1.5 Systems Software Flashcards
OS full form
Operating System
OS
manages hardware and runs software
- Communicates with internal + external hardware, using device drivers
- Provides a User Interface (UI) – allows for the user to interact with the computer
- Provides an environment for different applications to run
- Allows the computer to multi task by controlling memory resources + the CPU
- Deals with file management + disk management
- Manage system security + user accounts
UI full form
User Interface
UI
allows the user to interact with a computer system
Types of UI
Graphical User Interface (GUI)
Command-Line-Interface
Graphical User Interface (GUI)
- designed to be easy for everyday users, by being visual + interactive
- uses WIMP (windows, icons, menus, pointers)
Command-Line-Interface
- Text based
- User enters specific commands to complete tasks
- Less resources
- Not efficient for everyday users, but better for advanced users -> more powerful
Device driver software
used for computer system (operating system) to communicate with internal hardware or peripherals
What does every hardware/peripheral connected to a system need?
A device driver
What do device drivers do?
Act as a translator for the signals between the OS and the hardware
What happens when a computer is booted up in relation to device drivers?
the OS picks the correct device drivers for the hardware detected.
(If new hardware is connected to the system, the OS will install a new, matching driver for it.)
Why do device manufacturers release updates for device drivers?
To fix bugs
Add features
Improve performance
How can updates from device manufacturers be installed?
Automatically by the OS
Manually by the user
What is responsible for the file management?
The OS creates a file structure to make it easier for the user to organise and file data in a systematic way
What does the OS manage?
Naming, saving, moving, editing,, deleting of data
What is responsible for the disk management?
The OS splits the physical disk into storage sectors, and decides where to write data
Also keeps track of space
How does the OS maintain the hard disk?
Utility Software e.g. defragmentation software
Multitasking
When several programs are run at the same time
What helps the CPU do multitasking?
The OS
How does the OS help the CPU multitask?
Efficiently managing memory + CPU processing time
What happens when an application is opened?
The OS moves necessary parts of the application to memory, and additional parts when required
What does the OS do when multitasking
makes sure the applications don’t overwrite/interfere with each other -> memory manager allocates certain applications certain memory addresses, so that their data is placed in different locations
How many applications does the CPU process at a time?
One. Other applications have to wait
How does the OS prioritise CPU time?
Prioritises CPU time for open applications compared to other processes
What else does the OS manage?
The flow of data
The movement of data to and from virtual memory
How does the OS manage the flow of data?
Using memory buffers
What do memory buffers do?
store data until the component is ready to receive it, as different components have different processing speeds
User accounts
The OS can either be:
single user
multi user
Single User
Allows one user to use the computer at once
Example of a Single User OS
macOS
Multi user
Allows multiple users to use the computer at once
Example of Multi User OS
UNIX server
How is the OS stored?
In mainframes
What are mainframes?
Huge supercomputers
Example of a mainframe
ATMs give many people access to a bank’s mainframe
What manages User Account Control?
The OS
What do user accounts allow for?
Different users to have access to specific data
User accounts are password protected to avoid theft of data
Utility Software
Software designed to help maintain/configure the computer
Types of Utility Software
Encryption Software
Compression Software
Defragmentation Software
Encryption Software
scrambles (encrypts) data to stop third parties/unauthorised users from accessing + understanding it
Process of encryption
- Converts plain test (unencrypted) -> cyphertext (encrypted)
- An algorithm and key are used to encrypt the data, and the same algorithm and key are needed to decrypt the data
- Encrypted data cannot be read through a brute-force attack
Main advantage of Encryption Software
even if a hacker intercepts the data, it is still secure/cannot be read.
Compression Software
reduces the size of a file by permanently or temporarily removing data from them.
Types of Compression Software
Lossy
Lossless
Advantage of Compression Software
frees up disk space + quicker to download/transfer across a network
How are compressed files opened?
Compressed files need to be extracted before opened
Defragmentation Software
reorganises data on a hard drive to put fragmented files back together, to prevent further fragmentation
How does fragmentation occur?
- Ideally, files on a hard drive should be stored together
- Over time, as files are moved and deleted, lots of gaps are created on the disk = fragmentation
- This causes slower read – write speed (the read-write head has to move back and forth across the disk)
- Defragmentation software solves this problem.
Defragmentation effect on SSDs
As SSDs have no moving parts, fragmentation doesn’t slow them down – they can access data from any part of it at the same speed.
Defragmentation slows them down as they have a limited number of read/write cycles
