Fundamentals of a computer system Flashcards
What is a computer?
An electronic device which processes data according to given instructions and produces output
What are the five features of a computer?
Speed Accuracy Efficiency Versatility Storing and retrieving
Explain accuracy of a computer
It provides accurate output
Explain efficiency of a computer
It doesn’t become tired
Explain the versatility of a computer
It can be used to perform many tasks simultaneously
Explain the storage of a computer
It can be used to store a lot of data in a small space
What are the two ways by which computers are classified?
By physical size and technology
What are the four ways computers are classified according to physical size?
Super computers
Mainframe computers
Mini computers
Micro computers
What are super computers?
Large, expensive, rare and powerful computers
Where are super computers used? (3)
NASA
Large scale businesses
Military purposes
What are mainframe computers?
Smaller, less expensive and less powerful computers when compared to super computers
Where are mainframe computers used? (2)
Large scale businesses
E-businesses
What is a special place where mainframe computers are used?
Online transactions
What are mini computers?
Smaller, less expensive and less powerful computers when compared to mainframe computers
What is another name by which mini computers are called?
Common purpose computers
How are mainframe computers used?
Users connect to the central computer through terminals
What are the special features of mini computers?
Easy to use
Few users connect to the central computer through terminals
Where are mini computers used?
Medium scale institutions
What are micro computers?
Small computers meant for personal use
Name a few examples of micro computers (3)
Laptops
Handhelds
Smartphones
What are the two ways computers are classified based on their technology?
Analog and digital computers
What are analog computers?
Computers which use analog signals
Give a few examples for analog data (1-3)
Environmental parameters such as speed, pressure temperature
Give a few examples for analog computers (2)
Speedometers
Meteorological machines
What are digital computers?
Computers which use digital signals
What are hybrid computers?
A combination of analog and digital computers
What are the main functions of a computer?
Input, process, store data and output information
Computer system diagram (Page ?)
Page 36
Explain the process of a computer system
Data and instructions fed via input devices are sent to the primary memory and then sent to the CPU. Processed data stored in the primary memory is then sent as information to the output devices. The data to be stored is sent to the secondary storage. The control unit sends control signals to all devices. When a program is executed relevant data and instructions are sent to the CPU
What does the control unit do?
It sends signals to all devices
What happens when a program is executed?
Relevant data and instructions are sent to the CPU
What are input devices?
The devices used to feed data and instructions into the computer
Name a few examples for input devices (5)
Keyboard Pointing devices Media input devices Scanners Microphones
What are the types of keys found on a keyboard? (5)
Typing, function, special, control and numeric keys
What are standard number of keys on a keyboard?
101-108 keys
Give a few examples for pointing devices (4)
Mouse
Touch screen
Joystick
Light pen
Where are light pens used?
In Computer Aided Designs (CAD)
How do scanners work?
They emit laser beams which convert documents to digital data
Give a few examples for scanners (6)
Flatbed scanners Bar code readers Magnetic ink character readers (MICR) Optical character recognition devices (OCR) Automated teller machines (ATM)
What are the three different types of output?
Soft copy
Hard copy
Sound
Give an example for a device which outputs soft copy
Screens
Give another name by which monitors are called
Visual Display Unit (VDU)
What are the three different types of monitors?
Cathode Ray Tube (CRT)
Liquid Crystal Display (LCD)
Light Emitting Diode (LED)
Explain how LCD displays work?
They utilize two sheets of polarizing material with a liquid crystal solution between them
Where are LEDs used?
In symbols, billboards and name boards
Why are multimedia projectors used?
To get information to a wide screen so that several people can view it simultaneously
What is hard copy?
Tangible output of a computer system
Give an example for a device which produces hard copy
Printer
What are the two main types of printers?
Impact and non impact printers
Name two impact printers
Dot matrix printers
Line printers
Name three non impact printers
Laser printers
Bubble/ink jet printers
Thermal printers
What are impact printers?
Printers that have a head or a needle which strikes against an ink ribbon to make marks on papers
What are the features of impact printers? (2)
Noisy
Cheap
Why are impact printers used in shops?
Because their ink ribbon is cheap
What is a special feature of line printers?
Ability to print 3000 lines per minute
What are the features of non impact printers? (3)
Quiet
Quick
Expensive
How do laser printers work?
By applying the toner in the cartridge on paper
How do bubble/inkjet printers work?
The ink is deposited on paper via small nozzles
What are the common places where thermal printers are used? (3)
In ATMs, receipts and label printers
How do plotters work?
By moving a pen on paper
Where are plotters used? (2)
Architectural designs
Town plans
What is a CPU (Central Processing Unit)?
The brain of a computer system
What does a CPU do?
Manage the operating system and application software
What are the main components of a CPU? (3)
Arithmetic and Logical Unit (ALU) Control Unit (CU) Memory registers
What does the ALU do?
Perform mathematical and logical functions
What does the CU do?
Controls all devices
What do the memory registers do?
Temporarily stores data related to the ALU
What is unit used to measure the clock speed of a computer?
Hertz (Hz)
What are the two main types of memory in a computer?
Main and secondary memory
What are the two main components under main memory?
Random access memory (RAM)
Read only memory (ROM)
What is primary memory?
Memory that can be directly accessed by the CPU
How is RAM called based on it’s memory?
Volatile memory
What are the features of RAM? (2)
Data will be lost when the computer loses power
Both read and write capable
What is the function of RAM?
To store data from input and output devices
How is ROM called based on it’s memory?
Non volatile memory
What is the function of ROM?
It holds the BIOS of the computer
What is BIOS (Basic Input Output System)?
A list of commands needed to boot up the computer
What is cache memory?
The mediator between the CPU and primary memory
How does cache memory work?
First it is checked by the CPU for data to processed. If such isn’t found it is collected from RAM
Cache memory diagram (Page ?)
Page 47
What is secondary memory?
The device which stores data permanently
What are the different ways it is called? (2)
Secondary storage
External storage
What are the two kinds of secondary memory?
Internal and external secondary memory
Why is secondary memory called non volatile memory?
Because it’s memory is not erased when it loses power
Secondary memory diagram (Page ?)
Page 47
What are magnetic media devices?
Devices where data is stored using magnetic field
What are some examples for magnetic media devices?
Hard disk drive
Magnetic tape
Optical media
What is the range of capacity of a hard drive?
250GB-4TB
What are the seven components of a hard drive?
Platter Spindle Head Actuator arm Actuator Power connector IDE connector
What is the platter?
A metallic disk on which data can be stored on both sides using magnetic media. There can be multiple of them.
What does the spindle do?
Holds the platter and rotates it
What does the actuator arm do?
Enables reading and writing of data from any part of the platter
What does the head do?
Reads and writes the magnetic data on the platter
What does the IDE connector do?
Transmits data to the platter
What is the actuator?
The device which moves the arm via a motor
Where are magnetic tapes used?
Server computers
What is optical media?
A device where data stored digitally is read and written by a laser beam
What are the different types of optical media?
CD-ROM (Compact Disc- Read Only Memory)
CD-R (Compact disk- Write once)
CD-RW (Compact Disk- Re-writable)
DVD-ROM (Digital Versatile Disk- Write once)
DVD-R (Digital Versatile Disk- Write once)
DVD-RW (Digital Versatile Disc- Rewritable)
Blue ray Disc R (BD) (Recordable)
Blue ray Disc RE (Recordable Erasable)
Blue ray 3D
What is the capacity range of a CD?
600-900MB
What is the capacity range of a DVD?
4.7-9.4GB
What is the capacity range of a blue ray?
25-128GB
What are solid state drives?
Storage devices which do not contain moving parts
What are some examples of storage devices? (2)
USB drive
Memory card
Why are USB drives popular?
They are portable and fast
Where are memory cards used?
In digital cameras, mobile phones, gaming devices
What are ports?
The interface which connects computers to other devices
What are the ports found on a motherboard?
PS/2