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Unit 5.1 Operating Systems
Aims
Know the difference between operating system software and utility software
Know the key management tasks performed by the operating system and typical utilities they provide.
Know what is meant by the term program library and the benefits and drawbacks of using these to create programs.
Operating Systems
System Software - Manages and operates hardware (includes OS software & Utility Software)
OS - Manages computers hardware & software and allows communication from user to computer with a user interface
e.g OS is Windows, Utility helps to maintain the OS and run efficiently
Other Software - All others e.g. application and programming software’s installed on top of the system.
EXAM - KNOW DIFFERENT TYPES OF SYSTEM SOFTWARE, INCLUDING ROLES OF OS AND DIFFERENT TYPES OF UTILITY SOFTWARE PROVIDED BY OS.
Management Tasks Performed by the OS - PUSHFM
Process Management - e.g. creating/terminating processes, allocating tasks to CPU & handling interrupts
User Management e.g. multiple users having own accounts on computer, the OS retains settings and resource access.
Security Management - e.g. Controlling system and resource access on computer.
Hardware Management - e.g. communicating with peripheral devices, installing drivers to allow communication.
File Management - e.g searching/copying/moving/renaming files and folders and storing in secondary storage
Memory Management - e.g. Moving data between RAM-Secondary storage/Virtual memory
Utility Software
Performs general housekeeping that help monitor/manage/maintain a computer
Utility Software Provided by the OS BDDDFV
Back-Up - Keeps copy of data on another storage device (data can be recovered if lost/stolen/damaged)
Disk Formatter - Wipes contents of storage device and prepares it for new data
Disk Repair - Attempts to correct corrupted files & restore them to original working states
Defragmentation - Puts separated files back together and stores them in consecutive storage locations, reduces read/write head across disc surface speeding up file access (SSD’s shouldn’t be defrag as no moving parts and could break them)
File Compression - Uses algorithms to reduce file storage space required.
Virus Checker - Detect/prevent/remove malware and viruses
Software Libraries
Software libraries -sections of code previously written by other authors and contain useful routines for common tasks.
Pro’s | Con’s |
Saves time - less code needs to be written. | May increase program size as codes can contain unused lines of code. |
Not as much knowledge needed as expertise of others can be utilized when needing specialist knowledge. | User may not understand how they work, code can be hidden (black-boxed) so efficiency is unknown. |
Codes already been tested so it doesn’t need to be tested again. | Code may be unchangeable, so user may not be able to (or with difficulty) tailor it. |
Two types of program libraries - Static and Dynamic
Static- Software being developed is linked to executable code in library at time of compilation, library routines embedded directly into new program code.
Dynamic Link Library (DLL)
DLL files store collection of self-contained (or library) programs already compiled; provide common tasks which are filed separately but can be linked to a program when executed. used on OS e.g. Save as
Pro’s | Con’s |
Only needs to be loaded into memory when required, doesn’t need to be stored in memory throughout execution of program | Code isn’t self contained, all DLL files need to be available at runtime otherwise error/crash |
Available to several programs simultaneously so no duplicated code is stored to memory | Any DLL linking software need to be available at run time. |
If DLL is updated all programs linked to it can run the update. | If DLL has been changed (purpose/corrupt) could lead to unexpected results/crash |
DLL could have malware which could transfer to main program. |
Unit 5.1 Operating Systems
Aims
Know the difference between operating system software and utility software
Know the key management tasks performed by the operating system and typical utilities they provide.
Know what is meant by the term program library and the benefits and drawbacks of using these to create programs.
Operating Systems
System Software - Manages and operates hardware (includes OS software & Utility Software)
OS - Manages computers hardware & software and allows communication from user to computer with a user interface
e.g OS is Windows, Utility helps to maintain the OS and run efficiently
Other Software - All others e.g. application and programming software’s installed on top of the system.
EXAM - KNOW DIFFERENT TYPES OF SYSTEM SOFTWARE, INCLUDING ROLES OF OS AND DIFFERENT TYPES OF UTILITY SOFTWARE PROVIDED BY OS.
Management Tasks Performed by the OS - PUSHFM
Process Management - e.g. creating/terminating processes, allocating tasks to CPU & handling interrupts
User Management e.g. multiple users having own accounts on computer, the OS retains settings and resource access.
Security Management - e.g. Controlling system and resource access on computer.
Hardware Management - e.g. communicating with peripheral devices, installing drivers to allow communication.
File Management - e.g searching/copying/moving/renaming files and folders and storing in secondary storage
Memory Management - e.g. Moving data between RAM-Secondary storage/Virtual memory
Utility Software
Performs general housekeeping that help monitor/manage/maintain a computer
Utility Software Provided by the OS BDDDFV
Back-Up - Keeps copy of data on another storage device (data can be recovered if lost/stolen/damaged)
Disk Formatter - Wipes contents of storage device and prepares it for new data
Disk Repair - Attempts to correct corrupted files & restore them to original working states
Defragmentation - Puts separated files back together and stores them in consecutive storage locations, reduces read/write head across disc surface speeding up file access (SSD’s shouldn’t be defrag as no moving parts and could break them)
File Compression - Uses algorithms to reduce file storage space required.
Virus Checker - Detect/prevent/remove malware and viruses
Software Libraries
Software libraries -sections of code previously written by other authors and contain useful routines for common tasks.
Pro’s | Con’s |
Saves time - less code needs to be written. | May increase program size as codes can contain unused lines of code. |
Not as much knowledge needed as expertise of others can be utilized when needing specialist knowledge. | User may not understand how they work, code can be hidden (black-boxed) so efficiency is unknown. |
Codes already been tested so it doesn’t need to be tested again. | Code may be unchangeable, so user may not be able to (or with difficulty) tailor it. |
Two types of program libraries - Static and Dynamic
Static- Software being developed is linked to executable code in library at time of compilation, library routines embedded directly into new program code.
Dynamic Link Library (DLL)
DLL files store collection of self-contained (or library) programs already compiled; provide common tasks which are filed separately but can be linked to a program when executed. used on OS e.g. Save as
Pro’s | Con’s |
Only needs to be loaded into memory when required, doesn’t need to be stored in memory throughout execution of program | Code isn’t self contained, all DLL files need to be available at runtime otherwise error/crash |
Available to several programs simultaneously so no duplicated code is stored to memory | Any DLL linking software need to be available at run time. |
If DLL is updated all programs linked to it can run the update. | If DLL has been changed (purpose/corrupt) could lead to unexpected results/crash |
DLL could have malware which could transfer to main program. |
NoteStudied by 9 peopleNoteStudied by 21 peopleNoteStudied by 9 peopleNoteStudied by 10 peopleNoteStudied by 8 peopleNoteStudied by 51 people