Wednesday, April 3, 2013

Device of the processor and its appointment

Description and purpose of processors
    Actually that we call today the processor, it is correct to call the microprocessor. The difference is and is defined by a type of the device and its historical development.

    The first processor (Intel 4004) appeared in 1971.

    Externally represents a silicon plate with millions and billions (today) transistors and channels for passing of signals.

    Purpose of the processor is an automatic implementation of the program. In other words, it is the main component of any computer.

Processor device
    Key components of the processor are the arithmetic-logic device (ALD), registers and a control unit. ALU will execute the main mathematical and logical operations. All calculations are made in binary notation. Coherence of work of parts of the processor and its communication with others depends on a control unit (external for it) devices. The current team, basic, intermediate and final data (result of calculations of ALU) are temporarily stored in registers. Word length of all registers is identical.

    The cache of data and teams stores often used data and teams. The address to a cache occurs much quicker, than in random access memory therefore, the it is more, the better.

Operation of the processor
     The processor under control of the program being in random access memory works.

    (Operation of the processor is more difficult, than it is represented on the scheme higher. For example, data and teams get to a cache not at once from random access memory, and via the block of preliminary selection which isn't represented on the scheme. Also the decoding block which is carrying out transformation of data and teams in a binary form, only isn't represented then with them the processor can work. )

     The control unit in addition is responsible for a call of the next team and definition of its type.

    The arithmetic-logic device, having obtained data and team, carries out the specified operation and writes down result in one of free registers.

    The current team is in specially for it the taken-away register of teams. In the course of work with the current team value of the so-called counter of teams which indicates now the following team (if increases, of course, there was no transition or stop team).

    Often team represent as the structure consisting of record of operation (which is required to be executed) and addresses of cells of basic data and result. To addresses specified in team data undertake and are located in usual registers (that is not in the team register), the turned-out result too at first appears in the register, and then moves to the address specified in team.

Processor characteristics
   Clock frequency of the processor is measured today in gigahertzes (GHz), Earlier was measured in megahertz (MHz). 1MHz = to 1 million steps a second.

    The processor "communicates" with other devices (random access memory) by means of tires of data, the address and management. Word length of tires is always multiple 8 (clearly why if we deal with bytes), floatingly during historical development of the computer equipment and it is various for different models, and also it isn't identical to the tire of data and the address tire.

    Word length of the tire of data speaks about what amount of information (how many byte) can be transferred for time (for a step). The maximum volume of random access memory with which the processor can work in general depends on word length of the tire of the address.

     The capacity (productivity) of the processor influence not only its clock frequency and word length of the tire of data, also importance has volume a cache memory.

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