Topic 2 - Computer Architecture

Question 1

Fetch

Answer 1

• The program counter (PC) holds the memory address of the next instruction that is going to be read/written to
• The address is transferred to the MAR via the address bus
• The MAR sends the memory address to RAM via the address bus to signal it to read the instruction at the specified memory address
• The instruction is sent to the MDR via the data bus from the RAM and then copied into the CIR (Current Instruction Register) also via the data bus
• The PC is incremented to the next instruction

Question 2

Decode

Answer 2

• Th UI interprets and decodes the instruction in the CIR

Question 3

Execute

Answer 3

• The ALU carries out the decoded instruction by performing arithmetic or logical operations
• The ACC stores and accumulates the result of the calculations performed by ALU if needed.

Question 4

ROM

Answer 4

Read only memory that stores the permanent and persistent instructions to boot up the computer (BIOS)

Question 5

Cache memory is more _____ than RAM and is checked before/after the RAM

Answer 5

expensive

before

Question 6

Secondary Memory relationship to CPU

Answer 6

It is not directly connected to CPU unlike primary memory

Question 7

Virtual Memory

Answer 7

This is utilized when primary memory is overloaded. It works by sending less used data from primary memory to secondary memory in pages freeing up space in the primary memory. When primary memory needs the data sent again, it is sent back to the primary memory from secondary memory.

Question 8

Virtual memory 2 characteristics

Answer 8

• Slower
• Temporary

Question 9

Draw VM diagram

Answer 9

2 boxes next to each other with a gap in between

1 box = RAM

1 box = Hard disk (but secondary box inside it called Virtual memory (pagefile))

There are two arrows that connect the boxes.

One arrow on the top going from RAM to hard disk called “less used data”

One arrow under it going from hard disk to RAM called “data needed by the CPU”

Question 10

Operating system definition

Answer 10

Set of software that controls computer’s hardware and resources and provides services for computer programs

Question 11

3 examples of roles of OS

Answer 11

• User interface
• Memory management
• Multitasking

Question 12

User interface

Answer 12

It is what facilitates the link between user and hardware

Question 13

4 examples of UI

Answer 13

GUI
CLI
Natural LI (speak to computer like Siri)
MBI (like CLI but no commands only menu options)

Question 14

Memory management

Answer 14

A role of OS. It refers to keeping tracking of storage devices, allocating the appropriate amount of RAM to programs in use and organizing and managing data files and folders.

Question 15

Peripheral management

Answer 15

A role of OS. The OS works with the BIOS and device drivers to translate signals from peripherals into instructions the system can understand and use.

Question 16

Multitasking

Answer 16

A role of OS that allocates CPU time and resources to multiple programs in use, allowing them to run concurrently. This process is often managed using time slicing and ensures each program gets a fair share of CPU time based on priority and scheduling algorithms.

Question 17

Security (OS)

Answer 17

A role of OS. It involves the setting of usernames and passwords, setting user permissions and file permissions for reading and writing throughout the OS to enhance security.

Question 18

3 examples of types of Application software

Answer 18

• Word processor
• Spreadsheets
• Web Browser

Question 19

Translate

1 byte –> bits
1 kilobyte –> bytes
1 mb –> kilobytes
1 gb –> mb
1 tb –> gb

Answer 19

1 byte = 8 bits
1 kb = 1024 bytes
1 mb = 1024 kb
1gb = 1024 mb
1 tb = 1024 gb

Question 20

Bit

Answer 20

Binary digit. This is a measurement unit that can only have two states, 1 or 0 (or on or off)

Question 21

One extended ASCII character (e.g. A) into bytes

Answer 21

1 byte

Question 22

Binary is what base?

Answer 22

Base 2

Question 23

Hexadecimal what is it and what base

Answer 23

These more efficiently represent large binary values. These are base 16.

Question 24

3 uses of Hexadecimal

Answer 24

• HTML colors
• MAC addresses
• IP addresses

Question 25

Two formats of text

Answer 25

ASCII & Unicode

Question 26

How many possible characters in ASCII

Answer 26

128 possible characters

Question 27

Unicode

Answer 27

It is used to represent text in multiple languages. There are 3 types of UTF UTF-8 UTF-16 UTF-32 each number corresponds to amount of bits used per character

Question 28

Pixel

Answer 28

Smallest controllable element in a display

Question 29

Each pixel represented by what type of code

Answer 29

6 digit hex value. First 3 values represent red, second 2 represent green and last 2 represent blue e.g. 70EF5A

Question 30

How many possible color combinations in each pixel

Answer 30

256^3

Question 31

How to draw gates

Answer 31

And = mario bullet Or = space ship Not = Triangle with mini circle attached XOR gate = space ship with extra line (not connected) behind it) NAND and NOR = the same but with a mini circle