HARDWARE FUNDAMENTALS                         

  Types of computer memory :

   ROM : this form of memory contains programs

  which do not changed.

  EPROM: is a special type of ROM which can be

  programmed by the user , its contents can also

  be erased by exposing it to ultra- violet light .

  EEPROM: another type of ROM which can be

  programmed by the user, it contents are erased

  by applying a specific voltage to one of its input

  pins .

  RAM: this memory is used to store data and

  applications programs, this means the contents

  disappear when the power to the system is turned

 off, and there ere two types of RAM used in the pc

•   Dynamic                  

•   Static

  HARDWARE :

  The hardware, it consists from :

  1) central processing unit .

  2) Arithmetic and logic unit .

  3) control unit .

  4) main memory .

  5) secondary memory.

 6) input and output  devices.

 the central processing unit ( cpu ):

  the cpu is the chip which acts as a control center 

   for all operations . It executes a program which

  are contained in the memory section .

    Basic operations involve

•   the transfer of data between itself and the memory section

• manipulation of data in the memory section or stored internally

• the transfer of data between itself and input / output devices .

  CACHE MEMORY:

  cache memory is high speed memory which  interfaces between the processor and the system memory .

  BUS INPUT / OUTPUT:

 The I/O bus is the interconnection path between the processor and I/O devices (including memory).  the bus is divided into three main sections

• Address  :the address bus is used by the processor to select a specific memory location .

• DATA: the data is used to transfer data between the processor and memory devices.

• CONTROL: the control bus is like traffic signals , it provides timing ,clock and directional signals for each operation .