Operating System Flashcards
Access Rights
controls who can and cannot access or edit a file
Execute Access Rights
controls who can access the file
Read Access Rights
controls who can read the file
Write Access Rights
controls who can write to the file
Application Software
programs that perform useful tasks that the user wishes to undertake, e.g. word processors, PowerPoint packages, spreadsheets
Batch Processor
where input data is collected and saved for processing as a single large batch at a later time, thus records are not processed immediately on receipt. Batch processing is usually highly repetitive, involves large quantities of data, is usually performed at off-peak times when the system is idle and usually requires little, if any, human intervention
Block
a sequence of bytes or bits, usually containing some whole number of records, having a maximum length
Brian Kernighan
developed the C programming language in order to develop operating systems without assembly language
Buffer
area of memory used in transfer of data between devices; each hardware device is assigned a buffer during system start-up
Burst Times
amount of CPU time the process requires to complete its execution
Cleanse Operation
removes background noise from a voice input file
CLI
Command Line Interface
text-based interface operated using the keyboard to type commands using key words and parameters. Key words must be typed accurately and may be followed by a series of parameters
Context Switch
the process of saving the state of a currently running process and loading the state of the next process
Deadlock
where two programs sharing the same resource prevent either from executing
Dennis Ritchie
developed the C programming language in order to develop operating teams without assembly language
Device Driver
operates and controls a device attached to the computer
Directory
the location of the file in secondary storage
Disk Thrashing
where the wrong pages are swapped out for virtual memory, causing the system to spend more time swapping pages than completing work, which results in the system becoming unresponsive
Distributed Processor
a collection of independent networked nodes which may have its own hardware associated. System management software brings all the interconnected systems together that co-ordinate individual and collective activities on different nodes and processing its speed across the network allowing many smaller machines to work on the same task
Embedded Processor
have a dedicated function within a larger device, generally have low power consumption and cost and have limited hardware resources meaning the software needs to be written in a bespoke manner
FAT
File Allocation Table
this keeps a record of every cluster on the hard disk and each record points to another record so a chain can be traversed, considered to be a map of the physical locations of files on a storage device, storing file name, time stamp, starting address and access rights
FCFS
First Come First Served
processes are executed in the order they first arrive in the ready queue
File
a data structure that is always stored on a device that is a collection of records
File Heirarchy
a system for organising files on the operating system
File Management
manages file storage
File System
structure used by the operating system to organise and manage files on a storage device, details how data is stored, accessed and organised on a storage device
Folder
something that file allocation tables have no concept of: a folder is merely an entry for a file with special purposes, some are read only, some can be executed and some act as a container for other folders
Force Feedback
uses emulated touch to communicate and affect user sensation by changing physical resistance
GUI
Graphical User Interface
graphics based interface first developed by Xerox in 1981 using WIMP. Often it is merely placed on top of CLI with the CLI acting as an intermediary between the GUI and the OS
Hardware
the physical components of the computer system
Hardware Drivers
software that operates a specific hardware device
Input/Output Management
manages input and output devices
Interrupt
a signal to the CPU indicating that CPU time is required to deal with some event, can be generated by hardware, software and users
Kernel
a part of the computer’s operating system that generally has complete control over everything in the system
Latency
average amount of time taken for the other end of that link to respond
Logical Address
the address at which an item appears to reside from the perspective of an executing application program
New
process starts and the operating system allocates necessary resources
Running
the process has its timeslice and runs
Wait Queue
where the process is placed if it does not finish an operation within the timeslice
Ready Queue
where the process is placed if it is unfinished within the timeslice
Finished
when the process completes and the operating system can deallocated resources
Memory Addressing
memory can be considered as a series of sixed size locations with each location storing one bit of data; knowing the start address and length of the data allows it to be retrieved from memory when required