1.2 System Software

Question 0

What does the operating system do?

Answer 0

• It manages the physical resources of the computer. Some resources are limited and must be managed to maximise the use of the computer system.
• It provides a user interface
• It provides a platform on which the application software can run
• It controls access to the computer system, allowing the user to put passwords on files

Question 1

When using application software are you directly communicating with the computers hardware?

Answer 1

No - The application software communicates with the operating system which communicates with the hardware on its behalf

Without an operating system the computers useless no matter how many program’s there are

Question 2

What is batch processing?

Answer 2

A type operating system that doesn’t allow any interaction between the computer and the user. Lots of data are collected together to for a batch and they are processed all at once.

Question 3

What are the uses of batch processing?

Answer 3

• Where there are large amounts of data to be processed
• When the data are very similar in nature and require similar processing
• When the computer system has identifiable times when it is not being used and so has available processing time
• When the application doesn’t require user interaction

Question 4

Give examples of when batch processing would be useful

Answer 4

• The processing of pay roll information
• The production of bank statements from customer files at periodic intervals
• Production of utility bills from customer records

Question 5

What is a realtime operating system?

Answer 5

An operating system that can react quickly enough to affect the next input or process that needs to be carried out

• There is a continuous cycle of input, process or output and there is no waiting time between init and processing
• The processor almost always must be dedicated to the running job and cannot multitask

Question 6

What are some of the uses of realtime processing?

Answer 6

Most realtime systems are used in real world situations (where they process on a time scale of milliseconds), such as:

• A computer that controls the temperature in chemical plants reaction vessel. It receives input from a monitor. It uses realtime processing to ensure that the temperature stays within a certain range.
• A processor that controls a robot trolley and ensure that it doesn’t go beyond a black line. The processor receives input from a sensor. It uses realtime processing to ensure that the trolley stays within the black line.

Question 7

What is a single user operating system?

Answer 7

An operating system which has only one user and their program’s at a time

-Exclusive access to processing and storage facility for a single user

• However it’s idle most of the time
• User usually doesn’t use the full processing power

Question 8

Where would a single user operating system be used?

Answer 8

On a stand alone computer or a laptop it would be used so that only one person uses the computer system at a time but there can be different users at different times.

-This means security measured are important so that files are accessed by the right user

Question 9

What is a multi user operating system?

Answer 9

An operating system that allows the computer to service more than one user simultaneously

• There are two types of multiuser operating system:
• The network OS
• The time sharing OS

Question 10

How does the multi user operating system work?

Answer 10

In the network OS
-There is a single computer which is connected to a number of terminals. These terminals are not computers and have a very limited amount of processing power, therefore they rely on the main computer to carry out processing.

In the time sharing OS
-The computer sends a message to each of the terminals, asking if it wants any processing to be done. This is called a time sharing system or a round robin system, where each terminal gets a small amount of processor time called a time slice

Question 11

How do you ensure a time share system operates effectively?

Answer 11

• The main computers also known as a server and it saves the application software and user data files.
• The system needs to be fast enough that a user doesn’t have to wait for too long before being given processor time
• The response time for all users should be acceptable in order for this method to be effective

Question 12

What are the advantages and disadvantages the network OS and the time sharing OS?

Answer 12

In the network OS

• Centralised servers are more stable
• Security is provided by the server
• Cost of buying and running are expensive
• Requires regular maintenance and updates

In the time sharing OS

• It allows processing and storage to be utilised at full extent
• Hardware and software is shared
• Increases the risk of failure
• Data security is of concern

Question 13

What is a multitasking operating system?

Answer 13

This is an operating system that allows several applications to be available simultaneously

-This is done through the processor switching quickly between each program

Question 14

What is the user interface?

Answer 14

This is the way in which the computer system interacts with the user
This is also known as the human computer interface (HCI)

-The users give an input (e.g. The click of a mouse) and the computer gives a response

Question 15

What is the form based interface?

Answer 15

This is an interface that allows the user to input information into an on screen form. This is very useful if the majority of the input to a system is standardised.

-An example where this would be used is an operator inputting informations about a customer, into a database

Question 16

What are the advantages of the form based interface?

Answer 16

This interface:

• Prompts the user to ask each of the questions in turn
• Makes the user input information in the correct order and ensures that nothing is missed out
• Ensures that the user enters the information in the correct format
• Makes the checking of information easier

Question 17

How is a form based interface layer out?

Answer 17

In this interface there can be:

• A drop down list for restricted input, such as the persons title or a date
• Boxes for textual information, like the name or address of a customer
• Check boxes for yes or no information

Question 18

What is a menu based interface?

Answer 18

This is an interface used in situations where the user is unsure of the options available

-An example of this is information systems used for tourists. A list of choices is displayed and when the user selects an option, a further set of choices is displayed, and so on until a result is achieved

Question 19

What is the graphical user interface (GUI)?

Answer 19

This is the use of windows, icons, menus and pointers (WIMP) by the computer to interact with the user

• The user of the GUI expects it to be able to view different applications or files on the screen at the same time. This is done by putting each application into its own bordered are known as a window
• The user can select a command by clicking on a small picture (icon) that represents it and the user selects further options from menus, these are selected through the use of a pointing device such as a mouse

Question 20

Give an example where GUI can be used

Answer 20

The whole principle of GUI is to make using the system as simple as possible by hiding all the complicated bits

An example of this is when the user clicks on an icon that brings a piece of software to the screen, it involves only the action. However in the backgrounds, the computer is executing a complicated process involving a lot of instructions

Question 21

What is the natural language interface?

Answer 21

This is when the computed displays or speaks questions that gives the user the impression that the computer is talking to them

However the system restricts itself to questions that will provoke very simple responses which the computer can understand and the user must give an expected answer

Question 22

What is the command line interface?

Answer 22

In this interface, the user types a series of commands on the keyboard and the computer displays an output

-The computer doesn’t prompt the user to enter any particular information. If the user types a command incorrectly, the computer will output an error message

Question 23

In a command line interface, what is required of the user?

Answer 23

In a command line interface the user must:

• Know what commands are avaliable
• Understand the commands
• Understand how material is stored in the computer

Question 24

What are the main features of a command line interface?

Answer 24

In a comma line interface:
-The computer system is much more open

• Allows anyone who knows the commands of the computer, to have full access to the operating system and workings of the computer
• Can only be used by people who are computer literate. Users need to understand the commands and their uses
• The user also needs to understand how the computer operates in order to use this interface effectively

Question 25

What is utility software?

Answer 25

These are program’s that carry out tasks necessary for the operation of the computer

Question 26

What are the types of utility software?

Answer 26

Disk formatter software
Hardware drives software
File handling software
Automatic backup or archive software
Anti-virus software

Question 27

What is a disk formatter?

Answer 27

This is software that prepares a storage device for storing data

-The disk formatting process divides the disk into smaller areas, each of which can be searched more easily

Question 28

What are hardware drivers?

Answer 28

This is software that control the communication between the device and the operating system

-Any hardware device needs to be controlled and set up for communication with the processor

Question 29

What is the file handling utility program?

Answer 29

This is a utility program which is responsible for merging, sorting, storing and retrieving files

-These program’s organise data stored on a computer system into files

Question 30

What is the automatic backup/archive utility program?

Answer 30

This is a program that stores a computer systems data into a storage device, this is normally done at at periodic intervals

-This is done so that, if the original files are lost or damaged, they can use the back up files instead

Question 31

What is anti virus software?

Answer 31

This is a utility program that continually compares a dictionary of known viruses against the files accessed go the computer

• A computer virus is a small program that can reproduce itself
• It alerts the user if any of the files matches a virus signature. It is crucial that a virus dictionary is kept up to date on a daily basis, as new viruses are constantly appearing

Question 32

What is file compression software?

Answer 32

This is a utility program that reduces the size of a file by cutting out much of the duplications of data in the file