information technology
 
I Classification of Computer
 
MAINFRAME
MINICOMPUTER
MICROCOMPUTER
WORKSTATION
SUPERCOMPUTER
 
II  Evolution of Computer Hardware
 

FIRST GENERATION
SECOND GENERATION
THIRD GENERATION

FOURTH GENERATION

FIFTH GENERATION

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CLASSIFICATION  OF  COMPUTER
 

                      

MAINFRAME
- a powerhouse with massive memory and extremely rapid processing
- used for very large commercial, scientific, or military applications
- classified as having 50 megabytes to over 1 gigabytes of  RAM
 
  
MINICOMPUTER
- a mid-range computer, about the size of an office desk
- used in universities, factories or research laboratories
- had about 10 megabytes to over 1 gigabytes of  RAM
 
  

MICROCOMPUTER
- desktop on size or portable computer
- used as personal machine as well as in business
- classified with 640 kilobytes to 64 megabytes of  RAM
 
  
WORKSTATION
-desktop in size but more powerful mathematical and graphics processing capability
- with ability to perform several tasks at once
- with 8 - 300 megabytes of  RAM
 
  
SUPERCOMPUTER
- highly sophisticated and powerful computer
- can perform complex computations extremely rapidly
 
  Evolution of Computer Hardware
  
FIRST GENERATION:  Vacuum Tube Technology, 1946 - 1956
- comsumed a great deal of power
- short  -  lived
generated a great deal of heat
- collossal in size but limited memory and processing capability
- used for scientific and engineering work
- maximum MEM size = 2000 bytes
- speed is of 10 kiloinstructions per second
- rotating magnetic drums were used for internal storage and punched cards for external storage 
 
   
SECOND GENERATION: Transistors, 1957 - 1963
- much more stable and reliable than vacuum tubes
- generated less heat
- consumed less power
- magnetic core memory was the primary storage technology
- maximum MEM size = 32 kilobyte
- speed is reaching 200,000 to 300,000 instructions per sec
- used  for scientific work and business tasks as payroll and billing
 
  
THIRD GENERATION: Integrated Circuits, 1964 - 1979
- devices used were called semiconductors
-made of thousands of tiny transistors on small silicon chips
- memories were expanded to 2 megabytes of  RAM
- speed accelerated to 5 MIPS
- software introduced can be used by people with less technical training
- greater business role
 

 

FOURTH GENERATION :very large - scale,  1980 - present

- packed with hundreds of thousands - even millions of circuits per chip

- costs have fallen and wide availability for use in business and everyday life

- memory size have mushroomed to over two gigabytes

- processing speeds have exceed 200 MIPS

- fueled movement toward microminiaturization

 

FIFTH GENERATION COMPUTERS

- Conventional computers use Von Neumann architecture, which processes information serially, one instruction at a time. Now, computers use parallel processing and massively parallel processing to blend voice, images and massive pools of data from diverse sources, using artificial intelligence and intricate mathematical models