Week 3

Question 1

A CPU is also called a…

Answer 1

Microprocessor.

Question 2

What does ALU stand for?

Answer 2

Arithmetic and Logic Unit.

Question 3

What concept is von Neumann architecture based on? (back in the day, when computers were massive and were used for calculating big things, what would have been ideal?)

Answer 3

Memory and storage, all in one!!

Von Neumann architecture is based on the “Stored Program Computer Concept”, where instruction data and program data are stored in the same memory. This design is still used in most computers produced today.

Question 4

What is the CPU responsible for? (think about the actual function of the CPU and how essential it is)

Answer 4

Executing the instructions of a computer program - it does aaaaallll of the decision-making, data manipulation, arithmetic, etc. and performs billions of instructions per second.

Question 5

Which two major control units does the CPU contain?

Answer 5

The ALU and CU - plus a variety of registers.

Question 6

What does MAR stand for?

Answer 6

Memory Address Register.

Question 7

What is the MAR’s only job?

Answer 7

To tell RAM what memory address the CPU wants next, OR…

Holds the next memory location of data that needs to be accessed.

https://www.youtube.com/watch?v=cNN_tTXABUA

Question 8

What does MDR stand for?

Answer 8

Memory Data Register.

Question 9

What does the MDR do?

Answer 9

Holds data that’s being transferred to or from the memory, acting as a buffer between the processor and the memory.

Question 10

What does AC stand for? (hint: it’s not air conditioning - AC is the first two letters in the word…)

Answer 10

Accumulator.

Question 11

What does the AC do? (it’s not air conditioning, and it’s not what ya think)

Answer 11

It stores intermediate arithmetic and logic results.

Question 12

What does PC stand for? (the part in the CPU)

Answer 12

Program counter.

Question 13

What does a Program Counter (PC) do?

Answer 13

Contains the addresses of the next instruction to be executed.

Question 14

What does CIR stand for?

Answer 14

Current Instruction Register.

Question 15

What does the CIR do?

Answer 15

It contains the current instruction during processing.

Question 16

What does the ALU do?

Answer 16

It allows arithmetic and logic (AND, OR, NOT) operations to be carried out.

Question 17

What does CU stand for?

Answer 17

Control Unit.

Question 18

What does the CU do?

Answer 18

It’s like the captain in the army, receiving orders from the RAM and then breaking that instruction down into specific commands for other components. One of the most important things under the CU’s command is the ALU.

It controls the operation of the computer’s ALU, memory and input/output devices - it basically tells them how to respond to the program instructions that have just been read and interpreted from the memory unit.

Question 19

What is a bus? 🚌

Answer 19

The data wires that connect different computer components to transmit data.

A group of wires connecting multiple components inside a computer.

‘How a CPU Works’ - In One Lesson https://www.youtube.com/watch?v=cNN_tTXABUA

Question 20

What does a bus do?

Answer 20

It transfers data between all the major internal components, to the CPU and memory.

Question 21

What does a standard CPU system bus contain?

Answer 21

A control bus, data bus and address bus.

Question 22

What does an Address Bus do?

Answer 22

Carries the addresses of data between the processor and memory.

Question 23

What does a Data Bus do? (Buses carry, registers hold!)

Answer 23

It carries data between the processor, memory unit and input/output devices.

Question 24

What does a Control Bus do?

Answer 24

It carries control signals/commands from the CPU and other devices, so that all activities within the computer can be controlled and coordinated.

Question 25

What is the main, or primary memory?

Answer 25

RAM.

Question 26

What does RAM stand for?

Answer 26

Random Access Memory.

Question 27

RAM is directly accessible by the CPU.

Answer 27

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Question 28

What data does RAM hold?

Answer 28

A list of addresses. At each of those addresses is a piece of data which is processed by the CPU in order - but if the CPU is instructed to pull data out-of-order, it can - which is where the name Random Access Memory comes from. It's split into partitions, and each partition consists of an address that uniquely identifies every location in the memory.

Question 29

What is the 'bits' of a CPU referring to?

Answer 29

The number of bits the CPU can process in a single instruction + the width of the address bus.

Question 30

What does 'word size' refer to?

Answer 30

The amount of data that a CPU's internal data registers can hold and process at once. Modern desktop computers have 64-bit words. Computers embedded in appliances and consumer products have word sizes of 8, 16 or 32 bits. - https://www.pcmag.com/encyclopedia/term/word#

Question 31

What does CPU architecture (or microarchitecture) refer to?

Answer 31

The physical layout of the CPU design, registers and its instruction set. Some popular architectures are x86, AMD64 and ARM.

Question 32

What does ISA stand for?

Answer 32

Instruction Set Architecture - it's the logical layout of the CPU - different to CPU architecture because that's the physical layout. When people say CPU architecture, they generally do mean ISA.

Question 33

What is the physical layout of the CPU called?

Answer 33

The microarchitecture. It implements a particular ISA.

Question 34

What does a GPU do?

Answer 34

It renders images (and it stands for Graphical Processing Unit).

Question 35

CPU cores can work independently with its own instructions & registers.

Answer 35

No answer, just a fact ✏️

Question 36

Unlike modern programming languages, assembly code is specific to a particular CPU architecture. With programming languages, as long as we have the compiler for it, we can use it.

Answer 36

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Question 37

What two main categories can software be divided into?

Answer 37

Application software - the programs/apps that people use System software - the programs the computer needs to function, including the operating system and drivers.

Question 38

What is a driver? 🚙

Answer 38

A specialised piece of software that lets the operating system interact with a particular device. For example, a printer driver. Some drivers, like keyboard and mouse drivers, are already built into the operating system, while others need to be installed manually.

Question 39

When booting a computer, the operating system is loaded from the hard drive onto the RAM.

Answer 39

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Question 40

What does BIOS stand for in an IT context?

Answer 40

Basic Input/Output System. **Superseded by UEFI**.

Question 41

What does UEFI stand for? (it's a mouthful! You won't get it)

Answer 41

Unified Extensible Firmware Interface. It's a **newer system** that **replaces the BIOS system**.

Question 42

What is the job of BIOS and EUFI? (They are software!)

Answer 42

Get the operating system running when you first turn on a computer.

Question 43

Where is the BIOS/UEFI stored?

Answer 43

In ROM (on the motherboard).

Question 44

What does CMOS stand for? (this is the oxide one)

Answer 44

Complementary metal–oxide–semiconductor.

Question 45

Where is the CMOS in a computer?

Answer 45

On the motherboard.

Question 46

What does the CMOS hold? (hint: what commands CMOS?)

Answer 46

Any settings that the BIOS might have set, such as what hard drive to boot from. CMOS requires power to remember data - computers often have a small battery just for the CMOS and real-time clock.

Question 47

What is a register and what does it do? (hint: where are registers?)

Answer 47

It's a very simple component on the CPU whose job is only to store a number temporarily. It's similar to a RAM but much quicker, because it's inside the CPU.

Question 48

What is one disadvantage of a bus? (data-wise)

Answer 48

It can only hold one number at a time. It's not a bad thing, because there are in-built things to compensate for it, like the ALU having a temporary register for the next output.

Question 49

Quick recap: data moves around inside the CPU using the bus and is stored in each register according to how that data is going to be used. Modern CPUs can process multiple instructions per clock tick meaning that the computer you're using is likely processing tens or even hundreds of billions of instructions per second. That phenomenal speed is accomplished by using more than one of each component and making sure that all the components are active as much as possible. This makes modern CPUs much more complicated than the Scott CPU, but they are still fundamentally doing the same things as the Scott CPU.

Answer 49

'How a CPU Works' - In One Lesson https://www.youtube.com/watch?v=cNN_tTXABUA

Question 50

How many bits does 1 hexadecimal number represent?

Answer 50

4 bits - and there's 4 bits in a byte, so a byte is always two hex digits.

Question 51

What base number system is the hexademical system?

Answer 51

Base-16.

Question 52

What does ASCII stand for?

Answer 52

American Standard Code for Information Exchange.

Question 53

ROM stores permanent instructions for the device to start up, and ROM can't be changed after manufacturing.

Answer 53

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