Computer Systems

What is hardware ?

The electrical or electro-mechanical parts of a computer system

What is software ?

All the programs that makes computers function

What is system software ?

It's required to run and manage the computers hardware and application programs

Examples of system software

Allocating jobs to the process
Peripheral management
Maintaining security
Software installation
Translating program code to machine code

What is an operating system?

Links together the hardware

Examples of operating systems

Resource management
Provision of a user interface

What is memory management?

when the os allocates memory to each process and if there isnt enough space then less frequently used data with be moved to virtual memory

what is processor scheduling ?

controls which process can send data to the processor to be processed

what is scheduler ?

ensures the process time is used efficiently as possible

what is backing store management ?

it keeps track of where all files are stored on hard disk and where the empty space is

what is IO device management ?

checks that the required output devices is ready to receive data

Examples of utility software

Defragmentation
Keep software up to date
Virus checkers
Install/ uninstall software

What are libraries?

A collection of pre-compiled routines that can be used by other programs

What is application software ?

Programs that preform Specific tasks that would need doing even if a computer don't exist

What is a translator ?

Piece of software which translates high level language to lower lever language

Examples of translators

Compiler
Interpreter
Assembler

What is the function of the compiler ?

To translate high level language into machine code by translating it all in one go

what are advantages of a compiler ?

once compiled you no longer need the source code to run
the object code is more secure as machine code is hard to read/ copy

what are disadvantages of a compiler ?

can only be run on a computer with the same platform
difficult to debug

What is the function of an interpreter ?

To translate high level language in to source code and immediately preform the action

what are advantages of an interpreter ?

don't need to compile the whole code to run it
easy to debug

what are disadvantages of an interpreter ?

both source and object code needs to be present to run the program
have to retranslate everything after each debug

What is the function of an assembler ?

To translate assembly language in to machine code

where would you use an assembler ?

embedded system
sensors
device driver

what is machine code ?

its the code that computer processors execute

binary numbers. It is low level language

what are advantages of machine code ?

doesn't need to be translated
useful in embedded systems
quick execution
programmers are not restricted

what are disadvantages of machine code ?

not portable
difficult to understand
error are prone
difficult to debug

what is assembly language ?

simpifide version of machine code as it uses mnemonics

what are advantages of assembly language ?

compact
less error prone

what are disadvantages of assembly language ?

not portable
need to use an assembler

what is high level language ?

High-level languages are programming languages that resemble human languages

what is imperative high level language ?

similar to low level as its formed from instructions that specify how a task should be complete in contrast to declarative where it describes what a computer should do

what are advantages of high level languages ?

easy to learn/ understand
easy to debug
portable

what are disadvantages of high level languages ?

must be translated
time consuming to execute

what is source code ?

the code inputted into the translator

what is object code ?

the code outputted from the translator

what is byte code ?

an intermediate language that can be executed on any platform using a virtual machine