1.2 Computers are useless without an operating system
1.3 Manages the computers hardware
1.3.1 Every piece of hardware has a device driver which
enables the software to communicate with the hardware.
1.4 Manages the computers memory
1.4.1 When you close a program the operating
system removes it from its memory to free space
1.5 A Graphical User Interface
(GUI) provides the functionality
that enables you to create and
manage the windows on your
screen and also provides
features such as icons on your
desktop, buttons and scrollbars
1.6 Other features: handling files, security such as handling user names
and passwords, allocating resources on networks such as disk space,
scheduling the CPU processing cycles, moving data to and from the
hard disk and provides servces such as print spooling.
1.7.1 1. Explain what the operating system is used for
The operating system is used to provide a user
interface between the end user and the device
1.7.2 2. Explain what is meant by user interface
A user interface enables the end user to
communicate with the device by providing
an input/output source
1.7.3 3. Explain what is meant by memory management
Memory management is the act of keeping your memory
organized and making sure that there is free space when
you need it
1.7.4 4. Explain what is meant by multi tasking
Multi tasking is when the end user is doing
two or more tasks at once/ running two
programs at once
1.7.5 5. Explain how an operating system uses security
An operating system uses security such as using
user names and passwords to authenticate a
user's identity to make sure that the user is
authorised to make changes to the system.
2 Utility programs
2.1.1 An Anti-Virus quarantines a detected virus to protect important system files.
It also periodically checks the computer for viruses by checking it against a
database. Anti-viruses are needed because they quarantine viruses to
prevent them from spreading and infecting other files
2.1.2 Spyware protection works by warning the user that there is spyware on their computer and gives
the user a choice to quarantine the virus or remove files that are a threat. Another method is using
the spyware protection software to scan the hard disk for known spyware that has been recorded in
a database. This is needed to prevent software that allows a user to gather information about
another computer by transmitting data from their hard drive.
2.1.3 Firewalls work by checking the sent and received data packets between two users for viruses and
confirm with the user if the data packet should be blocked. They also work by informing the user if
they want the file sent to access other files in your computer. This is needed to protect your
computer so that viruses cannot find an open port on your computer.
2.2 Disk organisation
2.2.1 Disk formatting works by preparing a data storage device for initial use, essentially removing all
data from the disk. The formatting operation may also create one or more new file systems. Disk
formatting is needed because if your computer develops a serious problem then disk formatting is
an easy way to solve it and start over.
2.2.2 File transferring works by transferring computer files from one host to another host over a
TCP-based network, such as the Internet. It is also used to double-check by if the information
provided by the client is accepted by the server. File transferring is needed because it enables file
sharing between two computers. For example, without file transferring we would not be able to play
online games with other people because the files holding data about each computers game is not
2.2.3 Disk defragmentation works by rearranging files on a storage device to make finding data a lot
easier for the computer which makes to opening a file quicker and more efficient . It also reunites
the fragmented files to ensure that the data needed to open a file is in the same place. This is
needed to make your computer more efficient and also to speed it up because if your computer
becomes fragmented it means it would keep having to go to different areas to find the data required
to open a file.
2.3 System maintenance
2.3.1 System information works by keeping a record on the operating system of all of the hardware and
details about the operating system. This is useful when someone wants to know details about their
computer. For example, if someone was upgrading a component of their computer they would want
to know if it is compatible with the rest of the components. Diagnosis is used to test if the system is
fully working and everything is working properly. System information and diagnosis are needed to
check information about the components of the computer and what each components status is.
2.3.2 System clean-up tools work by checking the computer for unnecessary files that can be slowing the
computer down or are no longer needed. This tool also helps to clear storage space on the computer
by removing files that are no longer needed. This is needed to clear storage space that is wasted on
irrelevant files such as dead shortcuts.
2.3.3 •Automatic updating works by automatically searching the Internet for updated versions of
software such as the operating system or a web browser and installing the latest version. •It also
works to prevent the latest viruses from infecting your computer by downloading the latest patch to
make sure your computer is protected. Automatic updating is used to ensure that your computer is
up to date with updates and patches to prevent viruses.
3 Software types
3.1 'Off the shelf' software
3.1.1 Advantages: instantly available, cheap, regular
updates, community support online and the
software is heaviy tested for bugs
3.1.2 Disadvantages: may not have all of the software
you need and may have features that aren't
3.1.3 Off the shelf software is ready made software
available to everyone to use.
3.2 Open source software
3.2.1 Advantages: improvements can be made to
programs by other users that have studies the
source code, generally free to buy, more secure
as many will have tested it, can modify software
to fit your needs, can get help from forums and
more customizable as multiple people can edit
the source code.
3.2.2 Disadvantages: can be less user
friendly, malicious users can
potentially view bugs and exploit any
vulnerabilities, less support and relys
on the user to find bugs.
3.2.3 Software which
allows users to view
and modify the
3.3 Proprietary software
3.3.1 Advantages: Free from bugs
and viruses, easy to install,
regular updates, has a user
friendly support network.
3.3.2 Disadvantages: improvements may cost
money, can't edit the software without
permission and you can't share the software
3.3.3 Software which cannot
be copied or altered
without permission of
3.4 Custom written software
3.4.1 Custom written software is tailored to a specific user.
3.4.2 Advantages: tailored to you, doesn't have
features which are not needed, support with
developer, 1 to 1 training, no redundant features.
3.4.3 Disadvantages: very expensive
and takes a long time to be made
- lead time.