1.5 Operating systems Flashcards
Types of systems software
Operating systems
Utility software
examples of operating systems
Windows
IOS
Mac os
Android
Linux
Raspbian
What is systems software
System software is software which allows a computer to run and to be maintained.
Functions/features/purposes/functionality of an OS
The OS:
communicates with hardware via device drivers
Provides a user interface
Provides a platform on which users can run programs
Allows a computer to multitask by controlling memory
Deals with file and disk management
Manages the security of the system
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Provide a User interface
Memory management
Multitasking
Peripheral management
Drivers
User management
File management
Function of operating system
Provides a platform on which users can run programs
What is meant by a user interface
A computer design that allows the user to interact with the computer.
Function of utility software
Used to maintain the computer system
Types of user interfaces
Graphical User interface (GUI)
Command Line Interface
Menu Driven Interface
Natural language interface
State features of GUI
It has Windows, icons, menus, pointers (WIMP)
Visual
Interactive
Intuitive
Optimised for mouse and touch gesture input
(often known as WIMP interface)
What is meant by a Graphic User Interface
A user interface that uses graphics/images and words to represent the interaction between the end user and a computer.
Icons are used to represent actions and resources.
Features of Command Line Interface
Text based
Less resource heavy compared to GUI
More commands than a GUI
Efficient
For advanced users
Useful for automating processes with scripts
How is a Command Line Interface used
User provides a text input or command using the computer keyboard and the computer outputs text on the monitor.
What is meant by a CLI
An interface which allows the user to interact with a computer only by typing in commands from a set list
Features of Menu Driven Interface
Successive menus presented to the users
Single options chosen at each stage
Often with buttons on a keypad (Users interact with these devices with buttons on a keypad)
Identify two benefits of using a Command Line Interface instead of a GUI
Command line interfaces give greater control to Users than GUIs
They are less resource-heavy than GUIs
Where are Menu Driven Interfaces likely to be found at/on
Likely to be found at cashpoints and on chip-and-pin devices
Features of Natural Language Interface
Responds to questions in spoken language
Not always reliable
Getting better all the time.
How does the natural language interface work
A user can speak in their natural language into a computer system, so it responds to question said in spoken English
What is multitasking
Running multiple applications at the same time by giving each application a small time-slice of processor time.
State the advantages of multitasking
Multitasking allows more than one program to be held in memory at a time, and data to be shared between them such as copy and paste
It also enabled you to listen to music on your PC at the same time as word processing.
Explain why, when the Operating System is multitasking, it appears as if multiple programs are executing simultaneously
Multitasking is running multiple applications at the same time by giving each application a small time-slice of processor time.
As this happens so quickly it appears as if multiple programs are executing simultaneously
Explain how multitasking works
Multitasking is running multiple applications at the same time by giving each application a small time-slice of processor time.
Each program has a small time slice, (one program is allocated a time slice, once this is over, it is passed to the next program which has a small time slice, this process repeats.)
What is memory management
Management/organization of memory at the system level.
What is memory management used for
It is used to allocate free memory to programs that need it, and free up memory where it is not needed. - for computers to work efficiently
It is used to keep track of different program fragments
When programs are loaded, the operating system decides where they are held in memory
How can a hard disk become fragmented
Files have been loaded from the hard drive into main memory (RAM)
When the user closes a program, it is removed from memory and the memory is freed up
Another program is loaded into RAM. This program may be bigger than the spaces left by the deleted files.
Therefore the program is split up
A restaurant has a computer-based ordering system which is running slowly. A technician has
said that the hard disc drive is fragmented. The technician has suggested using utility software to
defragment the drive.
(a) Explain how the restaurant’s hard disc could have become fragmented.
- Orders have been saved onto the system as they order food and then
deleted once processed (1) - Once other orders have been made, new files are created (1) which may
be bigger than the spaces left by the deleted files (1) - The order files are split up (1)
What is peripheral management
Allows a computer’s external devices to communicate with the computer system.
Explain how peripheral management works
Peripheral management allows a computer’s external devices to communicate with the computer system.
It controls external devices by sending them commands.
Function of device drivers
Translates operating system instructions into commands that the hardware will understand
In terms of device drivers, what does each peripheral need
Each peripheral needs a device driver (each peripheral needs its own device driver)
Explain how device drivers work for printers
In the example of printers, a device driver translates the operating system instructions to print the document into a series of instructions which a specific piece of hardware will understand
Explain why we need to use device drivers
Computers have to be able to output to a wide range of devices.
Files should look the same no matter what model of a specific output device a user sends it to (for example a document printed from a word processor should look the same no matter what make or model of printer the user sends it to)
The technology behind each model of specific type of hardware is very different
To overcome this in consistency, we use device drivers.
Function of user management
Providing for different users to log into a computer
Explain how user management works
User management provides for different users to log into a computer
The operating system will retains settings for each user, such as icons, desktop backgrounds etc.
Each user may have different access rights to files and programs
A client server network may impose a fixed or roaming profile for a user, and manage login requests to the network.
In a network, what is meant by user management
The administrative feature of a computer system to allocate an account or control user access into a network.
Explain what is meant by file management
- A system that is used by the operating system to organise and keep track of files.
- A software that manages data files.
Features of file management
Features include naming, allocating folders, Moving Files, Saving files.
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Data is stored in files
An extension (e.g., .pptx, .docx) to the filename tells the operating system which application to load the file into.
The operating system may present a logical structure of files into folders, and allow the user to rename, delete, copy and move files.
Explain how the operating system manages memory and CPU time to allow the computer to multitask
When programs are opened, the OS moves the necessary parts to memory.
The OS will remove unneeded data from memory e.g. when programs or files are closed.
The OS divides memory into segments. When different programs are used, their data is placed into different segments so that running applications can not write over or interfere with each other.
The OS organises the movement of data to and from virtual memory
The OS divides CPU time between running programs, as it can only process one at time
The OS can prioritise CPU time for different programs in order for them to be processed in the most efficient order
