COMPUTER TYPES

MAGNETIC TAPE

Magnetic tape is also a storage device,it is made up of a plastic tape coated with magnetic substances,the tape is about 2400ft.long and 0.5 inch wide,it has got 7 or 9 tracks ,the capacity of data storring is 800 byte inch or 1600 byte per inch.

TYPES OF COMPUTER

There are many types of computers ,early computers were very big in size and slow in processing ,these days,the computer which is using in our life is very fast in procesing and small in size ,manufacturers have separated all the computers with name and types ,computers are classified into four groups ,according to their size,work ,brand and model.-on the basis of size-on the basis of work-on the basis of brand-on the basis of model1-ON THE BASIS OF SIZEEarly computers were very big in size ,they were slow in processing ,as the technology advanced ,new methods were developed and the sizeof computers has been reduced ,thus ,on the basis of size ,the computer are classified as-super computer-mainframe computer-mini computer-micro computerSUPER COMPUTERS:This is most powerful and expensive computers,they are multiiusers and multi control types ,in this computer 300 to 3000 terminals could be joined ,its working mode is MOPS,it can calculate about 400 milion no. every second and result are always exactly correct ,some of the super computers are -CRAY,ETA 10,NEC etc.MAINFRAME COMPUTERS:It is large machine ,which occupies alarge amount of space ,mainframe computers are generally used in big organizations and government departments for large scale data processing ,it consists of different devices like ,CPU,magnetic tapes ,hard disks ,card readers,disk drive units etc.mainfreame computers were early computers ,few of its ex.CYBER-76,IBM 3000,CRAY -I etc.MINI COMPUTERS:Physically ,it is smaller than mainframe computers ,like in mainframe many terminals or work -stations can be joined -up to it ,due to the networking many users could work at a same time,in different termianls ,some of the ex. are -HP 300,VAX 11 etc.MICRO COMPUTERS:The computers consisting microprocessor are micro computers,they are smallest gemera; purpose computers ,they are also called as personal computers ,as they are used by a single person at a time ,it varies from dekstop to laptop size ..for ex. IBM compatible PC ,APPLE ,PENTIUM etc.ON THE BASIS OF WORKThe computers are made to solve a particular job,this types of computers is used to scientific research ,we can clssify as-analog computer-digital computer-hybrid computerANALOG COMPUTERIt deals with measurement of physical values like temperature and pressure ,these are not having the wide aplications like the other microcomputers ex.speed ometer.DIGITAL COMPUTERIt deals with digital no. and performs calculations by counting ,int the form of digital no. 0-1,these computers are very popular and used on every field.ex. microcomptersHYBRID COMPUTERIt is the combinations of digital and analog computers,some of the processing are done according to the analog principle or some processed according to the digital principle ,these computers are used on the jetplanes.ONT HE BASIS OF BRAND-IBM COMPUTER-IBM COMPATIBLE COMPUTER-APPLE OR MACINTOSH COMPUTERAll the computers manufactured by the IBMare known as the computers ,they are also two types IBMPC and tje IBM compatible .all the computer used the c ompatible principle are called the IBM compatible and the general purpose computers are known as the IBM PC.All the computers manufactured by the Apple industry are called the Apple /Macintosh computer ,they are used only for the desktop publishing purpose.ON THE BASIS OF MODEL-extra technology-advacned technology ps/2All the computer which has used the extra technology are called the xt computer and used the advanced technology are called the At computer,these all are available on the form of the micro computer .other computer like the lap top are called the ps-2 computer and widely used for the personal purpose cause they are portable and have the maximum facility as the other microcomputer.

COMPUTER DISK DRIVES

DISK DRIVES

The internal fixed disk is called hard disk and one or two A,B are external disk drives ,for floppy disks ,the floppy disk may be of 5.25*5.25 inches or 3.5*3.5 inches in size with varying the capacity.
PRINTER
Printer is used to print the result on the paper ,it is an output devices ,there are many types of printer according to the types of printer the speed and printing capacity of printers are also different ,different types of printers are dotmatrix printer ,laser printer ,inkjet printer,line printer etc.
SECONDARY STORAGE DEVICES:
Programms or data cn be stored into these devices permatnently in the computer whenever it is required .ex. of secoundary storage devices:
-floppy disk
-hard disk
-magnetic tape.
FLOPPY DISK:
It is made up of a plastic plate coated with magnetic substances and has concentric circles called tracks and sectores varies from the capacity of disk.
floppy disks ar eone of the most common portable devices in computer system which cab be used to carry the information or data fromone computer to another .
HARD HISK:
It is used as input and output storage media ,it is made up of more than one plastic plate coated with magnetic substaances and fixed on an axix within a metal case so it is called fixed disk also ,hard disk is used to store a large no. of dta ,now adays most of the microcomputers has used the hard disk ,the capacity of the hard disk varies as 10 mb,40 mb,270mb,640 mb,1gb,2.1 gb etc.
the unite of memory is expressed as
1 alphabets or character- 1 bits
4bits - 1 nibble
8 bits -1 byte
1024 byte -1kb
1024 mb -1mb
1024 mb -1gb
1024 gb -1tb

COMPUTER MEMORY UNIT

MEMORY UNIT:

here i have given the memory structure which is used on the microcomputer of the fourth generation.INTERNAL
RAM
-SRAM
-DRAM
EXTERNALROM-PROM
-EPROM-PORTABLE-FLOPPY DISKETTES.-FIXED-HARD DISK-EEPROM
ROMIt is called as firm ware,informtaion stored on this memory can be read only ,it is electrically independent ,information is not destroyed even if one turns the computer off ,it is known as"non volatile memory",the newly developed ROM are ROM ,EPROM AND EEPROM.
RAMIn such types of memory ,one can read and write information ,whatever one types int he keyboard will be automatically stored in this memory ,information stored in this memory are electircally dependents ,it means if u turn the computer off ,the information will be destroyed ,it is divided into two parts as SRAM and DRAM ,it is known as the "volatile memory'".

COMPUTER PERIPHERALS

SOME COMPUTER PERIPHERALS

All the parts connected to the computer internally or externally are calle dthe computer peripherals .-MONITOR:It is also called as screen,it is like a tv screeen,which is displaying unit ,we can get different types of monitors ex. monochrome ,LCDtypes ,color types etc.KEYBOARD:It contains many keys ,it is the main input device ,all data and instructions are given through it, we can get different types of keyboard according to the no. of keys ,some keyboard has 101 ,some has 102 keys,some has 104 and others lates has the 105 keys ,it consists of numeric keys <0,1,2,3......9>,functional keys ,arrow keys (<-,->,...>,charactersand additional keys .CPU The full form of the cpu is central processing unit ,it is the main part of the compute ,so it is known as the heart of the computer ,it is very expensive than the monitor or keyboard ,it consists three sections: CPU
ALU
CU
MU
ALU
This unit is most important unit for data processing ,it acts as airthmetic operator a nd coparative operator ,all te logical and mathematical operations are processed on this unit.
arithmetic operator are+,-,*.....
comparative operator are=,>,<,>=,<=
CU
This unit contros the overall process of the CPU,this section interprets the data and instructions and gives to other components ,it controls the overalls processings unit ,this unit helps to control computer peripherals as well as the working process of the computer .
MU
This is brain of the cpu ,thousands of data nd instructions are stored on this unit given though the input devices ,in the early stage computer ,vacuum tubeswere used as memory device,william shockley and his two freinds,john burden and walter h. brattain invented"transistors '.one transistor is equals to 1000 vacuum tubes ,at the 3rd generation ,hardwick johnson in 1953 invented the most important device called IC chips as the memory devices.

COMPUTER HUMAN WARE

HUMAN WARE

Man has to switch on the computer to make the computer the active ,what operation is to be performed? where to locate required data?such question along with other applied questions are to be addressed by human beings which is termed as the human ware,computer has the processing ability but it has not decision making ability so it will owrk only on our instructions ,we have to design such a sysstem to store data,processing time ,types of process and the applied fields etc. which is also include on the human ware.
The union of these three elements is the core of computer system ,the absences of any one of these elements would cause computer systme incomplete.

COMPUTER LANGUAGE

LANGUAGE OF COMPUTER

We know that the function of a computer is controlled by a set of instructions and codes which are written sequentlially known as program, computer language is the media between user and computer ,user can communicates with the computer by the help of computer language .
there are two levles of computers languages
-low level language
-high level language
1>LOW LEVEL LANGUAGE
It is a media of communication which is a machine dependent or specific to a given computer ,low lelve language is computer's own language,machie code,assembly language are the ex. of the low level language ,some computer experts only know the low level languages cause it is difficult language.
2>HIGH LEVLE LANGUAGE
A medium of communication which is machine independent is called the high levle languages programs are written in these language can be executed on a machine using a translator ,instructions which are used in this language are more closer to the human language,some important high level language are :
BASIC -beginer's all purpose symbolic instruction code
FORTRAN -formula translations
PASCAL -pascal
COBOL - common business oriented language
ALGOL - algorithmic language
PROLOG -programming logic
C -c language

COMPUTER SOFTWARE UTILITY

UTILITY SOFTWARE
These are prewritten programs by manufactures and suppliers ,they supplied these program with the system software,utility software is used to check faulty ,disk ,recover disk errors ,and repair the disk.NDD nroton utility ,pc tools are the ex. of utility software.

SOFTWARE APPLICATION OF COMPUTER

APPLICATION SOFTWARE
These are user -written programs to do dsome specific jobs. the3se are the programs which u write to solve certain problem using computer language ,dbase,lotus 1-2-3,wp,foxpro,are the ex. of application software ,these are specially prepared to do certain specific tasks.
they are of two types:
-tailored software:ex. slc marksheet making ,departmental store bill etc.
-package software-ex. wp,ws,himali,dbase,lotus 1-2-2=3,foxpro,excel etc.

HARDWARE SOFTWARE AND HUMANWARE OF COMPUTER

COMPUTER HARDWARE ,SOFTWARE AND HUMANWARE

When one talks about the computers system,there must be the involvement of following elements,each elements has their own importance on their fields.

HARDWARESOFTWAREHUMANWAREHARDWARE:

All the physical parts of the computes which can be seen with our eyse,one can touch these parts of coputers known as hardwares ,tod study for design ,maintain,assemble and repair of the computers is called hardware study of the computers ,this is also very essential for the user of the computer.SOFTWARE:Software is a collection of instructions and programs in a logical order which tells the differents parts of computers to perform given task,in other sense computer software is the application of the computer in different fields ,if u have a computer but u don't know about the software ,u can not use the computer for urs applications.TYPES OF SOFTWAREWith out any instructions computer can not do anything and such instructions must be in logical order which is known as a program ,a numbers of programs may used to solve a specific applications in a computer ,thus the collections of programs is known as software.ther are three types of software-system software-application software-package software-tailored software-utility softwareSYSTEM SOFTWARE:This is a program or a series of program which generates electronic signlas to work with the components of the computers in response to instructions in the other programs or to commands from keyboard.system software means the operating system software ,it is the poweful unit of software without which hardware become dead,system softwar play the the vital roll between user and computer ,it creates a working envirnment for users,most of the operating systems are:
-cp/m
-ms-dos
-os/2
-apple -dos
-unix
-xenix

COMPUTER GENERATION

GENERATION OF COMPUTER

To simplify mattes and provide frame work for the growth of computer industry we shall look at different periods of the computer called generations of computer.
FIRST GENERATION COMPUTERS:-All the computer which has used the vacuums tubes as the memory device are called the ist generations of computer ,the memory unit used in these computers were 'vaccum tubes which was developed by lee deforest in 1908.MARK I AND ENIAC are the ex. of the ist generations computers ,these computers used the machine language ,the machine language used the binary codes 0's and 1's.
SECOND GENERATIONS COMPUTERS:-All the computers which has used the transistors as the memory devices are called the second generations computers,the memory unit used in these computers were transistors which can replaced 1000 vacuum tubes by one transistors ,the transistor ws developed by the TRIO-GROUP in1948-1949 ,the members of TRIO-group were william shockely ,john burden and walter h. brattain ,the second gerneration computers were more reliable and faster than the ist generation computers IBM 1401,IBM 650 and UNIVAC are the ex. of the second generation computers.
THIRD GERNERATION COMPUTER:-All the computers which has used the ICas the memory devices are called the third generation computers.the memory unit used in these computers were IC chips which was developed by Hardwick johnson in 1953 ,the IC is the integration of large no. of components like Diodes,capacitors ,resistors in a small hips ,so these computes are very samll in sizse than the first an second generation computers .IC -Chips were replaced by LSIand VLSIwhich are more fast ,has large capacity and small in size .IBM 360,UNIVAC 1108,UNIVAC 9000 etc.are the ex. of the third generation computers.
FOURTH GENERATION COMPUTERS:-All the computers used inevery field of computers are the fourth gerneration computers which used very high speed microprocessors ,the memory unit in these computers are also the IC chip but the chips are cut into small ,thin pieces and made from highly purified silicon crystals.the chips are divided into differents parts like-memory unit,arithmetic and logical unit ,control unit.so far computer has phased out its three generations ,now many of the computers available in markets are of fourth generations,although the announcement has been made for fifth gerneration,ist proposal for the fifth generation computers is given by japan in1978 ,now USA ,JAPAN AND EUROPEAN countries ar trying separately in three distinct groups for the quick developement of fifith generations computers.
THE features of fifth generations computers are
-artificial intelligence
-expert systems

COMPUTER DEVICES EXPLANATIONS

EXPLANATIONS OF THE DEVICES

Mechanical calculating devices
ABACUS:-It was the earliest calculating devices,invented around 3000bc. ,it is still used by traders and businessmen in some parts ,separated by a mid-bar,the upper part is called as heaven and the lower parts as earth ,heaven bead hasa a value equal to 5 and earth bead has a value equal to 1 each.
NAPIER'S BONES:-In 1614 a scottish mathematician john napier invented napiers bones ,it is a kind of rod,written different no. digits ,it consists of nine pieces of square,each divided diagonally again .
SLIDE RULE:-In 1620 ,william oughtred invented the slide rule ,this was based on the principles of napiers bones ,differents no.s are calibrated on the bones and perform the mathematical calculations.
PASCALINE:-It was invented by french mathematician ,blaise pascal in 1642,when he was just 19 years old ,he invented it for his father ,who was a tax collector,it is used for add and subtract,it consists of a train of no. wheels ,the no. of calculating capability of pascaline was 9 crores 99 lakhs 99 thousand 9 hundreds and 99.
<9,99,99,999>.
ANALYTIC DEVICES:
ANALYTIC ENGINE:The mathematician ,on arround 1820 designed the analytic engine and introduced the stored program concept .so charles babbage is known as the "father of computer".
LADY ADA LOVELACE,the student of charlesw babbage ,was the ist programmer in the world ,she developed several programms for perfroming mathematical calculations on the analyitc engine.
HOLLERITH TABULATOR:-In 1887,dr. herman hollerith invented holleriths tabulating machine and it was used in the american census work on 1890 ,his idea was to 'code'the data by representing it by punched hole combination on the card.
ELECTROMECHANICAL COMPUTER:-Mechanical devices were put aside and in 1937 ,howard h..aiken of harvard university ,along with his staff in collaborations with IBM corporation ,built automatic sequence controlled calculator.ass compared to modern computers,it was slow and had a very limited storage capacity.
ELECTRONIC COMPUTERS
University of pennesylvania ,constructed the fully electronic computer ENIAC .the instruction as well as data could be manipulated and stored internally in this computer.

COMPUTER HISTORY

HISTORY OF COMPUTER

THE history of computing begins with abacus ,though this is not a computer ,small wooden beads to represent numbers are usually linked in to a thread to make it.in the hands of skilled user,the abacus provides extremlu rapid arithmetic calculations ,it is one of the most widely used computing devices ,even in developed countries ,it was developed in east asia probably china ,two thousand years ago.The ist machine to add no. mechanically was invented by french mathematician blaise pascal in 1642 ,in this machine he had used geared counter wheels to automate arithmetic calculations.In1666,s .moreland developed adding and subtarcting device,following pascal's and moorland's idea g.w. leibnitzinveted calculating machine that could multiply and divide in 1673,he is the one who ist attempted to use binary arithmetic in mechanical calculator .charles babbage was a professor of mathematics at cambridge university,england ,he built a differentail engine in1822 ,which was asigned to do only one specific job,keeping in mind this limitaition ,he started his projet on building universal machine wiht the provsion of :-
-inputting no. using jacquard card with the help of input device.
-memory for storage no.,commands and infromations.
-arithmetic and logic unit to perform required processing.
-control device to look after a step by step operation of program.
-output devices to produces result of calculations.
where also the referred punch card and automatic printing devices as printer ,these provision still provide the basis in designing modern computers .a major development this field occured in 1886,when a stastistician was working on the 1890 census of usa and buikt tabulating machine to analyze 1890 census of the USA,along the used of new jacquard card in his tabulating machine to input no.
In 1935 built mechanical computing devices called z1,WHICH COULD PERFORM binary operations ,and in second models Z2,mechanical relays were replaced by electromagnetic relays and data were inputted using punched paper tapes .
A few years later,IBM started in the project called MARK-I calculator,which was based on electromagnetic relays ,it began operation in 1944 under the pressure of world war MARK-I Calculator was the general purpose,automatic digital computer ,following were the specific characteristic of MARK-I.
-about 3 addition/second.
-72 internal storage registers.
At the same time a group of engineers at the university of pennsylvania headed by ohn w,muchly and j.p eckert working on an automatic electronic digital computer named as ENIAC using vacuum tubes instead relays ,the ENIVAC was completed in 1947 with the following characteristic:
-5000 additions/second.
-storage capacity of 10 digits no. in 20 storage registers at time.
-weight of 30 tons.
-occupied room size 20*9 square meters.
In 1945, had start workign in the project EDVAC.he brought the concept of program controlled machine.
fuuly automatic calculation was performed in the computer .EDSACdeveloped by moris wilks,which came into operation in 2949. mai differences between this and the computers of the earliest versions frequent calculations and the use of special tools to find the errors in aprogramm ,for the ist time a operating system ; ex. a collections of programms that looks after the automatic processing of calculations and assigns peripherals to its systems according to its need was built for the computer EDSAV.
The development in computer technology however begun in1951,when computers were used for the ist time,by business house for a trail.
Transistors begun to replace all vaccum tubes after its invention in 2947 by bell telephone laboratories,thence after computers became more reliable and smaller in size.when IC was developed in 1960,single IC begun to replace a no. transistors ,computers became functionally more powerful while becoming smaller in size and more reliable.integrated circuites containing more than 2250 transistors in a single chip,that called a microporcessor ,was for the ist time designed and developed by INTERL corporation in1971.since then microprocessors have been playing revolutionary role in the field of micro computer,thus the heart of micro computer is essentially a microprocessor.

COMPUTER APPLICATION

APPLICATION OF COMPUTER
Computers are making an amazing effect on today's society ,computers are applied in solving many day to day's complex problems ,many scientific research works and higher studies are becoming impossible without the use of computes,it has wide aplications fields,here are few ex.
-in aviation-all modern aircraft consists of computers for manu purposes.
-medical field-in hospitals ,pharmacy labs,diagnosis illness,many medical research works.
-education-in schools ,collages ,helpings deaf and dumb people to communicate
-printing and publications.
-space technology :desigmomg rockets,missiles,aircrafts,making an artifical satellites.
-weather forecasting.
-fien arts- artists,musicians ,writers,designers ,uses computers.
-playing different types of games.
-in the R and DFIELD
-in the field of science and engineering.

CHRACTERISTICS OF COMPUTER

VERSATILITY
COMPUTER can be used to solve any rpoblems ,provided the problems can be broken into a logical sequence of operations ,that is why we use computers in almost all the fields .
AUTOMATION
A computer is automatic machine ,in computer once the process has begin,it would continue without the need of human interventions untill completions.
DILIGENCE
Since computer is a machine ,it never becomes tired ,it never looses it's concentrations ,if u give one million works to a computer at a one time it does last work with the same accuracy and speed as at the ist work.

CHARACTERISTICS OF COMPUTER

ACCURACY
The accuracy of the computer is consistently high ,almost without exception,the errors in computer are due to human rather than to technilogical weakness,there is apopular term in computer GIGO,that means if our input is correct the computer will give the correct output according to our input without altering the process,so before arising the question about the accuracy of computer we should be confirm that the input is correct or not .

COMPUTER STRUCTURES

STRUCTURES OF THE COMPUTER

Physically we see the computer like TV style monitor,central processing unit and key board,if we have the complete system of computer we can see additional volt guard,mouse, printer connected with the computer system ,here i given the command structure of the computer as follows.

THE MAIN CHARACTERISTICS OF COMPUTERSPEED

Electrical pulses travel at incredible speeds and it's internal speed is virtually instantaneous,we do not talk in terms of seconds or even millisecons ,our units of speed will be microsecond <10-6>,the nanosecond <10-9>and even the picosecond <10-12>.STORAGEAs a human brain retains important things in it's memory and relegates unimportants details to the back of the mind ,the computer also storage certain amount of information's in the internal memory of CPUand other data can be stored outside of the memory of the CPU on the auxiliaru or secondry storage device,usually magnetic tape and floopy disk.

COMPUTER INFO

INFO OF COMPUTER

Computer is an high speed electronic device which can process huge amount of data as well s the instruction ,but its entire function depends on the user's instructions ,data and instructions are given to the computer through the input devices which will stored on the memory unit of the cpu they are further processed on the CPU according to the input given to get the desired out put which can be received by the out put devices.All the devices from where we can give the input are called the input devices ,most popular input devices are keyboard ,scanners,mouse,floppy disk etc. all the devices from where we can get the result according to our input are called the out put devices ,most popular output devices are monier ,printer and sound etc.

COMPUTER INTRODUCTION

INTRODUCTION TO COMPUTER

NOW we are going to settle down on the 21it century,the age of electronics,the advent of modernization turned the life of man more and more complex ,so whne that limilted abilites surrendered before the mighty requirements ,he realized the need of a fast electronic device which was transcendently efficient and the solution was right infant of him-A COMPUTER.A computer is an efficient electronic device capable of performing a number of complex operations within no time ,it has internal storage ,a stored program and program modification capabilities .In other word computer is a data processor that can perfrom substantial computations including numerous ,arithmetic and logical operations with out intervention of a human operator durign the run time.