Introduction To Computer Science

Question 1

Secondary storage

Answer 1

The devices that are used to PERMANENTLY store your programs or work on. They are NON-VOLATILE (they don’t lose data when power is off).

Question 2

A computer system

Answer 2

INPUT—>PROCESS—>OUTPUT
| |
STORAGE

Question 3

Magnetic hard disk drive

Answer 3

Is a magnetised, rigid, plate or stack of plates with heads to read the platter as it spins around

Question 4

Magnetic hard disk drive

Advantages

Answer 4

Low cost
High capacity
Reliable

Question 5

Magnetic hard disk drive

Disadvantages

Answer 5

Bulky
Heavy
Fragile(moving parts)
Not portable

Question 6

What are the two types of optical disks

Answer 6

CD-ROM or DVD-ROM

CD-RW or DVD-RW

Question 7

What does CD and DVD stand for

Answer 7

CD=Compact Disc

DVD= Digital Versatile Disc

Question 8

What is the difference between CD-ROM and CD-RW

Answer 8

CD-ROM cannot be written but CD-RW can. CD-ROM holds more information than CD-RW. CD-RW stands for Compact Disc ReWriteable ,however, CD-ROM stands for Compact Disc Read Only Memory

Question 9

Optical Disc’s

Answer 9

Work by bouncing light from a laser onto the surface of the disc. Data is stored using raised and un-raised areas on the discs surface. These reflect the light differently.

Question 10

Optical Disc

Advantages

Answer 10

Light
Portable
Cheap
Thin

Question 11

Optical Disc

Disadvantages

Answer 11

Fragile
Not a lot of capacity
Scratch easily

Question 12

Flash memory

Answer 12

Flash memory is a form of Electronically Erasable Programmable Read Only Memory (EEPROM). Flash memory is found in Solid State Drives(SSD), USB memory sticks and memory cards

Question 13

Solid State Drive

SSD

Answer 13

An electric current is used to force electrons through a barrier to trap them in a layer in the other side. This “flash” of electric current gives the memory its name.

Question 14

Flash memory

Advantages

Answer 14

Fast access
Portable- Small, Light
Robust (no moving parts)
Reasonable cost for low capacity

Question 15

Flash memory

Disadvantages

Answer 15

Easily cost
Lower capacity than magnetic hard disk drives
More expensive than hard disk drive (SSD)

Question 16

Cloud storage

Answer 16

Cloud storage is a cloud computing model in which data is stored on remote servers accessed from the internet or “Cloud”

Question 17

RAM

Answer 17

Holds programs that are currently being used by the processor and any associated data (such as documents you are currently working on). RAM is volatile

Question 18

ROM

Answer 18

Holds instructions and data that the computer needs to start up when it is first turned on. These are called the BOOTSTRAP or the BIOs (Basic Input Output System). ROM is non-volatile

Question 19

ROM qualities

Answer 19

Stores is instructions required to start up the computer
Non-volatile- doesn’t need power to retain data
Read-only contents cannot be changed

Question 20

RAM qualities

Answer 20

Volatile- data is lost when power is off
Contents can be changed at anytime
Stores programmes and data that are currently being used by the processor

Question 21

CPU- Central Processing Unit

Answer 21

Carries out all processing inside the computer.A processors job is to fetch, decode and execute instructions.

Question 22

The FETCH-EXECUTE-DECODE Cycle

Answer 22

Instructions are FETCHED from the main memory. The instruction is DECODED to find out what processing to do. The instruction is EXECUTED.

Question 23

Factor effecting processing speed 
Clock speed ( measured in GHz)

Answer 23

The faster the clock speed, the faster the processor BECAUSE it can execute more instructions per second than a processor with a lower clock speed

Question 24

Factor effecting processing speed

Size of cache memory

Answer 24

The larger the size of the cache memory, the faster the processor BECAUSE it is quicker to fetch frequently used data from the cache memory compare to main memory

Question 25

Factor effecting processing speed

Number of cores

Answer 25

The more cores, the faster the process BECAUSE multiple cores mean multiple instructions can be executed at the same time (one per core)