Chapter 02 Computer Component

(Q#1) Define CPU and its ports? Also below the block diagram with functions.

The central processing unit (CPU) also called the microprocessor the processor or central processor is the brains of the computer. The CPU is housed on a tiny silicon chip. This chip contains millions of switches and pathways that help your computer make important decisions. The switches control the flow of the electricity as it travels across the miles of pathways. The CPU know which switches to turn on and which to turn off because It receives its instructions from computer program's. Programs are a set of special instructions written by programmers that control the activities’ of the computer. Programs are also known as software.

The CPU has two primary sections:

The control unit and the arithmetic logic unit.

Arithmetical and Logical Unit (ALU)

ALU is the part at CPU where arithmetical operation such as addition, subtraction, multiplication and division as well as logical operations such as comparison between two data’s are performed. The ALU includes a group of registers which hold the currently processed data. The registers are high speed volatile or temporary memory.

Control Unit CU

The control unit is the part of CPU where all computer resources are managed. It works like a traffic cop directing the flow of data between the components of the CPU and other devices. Control unit executes program instructions, it determines what operation perform first.

Functions of the CPU

·         Interprets the data and instructions.

·         Generates control signals.

·         Performs arithmetic and logic operations.

·         Produces the address bits needed by memory.

(Q#3)What is meant by secondary storage? Mention some secondary storage devices.

SECONDARY STORAGE

Secondary storage or secondary memory also referred as backing storage is used to supplement the capacity of main storage this memory stores a bulk of information. It is also called auxiliary storage or mass storage. The information stored in this memory is used by the CPU by first bringing it to main memory.

Example of secondary Storage devices:

Some Examples of secondary storage devices are as follows

1.      Magnetic Tape

2.      Magnetic Disks

3.      Mass Cartridge Systems

There are two types of secondary storage/backing storage access methods.

Sequential Access Storage

Access through sequential access storage is non addressable that is why an operator cannot refer directly to the contents of a particular storage location such as used with magnetic tape. This involves examining sequentially all beginning of the tape and continuing to search through all records until the desired information area is found.

Direct Access Storage

Direct Access Storage is addressable that is a given item can be selected from anywhere in storage by simply specifying the address where it is located direct access devices such as magnetic disks provide immediate access to individual records and do not require reading from the beginning of a tile to find a particular record.

(Q#4)What is Bus?

Buses are sets of wires or connectors used to transmit data/information from one place to another place inside the computer. There are three main buses in computer:

Types of Buses

1.      Address Bus

2.      Control Bus

3.      Data Bus

ADDRESS BUS

Address bus is a collection of wires connecting the CPU with main memory. It’s used to identify Particular Locations in main memory where data is stored.

CONTROL BUS

Control bus is a physical connection between the CPU and other devices within the computer.

DATA BUS

It is a communication route through which data can travel between the computer’s Central Processing Unit, memory, and peripheral.

(Q#5) Describe the function of ports in a computer? How many types of ports are generally preset in a computer system?

A system board with its processor and memory unit can work only when linked to input/output storage and communication devices to receive data and communicate results of processing. Peripheral devices such as a keyboard, mouse, monitor and a printer come with a cable are mtiltiple connector. To link a device to the PC you plug its connector into a receptacle called a port in much the same way you plug a lamp cord into a electrical outlet. A port is one of entry lines coming into the computer. A port provides a direct link to the microcomputers common electrical bus. There are two types of ports used in computer.

SERIAL PORT

A serial port provide connection or transmitting data one bit at a time. A serial port connects your computer to a device such as modem, which require two way data transmission, or to a device such as a mouse, which requires only one way data transmission. IBM compatible computers use either 9 pin or 25 pin connector’s tor their serial ports COM l, COMZ etc.

PARALLEL PORTS

A parallel port provides a connection for transmitting data eight bits at a time over a cable with eight separate data lines. Parallel transmission is fast because eight bits travel simultaneously. Parallel transmission is typically used to send data to the printer. The cable that connects two parallel ports contains 25 wires eight wire carry data and the remaining wires carry control signals that help to maintain ordinary transmission and reception. lBM compatible computers generally allow you to use up to three ports which are designated as LPTI, LPT2 etc.

(Q#6)What is memory? Define its types.

MEMORY: Memory is the storage device inside the computer where data/Information/Program reside There are' two types of Memory

Types of Memory:

1.      Internal Memory

2.      External Memory

Internal Memory

Random Access Memory RAM

This part of memory consists of blank chips and hence the computer can use it to store and retrieve (write and read) information during its processing. The information stored in RAM is volatile that is when the computer is shut down the stored information is lost.

Read Only Memory (ROM)

This part of memory contains permanently stored information. When the power is switched on ROM does not wash away. This information is available to a computer to read and process but not to be changed is kept on ROM. This information is stored on small pieces of memory chips before the computer is assembled.

External Memory

The Secondary Memory IS a nonvolatile, memory that is external to main memory of a computer. Its contents must first be copied into primary storage (Ram). It is also auxiliary memory.

(Q#7)What is the Mother Board?

MOTHERBOARD

It is a rectangular Card connecting the processor to the other hardware Microprocessor RAM and ROM chips are housed on the mother board. It contains many internal devices and drives. It was slots for other peripheral devices.

(Q#8) Define Register? How many registers are there in CPU?

A register is a type of volatile or temporary memory and is part of CPU. Data currently being processed is stored in registers. There are fourteen basic register shared by ALU and CU.

CHOSE THE CORRECT ANSWER

1.      CPU stands for:___________

a. Controlling Power Unit       b. Central Processing Unit    c. Central Processor Unit

2.      There are___________buses, namely

a.         Two, control bus, connecting bus                                          

b.         Three, address bus, data bus and control bus

c.         None of the above

3.      Bus is a set of__________that is used as a communication pat.

a. Wires          b. Processors               c. Register

4.      A port or interface that can be used for communication, in which only 1 bit is transmitted at a time is called_____________

a. Serial port              b. Parallel Port                      

c. Serial and Parallel port both transmit 1 bit            d. None of above

5.      _________port is reliable.

a. Serial           b. Parallel        c. Both are equally reliable    d. None of above

6.      __________is type of memory, which is permanent and retains data even the computer is turn off.

a. RAM            b. Primary Memory    c. ROM            d. External Memory

7.      Arithmetic logic unit of a computer system perform_________________

a. Logical decision                                          b. Arithmetic Calculation       

c. Simple Mathematical Calculation              d. Arithmetical & Logical Function

8.       1KB Byte= ___________Bytes.

a. 1024            b. 8                  c. 1G                d. 1M

9.      There are basically__________register.

a. Fourteen                 b. Eight                        c. Sixty five                  d. Seven

10.  There are___________typical components of CPU, namely

a. Two, arithmetic & logic unit and control unit

b. Three, ALU, CU and External storage

c. Two, arithmetic & logic unit and memory

FILL IN THE BLANKS

1.      CPU is the brain of computer.

2.      There are two major parts of CPU: ALU and CU

3.      ALU stands for Arithmetic logic unit

4.      Memory is the place to store data/ information/ programs.

5.      There are two types of computer memory: Internal memory and External Memory

6.      ROM is the abbreviation of Read only memory while RAM stands for Read Access memory

7.      Input devices are used to take data from user and supply it to the computer.

8.      Port are the places that are used to connect various external devices to the computer.

9.      Serial port is also known as male connector.