GCSE

Question 1

Control unit

Answer 1

• manages data flow inside the CPU (to registers, ALU, cache) and outside the CPU (to main memory and input/output devices)
• decodes instructions
• it controls and coordinates the activities of the CPU in the fetch-decode-execute cycle

Question 2

HDDS pros + cons

Answer 2

• High capacity —> up to several TB
• inexpensive —> compared to SSDs
• less durable than SSDs —> contain moving parts —> not so robust —> if dropped
• can be affected —> by magnetic fields + heat —> so requires expensive cooling systems —> less durable
• Fast + reliable —> means fewer repairs
• Slower than SSDs —> contains moving parts

Question 3

HDDs pros + cons

Answer 3

• High capacity —> up to several TB
• inexpensive —> compared to SSDs
• less durable than SSDs —> contain moving parts —> not so robust —> if dropped
• can be affected —> by magnetic fields + heat —> so requires expensive cooling systems —> less durable
• Fast + reliable —> means fewer repairs
• Slower than SSDs —> contains moving parts

Question 4

SSDs pros + cons:

Answer 4

• durable —> has no moving parts —> will be more robust when dropped
• reliable —> means fewer repairs
• portable + takes up little physical space —> due to no moving parts —> reducing the physical device size
• can be expensive
• creates little heat + has efficient power consumption —> therefore, doesn’t require —> expensive cooling systems
• high capacity
• high speed —> contains no moving parts

Question 5

Optical pros + cons:

Answer 5

• highly portable + lightweight —> easy to post or carry
• cheap
• not so durable —> will degrade over time —> with exposure to sunlights —> + is also susceptible to scratches
• slowest speed
• low capacity —> 50GB for Blu-Ray Dual layer

Question 6

Registers

Answer 6

super fast memory that can be accessed extremely quickly
it stores instructions, memory addresses and data

Question 7

Cache

Answer 7

it is very fast memory - but slower than registers
used to store instructions or data that the CPU is likely to reuse

Question 8

Increasing clock speed means

Answer 8

programs run faster

Question 9

An application and document is saved on a drive. You click on the document to open it. What must happen first before the CPU can process the document?

Answer 9

The application needs to be loaded into RAM. The document needs to be loaded to RAM.

Question 10

Effect of increasing the sample rate (frequency) or sample resolution (bit depth)

Answer 10

increases the quality
increases the file size

Question 11

A 2-place shift to the right effect:

Answer 11

divides the number by 4
causes a loss of precision

Question 12

How is MOP represented in ASCII

Answer 12

each character has its ASCII code stored in the order written
the ASCII code is converted into 8 bit binary

Question 13

Network protocol

Answer 13

is a set of rules for communication

Question 14

Layer

Answer 14

provides a division of network functionality

Question 15

Advantages of layers

Answer 15

• layers are self-contained - allows developers to only concentrate on one aspect of the network
• layers can be edited and removed without affecting other layers - provides more manageable divisions of work

Question 16

Clock speed

Answer 16

determines the number of instructions processed per second

Question 17

CPU speed dependent on

Answer 17

cache size
clock speed
number of cores

Question 18

PC performance improved by

Answer 18

RAM
GPU
CPU
hard disk (SSD or HDD)

Question 19

Explain how multitasking works

Answer 19

All running programs or data are stored in the RAM
which is managed by the memory management of the OS
one program can be run at a time by the CPU
so each process is allocated CPU time by the OS
one the allocated time is ended, the process is paused
the CPU time is then given to another process
this happens so quickly that to the user, it appears that multiple processes are run simultaneously