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.
Hardware - Physical components of a computer
System Software - Manages and operates hardware (includes OS software & Utility Software)
Think OS as a car and Utility as its MOT
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.
OS - Allows user to interact with hardware; controls hardware & software and provides a user interface for use and input to hardware
Memory Management - e.g. Moving data between RAM-Secondary storage/Virtual memory
File Management - e.g searching/copying/moving/renaming files and folders and storing in secondary storage
Hardware Management - e.g. communicating with peripheral devices, installing drivers to allow communication.
Process Management - e.g. creating/terminating processes, allocating tasks to CPU & handling interrupts
Security Management - e.g. Controlling system and resource access on computer.
User Management e.g. multiple users having own accounts on computer, the OS retains settings and resource access.
Performs general housekeeping that help monitor/manage/maintain a computer
Can only perform 1 or 2 tasks
Disk Formatter - Wipes contents of storage device and prepares it for new data
Virus Checker - Detect/prevent/remove malware and viruses
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)
Disk Repair - Attempts to correct corrupted files & restore them to original working states
File Compression - Uses algorithms to reduce file storage space required.
Back-Up - Keeps copy of data on another storage device (data can be recovered if lost/stolen/damaged)
Software is programming code
Software libraries are sections of code previously written by other authors and contain useful routines for common tasks (saves others writing them themselves.)
e.g. Random number
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.
Files store self-contained/library of previously compiled codes.
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
Only need to be loaded into memory when required, therefore don’t need to be stored in memory throughout whole execution of program.
Made available to several programs simultaneously therefore no duplicated code is stored to memory throughout program execution.
If DLL file is updated, all programs linked to it can run the update.
Con’s
Code isn’t self contained, all DLL files need to be available at run time otherwise error messages/crash
any DLL linking software needs to be available at run time
if DLL has been changed (purposefully/corrupted) could lead to unexpected results/crashing
DLL could have malware which could transfer to main program
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.
Hardware - Physical components of a computer
System Software - Manages and operates hardware (includes OS software & Utility Software)
Think OS as a car and Utility as its MOT
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.
OS - Allows user to interact with hardware; controls hardware & software and provides a user interface for use and input to hardware
Memory Management - e.g. Moving data between RAM-Secondary storage/Virtual memory
File Management - e.g searching/copying/moving/renaming files and folders and storing in secondary storage
Hardware Management - e.g. communicating with peripheral devices, installing drivers to allow communication.
Process Management - e.g. creating/terminating processes, allocating tasks to CPU & handling interrupts
Security Management - e.g. Controlling system and resource access on computer.
User Management e.g. multiple users having own accounts on computer, the OS retains settings and resource access.
Performs general housekeeping that help monitor/manage/maintain a computer
Can only perform 1 or 2 tasks
Disk Formatter - Wipes contents of storage device and prepares it for new data
Virus Checker - Detect/prevent/remove malware and viruses
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)
Disk Repair - Attempts to correct corrupted files & restore them to original working states
File Compression - Uses algorithms to reduce file storage space required.
Back-Up - Keeps copy of data on another storage device (data can be recovered if lost/stolen/damaged)
Software is programming code
Software libraries are sections of code previously written by other authors and contain useful routines for common tasks (saves others writing them themselves.)
e.g. Random number
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.
Files store self-contained/library of previously compiled codes.
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
Only need to be loaded into memory when required, therefore don’t need to be stored in memory throughout whole execution of program.
Made available to several programs simultaneously therefore no duplicated code is stored to memory throughout program execution.
If DLL file is updated, all programs linked to it can run the update.
Con’s
Code isn’t self contained, all DLL files need to be available at run time otherwise error messages/crash
any DLL linking software needs to be available at run time
if DLL has been changed (purposefully/corrupted) could lead to unexpected results/crashing
DLL could have malware which could transfer to main program
