Mock Revision

Question 1

Function of Control Unit?

Answer 1

. Coordinates all activities in cpu
. Directs flow of data between CPU and other devices
. Accepts next instruction, decodes it, handles its exectutions and stores data in registers
. Sends memory read and write requests to main memory on the control bus

Question 2

Function of the Program Counter?

Answer 2

. Holds address of the next instruction to be executed
. At the start of the FDE the address in the PC is copied to the MAR

Question 3

Function of the MAR?

Answer 3

. Holds address of memory location in which data or instruction is about to be fetched from or written to
. Sends address to memory down the address bus

Question 4

Function of MDR?

Answer 4

. Used to temporarily stort data which is read from or written to memory
. all data to and from memory must travel through the data bus and through the MDR

Question 5

Function of the CIR?

Answer 5

. Holds the current instruction being executed
. Contents of the MDR are copied to the Cir is its an instruction
. Contains the opcode and operand of the current instruction

Question 6

Function of the ALU?

Answer 6

. Performs arethmatic and logical operations on data
. Boolean logic operations
. Often uses general purpose registers to temporarily hold result of a calculation (eg ACC)
. Conduit for input and output

Question 7

Function of the ACC?

Answer 7

. one of the general purpose registers
. data or control info is stored in them
. more general purpose operators a processer has, the faster it’ll operate
. ALU Calculations are temporarily stored here

Question 8

What is opcode and operand?

Answer 8

Opcode - What process to do.
Operand - What/where to do that process to.

Question 9

What do each of the buses do?

Answer 9

Address Bus: Carries memory addresses
Data Bus: Carries the binary that make up the data carried.
Control Bus: Carries control signals (Read/Write) to other CPU components.

Question 10

What is waterfall?

Answer 10

Waterfall lifecycle works in linear stages that must be completed before moving the next one.

Question 11

Pros of Waterfall?
Drawbacks of Waterfall?

Answer 11

PROS

. It is easy to follow and understand - linear process
. Easy to manage a a team because it goes one stage at a time
. good for clearly planned projects - clear deliverables

DRAWBACKS

. Bad for overly complex projects - lots of documentation
. Inflexible - not possible to go back and make changes
. can casue delays and significant cost increases as additional work is required

Question 12

What is FCFS?

Answer 12

First Come First Serve - uses FIFO.

Question 13

What is RR?

Answer 13

Where each process is allocated a time slice or quantum if process is not done by the end of allocated time it returns to the back of the ready Q.

Question 14

What is SRT?

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Answer 14

Shortest Remaining time first.

Pre Emptive Algorithm - It will be suspended if a higher priority process joins the queue.

Question 15

What is MLFQ

Answer 15

Seperates processes based on priority - prioritises those with short CPU bursts and higher I/O bursts.

Question 16

What is Dictionary Encoding

Answer 16

Creates a token for each piece of data, reassembles the oroginal data when decompressed.

Question 17

What is Run Length Encoding

Answer 17

Frequency Data Pairs - contiguous data pieces

Question 18

What is Hashing

Answer 18

Turning a string of characters into a fixed length value (key) that represents the original output key.

Question 19

1NF

Answer 19

Field names unique
Records in a field must be from same domain
Data atomic
No two identical records