Computer fundamental for Varies competitive Exams

Computer Fundamental

Analytical Engine- made by Carles Babbge (Father of Computer)

-can do six degree of pronominal calculation.

Kananrd Zuse -made first computer and named it Z1 (FIRST PROGRAMMABLE COMPUTER)

• ENVIC-HAD 20,000 VACCUME TUBE,FIRST ELECTRONIC COMPUTER
• Lovelace was first computer programmer
• George Boolie- first develop Boolean Algebra
• Intel and Motorola Makes processor. Intel makes for IBM and IBM compatible computer Ex Pentium ,and Motorola makes for Apple ,latest one power PC ie G3 for I MAC

• COMPUTER-have two parts :

1. Hardware

• Input-Ex: Keyboard,Mouse,web cam,Joystick,Light pen,MICR,OMR,BIOMATRIX,STYLUS,MICROPHONE.
• Processing-Ex ; CPU,Motherboard,RAM,SMPS.
• Output-Ex : Monitor,Printer,Speaker,Plotter,Projector.
• storage-Ex :Hard drive,Floppy Drive,CD,DVD,BRD,Lip Drive,Memory Card,Pen drive,Magnetic tape

2. software

• Keyboard-Keys F1,F2 to F12 :are called as Function Keys

0123 to9 :are called as Numeric keys

ASDF :are called as Alphabets

ALT,CTRL :are called as Special Keys

INPUT-------> PROCESSING-------->OUTPUT----------------->STORAGE(SAVE)

Different computer generation

• First Generation:(1951-58) computer have Vacuum tube that's work on thermionic emission

Drum as Primary storage

Punched cards/paper tape as Sec storage media

Ex- ENVIC,EDVAC,EDSAC

• 2^nd Generation:(1959-64) Semiconductor with impurities best called as Transistor

Magnetic core as primary storage device\

tape sec storage device

FORTAN,COBAL language evolved

Ex IBM 700,1401

• 3rd Generation:(1964-71) IC( Integrated Chips) evolved ie Transistor packed on thin Wafer

Magnetic disc used for sec storage

COBAL,ALGOL Language evolved

First time Operating system used

Multiprogramming evolved

Ex-IBM 360/370

• 4^th Generation (1971-85)- have very large scale IC(VLSIC) that,s have huge unit of Transistors Packed.

Semiconductor used as primary as well as primary storage device.

Micro and personal computer developed

CRT monitor developed

Application developed

Virtual OS

Microprocessor used

• 5^thGeneration-Artificial intelligence
  LISP(Special Purpose Language) will be used

Prolog(pro-gramme for logic)

SMALL,TALK,

Truly 5^th Generation computer is not available

would use organic chips..

When computer start from scrap following steps would take place

1. computer on
2. on screen BIOS(Basic Input output system) will displayed.Bios is set of instruction in  ROM that controls how hardware and OS communicate to each other.The process of putting BIOS on RAM is K/A SHADOWING
3. After that computer will perform POST( power on Self Test) ie a set of test for hardware.
4. After that computer look for OS,first in floppy drive than in hard drive.
5. For DOS/Window KERNEL loaded first,Now computer look for three files ie

• command langauge interpreter:key stroke 1and 0's
• config-sys-what device connected: ex -mouse,cd drive,scanner,
• Autoexec.bat :does optional task like running prog.

Computer have 3 parts ie

• Peripheral Parts ---Hardware
• Buses and Cables-interconnecting wires

• Data given and output required

Bays-A space where hardware ,floppy drive or CD ROM drive sit.

ROM chips,RAM chips and CPU are all plugged to small socket on motherboard.

AUXILRY CIRCUIT BOARDS K/A cards,can be plugged into larger extension sockets. These sockets holds CD-Rom. Sound Card,Fax Modem Cards.

Transformer – convert normal hose hold current to much lower voltage which the mother can use.

PERIPHERAL DEVICES:Hardware component ie Input devices, output devices ,storage,processing.

• INPUT DEVICES

1. Keyboard :
2. Digitizer:used to draw pictures /scteches images through cursor pen.
3. Mouse
4. Scanner:Use optical character recognization technique .Varies types ie Flatbed Scanner,Shetheld Scannner,Handheld Scanner,Drum Scanner.

• OUTPUT DEVICES :

1. Printer: two types -Impact and Non impact Printer.Impact printer is of 3 types ie Dot matrix,Line printer,Daisey Wheel Printer(can Print short Images on Papper or on Sheet).Non Impact printer is of 2  types ie Inkjet/Bubblejet Printer and Laser/page printer. (Plotter are used to draw high quality images of various colors and draws continuous lines).
2. Memory:Two kind of Memory ie

RAM

1. Instuction Disappears when computer turned off,
2. OS ,programme,Data Kept
3. faster than other storage
4. Little storage capacity

More RAM faster PC

ROM:

1. Instruction data not disappear when computer turned off
2. also K/A as primary storage
3. Have switches that are permanently set factory

• PROM(programmable Read only memory)- one time writable
• EPROM(Erasible Prograbble read only memory)-Erased by Ultravoilet light,reusale,most commonly used.
• EEPROM(Electricaly Erasible Prograbble read only memory)erased by high electric current,Not necessory to remove from PC for erasing ,reusable limited life.
• FLASH RAM-Part of EEPROM,erased at normal PC voltage ,constantly powered,used in Digital Camera,LAN switches.
• DRAM(Dynmic random Access Memory )Most common RAM,require to refresh after little intervels of for few millisecound for retaining data,use capacitor and transister for storage cells.Capciter losses electric charges quickly ,need to charge .Slower than SRAM.
• DRDRAM(Direct Rhambus DRAM)
• SDRAM(Synchronus RAM)
• SRAM(Static RAM) used as cache memory.

The Magnetic media storage is of two types ie

1. Primary Storage /Internal Storage:Store data which are in current use.
2. Secoundary sorage /Auxillary storgae:store data which are not in current use.Under secondary storage comes-

>Floppy disk drive

>Hard disk: invented in 1950,

no.of mettallic disc mounted on a spindle that rotate at speed of 3600-7200 RPM .

Huge storage.

Immovable

>CD-ROM-optical disc:most popular and least expensive device.

CD-ROM-read only

CD-R/W-read and write

DVD-Digital versatil disk/digital video disk:


Bit---------------------0 or 1
Nibble-----------------4 bit
Byte---------------------8 bit
KB(kilo Byte)------1024 bit
MG(mega byte)----1024 KB
GB(Gega Byte)----1024 MB
TB(Tera Byte)-----1024 GB
PB(Penta Byte)----1024 Tb
EB(Exa Byte)-----1024 PB

Processing Devices:has 3 unit ie

1. ALU(Arthmatic Logic unit):

Microprocessor :does some rough work during processing ,thiss space for rough is callled as Register

Memory on Motherboard -RAM,Cache,Primary and secoundary storage

Memory on Microprocessor-Register

Microprocessor and co-processor on mother board resides on motherboard.
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                                          Operating System(OS)

• OS interface apllication with mechine
• OS is system software,provide easy to use command to user,
• Ist operating system automated the loading,compiling and assembling also do job transition and job sequencing ,It was K/A Batch OS
• OS responsible for

1. controlling input and out put
2. directing flow of information to and from processor
3. when computer start from scratch at time of booting,OS is first things that is loaded.OS checks all memory ,display error in case of problem
4. Apllication software need OS to make hardware do what user desire.OS work in Back ground
5. It manage all files ,directeries access permission on the files .
6. It memory allotment when user open application.

Screen where instruction are inserted through keyboard is K/A Interface /front end,Interface is of two types ie

1. Commandline interface:non graphical Ex DOS
2. Graphical Interface :Images,textboxes,buttons ,command buttons,radio buttons.Ex Window.

Mac OS-OS 1 and 8.x/9.x,OS10.1,x

IBM OS-OS 2

UNIX,LINUX,WINDOW NT/200-used in mainfarme computer.

UNIX is most secured OS.

Types of OS on basis of User point of View

1-single Program Os-Only one user programme resides in memory at time.

EX-CP/M-for 8 bi micro-computer.

2-Multiprogramming OS-Multi programme stored in memory at same time,but one programme at a time is processed.

Memory managment is needed.

Paging is very popular memory managment.Main memory brakes into pages frame.Programme brakes into pages.

OS allocate 1 or 2 pages frames to pages (depending on the size of the page).Pages are brought into main memory as and when required so at time memory appears than its hardware capacity this illusion is caled as Virtual Memory and process called as demand paging.

3-Time sharing OS:Its type of Multiprogramming.

Several user residing in main memory and CPU switched B/w them rapidly .

CPU shared among several user prog.and each one allocated a fixed time K/a time sharing system

system have special device K/A Tuner

Prog.have to wait but CPU fully utilized K/A round robi Scheduling

Paging and dynmic paging technique used.

4-Multi-Processor Os: more than one processor with common memory

Allows parallelism ie several instruction has to be executed simultenously

:::

5-Virtual storage Os: incorporate demand paging for main memory.

Large and expensive.

6-Real Time OS : Used in Airtraffic control system,patient monitoring.

Have rapid response and reliable.

Commonly used OS

Windows: Microsoft,Graphical interface,expansion of MS-DOS,

Multi-tasking OS

from 4^th verion ie Window 95 its independent from MS-DOS

Window NT-used in Networking.

UNIX_-Devloped by AT and T Beu Lab in 1969

Not GUI type

Muti-programing ,multitasking,multiuser, cryptic,userfrandily,very secure,

2 agencies work for it -

1. Kernel-K-interect with mechine
2. Shell-interface B/W user and kernel.

OS/2:Devloped by IBM

for mainframe

32 bit

faster than DOS,suitable for multimedia

multitasking,networking

MS-DOS:version 3.2,4.0 etc

single user

non GUI

CP/M(control programme /micro-computer)most commonly used OS for 8 bit intel 8080 or Zilog microprocessor.

OS used in Mobile device

1. Ios:Apple
2. Window:Microsft
3. Android:Google,open source,Linux based
4. RIM:Blackbery
5. Web Os: from HP,devloped by PALM,Linux based
6. BADA:samsung
7. Linux:open source

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COMMON COMPUTER LANGUAGE:

Programming language is a medium through which instruction when given to computer makes computer follow them,

This sequence of instruction is called as Programme.

Different languges are


1-Pascal:Syntax-
surface form of any language.
Semantics-meaning of language.


2-C Language:

3-COBAL (Common business Language)

4-FORTAN(formulla Translator

5-Basics(Beginners all purpose symbolic instruction)

6-C++- objective oriented programming(opp)

7-Java-OPP

Mechine Language:Directly understood by computer

Only binary system used

not easy to understand

compiller-convert certain language to mechine languge

Every computer has its own binary code.

Assembly Language: 2^nd genration Language

low level languge

most appropriate for writing OS

High level language:have low tendency to produce bugs(errors),

Debugging-correction of error.

1^st Genration-0 1 binary digits.

2^nd genration-use symbolic names instead of just no.s

3^rd Generation-use words instead of just number and symbols.

Has syntex much easier to understand

high level language

Ex-c.c++ Java.java scripts,

4^th Genration -close to human language

used to access and include SQ2 and cold fusion ,among others

5^th Genration-used for neuronal network

form of artificial intelligence

Web languages used for creating webpages.

1. HTML-hypertext markup language
2. xml-extenseble markup language
3. Javscipts-for animation
4. VB scripts-visual basic sripts,Ex-Internet explorer
5. PHP-hypertext preprocessor
6. Java-

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SHAPES OF COMPUTERS

1-Supercomputer-most powerfull,largest,

perform 1 trillion calculation /Sec

need lots of power and cooling

expensive

used for scientific work

Ex-K-computer-Japan- speed 8.162 Pentaflops

Tiahe-1A -China-speed 2.57 pentaflops

Cray XT-5 Jaguar-USA-Speed 1.75 pentaflops

2-Mainframe computer:Largest commony used computer,

Used in Banking and insurance sector

Used where same data are access again anad again

used as server for www

computer terminal (Doesnt have CPU) wired to mainfame

Largest Mainframe EX IBM S/390-can support 5000 user simultanously

3-Minicomputer:Capabilties lies in B/W Mainframe and Midrange computer

Handle much more I/O(Input Output) than PC

can be used as web server

used in animation work

can attach 500 user simultanously

4-Workstation :lies in B/W Midrange and PC

have sophosticated software like CAM,CAD

OS used in it are UNIX,Window NT

Ex-SPARC(From SUN),IBM RS/6000

5-Personal computer invented in 1970,small and enexpensive

K/A microcomputer

single used

use microprocessor

First Pc Apple II,IBM PC

6-Net book-lightwt less than 6 pound

7-Laptop-fit in your lap

8-Handheld computer-PIN(Personal information manager)

PDA(personal digital assistant),Palmtop

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Connectivity
• OSI Refrence: International Standerd Organization
  Seven Layer model

Each layer perform single activity

1. application layer:Interface between computer and user
2. presentation Layer:Covert text into binary or encryptist,puts wrpper or header on data
3. session layer:Deciedes which rule/protocol followed for transmission.
4. Transport :assures correct transmission of data,receipent send acknowldgement to this layer
5. Network:segment data into packets.Network head started and role of Hardware start
6. Data Link: brakes packets in frames
7. Physical: encodes 0 and 1 to +,- voltage

• TCP/IP Refrence model: Internet was based on TCP/IP refrence model

It has following layers

1. Transport layer: same as OSI, Two protocol ,only one protocol work at a time.

a)TCP(Transmission control protocol) >reliable connection oriented protocol.

>Assures bytes stream (data from)one mechine to another without any error.

>divides data into packets and rejoin it at distination

>control flow of data.

b)UDP(user data gram protocol):>unreliable

>just transmit data

>no error or control flow handling

>used when time delivery is importent ,Ex Video confrencing.

2-Application layer:all higher level protocol

a)Telnet(virtual terminal Protocol)It helps user one mechine to log into distant mechine and work here.

b)FTP(file transfer protocol)

c)SMTP(simple mail transfer protocol) used in E mail

d)DNS(domain name system) mapping host on their net addresses

e)NNTP

f)HTTP-to fetch pages on www

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Networks:interconnection of computer/terminal/teliphone,

There are 6 types of networks

1-Mesh Topology:Every computer is connected to others.

Have high fault tolerence

expensive

2-star Topology : every node is connected to centrall node

server fails -network fails

easy to install,wire and troubleshoot

3-Tree Topology-One star topology connected to other via HUB

4-Bus Topology-

5-Ring Topology




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Security issue of Internet:is of following types

Insecurity:1)loss of missing data

2)data read by unauthorized PERSONAL

3)you may receive dirty data

solution :

1)Missing Data:least harmfil solution is retransmission

2)Unauthorized access:called as hacking

solution is called as access control mechanism ie

a)passoword varfication

b) encryption

3)Dirty Data: They are of folowing types

a)TROJANS:Programme appear normal but carrying destructive payload.

b)stealth Virus:a train virus that is the fastest in replication and relocation

c)Virus:is of following types

1>Boot Infecters:reside in boot secter,take complete control over system

2>System Infecters-destroy Operating system,attach to command .com file,slow down computer

3>exe infecter

solution is- ------ to dectet them before entry ie by firewall(check outgoing and incoming information) or by antivirus

---cure the infected portion

d)Worm:are similar to virus ,but they differ from virus in following points

.>It has capabilties to travel to another computer without human activites

.>It have capabilty of replication.