Computer Systems: Chapter 5 (Computer Software)

Question 1

What is the bootstrap loader?

Answer 1

The bootstrap loader is a program held in ROM that loads the operating system when the computer is switched on.

Question 2

What are the 6 main functions of a single user operating system?

Answer 2

• Interpreting user commands
• File management
• Memory management
• Input/Output management
• Process Management
• Resource allocation

Question 3

What is the Computer Language Interpreter? (CLI)

Answer 3

The CLI is the outer layer of the operating system, which the user interacts with in order to give instructions to the computer

Question 4

What is the File Management System? (FMS)

Answer 4

The FMS is the second layer of the operating system, and it organises and tracks files

Question 5

What are the functions of the File Management System (FMS)? (2)

Answer 5

• Maintaining a directory which keeps track of where files are stored
• Providing a connections between the user’s logical view of the files and the actual physical location of the files

Question 6

What is the Memory Management System? (MMS)

Answer 6

The MMS is the third layer of the operating system, and controls where programs and data are placed in memory

Question 7

What are the functions of the Memory Management System (MMS)? (2)

Answer 7

• Monitoring the use of memory

* Freeing memory locations where data is no longer needed

Question 8

What is the Input/Output Management System? (BIOS)

Answer 8

The BIOS is the fourth layer of the operating system, and it communicated directly with the peripherals and handles the transfer of data between the peripherals and the processor

Question 9

What are the functions of the Input/Output Management System (BIOS)? (2)

Answer 9

• Data buffering to regulate the speed between the processor and main memory
• Detecting errors such as mechanical or electrical faults

Question 10

What is Process Management?

Answer 10

Managing processes takes place in the Kernel, which is the bottom layer of the operating system. The Kernel manages processes and handles any interrupts.

Question 11

What are the functions of the Kernel (Process Management)? (2)

Answer 11

• Schedules CPU time

* Maintains the integrity of the process

Question 12

What is Resource Allocation?

Answer 12

Resource Allocation is the way of managing which resource is available for use at any one time by a process

Question 13

What is a Utility Program?

Answer 13

A Utility Program is a program designed to carry out .specific tasks related to the management or maintenance of a computer system

Question 14

What are examples of Utility programs? (3)

Answer 14

• Virus Checker
• Disk Editor
• Disk Defragmenter

Question 15

What is a Virus Checker?

Answer 15

A Virus Checker is a program that can detect a virus infection and remove it from a computer system

Question 16

What is a Disk Editor?

Answer 16

A Disk Editor is a program that allows the user to get rid of any unnecessary files that clutter up a system.

Question 17

What is a Disk Defragmenter?

Answer 17

A Disk Defragmenter is a program that rearranges the contents of the hard disk so that data blocks that make up files are next to each other.

Question 18

What are 2 advantages of using a Disk Defragmenter?

Answer 18

• It speeds up access times

* It frees up space

Question 19

Name 3 standard graphic file formats

Answer 19

• .jpeg (joint photographic experts group)
• .gif (graphics interchange format)
• .tiff (tagged image file format)

Question 20

What are the advantages of using a .jpeg? (2)

Answer 20

• It uses lossy compression to cut out data which cannot be seen by the human eye
• They take up less storage space than most formats so can be sent easily

Question 21

What are the advantages of using a .gif? (2)

Answer 21

• Only uses 8 bit colour so takes up less space

* It uses lossless compression so can be used on the Internet

Question 22

What are the advantages of using a .tiff? (2)

Answer 22

• Uses 24 bit colour so can be used in desktop publishing packages
• It can represent every type of graphic from monochrome to greyscale graphics

Question 23

What software would you used to produce a multimedia catalogue and why? (2)

Answer 23

• Mediator Pro 7
• It is a multimedia authoring package
• It allows you to create interactive multimedia presentations combining text, sound, graphics and video

Question 24

What software would you use to set up a LAN in a school and why? (2)

Answer 24

• Windows 2000 Professional
• It is a network operating system application
• It allows you to configure network aspects such as the security, group permissions and network protocols

Question 25

What software would you use to produce a school website and why? (2)

Answer 25

* Microsoft FrontPage * It is a web authoring package * It allows you to create web pages using a full GUI interface, and gives you access to feature such as page templates and sound and video

Question 26

What are 3 software compatibility issues?

Answer 26

* Memory requirements * Storage requirements * OS compatibility

Question 27

Why is memory requirement a software compatibility issue? (2)

Answer 27

* Software needs RAM to hold programs and data when it is being processed * If there is not enough RAM then it will take too long to process.

Question 28

Why is storage requirement a software compatibility issue? (2)

Answer 28

* Software requires a certain amount of backing storage space to be installed * If there is not enough space then a program cannot fit in backing storage

Question 29

Why is OS compatibility a software compatibility issue? (2)

Answer 29

* Some software will have been designed for one specific operating system * If a computer does not have a certain type of operating system then software may not work on the computer

Question 30

What is a virus?

Answer 30

A virus is a destructive piece of software that attaches itself to a file, reproduces itself and spreads to other files.

Question 31

What is a worm?

Answer 31

A worm is a destructive piece of software that spreads from computer to computer via security holes in a network, and then reproduces itself.

Question 32

What is a trojan horse?

Answer 32

A trojan horse is a piece of software that appears to be carrying out a legitimate operation, but is secretly damaging or copying files in the background.

Question 33

What is the difference between a virus and a worm?

Answer 33

A virus needs to attach to another file to spread from computer to computer, a worm does not need to.

Question 34

Name 3 typed of viruses

Answer 34

* File virus * Boot sector virus * Macro virus

Question 35

What is a file virus?

Answer 35

A file virus attaches itself to an application file, and is then activated when the program is loaded

Question 36

What is a boot sector virus?

Answer 36

A boot sector virus infects the system files that your computer uses every time you power up

Question 37

What is a macro virus?

Answer 37

A macro virus is when a destructive macro is attached to a file, and when it is opened this macro duplicates itself into the macro library and spreads even further

Question 38

Name 4 techniques used by a virus to disrupt a system

Answer 38

* Replication * Camouflage * Watching * Delivery

Question 39

What is 'replication'?

Answer 39

Replication is when a virus makes copies of itself to infect other files on a computer

Question 40

What is 'camouflage'?

Answer 40

Camouflage is when a virus disguises itself to avoid being detected by anti-virus software, by adding fake instructions to mask its distinct virus pattern.

Question 41

What is 'watching'?

Answer 41

Watching is when a virus waits until a particular action or data before its activated, to infect the greatest number of systems

Question 42

What is 'delivery'?

Answer 42

Delivery is the method in which the virus carries out destructive tasks to computer systems to infect them

Question 43

Name 4 techniques used by anti-Virus software

Answer 43

* Searching for virus signatures * Use of checksum * Memory resident monitoring * Heuristic detectors

Question 44

What is 'Searching for virus signatures'?

Answer 44

Anti-virus software looks for virus signatures, which are characteristic patterns of bytes which are parts of virus, to notify the user of the virus in the file.

Question 45

What is 'Use of checksum'?

Answer 45

Anti-virus software can carry out a calculation using binary values of an uninfected program. If this calculation changes after it has been run, then the code has been altered, possibly by a virus.

Question 46

What is 'Memory resident monitoring'?

Answer 46

Anti-virus software can constantly monitor a computer for the presence of viruses when it's switched on. If any unusual activity is detected the user is notified.

Question 47

What are 'Heuristic detectors'?

Answer 47

Anti-virus software can look for code that would generally be considered to look like a virus, and notifies the user of these viruses.

Question 48

Why does Fragmentation reduce system performance? 2)

Answer 48

* Unused data blocks are spread across a hard disk and each requires a separate disk access * This slows down access times for files made up of these blocks