Lecture 8

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					INTRODUCTION TO COMPUTER                                        LECTURE 08


     HOW A COMPUTER PROCESS DATA

     There are two components that handle processing in a computer.
           i)     Central Processing Unit (CPU)
           ii)    Memory

i)   The CPU

     The CPU is the brain of the computer, the place where data is
     manipulated. In a microcomputer, the entire CPU is contained on a tiny
     chip called a Microprocessor.
     Every CPU has at least two basic parts.
            a)     The Control Unit
            b)     The Arithmetic and Logic Unit.

     a)    The Control Unit

           All the computers resources are managed from the control unit.
           Control unit works as a traffic cop, directing the flow of data. The
           CPU’s instructions for carrying out commands are built into the
           control unit.


                                    CPU

                                  Arithmetic
                                     And
                                  Logic unit


       Input                                                Output
                                 Control Unit
      Devices                                               Devices



                                Memory (RAM)



                              Storage (Hard Disk)




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PREPARED BY SADIQ A. BUGTI LECTURER BUITMS QUETTA
INTRODUCTION TO COMPUTER                                          LECTURE 08




      b)    The Arithmetic And Logic Unit

            As we know that the computer can perform only two types of
            operations, namely arithmetic operation and logical operations.
            Arithmetic includes addition, subtraction, multiplication and
            division. Logical operations include comparison such as
            determining whether one number is equal to, greater than, or less
            than another number. Also every logical operation has an opposite
            e.g. in addition operation “equal to” has “not equal to”.
            Now when the control unit encounters an arithmetical or logical
            instruction, it passes that instruction to the second component of
            the CPU, the arithmetic and logic unit or ALU. The ALU includes a
            group of registers, high-speed memory locations built directly into
            the CPU, that are used to hold the data currently being processed.
            For example the control unit might load two numbers from
            memory into the registers in the ALU, then it might tell the ALU to
            divide the two numbers or to see whether the two numbers are
            equal.
ii)   Memory
      Physically memory consists of chips either on the motherboard or on a
      small circuit board attached to the motherboard. This electronic memory
      allows the CPU to store and retrieve data very quickly.
      There are two types of built in memory permanent and non permanent.
      Some memory chips always retain the data they hold even when the
      computer is turned off. This type of memory is called non-volatile. Other
      chips in a microcomputer do lose their contents when the computer power
      is shut off, these chips have volatile memory.
             a)       ROM
             The data in this memory cannot be changed. In fact, putting data
             permanently into this kind of memory is called burning in the data,
             and it is usually done at the factory at the time of manufacturing.
             The data in this chip can only be read it cannot be changed so the
             memory is called read only memory (ROM).
             ROM contains a set of instructions, which ensure that the rest of
             memory is functioning properly, check for hardware devices and
             check for an operating system on the computer’s disk drives.
             b)       RAM
             The purpose of Random Access Memory (RAM) is to hold
             programs and data while they are in use. Physically RAM consists
             of some chips on a small circuit board. This memory has the
             capability to access each byte of data directly. This memory will be

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PREPARED BY SADIQ A. BUGTI LECTURER BUITMS QUETTA
INTRODUCTION TO COMPUTER                                      LECTURE 08


           available till our computer is on. If we shutdown our computer the
           data In this memory will be lost.
           RAM Technologies
           Many advancement in RAM technology have been made over the
           years. The following are the major types of RAM used in PC
           computers.
          First Page Mode (FPM) RAM
           FPM RAM is the oldest and least sophisticated type of RAM, Its
           still used in many PC’s available today.
          Extended Data Output (EDO) RAM
           EDO RAM is faster than FPM RAM and is commonly found in the
           fastest computers.

          Burst Extended Data Output (BEDO) RAM
           BEDO RAM is very fast RAM and is supported by a limited
           number of CPU’s manufactured by VIA.
          Synchronous Dynamic RAM (SDRAM)
           SDRAM delivers burst of data at very high speeds (up to 100 MHz),
           which provide more data to CPU at given time than older RAM
           technologies. SDRAM is supported by popular type of RAM on the
           market today.




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PREPARED BY SADIQ A. BUGTI LECTURER BUITMS QUETTA

				
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