T4 - Operating systems/ Utility software Flashcards
Examples of OS:
Windows
MacOS
Linux
Android
Chrome OS
System software
- software that provides a platform for other software to work
includes OS and utility programs
OS
- manage computer hardware, users and the resources used by software
OS components
The user interface
Memory management
Multitasking
Peripheral management and drivers
User management
File management
User interfaces:
provide a method for users to interact with a computer
graphical user interface (GUI) -
uses icons
CLI: Command Line Interface
Text commands are entered into the interface
eg of user interfaces
Menu-driven interface
Voice activated
Real-time = sensors detect inputs
CLI: Command Line Interface
GUI
Command line interface:
text commands are entered into the computer
Command line interface: pros
Little processing
far faster to enter commands than using a mouse
interface requires much less hard disk storage space
requires less RAM
Menu-driven interfaces:
used by devices that have a dedicated function including MP3 players
Memory management:
- Data used by the program is copied into main memory
- The operating system keeps a record of where each program and its data are located
- The operating system will make sure not to overwrite existing programs and data
Multi - tasking:
where an operating system manages many tasks happening at the same time
Eg = a web browser open whilst playing music
Interrupts:
signals sent to the CPU by external devices to indicate an event that needs immediate attention
tell the CPU to suspend its current activities and execute appropriate instructions
Hardware interrupts
are generated by hardware devices – for example, printer out of paper
Software interrupts
are generated by programs – for example, a divide-by-zero error will cause an error message to be displayed
Peripheral management:
Getting inputs from and sending outputs to peripheral devices
Peripherals include
mice, keyboard, printers,
Device drivers:
program that controls peripheral devices such as printers, mice and displays
Each device communicates with the OS via its own driver
Eg printers communicate through this = ‘out of paper’
Disk management: OS
OS:
manages where on the disk files are written
keeps track of where they are so they can be retrieved
makes sure no file overwrites another file
File management:
Naming files
Allocating files to folders
Moving files
Saving files
Copying files
Deleting files
Disk management: Hard disk
The hard disk = storage peripheral
User management:
responsible for user logins and passwords
Access rights:
If a computer is used by more than one person, each user should be able to see only their own files
Users and system administrators have different levels of access rights
Some users may be allowed to read files but not edit them
User interface summary meaning
– a method of the user interacting with the computer – windows, icons, menus, pointers, drag/drop – can be GUI, menu interface or command line interface
Memory management summary meaning
– manages programs and data stored in RAM, frees up memory when a program is closed
Multitasking summary meaning
– running two or more programs at once
Peripheral management and drivers summary meaning
– the management of devices such as mice and printers
User management summary meaning
– management of usernames and passwords along with what they have permission to access
File management summary meaning
– the organisation of files on storage drives
Utility programs -
perform extra functionality and housekeeping tasks that keep computers running efficiently
Encryption software:
used to encode text
- that it cannot be understood without knowing the key to decode it
Encryption eg
- Encrypt entire hard disks so that the data cannot be understood if the computer is stolen
- Encrypt files and folders on a portable disk such as USB removable storage
- Encrypt communication with websites
- Encrypt data in an organisation’s database – especially sensitive data such as passwords
Disk Defragmentation:
In order to read the file, the drive head will need to move to more locations
This makes it far slower to access files and programs
Defragmenting the hard disk reorganises files so they are stored together
Fragmented files
- When you save a large file it may not fit on the disk in consecutive memory locations so it is split up
Disk Defragmentation: pros
Read times are far faster
Free space is also in one place so new files do not need to be fragmented
Data compression software:
enable users to compress and decompress files or folders
reduces the amount of storage space needed on a disk
Data compression software: pros
If sending the files, it reduces the amount of data that is sent
Compression may allow attachments to be sent via email that would otherwise have been larger than a file-size limit
More data can be stored on backup media
