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.