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