There are two basic types

IDE    (Integrated drive electronics)
SATA(Serial Advanced Technology Attachment)


                        Data stored  on HDD
heads write the data to the drive,and drivers often have multiple heads to speed up the tasks of reading to the disk.A track is the area that passes under the head during one rotation of the HDD.sector device the tracks in to smaller parts.these sector are bundled in groups called clusters. A concept that is  rarely used except when hard drive installation is that of cylinders.a cylinder on a hard disk drive is the space located heads at one time.

Hard disk Data transfer rate

3400rpm

4700rpm

5400rpm

7200rpm

new 10000rpm

  Capacity (.. 4GB-500GB-1TB..)

       

                                  

The CPU is the brain of any PC.The CPU works by taking data out of memory,processing it,and placing it back into memory.it is through memory that the other devices that make up the PC interact with the CPU.it may be helpful if you think of the CPU as an agent,spending its time going from one device to another,asking if its help is needed.if the processing job is completed this process explains why some time you can type a con type a commend and it see ms.take a while for the computer to respond The Cpu was processing another instruction,and took a,moment for it to go to the keyboard's memory location,retrieve your key stroke,determine what keystroke meant,and execute the instruction.


                             Cache memory

                                                
                      

                  

                    Intel,Asus,Msi,Asrock,Aopen,Gigabyte,Mercury,Biostar,Foxconn,Amd


                       

  Rom chip

The bios(basic input output system)on the mother board is contained in the ROM chip on the board,which contains the initial software drivers needed to get the system running


Rom chip manufactures
                              Awards,Phoenix,Ami,

                 
                            

             There are two method

peripheral devices -devices which are out side the system box
devices in the system box -devices in the casing of the pc


peripheral devices               Devices inside the system box
monitor                                 mother board
keyboard                              cpu
mouse                                   ram
printer                                  expansion cards
scanner                                cd/dvd drive
web cam                               floppy disk drive
                                             power supply
                                             data cables
                                             cooling fans

1.Identify components
2.check the power supply
3.check the motherboard display(ram,vga other )
4.fix the other components

O/S                                         File system

95                                             Fat12
98                                           Fat12,Fat16
2000                                       Fat16,Fat32
Xp                                          Fat32,Ntfs
Vista                                       Fat32,Ntfs
Win 7                                         Ntfs

Fat     :-Fle allocation table
Ntfs   :- New technology  file system

what is a virus ?                                


1.virus is a computer program                       
2.copies itself                                   
3.may do other damage
4.may modify system
5.may have obvious effect

virus symptoms

1.program takes longer than normal to load
2.less memory than usually available
3.file extensions or file attributes change
4.files constantly get corrupted
5.noticeable reduction in disk space

Best antivirus software
kaspersky,bit defender,avira, f-secure,norton,AVG
                                                  

AT                       12pin
ATX                     20hole
Micro ATX          20hole,4hole
Umicro ATX        24hole,4hole


                                                       

Simm(single inline memory module)
   30pin simm                       72pin simm

  16kb-2mb                          1mb-64mb

SD( Synchronous dynamic random access memory)

                             168pin

                         32mb-512mb  

Rimm(Rambus in-line memory module)

                             184pin
                           64mb-2gb

DDR (Double-Data-Rate ram)

                             184pin
                          64mb-2gb

DDR2
      
                             240pin 
                         128mb-4gb 

DDR3 

                             240pin
                        512mb-16gb


                                                             
              

Pin socket 423             1.2Ghz -1.5Ghz   merely
Pin socket 478             1.5Ghz -3.4Ghz    " "
Pin socket Lga 775       2.0Ghz -3.8Ghz   " "   
Pin socket Lga 1156     Core i3,Core i5    " "

The objective of this module is to give a basic knowledge about


          1.Functions of a computer
          2.Total computer system
          3.Types of computers


                                              1. Functions of a Computer
what is a computer ?
a machine that can follow instructions to process data in a desirable way and perform at least some operations without human intervention
                       there are three basic functions available on a computer
                                1.input
                                2.processing
                                3.output
INPUT
input is the first stage of computing,referring to any means that moves data(information)from the outside world into the processor or from one component of the computer to another..
             example:-any information entered into a computer is called as input


PROCESSING
processing is the second stage of computing.this is the actual manipulation of data by the computer..
             example:-the execution of program instructions by the computers central processing unit (CPU)transforms data into the information.


OUTPUT
output is the third stage of computing.all the input and processing in the world won't do us any good unless we can get the information back from the computer in a comprehensible and usable form.
            example:-the process of displaying or printing the results of processing operations is the output.

                                              2.Total Computer System

Total computer system consist of four main parts.
                               1.Hardware
                               2.software 
                               3.Liveware
                               4.Firmware
(Hardware)
 The physical devices of a computer system that can be touched or tangible are called computer hardware.

(Software)
A set of instructions (programs)that drive the hardware of a computer system.

(Liveware)
The person who operates the hardware through the software

(Firmware)
Also software which is stored inside the hardware
  example:-Boot strap program (which is loaded at the start up)






                                            3.Computer Hardware


Pc Hardware equipment involved in the function of a computer.computer hardware consists of the components that can be physically handled.based on the functions of the components are typically divided into three main categories
                       Input devices    :- mouse,keyboard,scanner
                       output devices  :- monitor,printer,speaker
                      storage devices :- hard disk,floppy.pen drive