chapter 1 heehoo systems architecture memory n storage

Question 1

Def. hardware

Answer 1

any physical component that makes up the computer

Question 2

def. software and firmware)

Answer 2

software - any program that runs on the computer

firmware - software that comes predownloaded and cannot be deleted

Question 3

purpose of CPU

Answer 3

• performs the FDE cycle

- manages the rest of the hardware

Question 4

what is the CPU made up of?

Answer 4

main memory (RAM), the processor(s), cache memory

Question 5

purpose of address bus

Answer 5

carries addresses from the processor to memory and input/output devices

Question 6

purpose of data bus

Answer 6

sends data between the processor, memory and input/output devices

Question 7

purpose of control bus

Answer 7

carries signals to coordinate all the computer activities

Question 8

purpose of control unit (4 points)

Answer 8

• controls the execution of instructions in the correct order
• decodes instructions
• regulates and controls processor timing using regular pulses from the system clock
• sends and receives control signals to and from other devices within the computer

Question 9

functions of ALU

Answer 9

• logical operations ( and, or, not)
• shift operations (binary shift)
• arithmetic operations

Question 10

MAR purpose

Answer 10

holds the address of the instruction/piece of data to be fetched or stored

Question 11

MDR purpose

Answer 11

where the data/program instruction is temporarily held after being fetched from memory

Question 12

program counter purpose

Answer 12

holds the memory address of the next instruction to be processed
increments every time the FDE cycle is carried out

Question 13

CIR purpose

Answer 13

holds the current instruction to be executed, which has been fetched from memory and is temporarily held in the MDR before being copied to the CIR

Question 14

accumulator purpose

Answer 14

a general purpose register where all calculations are carried out

Question 15

what is clock speed? units?

Answer 15

the number of instructions/data processed per second

hertz

Question 16

define cache memory

Answer 16

the small amount of very fast memory where frequently used instructions and data can be stored temporarily

Question 17

what is an embedded system?

Answer 17

a computer system that has a dedicated function as a part of a larger device

Question 18

5 examples of embedded systems

Answer 18

microwave
dishwasher
dvd player
MP3
car engine management systems

Question 19

factors affecting CPU performance

Answer 19

clock speed
number of cores
amount of cache memory
amount of ram

Question 20

3 advantages of embedded systems

Answer 20

• low power devices so they can operate effectively from a small power source
• small in size to fit inside a wrist worn device (e.g. a fitness bracelet)
• rugged so they can be used in a wide range of appliances e.g. car engine management systems
• low cost making them suitable for mass produced products
• dedicated to just one task with dedicated interfaces and software

Question 21

define volatile

Answer 21

needs power to be maintained - if the power is turned off, RAM loses its contents

Question 22

what is stored in RAM?

Answer 22

• loaded operating system

- any instructions, data or programs currently being executed/in use

Question 23

difference between DRAM and SRAM

Answer 23

DRAM is cheaper and stores more

SRAM is faster

Question 24

ROM- volatile? contents?

Answer 24

not volatile

BIOS/bootstrap loader (small program that loads the OS)

Question 25

features to consider when choosing a secondary storage medium

Answer 25

``` capacity speed reliability durability cost portability ```

Question 26

pros of magnetic disk drives (HDD)

Answer 26

pros - massive fuckin capacity - low cost per GB

Question 27

pros of solid state drives

Answer 27

pros - less susceptible to shock and damage because there are no moving parts - lighter - more suitable for portable device - faster access time than HDDs - lower power consumption than HDDs - run much cooler than HDDs - thin because no moving parts

Question 28

pros of cloud storage

Answer 28

pros - you can access data from anywhere with an internet connection - you can share data with people in different locations - backup isn't an issue as it is the responsibility of the provider to keep the data safe - automatic updates

Question 29

what is virtual memory

Answer 29

memory management procedure needed when RAM is full the OS creates a temporary section of volatile memory that acts as RAM in secondary storage data currently not in us is sent here

Question 30

cons of cloud storage

Answer 30

cons - you can't access your data without an internet connection - some users are concerned about security in the cloud and whether their data could be accessed by a hacker

Question 31

cons of magnetic disk drives (HDD)

Answer 31

``` cons -moving parts so • slow to read from/write to • more susceptible to damage - vulnerable to magnetic fields ```

Question 32

cons of solid state drives

Answer 32

cons - more expensive per GB - less dense