4.1 Types of Software & Interrupts
System & Application Software
The system software provides the services that the computer requires (e.g. OS & utility software). Without this, a system is useless.
Utility Software
Utility software performs specific tasks. They help configure the system, analyse it and optimise it to improve efficiency.
Security Utilities
Antivirus -> scans the system and ensure that files are safe from malware
Encryption -> uses an algorithm to encrypt a file to make it unreadable
Firewall -> monitors network traffic and blocks unauthorised access
Disk Organisation Utilities
System clean-up tools -> removes files that are no longer needed to reduce storage space
Disk defragmentation tools -> rearranges the parts of files on a disk drive
Data Compression Utilities
File compression software -> makes files smaller to take up less storage space
File Backup Utilities
Full backup -> stores all files and software on the system
Incremental backup -> only backs up files and software that have been added since the last backup (more efficient)
Application Software
These are designed to carry out specific tasks. They are the applications that the OS would process and allow users to complete their tasks.
Word processing software -> allows users to create documents Spreadsheet software -> another documents where mathematical calculations are key Presentation software -> allows users to create presentations for an audience Multimedia software -> used to create interactive content, to do with photography and videography Web browsers -> for users to access the internet
Do not use the Microsoft terms in the exam as this will cost you marks!!!
Distribution Methods
Free software -> user can access source code, cost to buy, has the right to edit the software
Freeware software -> user cannot access source code but is free to use, no right to edit
Shareware software -> user is given a trial version of the software for a limited time
Paid software -> user pays a fee to use the software
Know the ethical considerations when distributing software as you may be asked about it.
The Operating System
The OS can do various things such as:
Managing files
Handing interrupts
Providing an interface
Managing peripherals and drivers
Managing memory
Manage multitasking
Providing a platform for running applications
Providing a system security
Managing user accounts
How it all links together?
The hardware has some firmware on it which loads the operating system. In turn, the OS loads the application software. A device is powered off in the same sequence but backwards.
Sample answer:
Performs basic functions of a computer Manages the hardware Provides a platform to run software Provides a user interface
Interrupts
Interrupts will need to ensure that the CPU can stop executing its current program to run code for the overall interruption. Interrupts need to be added to an area called the interrupt service routine.
There are two types of interrupt:
Hardware interrupt (i.e. moving the mouse or pressing something on a keyboard)
Software interrupt (i.e. a program doesn't respond)
The interrupt service routine is simply added to a particular area where a certain set of instructions are sent that will need to be fetched, decoded and executed to complete the commands of the interrupt.
Sample answer:
An interrupt signal is sent to the CPU or processor CPU stops the task its currently doing to service the interrupt An interrupt service routine is used to service the interrupt A message is displayed to the user to notify them
Exam Questions
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