Informational Communication Technology

Laboratory work 2

Name: Madina Shukur BA16/351

In this laboratory work, you will learn about computer components.  First, you will learn about how the computer processes information and how memory works. Then you will learn about how data can be moved among components inside and outside the system unit. You will also become familiar with different media for storing data. By the end of this lab, you should have a basic understanding of how a computer works. Understanding this lab will also help you become an informed consumer of computer equipment.

Processor

A computer's processor is usually referred to as the microprocessor due to its size, which is about the size of your fingernail. A microprocessor processes all the instructions given to the computer (for example, add two numbers, execute program instructions, or print documents). Physically, the microprocessor is a single chip known as an integrated circuit (IC). Each chip is made out of silicon and it contains millions of transistors packed onto a chip. Processor consists from CPU, L1, L2.

Performance of processor

The rate at which instructions are processed is controlled by an internal clock, also known as the system clock. The internal clock sends pulses at a fixed rate to synchronize all computer operations. The unit of measure for cycles per second is the hertz (Hz). One Hz means one cycle per second, one kHz (kilohertz) means one thousand cycles per second, and one MHz means one million cycles per second. Computer clock cycles are closely related to the execution of instructions. So, a 3 GHz Pentium 4 machine can execute more instructions per second than a 2 GHz Pentium IV machine. The greater the hertz, the faster the execution speed.

Components of processor:

• CPU

A central processing unit (CPU) is the electronic circuitry within a computer that carries out the instructions of a computer program by performing the basic arithmetic, logical, control and input/output (I/O) operations specified by the instructions. 

• Level 1 (L1), Level 2 (L2)

cache memory or primary cache memory is located on the CPU to provide the CPU with the fastest access to data. There is also a slower cache, the Level 2 (L2) cache memory or secondary cache, located between the RAM and the CPU (sometimes on the CPU). If data cannot be found on either cache, it will be retrieved from RAM. Relative to the physical distance between the CPU and storage areas for data and instructions, data is retrieved more quickly from the L1 cache, then the L2 cache, and then the RAM.

Types of Memory

Memory components include the main memory, also known as RAM, and the memory components needed to boot or start a computer, ROM and CMOS. Each of these memory components will be discussed in the following pages.

RAM

RAM (random access memory) is a temporary holding area for both data and instructions. It is also referred to as main memory. RAM stores data and instructions needed to execute programs. The data in RAM is lost when the computer is turned off. In contrast to accessing data serially, searching sequentially for the data to be retrieved, data in RAM can be accessed directly via its address. Therefore, RAM stands for "random access memory." Random access is similar to accessing a song on a CD directly via its track number, as opposed to finding a song serially on tape.

ROM

Read-only memory (ROM) is programmed with data hard-wired when it is manufactured. Data and instructions on a ROM are permanent, or nonvolatile, which means they are not lost when power is turned off. Why is ROM needed when RAM enables all the memory operations necessary for a computer? Because data in RAM is lost when the computer is turned off, some instructions are needed for the CPU to start or boot the computer when the computer is first turned on. Therefore, ROM contains a set of instructions that is needed to start the computer. These instructions tell the computer how to access the hard disk, find the operating system, and load it into RAM. Then RAM stores all subsequent instructions to be executed by the CPU.