Monday, 22 August 2016


Explain the functions of the CU and ALU in the CPU of a computer.

The characteristics of the CU or control unit are as follows:

- This part of the of the CPU is the one that is in charge of all the operations being carried out.

- It is responsible to direct the system to execute instructions.

- It helps in communication between the memory and the arithmetic logical unit.

- It also aids in the loading of data and instructions residing in the secondary memory to the main memory as required.

The characteristics of the ALU are as follows:

- The ALU is responsible for performing all logical and arithmetic operations.

- Some of the arithmetic operations are as follows: addition, subtraction, multiplication and division.

- Some of the logical operations are as follows: comparison between numbers, letter and or special characters.

- The ALU is also responsible for the following conditions: Equal-to conditions, Less-than condition and greater than condition.

Difference b/w app software and system software

Operating System is the System Software that makes the Computer  work. We can say that an Operating System (OS) is Software that acts as an interface between you and the hardware. It not only contains drivers used to speak the hardware's language, but also offers you a very specific graphical user interface (GUI) to control the computer.
An OS can also act as an interface (from the hardware) to the other software. A complex OS like Windows or Linux or Mac OS offers the services of an OS, but also has applications built in. Solitaire, Paint, Messenger, etc. are all applications
Application software is the software that you install onto your Operating System. It consists of the programs that actually let you do things with your computer. These Applications are written to run under the various Operating Systems.
These include things like your word processing programs, spread sheets, email clients, web browser, games, etc. Many programs, such as most of the Microsoft Office suite of programs, are written in both Mac and Windows versions, but you still have to have the right version for your OS.
 For example - Tally for Accounting, MS-Word for Word Processing etc.
So, the Operating system of a Computer is the Software that allows the Computer work. It provides the framework under which the Applications run. An operating system is the type of Computer system you have such as Window XP or Window 95, 98, Mac, etc.
The Applications are the Software that actually allows the user to do something with the Computer. Without the applications, all you can do is change settings and navigate among the folders. You can purchase its CD from a software company or download from a software company’s web site.
Examples of System Software are - Operating Systems, Language Translators etc.


    Explain what do you understand by registers, briefly explain the various types of registers.

    - Registers can be considered to be special purpose memory which reside within the CPU.

    - The registers are high speed temporary memory used to help the CPU get access to data and instructions quickly and effectively. There are various type of registers such as Instruction register, Status register and data register.

    - The instructions register is responsible for the storage of the of the instructions that are being currently executed.

    - The status register is used to keep a tab of the status operations of the arithmetic logical unit.

    - The data register is used to store information or data that is to be processed, it is also used to store information or results that have been derived from a process.

    data representation

      What are the different ways in which data can be represented?

      There are three ways in which data can be represented namely Bit, Byte and Word:

      - Bit: This is also the short name for binary digits. By being binary it means that BIT can only have two values zero and one. A characteristic of BIT is that it can never be empty. Zero implies a power off state whereas one means on state.

      - Byte: A byte is a collection or group of 8 bits. A byte can store a single character which can either be an alphabet, a number or a special character. The byte is generally used to measure the storage capacities.

      - Word: The number of bits that a cpu possess indicates the power of the computer. It also indicates how many number of bytes are present. In today`s date most computers can handle 32 or 64 bit length.

      cache memory

        What is cache memory?

        It is a temporary memory storage area which helps to speed up data transfer within a computer. A Microprocessor looks for the data in the Cache memory as the data transferred Cache is much faster. If the data is not found in the cache, the CPU looks for it in the memory.

        The following are two types of Cache-
        i. Internal or Level 1: In this, the Cache is built into the Microprocessor.
        ii. External or Level 2: In this, the Cache is built on a separate chip.

        The Internal Cache is the fastest but it is very expensive.


          What do you mean by RAM?

          In RAM or Random Access Memory, Data can be accessed randomly. There are two types of RAM-

          - Static RAM: It retains its contents with the help of CPU. It is faster and more expensive than Dynamic RAM. It is generally used for Level 2 cache.

          - Dynamic RAM: It cannot retain its contents if not continuously refreshed by the CPU. Its types are- 
          i. Synchronous DRAM: It is the faster type of DRAM, used in modern and more advanced systems.
          ii. Rambus DRAM: It is faster than Synchronous DRAM and is expected to become more commonly used.

          CPU problems

            Are there any problems that the CPU faces? Have any measures been taken to make it more efficient?

            Although the CPU needs only a few parts to do its job, it has been modified to 
            increase its performance. The enhancements are made in order to process data faster. 

            - One of the weaknesses of the basic CPU was that it was not doing any processing during the time that it fetches an instruction from the computer memory. 
            To reduce this, a memory storage area was created inside the CPU called Cache or 
            L1 type Cache. The Cache is very fast, and is used to store information that the CPU 
            needed to access the most. Level 2 Cache was also developed.

            - Now that the CPU has to wait much less for the data to be processed, the speed at which the data can be processed had to be enhanced. To do this, multiple ALUs 
            (Arithmetic Logic Unit ) were placed on the CPU, so that many more calculation was done each clock cycle.

            - In addition, the FPU (Floating Point Unit) was added. The FPU is similar to the ALU, except that it is more advanced. It can handle extremely large and extremely small numbers, allowing greater processing speeds. Also, it can simultaneously process multiple graphics and sounds at a time.