Transcript (PPTX, Unknown)

Chapter 3: Software
Explain the difference between systems software and application software
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).
Software categories
• System 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.
System software
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
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Windows Vista,
Windows 7,
Unix,
Linux
MacOS.
Application
software
Operating system
Hardware
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
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.
System software
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:
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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.
System software
Drivers
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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!
System software
Drivers (cont.)
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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.
Applications software
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 email, 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
Applications software
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.
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?
Applications software
Issues to consider when acquiring
software
• Is it better to buy proprietary software or
open-source software?