Unit 4 - Continuation... Flashcards
(24 cards)
What is an Operating system?
Software that manages and controls a computer’s hardware and provides a user interface
What are the functions of an operating system?
. Provides a user interface
. Manages:
- memory
- multitasking
- peripherals
- files
- user access rights
What are the two types of systems software?
Operating system
Utilities
What is a user interface?
The method by which a user interacts with a computer system.
What are the types of user interface?
. GUI: Graphical User Interface (WIMP: Windows, Icons, menus, pointers
. Menu-driven interface
. CLI: Command line interface (Just text like Windows command prompt)
. Voice activated
. Real-time (sensors detect input, actuators output actions)
What are interrupts?
Signals sent to the CPU by external devices to indicate an event that needs immediate attention
e.g. hardware interrupts - generated by hardware (“printer out of paper”)
Software interrupts - generated by programs( divide by 0 error causes calculation abandonment, and an error message is displayed)
What must the operating system manage in peripheral management?
. Getting input and sending output
. Copying files from disk to main memory
. Copy data files back to the secondary storage
What is a device driver?
A program that controls peripheral devices such as a printer, VDU, CD-ROM, drive, etc.
Each device communicates with the operating systems via its own driver
What are peripherals?
All the devices outside of the CPU.
Includes input and output devices, secondary storage
The access speed of these is relatively slow
What is memory management?
Allocating and managing computer memory (RAM) for different processes and programs.
Computer memory must be managed to ensure that:
. More than one program can run at the same time
. More than one document can be opened at the same time
What is multitasking?
The ability of an operating system to run more than one program or task simultaneously.
Multitasking is possible only if:
. The operating system can support multitasking
. The computer has enough memory to hold more than one program in primary memory at the same time
What is user management in operating systems?
Operating systems also manage users. They allow:
. Individual users to be created and deleted
. Access levels to be given to users, such as administrator rights or standard user rights
. Auditing (keeping a log) of files a user creates, accesses, edits and deletes
What is file management in operating systems?
The operating system allows users to:
. Create, modify and delete files and folders
. Copy and duplicate files and folders
. Move files and folders
. Rename files and folders
. Sort items into different orders, according to name, file type, date created and more.
. Search for particular files and folders
. Restore deleted files
. Set access rights to files, such as read-only or edit
What is the utilities system?
Utility software helps maintain the system and provides extra functionality that make it easier to use
What does the utility software include?
Utility software includes:
. Encryption software
. Defragmentation software
. Data compression software
. Backup software
What is encryption software?
Utilities: Used to transform text so that it cannot be read without knowing the key to decode it.
What is encryption software commonly used for?
. Encrypt files and folders on a portable disk such as a USB memory stick
. Encrypt web communication
. Encrypt data on an organisation’s database
What is fragmentation?
When a file is stored on a hard disk, it is stored not as a whole file, but as a series of segments. Sometimes the segments run together in sequence, and sometimes the segments are split up over a disk. This is known as fragmentation.
What is disk defragmentation?
Utilities: Due to file being fragmented, it may take more processing time to retrieve the data, which would reduce performance.
Defragmenting the hard disk reorganises the files so they are stored together. This allows for the processing time to improve and new files are then not required to be fragmented.
What is data compression?
Utilities: Compression software reduces the size of a file stored on secondary storage.
Smaller files are easier to transmit across a network as they require fewer packets to be sent. Their reduced size also means more files can be stored in any given area of storage.
What is backup software
Utilities: To prevent data loss, regular copies of the data should be made. A copy of data is known as a backup. Backups can contain a copy of all files on a computer, or just ones specified by a user.
What are the two types of backup?
. Full backup
. Incremental backup
What is full backup?
. Complete backup of everything which can be restored independently of any other backup.
. Takes greater time and disk space to create the backup
What is incremental backup?
. Records only the changes made since the last backup
. An entire chain of backups is required to fully restore files
