A Computer, in simple terms, can be defined as an electronic device that is designed to accept data, perform that required mathematical and logical operations at high speed, and output the results. The "computer" is derived from the word "COMPUTE", which means to calculate.
Disadvantages
generation of computers
The evaluation of computers started from 16th century and resulted in the form that we see today. This period, during which the evaluation of computers took place, cab be divided into five distinct phases known as generations of computers. Each phase is distinguished from others on the basis of the type of technology used.
1st generation computers
First generation computers used thermion values or Vacuum tubes for circuitry, magnetic drums for memory, and where often enormous, occupying entire room. They where very expensive to operate and in addition to using a generate deal of electricity, generated a lot of heat, which was often the cause perform operations and could only solve one problem at a time. Input was based on punched cards and paper tape, and output was on paper.
Example of this generations include: UNIVAC, ENICA, EDVAC
Magnetic Drums |
Punched Cards |
Paper Tape |
Disadvantages
- They generate a lot of heat
- They consume of a lot of electricity
- They where very bulkey in size
- They were expensive.
second generation computers
second generation computers where manufactured using transistors, rather than vacuum tube. Transistors were far superior to vacuum tubes.
Computers manufactured using transistors were smaller, faster, cheaper, and more energy-efficient and reliable that their first generation predecessors.Input was fed ti the second generation computers using punched cards and out put was generated as printouts.
Second generation computers moved towards symbolic (OR) assembly language, which allowed programmers to specify instructions in words. At this time, high level programming languages such as COBOL, FORTRAM, ALGOL, and SNOBOL where also being developed.
Second generation computers where the first to store instructions in memory, which moved from magnetic drum to magnetic core technology. These computers where first developed for the atomic energy industry.
Disadvantages
These computers were manufactured using transistors, which had to be assembled manually. This made commercial production of computers difficulty and expensive.
third generation computers
Used Integrated Circuit(IC) for circuitry which drastically increased the speed and efficiency of computers.
These computers had as few megabytes of main memory and magnetic disks that could store a few tens of megabytes of data per disk drive.Languages like COBOL and FORTRAM where standardized by the ANSI and languages like PL/I PASCAL and BASIC where introduced at this time.
Third generation computers where the first to implement time sharing operating systems. Input to these computers could now be provided using the keyboard and the mouse.
Disadvantages
These computers were difficult to maintain and they got heated very quickly.
fourth generation computers
The journey of fourth generation computers where started with the invention of microprocessor. A single silicon chip that contain thousands of integrated circuits forms a microprocessor. During this period of time, semiconductors memories that were very fast were used and Hard Disk Drives also become very cheaper, smaller in size, and larger in capacity.
For input, floppy disks were used to port data and programs from one computer to another. During this period many operating systems were developed, including MS-DOS, Microsoft Window, UNIX, and APPLE's propriety operating system. They also saw the development of graphical user interface(GUI), the mouse, and handheld device.
Disadvantages
They were not intelligent systems.
fifth generation computer
fifth generation computer are completely based on the new concept of artificial intelligence(AI). Such computers are still in development.
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