general theory

Question 1

operating system

Answer 1

a collection of suite programs that manages and controls the computer. It keeps the details of how this is done hidden from the user

Question 2

the main functions performed by an operating system (4)

Answer 2

1. file management
2. process management
3. hardware management
4. user interface management

Question 3

common operating systems (5)

Answer 3

1. Microsoft Windows
2. macOS
3. Linux
4. Android
5. iOS

Question 4

how is data stored in files within folders within drives

Answer 4

by creating a virtual file structure of the physical components. It has a hierarchal structure starting with the root directory, a bit like an upside down tree

Question 5

the file system assigns meta data to each file including:

Answer 5

1. date created
2. date modified
3. last date accessed
4. last backup
5. file creator user ID
6. access permissions
7. file size

Question 6

functions users can perform on files (6)

Answer 6

1. create
2. name/rename
3. save
4. copy
5. move
6. delete

Question 7

multiprograming

Answer 7

enables several programs to run at the same time

Question 8

process

Answer 8

when some of the program instructions are running

Question 9

what is process management

Answer 9

since the main memory is too small to run all the processes, the operating system uses multi-processing to allocate the use of the main memory and the CPU.

Question 10

what is hardware management?

Answer 10

when the operating system manages input and output from hardware devices and the use of any resources needed by a process

Question 11

input/output management

Answer 11

device drivers allow devices created by different manufacturers to communicate

Question 12

resource management

Answer 12

the operating system allocates the required resource to the processes that are currently running. Internally, the operating system ensures that any data and/or instructions in main memory do not conflict with each other, and allocates the memory that the process requires

Question 13

user interface management

Answer 13

operating systems provide interfaces to users of the computer system, allowing them to communicate with the hardware. The operating system uses abstraction to hide complexity from the user

Question 14

the two types of interface

Answer 14

1. graphic user interface (GUI)

2. command line interface/interpreter (CLI)

Question 15

graphical user interface (GUI)

Answer 15

a desktop view where everything is displayed and use WIMP (windows, icons, menus and pointer) to describe the features of this interface

Applications run in windows and all objects (apps, hardware and files) are represented by icons.

Application features are accessible through the use of menus.

Users interact with the interface by using a mouse and onscreen pointer.

GUIs are powerful and easy to use but require a lot of processing power

Question 16

command line interfaces

Answer 16

CLIs are text based. Users control the computer by typing in commands.

CLIs require little processing power and are extremely powerful

but they take longer to learn how to use than GUI

they exist within modern operating systems e.g. the command prompt app in windows, and terminal in macOS

Question 17

utility software

Answer 17

helps maintain the system

Question 18

what is utility software used for?

Answer 18

1. compression
2. defragmentation
3. backing up
4. anti-virus
5. anti-spyware

Question 19

T/F most basic utility is part of the operating system, but additional utilities can also be installed separately

Answer 19

true

Question 20

data compression

Answer 20

compression software reduces the size of a file on secondary storage

Question 21

why do we have data compression?

Answer 21

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

Question 22

fragmentation explanation

Answer 22

when a file is stored on a hard disk it is not stored as a whole file, but as a series of segments. Sometimes the segments run together in sequence and sometimes are split up over a disk

Question 23

fragmentation

Answer 23

the storing of a file in several separate areas of memory scattered throughout a hard disk.

Question 24

why can fragmentation make a computer run slower?

Answer 24

over time, more and more files become fragmented. A fragmented disk takes longer to read from and write to making a computer run slower

Question 25

defragmentation

Answer 25

defragmentation takes the fragmented files and rearranges the segments so that they run contiguously, This decreases the read/write time, thereby speeding up computer performance

Question 26

why do we need data back up?

Answer 26

data can be lost accidentally or deliberately. A user may accidentally delete or overwrite a file or a hard disk may fail, preventing access to any files stored on it. A hacker or malicious user may deliberately delete or overwrite data

Question 26

why do we need data back up?

Answer 26

data can be lost accidentally or deliberately. A user may accidentally delete or overwrite a file or a hard disk may fail, preventing access to any files stored on it. A hacker or malicious user may deliberately delete or overwrite data

Question 27

data back up

Answer 27

regular copies of the data are made to prevent data loss. if data loss occurs, data can be retrieved from backup. The software allows all backed up files to be retrieved, or just special files

Question 28

what are the two types of back up that are possible?

Answer 28

full backup incremental backup

Question 29

full backups

Answer 29

involves making a copy of every file on the computer network. This can require a lot of storage space and can be consuming to make

Question 30

incremental backups

Answer 30

incremental backups take a copy of any new files created since the last backup and of any files that have been edited, such as user documents

Question 31

how do network managers ensure all data is backed up and daily backups are small and less time consuming?

Answer 31

most network managers make an initial full backup and then switch to daily incremental backups

Question 32

anti-virus

Answer 32

scans the computer system, with when activated or automatically at a specific time and identifies potential viruses. Many anti-virus software can delete or fix potential threats.

Question 33

why do we need anti-spyware?

Answer 33

spyware installed without the knowledge of the user, designed to collect data about the user such as personal info or bank details that can be passed on in identity theft.

Question 34

anti-spyware

Answer 34

anti-spyware software can find, then delete, the spyware. Some versions can prevent it being installed in the first place

Question 35

simulation

Answer 35

computer simulation can be used to simulate and model aspects of the real world. Simulation is used to test a theory before it is turned into a physical or practical form

Question 36

why is simulation useful?

Answer 36

physically dangerous situations can be prevented different simulations can give options that can help decision making unnecessary costs can be avoided

Question 37

modelling

Answer 37

a model is a representation of a real life situation