Week 4: Memory, Stacks and Computing Architectures

Question 1

What do we call storing data onto the stack?

Answer 1

Pushing

Question 2

What do we call recalling data off of the stack?

Answer 2

Popping

Question 3

What are hardware stacks made up of?

Answer 3

Shift registers

Question 4

What are the different types of memory?

Answer 4

ROM, RAM and flash memory.

Question 5

What are the trade-offs using RAM vs ROM?

Answer 5

RAM is a form of read-and-write memory that can be accessed without rewriting it.

ROM is read-only memory and by default isn’t to be changed because it holds hardware info like the BIOS.

Question 6

Stacks

Answer 6

A data structure used for efficiently storing and recalling data.

It uses the principle of first in last off (FILO)

Question 7

What are the two common computing architectures?

Answer 7

Von Neumann

Harvard

Question 8

Polling and interrupts are two methods for the ___ to ___

Answer 8

CPU

Switch between different tasks

Question 9

What type of memory is used in USB thumbs drives? Why shouldn’t we rely on this for critical storage?

Answer 9

Flash memory.

Damages the insulators in the thumb drive to write to it, meaning that it has a limited lifespan of around 30k writes.

Question 10

What are the differences between Von Neumann and Harvard computing architectures?

Answer 10

Von Neumann stores the data and control bits in the CPU, but are separated in the Harvard architecture.

Processing speeds of Harvard are greater with more security, but Von Neumann is more flexible and makes use of a stack, therefore multitasking.

Question 11

What is cache memory and what’s its primary role?

Answer 11

Cache memory is storing frequently used memory nearby in high-speed memory locations.

This means that the CPU can locate and decrease the access times which in turn increase the processing speed of the system.

Question 12

What are 4 common examples of an interrupt?

Answer 12

Keyboard/mouse, clock, network packets and ALU errors.

Question 13

Interrupt

(Giving food to crying baby)

Answer 13

The response to a device seeking attention from the CPU. This is where a current task is pushed onto the stack for another to be worked on.

Continues until the task is completed, then the routine handler tells where to return to.

Question 14

Where is the BIOS stored?

Answer 14

In the ROM

Question 15

When booting the OS, where will the BIOS be stored?

Answer 15

It will be loaded onto the RAM because it’s faster and is able to randomly access the parts of the BIOS that it needs to boot the computer

Question 16

What’s the typical boot process of a PC?

Answer 16

OS on Hard Disk -> OS is loaded onto computer memory (RAM) when computer turns on -> Once main part of OS, Kernel, has control it loads the rest of OS -> BIOS from the ROM loads and manages ‘boot process’ -> OS has control and BIOS translates between peripherals and OS.