Computer Science - system architecture

Components of the CPU

Bus, Clock, ALU, control unit

what does the clock do?

keep the CPU components synchronised

what does the bus do?

wires where data and instructions are transferred between computer components

what does the ALU do?

arithmetic’s and logic operations

factors affecting CPU performance

clock speed, cores, cache size

what is clock speed?

number of processed carried out in a second

how do cores increase CPU performance?

having multiple cores allows instruction to be carried out at the same time.

how do cache size increase CPU performance?

the bigger the cache the more data and instructions stored

is cache size volatile or non-volatile?

volatile

what is the difference between RAM and cache?

Cache is faster but smaller. cache is used for frequently used instructions and data

explain the fetch, decode execute cycle

1. instructions are loaded into memory

2. processor fetches the instructions from memory

3. instructions are decoded for the CPU

4. processor executes instructions

5. result is stored

6. repeated

Magnetic hard disk contain

• tracks contain tiny magnets each holding 1 bit of data

• they are either positive or negative

advantages of magnetic storage

• cheap

• large capacity

disadvantages of magnetic storage

• contains moving parts

• data can corrupt

• slow spead of read/write access

examples of optic disks

blue-ray, DVD, CD

advantages of optical storage

can transfer easily with computers

disadvantages of optical storage

• easily scratched

• less storage

• limited writes

SSD advantages

• fastest

• quiet

• reliable

• no moving parts

disadvantages of SSD

• more expensive per volume

• not very reliable

cloud computing advantages

• only pay for the storage you use

• any device with internet can access it

• automatically backed up

• collabiraiton

disadvantages of cloud computing

• need a reliable network

• security concerns

what is an embedded system

• computer systems designed for specific functions

what is system software?

runs and maintains the computer. controls the computer hardware and manages the application software

example of system software

operating systems, antivirus, hardware drivers.

application software?

a program desighned to preform a specific task that the user directly interacts with

examples of application software

word processor, spreadsheet

components of the Operating system

• application management

• processor resources

• memory management

• security

• input/output devices,

what does the application managment do?

runs on top of the OS it is an intermediary and it takes care of interaction with the hardware

what does the processor resources fo?

allow multiple applications to run simultaneously using cores.

what does the memory management do?

distributes memory resources between the programs and manages transfer of data and instruction code in and out of memory

what is securtiy?

password,

antiviruses

firewalls protect the computer

input/output devices

• OS controls input (e.g keyboard) outputs (e.g. monitor) and storage using hardware drivers

• allows users to print documents, save files

advantages of high level language

• easier to understand

• more built ins

• easier to maintain/ decode

disadvantages of high level language

• slower to execute

• compatibility issues

• more memory is used

• need a compiler

machine code (low level)

• expressed in 1 and 0

• all code needs to be translated to machine code

• specific to proseccor

assembly code (low level)

• basic computer instructions for programs to run

• has the same structure as machine code

• uses mnemonics → easier for programmer

low level language advantages

• faster,

• directly interact with hardware

• less memory used

• no need for compiler

disadvantages of low level

• difficult to decode

• difficult to understand

difference between compiler and interpreter

• the compiler translates the code before the program is ran

• the interpreter translate while the program is running