Computer Organization
1. Introduction
STUDY MATERIALS ON COMPUTER ORGANIZATION
1. INTRODUCTION
1.1 GENERATION OF COMPUTERS
The first electronic computer was designed and built at the University of Pennsylvania based on vacuum tube technology. Vacuum tubes were used to perform logic operations and to store data. Generations of computers has been divided into five according to the development of technologies used to fabricate the processors, memories and I/O units.
I Generation : 1945 – 55
II Generation : 1955 – 65
III Generation : 1965 – 75
IV Generation : 1975 – 89
V Generation : 1989 to present
First Generation
(ENIAC - Electronic Numerical Integrator And Calculator
EDSAC – Electronic Delay Storage Automatic Calculator
EDVAC – Electronic Discrete Variable Automatic Computer
UNIVAC – Universal Automatic Computer
IBM 701)
Vacuum tubes were used – basic arithmetic operations took few milliseconds
Bulky
Consume more power with limited performance
High cost
Uses assembly language – to prepare programs. These were translated into machine level language for execution.
Mercury delay line memories and Electrostatic memories were used
Fixed point arithmetic was used
100 to 1000 fold increase in speed relative to the earlier mechanical and relay based electromechanical technology
Punched cards and paper tape were invented to feed programs and data and to get results.
Magnetic tape / magnetic drum were used as secondary memory
Mainly used for scientific computations.
1. INTRODUCTION
1.1 GENERATION OF COMPUTERS
The first electronic computer was designed and built at the University of Pennsylvania based on vacuum tube technology. Vacuum tubes were used to perform logic operations and to store data. Generations of computers has been divided into five according to the development of technologies used to fabricate the processors, memories and I/O units.
I Generation : 1945 – 55
II Generation : 1955 – 65
III Generation : 1965 – 75
IV Generation : 1975 – 89
V Generation : 1989 to present
First Generation (ENIAC - Electronic Numerical Integrator And Calculator
EDSAC – Electronic Delay Storage Automatic Calculator
EDVAC – Electronic Discrete Variable Automatic Computer
UNIVAC – Universal Automatic Computer
IBM 701)
Vacuum tubes were used – basic arithmetic operations took few milliseconds
Bulky
Consume more power with limited performance
High cost
Uses assembly language – to prepare programs. These were translated into machine level language for execution.
Mercury delay line memories and Electrostatic memories were used
Fixed point arithmetic was used
100 to 1000 fold increase in speed relative to the earlier mechanical and relay based electromechanical technology
Punched cards and paper tape were invented to feed programs and data and to get results.
Magnetic tape / magnetic drum were used as secondary memory
Mainly used for scientific computations.
Transistors were used in place of vacuum tubes. (invented at AT&T Bell lab in 1947)
Small in size
Lesser power consumption and better performance
1 Computer Organization
1. Introduction 2
Lower cost
Magnetic ferrite core memories were used as main memory which is a random-access nonvolatile memory
Magnetic tapes and magnetic disks were used as secondary memory
Hardware for floating point arithmetic operations was developed.
Index registers were introduced which increased flexibility of programming.
High level languages such as FORTRAN, COBOL etc were used - Compilers were developed to translate the high-level program into corresponding assembly language program which was then translated into machine language.
Separate input-output processors were developed that could operate in parallel with CPU.
Punched cards continued during this period also.
1000 fold increase in speed.
Increasingly used in business, industry and commercial organizations for preparation of payroll, inventory control, marketing, production planning, research, scientific & engineering analysis and design etc.
ICs were used
Small Scale Integration and Medium Scale Integration technology were implemented in CPU, I/O processors etc.
Smaller & better performance
Comparatively lesser cost
Faster processors
In the beginning magnetic core memories were used. Later they were replaced by semiconductor memories (RAM & ROM)
Introduced microprogramming
Microprogramming, parallel processing (pipelining, multiprocessor system etc), multiprogramming, multi-user system (time shared system) etc were introduced.
Operating system software were introduced (efficient sharing of a computer system by several user programs)
Cache and virtual memories were introduced (Cache memory makes the main memory appear faster than it really is. Virtual memory makes it appear larger)
High level languages were standardized by ANSI eg. ANSI FORTRAN, ANSI COBOL etc
Database management, multi-user application, online systems like closed loop process control, airline reservation, interactive query systems, automatic industrial control etc emerged during this period.
Fourth Generation (Intel’s 8088,80286,80386,80486 .., Motorola’s 68000, 68030, 68040, Apple II, CRAY I/2/X/MP etc)
Microprocessors were introduced as CPU– Complete processors and large section of main memory could be implemented in a single chip
Tens of thousands of transistors can be placed in a single chip (VLSI design implemented)
CRT screen, laser & ink jet printers, scanners etc were developed.
Semiconductor memory chips were used as the main memory.
Secondary memory was composed of hard disks – Floppy disks & magnetic tapes were used for backup memory
Parallelism, pipelining cache memory and virtual memory were applied in a better way
LAN and WANS were developed (where desktop work stations interconnected)
Introduced C language and Unix OS
Introduced Graphical User Interface
Computer Organization 1. Introduction 3
Less power consumption
High performance, lower cost and very compact
Much increase in the speed of operation
Fifth Generation (IBM notebooks, Pentium PCs-Pentium 1/2/3/4/Dual core/Quad core.. SUN work stations, Origin 2000, PARAM 10000, IBM SP/2)
Generation number beyond IV, have been used occasionally to describe some current computer system that have a dominant organizational or application driven feature.
Computers based on artificial intelligence are available
Computers use extensive parallel processing, multiple pipelines, multiple processors etc
Massive parallel machines and extensively distributed system connected by communication networks fall in this category.
Introduced ULSI (Ultra Large Scale Integration) technology – Intel’s Pentium 4 microprocessor contains 55 million transistors millions of components on a single IC chip.
Superscalar processors, Vector processors, SIMD processors, 32 bit micro controllers and embedded processors, Digital Signal Processors (DSP) etc have been developed.
Memory chips up to 1 GB, hard disk drives up to 180 GB and optical disks up to 27 GB are available (still the capacity is increasing)
Object oriented language like JAVA suitable for internet programming has been developed.
Portable note book computers introduced
Storage technology advanced – large main memory and disk storage available
Introduced World Wide Web. (and other existing applications like e-mail, e Commerce, Virtual libraries/Classrooms, multimedia applications etc.)
New operating systems developed – Windows 95/98/XP/…, LINUX, etc.
Got hot pluggable features – which enable a failed component to be replaced with a new one without the need to shutdown the system, allowing the uptime of the system to be very high.
The recent development in the application of internet is the Grid technology which is still in its upcoming stage.
Quantum mechanism and nanotechnology will radically change the phase of computers.
1.2 TYPES OF COMPUTERS
1. Super Computers
2. Main Frame Computers
3. Mini Computers
4. Micro Computers
1. Super Computers E.g.:- CRAY Research :- CRAY-1 & CRAY-2, Fujitsu (VP2000), Hitachi (S820), NEC (SX20), PARAM 10000 by C-DAC, Anupam by BARC, PACE Series by DRDO
Most powerful Computer system - needs a large room
Minimum world length is 64 bits
CPU speed: 100 MIPS
Equivalent to 4000 computers
High cost: 4 – 5 millions
Able to handle large amount of data
High power consumption
High precision
Computer Organization 1. Introduction
Large and fast memory (Primary and Secondary)
Uses multiprocessing and parallel processing
Supports multiprogramming
Applications
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
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
In Automobile industry – to do crash simulation of the design of an automobile before it is released for manufacturing – for better automobile design
In structural mechanics – to solve complex structural engineering problems to ensure safety, reliability and cost effectiveness. Eg. 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.
Meteorological centers use super computers for weather forecasting
In Biomedical research – atomic nuclear and plasma analysis – to study the structure of viruses such as that causing AIDS
For weapons research and development, sending rockets to space etc
2. Main Frame Computers E.g.:- IBM 3000 series, Burroughs B7900, Univac 1180, DEC
Able to process large amount of data at very high speed
Supports multi-user facility
Number of processors varies from one to six.
Cost: 3500 to many million dollars
Kept in air conditioned room to keep them cool
Supports many I/O and auxiliary storage devices
Supports network of terminals
USERS ROOM
(Entry restricted to authorized persons)
SYSTEM ROOM
(Entry restricted to system Administrators & maintenance staff)
User Terminals
Printer
Plotter
Magnetic
Tape Drives
Magnetic Tape Library
Console
Host Processor
Front-end Processor
Back-end Processor
Magnetic
Tape Drives
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Applications
Used to process large amount of data at 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
Used as controlling nodes in WANs (Wide Area Networks)
Used to mange large centralized databases
3. Mini Computers E.g.:- Digital Equipments PDP 11/45 and VAX 11)
Perform better than micros
Large in size and costlier than micros
Designed to support more than one user at a time
Posses large storage capacities and operates at higher speed
Support faster peripheral devices like high speed printers
Can also communicate with main frames
Applications
These computers are used when the volume of processing is large for e.g. Data processing for a medium sized organization
Used to control and monitor production processes
To analyze results of experiments in laboratories
Used as servers in LANs (Local Area Networks)
4. Micro Computers E.g.:- IBM PC, PS/2 and Apple Macintosh
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
They are designed to be used by only one person at a time
Small to medium data storage capacities 500MB – 2GB
The common examples of microcomputers are chips used in washing machines, TVs, Cars and Note book/Personal computers.
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:-
a) Personal computers:- The name PC was given by the IBM for its microcomputers. PCs are used for word processing, spreadsheet calculations, database management etc.
b) Note book or Lap Top:- Very small in terms of size – can be folded and carried around – Monitor is made up of LCD and the keyboard and system units are contained in a single box. Got 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.
c) Palm Top:- Smaller model of the microcomputer- size is similar to that of a calculator – pocket size- It has a processor and memory and a special connection to connect to the desktop PC which can be used to transfer data.
d) Wrist PC:- Smallest type of microcomputer – can be worn on our wrist like a watch- It has a processor and memory and a wireless modem
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