Operating Systems 1.2 Flashcards
4 main components of an os
- kernel
- device drivers
- User interface
- System utilities
Operating system -state 4 points
- set of programs that controls the hardware of a computer
- means of communication between the user and the computer
- deals with loading/running of applications
- manages the transfer of data/files to/from peripheral devices
Peripheral devices
Connected to a computer internally/externally attached
I.e speakers , monitor
Software application importance
- Allows users to carry out tasks
- Software needs to communicate with hardware
Application software meaning
Programs on a computer that users use
- ie word
Function of os = accepting data
- accepts data from input devices
- transfers it to the computers memory
Function of os = checking output devices
- confirms that any output is sent to the correct output device
- I.e words are displayed on a monitor
Function of os = managing data
- manages transfer of data
- between ram and hard drive
- I.e saving documents
Function of os = allocating memory space to data
- decides where to store data
- in the next available space of hard drive
Function of os = loading applications
- loads programs into memory
- controls running of them
- ie opening a document on ram and editing it
Function of os = human interface
- provides a human interface for user
- ie login screen is the first page you see when you turn a computer on
- eg homepage when you open a software
Function of os = dealing with errors
- Deals with errors displayed by program
- inform user
- eg password incorrect, updates required
Function of os = special facilities
-provides facilities for multi programming
Function of os = System security
- manages security
- restricts access to prevent unauthorised access to system
- eg user ID and password
Multi programming
Holds more than one program in memory
Multi tasking
- doing more than one thing in memory
- swaps programs in/out depending on usage
- eg playing music while editing a document on word
Multi user
- allows different users at different terminals in a network to share processing time on a central computer
- logging onto the same server = stores all info in the same place
- allows os to switch quickly between terminals = giving each one a time slice
Time slice
Giving each terminal a small amount of processing time on a central computer
The kernel
- manages computer memory through a piece of software called ‘memory manager’
- schedules tasks
- deals with data security
Memory manager job inside kernel = 4 points
- allows more than one application to be open in RAM
- ensures applications stay separate/don’t interfere with each other
- gives each application a private memory space in ram
- responsible for moving programs within/between ram/vm
Data security within the kernel
- responsible for user permissions/ access rights
- ensure user has correct permission to perform certain tasks
- eg delete files /edit files
Scheduling tasks within the kernel
- sorts files in order of priority
- less priority files are used by the cpu later
Device drivers
- piece of software that tells os how to communicate w piece of hardware
- is os specific
- is hardware specific
User interface
- enables a user to interact with the computer
- eg = graphical, menu, command line interface
GUI
-most common UI
-provides easy and visual ways of interacting with os
-uses images, icons, graphics
#eg windows
Command line interface
- user has to type commands in a particular way
- similar rules to programming languages
System utilities
-collection of useful specialist software that performs specific tasks
Compression utilities within system utilities
Reduces file size to increase space on hard drive
Examples of system utilities
- compression utilities
- System restore utilities
- defragmentation utilities
- backup utilities
Defragmentation utilities
- cleans up hard drive
- organises files so that similar ones are closer together
- speeds up fetching as allocating becomes easier
- increases performance if computer
Backup utilities
Backs up data to keep safe
