4.3 Operating systems Flashcards
Give examples of operating systems
MS DOS Windows Android Chrome OS macOS Linux (aka the best)
System Software
System Software is the software that provides a platform for other software to work
Give some features of system software
Operating systems, utility programs, program translators
Operating Systems
Operating systems manage computer hardware users and the resources used by the software
What are operating systems responsible for managing
The user interface Memory interface Multitasking Peripheral management and drivers User management File management
User Interfaces
Provide a method for users to interact with a computer
GUI
A Graphical User Interface use pointers, windows, menus, icons and drag and drop features. However on smartphones they are more touched base and do not have pointers. Windows apps typically take up the whole screen
Give types of UI
Graphical User Interface Menu-Driven interface Command Line Interface Voice activated Real-time
Command Line Interfaces
Text commands are entered into the computer (this is very low resource and can save the need for expensive hardware)
Why is it worth learning CLI
For experts who know commands it can be much faster than having to use a mouse because it requires much less disk storage and requires less RAM
Menu-driven interfaces
Menu driven interfaces are often used by devices that have a dedicated function
Give some examples for Menu Driven Interfaces
MP3 players
ATM machines
Self service checkouts
Why must the computer copy the program from the storage into main memory? (memory management)
Because the OS must keep a record of where each program is and where it’s data is located. Then the OS will make sure none of its data are overwritten
Multi-tasking
This is where an OS manages many tasks happening at the same time. For example you may be running a computer game, but also you are searching the web on another monitor or many background processes. The OS decides on which process will be run next by the CPU and how long for
Interrupts
Interrupts are signals sent to the CPU by external devices to indicate an event needs immediate attention by suspending it’s current activities and execute appropriate instructions.
Hardware interrupts
Generated by hardware devices. For example out of printing paper
Software interrupts
Generated by programs. For example, a divide-by-zero error will cause an error message to be displayed
Peripheral management
The OS manages getting inputs from and sending outputs to devices. For example keyboards, printers, displays, cameras etc.
Device drivers
A program that controls peripheral devices such as printers, mice and displays.
How do devices communicate with a computer?
Communicates with the OS via its own driver
What is a hard disk an example of?
Storage peripheral
How does the operating system manage files?
The OS manages where the disks are written on the files, they keep track of where they are so they can be retrieved, and make sure no file overwrites another file
What features are available given by the OS in file management?
Naming files Allocating files to folders Moving files Saving files Copying files Deleting files
How does an OS manage login systems?
It stores usernames and passwords in a file or database
What are access rights?
If a computer is used by more than one person, each user should be able to see only their files
Users and system administrators have different levels of access rights
Some users may be allowed to read files but not edit them
