Operating Systems

1) An operating system is necessary because it: 

• – controls the backing store and peripherals such as disk drives and printers
• - controls the loading and running of programs
• -organises the use of memory between programs
• -organises processing time between programs and users
• -organises priorities between programs and users
• - maintains security and access rights of users 
• - deals with errors and user instructions

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  2) 4 tasks than an operating system does:

• –deal with the transfer of programs in and out of memory
• –allow the user to save files to a backing store
• –control the transfer of data to peripherals such as printers
• –provide the interface between user and computer - for example, Windows XP and OSX

3) 4 Brands of an operating system: 

1. Microsoft Windows 
2. Apple Mackintosh 
3. Linux 
4. Samsung 

4) Multi-tasking operating system:

A operating system can manage many people on the it at the same time by having a central processor which will allocate time slices to each user within the system.

5) Utility Programs

A utility program provides a 'toolbox' of common tasks which help the computer to run more efficiently. A utility program can:

1. manage folder now 1.5- this can hide folders and create short cuts to the folders being viewed
2. novaPDF.std 1.2 - this will print any document to a PDF file 
3. IsoBuster 1.9 - this will recover data from a DVD or CD 

6) Transaction Processing

Inputs are noted by the computer, but it deals with them after a short delay. It spends that delay handling other inputs and managing data movements.

The delay may be so brief that it looks to you as if it has happened straight away. But in terms of 'computer time', where each computer cycle is far less than a millionth of a second, it will have spent many cycles doing other things.

• Booking tickets
• Ordering books online 

7) Batch Processing  

It is often not desirable to deal with the inputs until a certain number have occurred or a set time has passed.  So they are stored until the system comes online to process the data in one 'batch'.

• Producing money bank statements 
• Electricity, gas and telephone bills calculated on a monthly basis

 8) Operating System or Application?

1. Controlling the engine management for a car - APPLICATION 
2. Writing a letter - APPLICATION 
3. Backing up the system - OPERATING SYSTEM 
4. Calculating company accounts - APPLICATION
5. Allocating memory to allow programs to run - OPERATING SYSTEM 
6. Writing a report - APPLICATION 
7. Communicating with a printer - OPERATING SYSTEM 

User Interfaces

DEFINITION 

The user interface is what you see on the screen when the computer is running.  It consists of the cursor, prompts, icons and menus that allow you to use the computer to get something done.

TYPES OF USEFACE

COMMAND LINE INTERFACE                    

                          

To use the command line interface you will need to know all of the exact fuctions to be able to type the in to perform the operation on the computer.  

Advantages

• If user knows commands it can be much faster than using lots of menus
• It does not need windows to run
• It does not take up much memory to run

Disadvantages

• Commands have to be typed in precisely
• Can be confusing to understand commands
• Cannot guess instruction
• A lot of commands need to be learnt

DOS means 'Disk Operating System'. This was created before windows and can be used to do simple operations such as paste and copy.

MENU INTERFACE

This type of userface lets the user interact with a computer or device by going through a series of menus. Menu interfaces can be visual or verbal e.g a cinema phone service or a cash machine.

Advantages

• They are easy to use
• No commands need to be learnt
• They are user friendly
• They do not need to be visual

Disadvantages

• If there are too many levels it can get annoying
• It is essential that they are well designed
• You cannot go to the exact place that might be required first

GRAPHICAL USER INTERFACE

A graphical user interface is the most common type of userface that is used today.

Windows

- a rectangular area where operations are usually performed

 Icons

- a picture of symbol to represent a hardware device

Menus

- a list of options that the user can perform reguarly

Pointers

-  a symbol such as an arrow to help move around the screen

 Advantages

• Easy to use (especially for beginners
• Easy to find a way round using WIMP
• There is usually a help system if the user gets stuck
• Data can be exchanged through different softwares

Disadvantages

• It takes up a lot of hard disk within the computer
• They usually need more RAM to be able to run
• They can be slow for experienced workers to use

Web Logs and Social Networking

WEBLOGS

PURPOSE

A weblog is a website for providing commentary, personal thoughts on news or a particular subject. Blogs can be stored on a server with a to the internet or more usually on a server owned by someone else

FACTS

• Blogs enable other people to comment on the material posted 
• Blogs can be created quickly by anyone with an internet connection
• Blogs can be considered as journals. 

USE

Blogs can be used by anyone who wants to get a message across. There are blogs about a lot of things. These are the most popular:

• Personal Online Diaries - lets you know what people are up to
• News - this can be the news from ordinary people or professional journalists
• Entertainment - you can post information about good and bad concerts, films, books
• Food - people can let others know about good and bad restaurants and exchange recipes 
• Politics - many politicians have their own blogs in which you can let them know whether they're doing a good job or not 

Examples Of Blogs 

SOCIAL NETWORKING

PURPOSE

Social networking sites are the use of computers connected to the internet to keep in touch with friends, exchange photos, post status' etc. 

ADVANTAGES 

• Helps build online communities 
• Allows you to make friends 
• Useful place for expressing your opinion on matters
• Allows you to find out what your friends and family are up to
• Useful place to exchange photographs 
• Students can access blogs so they can chat about their learning and help each other

DISADVANTAGES

• Your image might be posted on an inappropriate website
• Pedophiles use blogs and social networking sites to obtain images 
• You may be identified from your image even though there are no contact details
• Employers sometimes look at profiles of job applicants on social networking sites to see if they are suitable for a job
• Addiction to social networking sites as some people cannot go for more than a few minutes before the need to check the sites
• You may encounter stalkers or be pestered by e-mail, or worse still they may find out where you live and your phone numbers 

FACEBOOK

This can be used as a way to keep up to date with friends online. Facebook offers a great way of getting in touch with people you have not kept in contact with. 

MYSPACE 

Myspace is a site that is held together through the connection of music. Many people put personal details on this website and although some settings allow you to see this, you can set your profile to private.

ICT Laws

COMPUTER MISUSE ACT

PURPOSE
The Computer Misuse Act was passed in 1990 to deal with misuses of the computer.
The act made it an offence to:

1. deliberately plant viruses to damage programs and data 
2. use an organization's computers to carry out unauthorized work 
3. hack into someone else's computer system with a view to seeing the information or altering it
4. use computers to commit various frauds.

1 - Computer Viruses 

A virus is a program that replicates itself automatically and usually carries some payload that may cause damage. 

Protection against viruses:

• Install virus checking software
• Preform regular virus checks
• Do not open file attachments from unrecognized users
• Treat all files with suspicion 

Most viruses are designed to do something apart from copying themselves they also:

• Display annoying messages on the screen
• Delete programs or data
• Use up resources making the computer run slower 
• Spy on online use and collect passwords, usernames and card number to make illegal purchases

3 - HACKING

Hacking is attempting to or actually gaining access to in ICT system without permission. 
Protection against hacking:

• Firewalls - filter out unauthorized requests from outside users to fain access to a network. They also filter data so that only allowable data comes into the system
• Intrusion Detection - this detects unwanted attempts of accessing a computer system usually by seeking out hackers from the interned. 

Once a hacker has gained access they may: 

• Do nothing and be content that they have gained access
• Gain access to sensitive or personal data 
• Use personal data to commit blackmail
• Cause damage to data
• Deliberately alter data to commit fraud

Copyright and Patents Act

PURPOSE

The act was introduced to protect the investment of time, money and effort by people who create an original piece of work to ensure that this could not be claimed by someone else. 

The two main purposes are:

1. To ensure that people are rewarded for their endeavors 
2. To give protection to the copyright owner if someone tries to steal or copy their work

Generic Software

OVERVIEW

There are many different types of computer "applications" software. Whilst some is custom-designed by specialist programmers to perform one task, most is generic, providing features that can be adapted for a variety of different tasks.

GENERIC

• Save
• Refresh
• New Page
• Play
• Settings 
• Print 
• Back 
• Zoom in
• Zoom out 
• Add Page

None-Generic (Windows Only)

• My Computer
• My Internet
• My Documents
• My Pictures
• Recycle Bin
• My Music
• Control Panel 

Networks

DEFINITION 

The situation where 2 or more computers are linked together in some way. 

WAN (Wide Area Network)

A wan is a computer network that spans a relatively large geographical area.

They are connected through:

FIBER OPTIC CABLES        METAL CABLES          SATELLITES 

Less interference              Less Expensive          Very Expensive

TERMINALS

Terminals are a general purpose device for input and output devices

An intelligent terminal do processing that is shared with the central computer 

LAN (Local Area Network)

A LAN is a computer network than spans over a local geographical area that connect computers together so they can share documents and files. 

They are connected through FIBRE OPTIC CABLES. These send signals in a light form that reflect off the mirrors. The cables can be bent and shaped in different ways to reach the computers. 

SERVERS 

FILE SERVERS

This is a computer attached to a network which has the primary purpose of providing a location for shared storage. 

PRINT SERVERS

This is a device that connects printers to computers over the same network. 

NETWORK TOPOLOGIES