1.The functional components of a computer system are: (8 Marks)
a)Input
b)Central Processing Unit
c)Storage
d)Output
By the use of a well labeled diagram, show the electronic components of a computer
2. Briefly describe the function of the Main Memory unit in a CPU (3 Marks)
Main Memory refers to physical memory that is internal to the computer. The word main is used to distinguish it from external mass storage devices such as disk drives. Another term for main memory is RAM.
The computer can manipulate only data that is in main memory. Therefore, every program you execute and every file you access must be copied from a storage device into main memory. The amount of main memory on a computer is crucial because it determines how many programs can be executed at one time and how much data can be readily available to a program.
3.List down AND explain the purpose of the following registers (4 Mks)
a)Memory Address register
The Memory Address Register (MAR) is a CPU register that either stores the memory address from which data will be fetched to the CPU or the address to which data will be sent and stored.
In other words, MAR holds the memory location of data that needs to be accessed. When reading from memory, data addressed by MAR is fed into the MDR (memory data register) and then used by the CPU. When writing to memory, the CPU writes data from MDR to the memory location whose address is stored in MAR.
They store memory addresses which tell the CPU where in memory an instruction is located.
b)Instruction register
instruction register is the part of a CPU's control unit that stores the instruction currently being executed or decoded. In simple processors each instruction to be executed is loaded into the instruction register which holds it while it is decoded, prepared and ultimately executed, which can take several steps.
A hardware element that receives and holds an instruction as it is extracted from memory; the register either contains or is connected to circuits that interpret the instruction (or discover its meaning). Also known as current-instruction register.
4.List down three buses found in a System Unit
Address bus - ( also Memory bus)Transport memory addresses which the processor wants to access in order to read or write.It is a unidirectional bus.
Data bus - Transfers the instructions coming from or going to the processor.It is a bidirectional bus.
Control bus - (Also command bus)Transports orders and synchronization signals coming from control unit and traveling to all other hardware components. It also transmits response signals from the hardware. It is a bidirectional bus.
5.State two factors that determine the computers’ operating speed (2 Marks)
RAM Capacity - The more RAM capacities the faster the operation. RAM (Read Only Memory) hold data and instructions while the computer is running making it easier for the computer to access data and instructions required at hand. The CPU does not have to wait alot for data transfer.
Data bus width - The wider the width the faster the operation.Computers that have 64 bit(bus width) are faster in operation as compared to computers that have 34 bit processors.
Clock speed - Measure of how many instructions the processor can execute in one second.( Measured in Megahertz or Gigahertz) The quicker the rate faster the operation of a computer.
6.Explain two main branches of software (4 Marks)
System softaware
System software consists of programmes that coordinates the activities of hardware and other programs. System software is designed for a specific CPU and hardware class. The combination of a particular hardware configuration and operating system is called a computer platform. These programmes manage the “behind the scenes” operation of the computer.
Examples
§ Operating systems - This are programs that manages the computer resources.
§ Utility Programmes - Utility programmes often come installed in computer systems or packaged with operating systems. Utilities can also be purchased individually. Utility programmes perform useful tasks, such as virus detection, tracking computer jobs and compressing data.
§ Language processors – Compilers and interpreters
Application software
Application software is computer software designed to help the user perform singular or multiple related specific tasks.
These are special written programs to perform specific tasks in real life.Application software refers to any program designed to be carried out by a computer to satisfy a user's specific need.As the name suggests 'Application' this type of software is limited by application. For example the software we use for drawing cannot be used for our calculations and vise versa.
Examples include enterprise software, accounting software, office suites, graphics software and media players,spreadsheets,Word Processors,Presentation,Database amongst others. Many application programs deal principally with documents.
7.Suppose you are provided with a computer system and asked to carry out the following tasks, indicate which program(s) or application programs you are going to use to accomplish each task. (6 Marks)
a)Typing a memo - Microsoft Word, Word Star, Word Perfect
b)Preparing advertisements - Microsoft PowerPoint
c)Creating tables,queries,forms and reports -Microsoft Access,Oracle,Dbase,FoxPro
d)E-mailing - Internet Explorer, Mozilla Firefox, Opera mini
e)Installing a brand new computer - Windows XP, Windows 7, Linux
f)Designing menus - Microsoft Publisher
QUESTION 2 (40 Marks)
1.List two advantages and two disadvantages of computers (2 Marks)
Advantages
Speedy processing
Accuracy and reliability
Compact storage
Secrecy
Versatility - Can do the same thing over and over without being worn out.
Consistency - Gives the same results given the same instructions
Disadvantages
They are expensive to buy
Cuts down employment - leads to unemployment
Needs technical know how to operate
Health hazard -eye problems, backaches etc
Define: (10 Marks)
a)BIT - The smallest and the most fundamental unit of data storage. Usually 0,s and 1,s.
b)Byte - A combination of eight bits
c)Bus - Communication channels found in the system unit of a computer to enhance communication between components of a computer.Also, paths between the components of a computer located on the motherboard to enhance communication in the CPU.
d)Software - Software is detailed step-by-step sequence of instructions which guide computer hardware.
e)Program - Sets of instructions designed and directed towards performing a particular task.
f)Icon - Graphical representations of computer programs.
g)Operating System -This are programs that manages the computer resources.
h)Register - Additional temporary storage locations that are on the CPU itself.The registers are controlled by the control unit and are used to hold and transfer data and instructions, and perform the logical and arithmetic operations.
i)Virus - These are programs that are designed with an ill motive by a malicious,mischievous individual with an intention of causing harm to your computer.
j)RAM - Temporary memory location within the CPU that holds data and instructions while the computer programs are running. It is a volatile memory and must be powered whenever in use.
2.Describe at least four types of operating systems outlining examples of each
(8Marks)
1.Real-time operating systems (RTOS)
Used to control machinery, scientific instruments, and industrial systems. In general, the user does not have much control over the functions performed by the RTOS. Examples of real-time operating systems are Chimera, Lynx, MTOS, QNX, RTMX, RTX, and VxWorks
2.Single-user, single task operating systems
Allow one user to do one thing at a time. And example of a single-user, single task operating system is the operating system used by personal digital assistants (PDAs), also known as handheld computers, Ms Dos.
3.Single-user, multi-tasking operating systems
Allow a single user to simultaneously run multiple applications on their computer. This is the type of operating system found on most personal desktop and laptop computers. The Windows (Microsoft) and Macintosh (Apple) platforms are the most popular single-user, multi-tasking operating systems. Example Windows XP,
4.Multi-user operating systems
Allow multiple users to simultaneously use the resources on a single computer. Unix is an example of a multi-user operating system.
3.Give a brief account on how data is represented in (5 Marks) computers
Computers represent information in binary code, written as sequences of 0s and 1s. Each binary digit (or "bit") may be stored by any physical system that can be in either of two stable states, to represent 0 and 1. Such a system is called bistable. This could be an on-off switch, an electrical capacitor that can store or lose a charge, a magnet with its polarity up or down, or a surface that can have a pit or not. Today, capacitors and transistors, functioning as tiny electrical switches, are used for temporary storage, and either disks or tape with a magnetic coating, or plastic discs with patterns of pits are used for long-term storage.
It takes a certain number of bits to make one byte (normally eight), and when bytes are grouped together at a single address they make up a word in the computer's memory. When data is recorded on some type of magnetic storage medium, such as disk or tape, it is normally organized by bits, characters (bytes), fields, records, and files.
4. Classify computers according to their processing mode and briefly describe on each ( 3 Marks)
Analog Computers - computers that uses the continuously-changeable aspects of physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved.Process continuous data. i.e representation of temperature
Digital computers -computers that perform calculations and logical operations with quantities represented as digits, usually in the binary number system. 0s and 1s.Process discrete data.
Hybrid computers - Computers that are capable of processing both the discrete data and continuous data. They combine analog and digital technology for data processing.
