1. Chapter 3: Software
Explain the difference between systems software and application software

2. What is software?
A computer is an electronic machine that can process data. But it needs to be told what to do in the form of a set of instructions. These instructions are called a 'software program'.
Software allows the hardware to do something useful;  without software, the hardware wouldn't know what it was supposed to do. So software depends on hardware and hardware depends on software. Together they form a computer system.
Software programs are stored as files on a storage device such as the hard disk, DVD or memory sticks.
When they need to run, they are loaded into the computer's memory (RAM).

3. Software categories System software Application software
controls how the computer system works & enables the user to access the system hardware and application software
the Operating System, utility programs and drivers
Application software 
the everyday programs that you use such as Microsoft Office, graphics packages and web browsers.

4. Operating systems The operating system is part of the system software.
All computers and devices have an operating system, they cannot function without one. 
The operating system is a program that allows applications software to communicate with the hardware.
Examples of operating systems are
Windows Vista,
Windows 7,
Unix,
Linux
MacOS.
Application software
Hardware
Operating system

5. Operating system tasks
System software
Operating system tasks
Memory management – organising the memory
Multi-tasking – allowing several programs to run at the same time
Providing basic security – like logins and file user rights.
Sorting out where to store data on disk drives
Dealing with saving, deleting, opening, closing files
Organizing files and folders
Managing data transfer from the CPU to the peripherals e.g. printer, monitor

6. User interface A user interface is part of the systems software.
System software
User interface
A user interface is part of the systems software.
People need a way of interacting with machines such as computers, notebooks, mobile phones, cash machines (ATMs) etc.
A user interface is the software that enables a user to provide instructions to, interact with and control a computer or device e.g. a mobile phone.
The user interface is often part of the operating system.

7. Utility programs Utility programs are part of the system software.
Utility programs are designed to do one or two specific but vital tasks very well.
Some utility programs might be supplied as part of the operating system, others are purchased separately.
Some common tasks carried out by utility programs are:
File compression
File sorting
File renaming
File conversion (e.g. convert a sound file to MP3)
File repair
Disk defragmentation (defragging)
Printing jobs
Backing up data
Anti-virus checks
Note that a utility program only does one or perhaps two of these.

8. Drivers A driver is another essential piece of system software
A driver is a specially written program which translates the commands from the operating system into commands that the hardware will understand. 
Each piece of hardware e.g. printer, monitor, scanner, keyboard etc will have its own driver.  Printers from different manufacturers work in different ways, so a printer from manufacturer A will need a different driver than printer from manufacturer B.
If you try to use a device without the correct driver, then it probably won’t work.  If you do manage to get your new printer working without installing its driver, it will probably just print gobbledygook!

9. Drivers (cont.) System software
When a new operating system such as Windows 10 is first released, the software developers will have been working closely with the hardware manufacturers and so the operating system will contain all of the drivers needed for the hardware currently on the market. 
However, operating systems are only released every 3-4 years and so the operating system will not contain the drivers for any new hardware developed after its release.
When you buy a new piece of hardware, it will usually come with an installation disk which will load the new drivers into the operating system.  Very often, you can also download the drivers from the internet.
Drivers also need to be updated on a regular basis because bugs can be found in the software and as they are found, the developers release a patch or fix. Also, they might release patches which optimise the way the driver works.

10. Applications Software
Applications software is different to systems software. 
They allow you to do your every day tasks on a computer such as writing a letter, sending an , making a poster or downloading a web page
Software applications work through the operating system to gain access to the hardware.
Typical software applications that you might use are:
Word processors, for example, Microsoft Word or the free OpenOffice Writer
Spreadsheet software, for example, Microsoft Excel or OpenOffice Calc
Graphics software, for example, Microsoft Paint, Adobe Photoshop, Corel Paintshop Pro
Web design software, for example, Adobe Dreamweaver

11. Applications Software
NOTE: whenever you write about applications software in your exam, always use the generic term e.g. word processing software, DTP software.
Do not say, 'Word' or 'Excel' unless you are supporting your first statement with an example.

12. Categories of application software
Applications software
Categories of application software
Application software can be classified in different categories:
custom-written software
off-the-shelf software
Is it better to get off-the-shelf software which is ready now, or to commission custom-made software?

13. Issues to consider when acquiring software
Applications software
Issues to consider when acquiring software
Is it better to buy proprietary software or open-source software?