1.6 System Software (OS) Flashcards
What is system software
It is a type of software that controls the computer hardrive.
It provides an interface between the user of the computer and the hardware.
What are the six functions of the operating system
Communicates with internal and external hardware via device drivers
provides a user interface
provides a platform for applications to run on
allows the computer to multi task by controlling memory resources and CPU
deal with file management and disk management
manage the security of the system
What is an operating system
complex piece of software found on most computer systems
What does CLI stand for
Command line interface
What does GUI stand for
Graphical user interface
What is a CLI
Text based. The user has to enter specific command words to complete tasks
GUIs are WIMP based. What does it stand for
Windows Icons Menu Pointers
Key differences between GUI and CLI
CLI can be used on low resource equipment but GUI is very resource heavy (because of all the icons and menus).
CLI is much harder to understand as you have to memorise all the commands but GUI is icon based.
Identify two benefits of using CLI instead of GUI
CLI gives greater control than GUI
They are less resource heavy than GUI
How does the OS allow multi-tasking by managing resources
By giving the processor a small time slice for each task that means that all tasks appear to be executing at the same time.
to the user it appears that we can multi task and have lots of programs open at once
in reality resources such as memory and the processor are being shared amongst tasks
What is the most common type of memory
RAM (volatile) It stores currently used data and instructions
Explain how the operating system efficiently manages the memory to allow the CPU to multi task
When application is opened the operating system moves the necessary points into the RAM
To run multiple applications the OS needs to ensure the applications do not overwrite themselves in memory
Only one application can be processed at once. The OS splits the CPUs time into slices and manages the application time in the CPU
Where is data stored long term and why
Secondary storage because it is long term and non volatile
What role does the OS play in disk management
Identifies where files are stored for long term storage on, for eg the HDD or SSD
User does not need to know the specific track sector and surface address.Operating system does in order to accurately locate a file on the HDD.
Explain defragmentation utility
The process of reordering files stored on a hard disk so that their segments run continuously
Entire files stored on HDD in available spaces
Files are moved, deleted, can change size and have small gaps
Operating systems can be either single user or multi user accounts, what is the difference
Single user allows only one user to access the system at once
multi user system allow multiply users to access the system at the same time
An example of a single user system
home desktop pc running Windows 10
An example of a multi user system
a file server in a school will run a multi user operating system
what are device drivers
a piece of hardware used to control a piece of hardware
allow a peripheral device to be connected to a computer and to be used by an operating system
may get drivers for graphics cads, mouse, network interface cards
they are OS specific and regularly updated by companies
what are utilities
designed to do 1 0r 2 tasks
what is encryption used for
to scramble data in a way that is unreadable to anybody that doesnt have a key to unscramble it.
how does encryption work
data is encrypted by a key and then decrypted by a key. Data is encrypted so that it is unreadable if anyone is to intercept it.
what is compression
to reduce the size of the file
reducing the size of the file by preforming an algorithm on the original data.
what are the two types of compression
lossy
lossless
what is lossy
some of the original data is lost and the original file cannot be created
what is lossless
the original file can be recreated as no data is lost
advantages and disadvantages on lossy
ad:
very small file size - more files can be stored
commonly used
disad:
loss in quality
cant get back original copy after compressing (deleted)
advantages and disadvantages on lossless
ad:
quality not lost
nothing is removed or deleted just smaller
can be used on text and software files
disad:
files are larger than if you used lossy
why is file backup needed
to ensure there is a way of storing files/data/programs incase of computer failure
copies of data and/or software are taken regularly and usually stored in different locations
what is backup utility
It ensures that if computers are stolen or damaged their data can be restored
What are the two types of back ups
Full backups and incremental backups
Explain full backups
copy of all data and software
medium is kept at a different location
take a long time to complete
recovery takes a long time as it restores all data and programs
Explain incremental backups
full backup made initially
only the files have been changed since the last incremental backup
faster to complete than full backups
takes much longer to restore than a full backup
as a full backup would need restoring first and then every incremental backup since the last full backup
