)
Card name: Intel(R) 82845G/GL/GE/PE/GV Graphics Controller
Manufacturer: Intel Corporation
Chip type: Intel(R) 82845G Graphics Controller
DAC type: Internal
Device Key: Enum\PCI\VEN_8086&DEV_2562&SUBSYS_25621849&REV_03
Display Memory: 64.0 MB
Current Mode: 1024 x 768 (32 bit) (75Hz)
Monitor: Plug and Play Monitor
Monitor Max Res: 1600,1200
Driver Name: ialmrnt5.dll
Driver Version: 6.14.0010.3943 (English)
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