Q&A-Operating Systems

What is an Operating System?

• It refers to a system software that provides a platform for installation and execution of an application software and also manages the computer hardware

State three categories Operating Systems grouped according to user interface

• Commandline/ Character interface Operating systems
•  Menu Driven Operating Systems
•  Graphical User Interface Operating Systems

Identify and describe four roles of the operating system when managing the resources of a personal computer.

Manages memory (RAM) 

• Allocates memory to programs currently executing •

Ensures programs/data do not corrupt each other: Ensures all programs and data including itself is stored in correct memory locations

Manages processes: Ensures different processes can utilise the CPU and do not interfere with each other or crash •

Allows a user to run programs : On a multi-tasking O/S ensure that all tasks appear to run simultaneously

• Allocates time slices 
• Scheduling of programs
• Handles interrupt
• Allows a user to configure hardware

(b) The computer needs an operating system and utility software.

(i) The operating system controls the scheduling of processes.

Describe how the operating system uses scheduling to allocate processor time.

 

• All processes are held in a queue 
• Processes are prioritised 
• Processes are switched On each clock cycle

 Describe four features of the operating system when providing a graphical user interface on a personal computer. Give a suitable example of each feature.

Windows for example a word processing application and a spreadsheet
 
Menus, for example, allow the user to perform operations or run applications such as right-click to create a new folder  
 
Icons for example a picture of linked computers for networking
 
Pointers(mouse or touchscreen)  for example to select items/trigger events  
 
Shortcuts for example to frequently used applications for example having a shortcut to your mail client on your desktop
 
File navigation for example when searching the hard disc for a file/folder using a browser
 
copying / deleting / moving/sorting/naming/searching of files or folders for example copying of a file from the hard drive to a USB pen drive (File handling)
 
Desktop customisation for example changing the colours and background image
 
Copy and paste for example between applications e.g. copying a graph from a spreadsheet to a word processor
 
Error messages for example provide users with error/warning/help messages for example ‘printer out of paper’ 

Identify and describe four roles of the operating system when managing the resources of a personal computer.

Manages memory (RAM)

•  Allocates memory to programs currently executing 

Ensures programs/data do not corrupt each other

• Ensures all programs and data including itself is stored in correct memory locations

Manages processes

• Ensures different processes can utilise the CPU and do not interfere with each other or crash  

Allows the user to run programs 

• On a multitasking operating system, it ensures that all tasks appear to run simultaneously 

Other roles

• Allocates time slices
• Scheduling of programs
• Handles interrupts
• Allows the user to configure hardware

Describe four features of the operating system when providing a graphical user interface on a personal computer. Give a suitable example of each feature.

• Windows for example a word processing application and a spreadsheet

• Menus, for example, allow the user to perform operations or run applications such as right-click to create a new folder  

• Icons for example a picture of linked computers for networking

• Pointers(mouse or touchscreen)  for example to select items/trigger events  

• Shortcuts for example to frequently used applications for example having a shortcut to your mail client on your desktop

• File navigation for example when searching the hard disc for a file/folder using a browser

• copying / deleting / moving/sorting/naming/searching of files or folders for example copying of a file from the hard drive to a USB pen drive (File handling)

• Desktop customisation for example changing the colours and background image

• Copy and paste for example between applications e.g. copying a graph from a spreadsheet to a word processor

• Error messages for example provide users with error/warning/help messages for example ‘printer out of paper’ 

Interfaces enable computer users to interact with the operating system.

(a) State four advantages for using a graphical user interface in loading programs and files

(b) A vehicle assembly company has introduced robots to replace the human workforce.  State two effects this would have on the workforce

State four advantages for using a graphical user interface in loading programs and files

• User friendly
• No need to know command language as commands are executed by clicking on icons
• Allows multitasking as several programs open at the same time therefore easier to switch between applications
• Selecting an item using a mouse is easier and faster than entering commands

Or any other correct response

Advantage @ 1 Mark

Total = 4 X 1 Mark

= 4 Marks

 

A vehicle assembly company has introduced robots to replace the human workforce.  State two effects this would have on the workforce                

• Unemployment
• Need to retrain
• No longer need to do hazardous or tedious jobs
• Employment of skilled staff who will manipulate the robots

Or any other correct response

Effect @ 1 Mark

Total = 2 X 1 Mark

= 2 Marks

Distinguish between a file and a folder

A file is a collection of related data given a unique name while a folder is named storage location on a storage media that contains related files

Define disk formatting and state three reasons for formatting a disk

Definition

• Disk formatting is the process of preparing a data storage media for initial use

Reasons:

• To make a disk blank for reuse
• To make it compatible with another operating system
• to create tracks and sectors for first time use

State ways in which an OS secures a computer system

• Access Controls: Authentication of users in order to access files
• Performing regular patches of updates
• creating secure accounts with required privileges
• scrutinizes all incoming and outgoing packets of data through a firewall
• encryption of data, during transmission
• Log files to detect any breach

Describe two different functions performed by an operating system

Memory management

• Manage the computer’s memory;
• It can control which parts of the memory are being used by which process

Processor management

• Manage the computer’s processor(s)CPU;
• Schedules of which processes are to be executed;

Input/output management

• Manages input/output devices;
• Interacts with/manages/handles the (automatic) installation of device drivers;
•  Handles peripheral device interrupts;
• the computer can communicate with the outside world;
• Control network communication;
• Allow devices to send and receive data;

Managing storage

• Manage secondary storage devices;
• Loading data and programs into the computer’s memory;
• Storage space management (disk quotas);
• To ensure that storage space is allocated fairly and efficiently to specific tasks\users;

Managing security

•  User authentication;
• To make sure that users must prove who they are to access the system;
• Protect against malware;
• Block access to specific vulnerable operations or system areas. For example, software can only be installed with admin access;

Managing applications

• Control access to applications;
• Prevent users or processes from using unauthorised programs // allow users or
• processes to use authorised programs;
• Control application access;
• Prevent/allow an application access to data (or devices);

 

Give two reasons why some microprocessor controlled devices do not require an operating system

• They run only one program/task
• OS would increase development and manufacturing cost as more storage will be needed

Shaneela is designing and coding a website. The files she creates will be stored on
a computer.
(a) File management is a function that an operating system performs.
Describe how an operating system organises files

The organisation of files is in a hierarchy/tree structure
A node is either a folder/directory/sub-folder/sub-directory or the file itself
The top node/folder/directory/drive is the root

Describe the following features of a graphical user interface:

(a) Pointer

(b) Desktop

(a) Pointer

•  A graphical object on a computer screen that responds to move movement and allows the computer user to select and execute commands in graphical user interface operating systems

(b) Desktop

• It Is a special folder in the file system that is displayed when no other windows are open

• Explain the purpose of an operating system

• provides an interface between the computer user and the hardware
• Manages the allocation and deallocation of the CPU to processes.
• manages Input-output devices by use of drivers

Compare and contrast CLI and GUI

CLI

• Commands have to be typed in full with no mistakes
• Requires memorization of commands
• Uses less memory

GUI

• Due to graphics, GUI uses a lot of memory
• GUI is more user friendly
• Cannot operate properly if memory is low

Comparison

• Both carry out file management
• Both are operating systems
• Both control software and hardware

What is a defragmentation software

• It is a utility software that places file data in adjacent sectors to free up space for more data and reduce access time for files stored

Distinguish between application and system software

• Application software refers to software that is designed to help the computer user to accomplish specific tasks
• Examples of application software include; Internet browsers, word processors, spreadsheets, databases etc
• System software is software that performs tasks needed to operate the hardware and provide services to other software
• Examples Operating Systems, Networking software, utility programs(encryption, backup, disk defragmentation software, ...)

Explain how the operating system performs job/process scheduling/management

• The OS allocates CPU time to each process, and prioritises them in the order of importance

What is utility software?

• System software that analyses, configures, optimises and maintains a computer system

Which files are backed up in an incremental backup scheme?

• Any new or changed files since the last backup

State Examples of utility programs

 

Encryption software

• Scramble/encode/mix up data so it cannot be read/understood if intercepted/stolen

Defragmentation s/w

• Move free space together and Move files together hence enabling Faster access to files

(Data) compression s/w

• Reduce the file size of files or makes files smaller inorder  To use less storage space
• enables Faster transmission
• enables storage of more files

Anti-virus / anti-malware s/w

• To help protect computer/data against viruses/malware
• To scan the computer to look for/quarantine/remove viruses/malware

Disk analysis and repair s/w

• Scan disk and look for faults
• Prevent the loss of data due to faulty disk

Auto-update

•  Checks Internet for new versions of software/OS
• Downloads and installs without user interaction

Firewall

• Examine incoming and outgoing traffic
• To help restrict/prevent unauthorised access over a network

 ...over a network/external source

State ways of identifying illegal copies of an operating system

• No licence agreement as a certificate of authenticity
• Prices that are extremely cheap
• No documentation manual
• when one connects to the internet for authentication, the report from the manufacturer indicates that the user may be a victim of software counterfeiting
• frequent runtime or occurrence of fatal errors when using the machine

State three features of a typical operating system

- (provides) user interface
– input/output control
– security
– handling interrupts
– spooling
– memory management
– processor management
– utilities (e.g. copy, save, delete, re-name, etc.)
– maintain user accounts
– load/run software
– error reporting/handling
– multiprogramming
– batch processing (JCL)/real time processing
– multitasking/multiuser/multi-access
– file management

Define patch as used in the operating system

Refers to a small piece of software designed to update, fix, or improve a specific part of the operating system or an application.

NB: Patches are typically released by the software's developer or the operating system vendor to address security vulnerabilities, software bugs, or to add new features or enhancements

a) What is an operating system? (1 mark)

b) Briefly explain any four functions of an operating system. (8 marks)

c) Describe each of the following data processing methods: [6 marks]

a) What is an operating system? (1 mark)

• It is a system software that manages the computer hardware. It provides a platform for installation & execution of application software.

b) Briefly explain any four functions of an operating system. (8 marks)
Interrupt handling - When an interrupt occurs, the current state of the CPU is saved & the OS handles the request, after which the OS restores the previous state of the CPU & resumes the interrupted process.
Process scheduling - OS decides which process runs next & for how long.
Memory management - Ensures that each process has enough memory allocated to execute without interfering with other processes.
Error handling - OS provides a mechanism to detect & respond to errors such as segmentation faults, hardware failures, or invalid instructions.

 

Briefly describe the following

Multitasking - the  capability of an operating system to enable users to run two or more programs at once on a single computer

Real time processing - data processing system in which the time interval required to process and respond to inputs is so small that the response itself is useful for controlling the physical activity of a process

Time-sharing processing  - a processing mode in which the central processor serves two or more users with different processing requirements (tasks)

On-line processing - is that type of processing where the result of data processing transaction is available immediately