Hardware and Software Flashcards
what is an operating system
a program that acts as a bridge betweeen a user of a computer and the computer hardware
what are the purposes of an operating system?
- manages hardware
- manages the applications installed
- creates a user interface
- provides a layer of security
what are the types of user interfaces
- command line - shell responding to successive commmands
- GUI -use icons and other visual indicators to issue commands
what are the four functions of an operating system
?
- processor scheduling
- backing store management
- memory management
- peripheral management
explain memory management
- program needs to be loaded into RAM
- OS controls the allocation and management of RAM
- if there is no free space virtual memory is used
explain backing store management
OS mantains records of all files stored in secondary storage including information like their location and what user can access what
explain processor scheduling
OS controls which programs can send data to the processor to be processed
explain multi-tasking
processor executes 1 process at a time but allows multiple applications to run by rapidly switching between processes
what are the types of schedulers and explain
- round robin - each process is given a slice of processing time
- shortest job first
Explain peripheral management
- OS uses device drivers which are programs that convert between the peripheral signals and the OS signals
- driver is the interface hiding the complexities of the hardware
what are the types of software
system software and application software
what are the types of application software
- special purpose
- general purpose
- off the shelf
- bespoke
explain special purpose software
performs a task for a single specific job e.g. payroll, media playhers, calendar programs
explain general purpose software
performs a range of generic tasks e.g. word processor, spreadsheet software
explain bespoke software
softwaare which is created to fulfil exact specifications
explain off the shelf software
it is a type of special purpose software which is readily available
what are the drawbacks of off the shelf software
- you have little or no control of the features
- it may not do exacty what you want
what are the benefits of off the shelf software
- readily available
- cost is cheaper
- likely to be well tested
what are the benefits of bespoke software
- fulfils exact specifications, you have complete control over functionality
what are the disadvantages of bespoke software
- may take a long time to produce
- signifcant increase in price
what are the types of system software
- Library programs
- Utility programs
- Translators
- Operating system
what is system software
required to run and manage the computers hardware and application programs
what is utility software
designed to analyse configure or mantain a computer system e.g.
- disk defrag
- virus checker
what is a library?
it is a collection of precompiled routines that can be used by other programs e.g. python has random and math
what is a translator?
it is used to translate code written in assembly language or high level languages into machine code
define machine code
instructions comprised of pure binary, low level language
what are the three types of translators?
- compilers
- interpreters
- assemblers
what does a compiler do?
translates high level language into an executable binary file which can be run without source code
what does an interpreter do
translates high level langauges into machine code one line at a time immediately executing the instruction
what does an assembler do
it converts assembly code into machine code
point about low level languages
- has the least abstraction (executed directly)
- not portable as it corresponds to specific processor instruction set
- requires less system resources, useful in embedded systems
points jabout high level languages
- understandble as it is close to english and math
- portable
- more abstract
define imperative high level language
consists of commands for the computer to perform
define declarative language
focuses on what the program should do without listing how
what is byte code
program code that has been compiled from source code into low level code designed for a software interpreter
what is an API
an application programming interface that hides the commplexities of the operating system
