General Purpose Packages - Graphics - eduBuzz.org · General Purpose Packages – SPREADSHEETS A...

Mrs D Hennessey Mr C K Roderick North Berwick High School

General Purpose Packages - Graphics What is a graphic package? A Graphics package is a General Purpose package used to draw pictures. What is it used for? • Drawing pictures to illustrate a report, letter, book • Computer games • Creating computerised designs of objects you want to build (CAD/CAM) • Producing special effect (animations) • Editing scanned pictures or pictures downloaded from a digital camera/www Features of graphics packages Draw Graphic: You can draw graphics such as line, boxes, circles by selecting tools from a tool palette. Tools include: circle, line, pen, paint brush, spray can, freehand, box, pipette, text. Enter Text: Text can be used to label diagrams and pictures. Rectangle Alter tool attribute: Each tool can have its properties changed ie a line can have its thickness changed, a box can have a different shading or colour Scale Graphic: You can change the size of the picture very precisely by entering a percentage number or very roughly by stretching or squashing a picture by dragging one of the handles. Rotate graphic: The user can turn a picture by using free rotation or do a more precise rotation by entering the number of degrees. Images could also be flipped (horizontally or vertically)to appear back to front. Scan & Edit Photographs in a book need to be converted into a digital image using a scanner. These images are usually stored as bit map files and therefore are very large. However they could


be converted to other formats such as JPEG, which is a compressed bitmap. This will reduce the file size considerably. Cropping Cropping removes or cuts parts of the image you do not want. Comparing PAINT and DRAW There are two types of graphics packages. The main differences are to do with how they store the picture and how the picture is edited Painting software (also known as pixel-based software):

• Painting packages are often used to draw artistic pictures or to edit photos or scanned pictures.

• The graphic is saved as a series of small dots called pixels in a file called a bitmap. • Files are large because the information about each pixel is saved. • To edit the image, you basically alter each pixel individually with a pen although there

are lots of different tools to make this easier (spray can, paint brush, paint bucket). • They are more difficult to use because when two shapes overlap the shape, which is on

top, rubs out the shape underneath and is lost. • Enlarging a shape makes it fuzzy. The image looses its definition or sharpness.

Drawing Software (also known as object based software):

• Drawing packages are more suitable for pictures made of simple shapes such as logos and cartoons.

• The graphic is made of shapes called objects. • Each object is saved as coordinates and equations. For example, a red circle might be

represented by its radius, the coordinates of its centre, colour, fill, pattern, line thickness.

• Therefore files are small and their sizes will depend on how complicated the picture is.

• The graphic is easily edited by clicking on the object or if several objects are grouped together. They can be separated before manipulating them. They can be moved, resized, re-coloured, flipped horizontally or vertically, move to be back or to front of other shapes, grouped together…..

• It does not loose definition if you enlarge it. Graphics resolution The quality of the picture is determined by the resolution of the graphics. The smaller the size of the pixels the sharper the picture is and the larger the file is. Also the more pixels there are (Compare 640x640 and 1080x1080) the sharper the picture is (e.g. teletext versus TV) Animation It is the process of moving graphics on screen.


General Purpose Packages – Word Processing A Word Processor is the software/ program/ application that allows a user to do word processing. Word Processing is the act of entering, editing, formatting of words, etc... Word Wrap : the word processor automatically takes a new line when a word that comes to the end of the line is too big to fit. Text Alignment : text can be

• LEFT aligned so that the text starts on the left (jagged on the right); • RIGHT aligned so that the text starts on the right (jagged on the left); • FULLy aligned (justified)so that the text starts on the left (straight on both the left

and the right sides) • CENTRE aligned so that the text starts in the centre (jagged on the left and right)

Text Styles : text can be highlighted by making it bold, underlined and italics To make text fit onto one page or to fit the text into a particular size, one could do the following :-

a. alter the page size (e.g. A4, A5, A3, envelope size, etc…) b. change the margins. Reducing the left and right margins increases the line length.

Reducing the top and bottom margins increases the number of lines per page c. change the page layout from Portrait to landscape d. make the font size smaller e. change the font type

Standard Paragraph are individual paragraphs that are saved as individual files. These paragraphs/ files can be inserted into a document, or letter without having to re-type the paragraphs again and again for different letters. This saves time re-tying data. Example :- estate agents can insert paragraphs/ files into a letter about houses that a customer has requested information about. Search and Replace allows the user to search for a word or words and to replace it with another word or words.

• Global Search and Replace replaces all the words that are found by the word processor automatically, e.g. John with Mary

• Local Search and Replace only replaces the words that the user wants to Spelling Check works as follows :- the word processor has a dictionary of words. It compares each word in the document with the words in the dictionary. If the word is not in the dictionary, then it is a spelling mistake; and, it suggests a few correctly spelled words. If it is in the dictionary then the words are correct. (any words the user knows to be correct can be added to the custom dictionary, so that the spell check knows that these words are correct in the future.)


Note :- Spelling mistakes that are detected might actually be correct. This is because the word might be a slang word, abbreviation, a name or a place. Grammar Check. Some spelling mistakes are not detected as they are grammatical errors; words used in the wrong context. For example :- their, they’re, there, dare; two, too. However, modern word processors have built in Artificial Intelligence. It can detect good and bad grammar and suggest alternative ways to writing a sentence. Tabulation : the TAB key is set automatically, but the user can set tabs wherever needed on the ruler. There are various types of TABS to use, e.g. Left Tab (text starts from the left), Right, centre and decimal tab (for keeping numbers in line with the decimal point TABS help get text laid out in perfect columns. Table : instead of using tabulation, one can insert tables and choose the number of rows and columns (like a spreadsheet ). One can even do simple calculations like sum and average! There is also a facility that allows one to draw a table of any shape and with any number of rows and columns and type text in it. A very useful tool. Page Breaks : this allows a user to go onto a new page without having to press the [Return] key. If the user wants to add a few more lines, it will not affect the page underneath by moving the text down a few lines.

CREDIT A Standard Letter is a letter sent to a lot of people. Most of the content is the same, but parts are different so as to personalise the letter. For example, name, address, customer number, money owed. Standard letters include bills, newsletters, junk mail, etc… Mail Merge is the name given to the process in making standard letters :-

• a word processor is used to create a letter with blanks where the personalised data goes

• a database is used to search for specific records. • the records are then merged into the word processed document to produce the

standard letters (either saved as separate files or sent to the printer for printing) Templates : one can create or use templates. Templates are created so that the same style and layout of document can be used time and time again without wasting time setting up the document. This means that all documents produced from the template are the same throughout and it looks very professional. There are templates available within the word processor like CVs, web pages, professional letters, memos, calendars, etc… Optical Character Recognition (OCR) : you can use a scanner to scan computer or typed text. The software (Artificially Intelligent to detect the English alphabet and characters found on the keyboard) that comes with the scanner converts the scanned images of the text into word processed text. The advantage is that if you have lost or do not have an electronic copy you can get one very quickly without having to type out the text again.


General Purpose Packages – SPREADSHEETS A spreadsheet is made up of ROWS and COLUMNS forming CELLS. Each cell has a CELL REFERENCE (starting with a Column letter and a Row number, e.g. B4) The TYPE OF DATA a cell can contain are Text, Numbers(values) and Formulae. A RANGE OF CELLS is referred to when more than 1 cell has been selected for a calculation or for making a chart Spreadsheets can be used for a multitude of PURPOSES such as :-

• keeping track of your bank account; working out bills, profit and loss; preparing budgets;

• representing data as charts; keeping track of pupils’ register, marks, grades; • as a database to store related information like names and addresses which can be

sorted into alphabetical order or numerical by marks/ grades, etc... SIMPLE FORMULAE that can be used in a spreadsheet package are :-

• + (add) e.g. = A3+A4 • - (subtract) e.g. =B2-B1 • * (multiply) e.g. =A3*A5 • / (divide) e.g. =K11/E4

COMPLEX FORMULAE/ FUNCTIONS

=SUM(B2:B8), which means add a RANGE of values from cell references B2 to B8 =AVERAGE(B2:B8), which means to average all the values between cells B2 to B8 =MIN(C2:C8), which means output the minimum between cells C2 and C8 =MAX(C2:C8), which means output the maximum between cells C2 and C8 =IF(D3>=50,”Pass”, “Fail”), which means if the contents of cell D3 >=50 then output “Pass” else output “Fail”. This is known as a Conditional formula

CALCULATIONS

Automatic Calculation : when a formula is typed in a cell, the answers are calculated automatically. When a spreadsheet is very big and has lots of formulae all over the place, then if a value is changed, the spreadsheet takes a while to recalculate the answers. So, automatic calculation can be turned off to manual calculation. So, when you want the answers to be calculated, just press a button to tell the spreadsheet to do so. Manual Calculation : Enables user to calculate answers or update answers when they are required.

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FORMATTING The spreadsheet can be altered in several ways :-

• Insert or Delete rows and columns • Insert or Delete cells • enlarge or reduce the Column Width and Row Height • data in cells can be centred, left or right justified or centred across columns (many

cells) • Cell protection • the Cell Attributes can be changed

CELL ATTRIBUTES The data in the cell can be changed to look different; such as being a Currency style, percentage, centred or bold, different Font, colour, border, etc... Examples :- 12.78 -> £12:78 Name -> Name 34.567 -> 34% 78.789 -> 78.8

CELL PROTECTION

Data in cells can be protected so that they cannot be deleted accidentally or deliberately. Data that does not change often, like headings and items, and names in a list/ column, certain values like VAT and cells that contain formulae should be protected.

CHARTING Charts can be made by selecting a range cells/ data and with the help of a Chart Wizard. The chart wizard allows you to select bar, column, line, pie and several more type of charts; and then allows you to fully label and format it (shape, colour, etc…). You can add Titles, x and y-axis data, legends and add percentages as well

REPLICATION Replication is a word used when Formulae are copied from one cell into other cell/s. The formulae in the other cells change their cell reference. There are 2 types of replication or 2 methods of copying formulae.

COPYING FORMULAE RELATIVE REFERENCING When a formula is copied down a column, the column letter stays the same and the row numbers change accordingly. Example, Cell G2 =sum(B2:F2) . Copying the formulae DOWN the COLUMN, looks like this :- G3 = sum(B3:F3) G4 = sum(B4:F4)


When a formula is copied across a row, the row number stays the same and the column letters change accordingly. Example,

Cell B10 =sum(B2:B9) . Copying the formulae ACROSS the ROW, looks like this :- C10 = sum(C2:C9) D10 = sum(D2:D9)

This is known as RELATIVE REFERENCING ABSOLUTE REFERENCING When a formulae has a $ sign in front of a cell reference, either the row number OR column letter OR both; and it is copied; the row number AND/ OR the column letter stays the same REFERING to one Row OR Column OR Cell. Example, Cell C2 = B2*$A$1. Copying the formulae down, look like this C3 = B3*$A$1 C4 = B4*$A$1

This is known as ABSOLUTE REFERENCING


General Purpose Packages - Databases What is a database? A Database is a structured and ordered collection of data. A data file is a collection of structured data on a particular topic. It is made up of several records. Each record may consist of one or more fields. A field is an area on a record, which contains an individual item of data. What is it used for? They are used in many applications by many different organisations. Here are a few: • The telephone directory • The Police National Computer • The Inland Revenue • The Driver and Vehicle Licensing Centre • A personal Christmas card list or an address book • A magazine mailing list Features of databases Create fields: When you start a database application, you must create fields to hold the information you want to store You will be ask to enter the type of information and sometimes the size of the field. Types of field: • Text: holds only letters e.g. name, addresses, telephone number such as 0131-667-3456 • Numeric: stores only numbers e.g. price, age, number of items bought • Graphic: holds a picture • Date and Time: contain numbers but organised in a particular way e.g. 12/11/03 or 12pm Computed or calculated Field: A computer field contains a formula to carry out a calculation using another field or fields. Example: The field [VAT] will hold the following calculation =[item cost]*17.5% Key Field: A key field contain an item of data that is unique to that record e.g. a payroll number, a pupil ID, a national insurance number. This helps to find one specific record instantly. Add and edit record: After the fields are defined, the information has to be entered. At this point the database is empty. You must create a new record for each item before entering the data.


Searching or Queries: The searching facility allows you to look through the database for information. You must select the field (simple query) or fields (complex query) that you want to search and type in the details that you want to find ( In Microsoft Access it is called Criteria). Examples: Simple search: You would like a list of all the items costing more than £50.

SEARCH on field Product cost for >£50. Complex search: You would like a list of all the boys in S2.

SEARCH on field gender for M AND on field Class for S2. Searching information on CD-ROM/WWW (Internet): To find information on a given topic, you can use keywords. A keyword will be an important word, which will represent the topic you are trying to find. By choosing your keywords carefully you can save a lot of time when using a database. Simple search: You can perform a simple search by entering a keyword in the search box. Complex search: AND lets you search for articles with two keywords in them. For example Edinburgh AND Castle. This will give you a list of all the articles that contain both the word Edinburgh and the word Castle. OR lets you search for articles with one of two words in them. For example Edinburgh OR Castle. This will give you a list of all the articles that contain either the word Edinburgh or the word castle. NOT lets you search for articles that contain a specified word but doesn’t mention another specified word. For example Edinburgh NOT Castle. This will give you a list of all the articles that contain the word Edinburgh, but not those that contain the word Castle. Sorting: Sorting allows you to arrange the records in some order (alphabetical, numerical). To start a sort, you must choose the field (Simple sort) or fields (complex sort) on which to sort the database and select the required order (Ascending or Descending). Examples: Simple sort: You would like to put the names of pupils into alphabetical order.

SORT on field surname into ascending order. Complex sort: You would like to sort the database of runners in alphabetical order starting with the first one in the race to the last one.

SORT on field Running time into ascending order

AND on field Surname into ascending order

Altering input and output formats: You can choose how the information in your database is presented to you by altering the format. You can set up screen input formats to ease the problem associated with data collection. You can also alter output formats and select fields in the printout and rearrange the position of these fields to produce documents such as invoices.


Validation and Verification: Here are the two main methods of making sure that the data entered is accurate.

• Validation checks that the data is of the right type. Validation is performed automatically by the computer whilst the data is being entered. Here are some examples of validation check:

o A Range check checks that the data is within a specified range e.g. between 1 to 10

o A Presence check checks that important data has actually been entered. o A check digit checks that numerical data has been entered accurately e.g.

check digit at the end of a bar code. o A Data type check checks for example, that text has not been entered where

numbers are needed.

Validation only makes sure that the data is of the right type, not that it is accurate.

• Verification is different. It means making sure that data which has been input is the same as the original. There are two main verification techniques:

o Proof-reading is when a person compares the data entered with the original. Any mistakes is corrected.

o Double-entry is when the data is entered twice by two different people. The computer compares the two versions. Any errors found are corrected.

Verification is time consuming and therefore can be expensive.

Privacy and Security Computer systems are being used to store and process records about you and millions of other people. This can help you to get the goods and services you want and can lead to better services e.g. improving medical care or helping the police to fight crimes. However the growth of computerised record keeping brings dangers. The information may be entered wrongly, get out of date or it may be mixed up with information on someone else. The effects can be serious – people can be refused a job, housing, benefits or loans, be overcharged for goods or services or be wrongly arrested. Organisations, which hold this type of information, are called Data Users. They are expected to make sure that data is not stolen, lost, out of date, damaged or changed by computer failure, hacking, viruses or accidental mistakes. The Data controller will be the person in an organisation who has the sole responsibility of ensuring that all the users are following the rules. The people about whom information is held are called Data subjects.


Here are the laws to control computer use: Data Protection Act (1984) controls the use of Personal data 1. All users must register with the Data Protection Registrar. 2. Subjects must be told why data is being held about them 3. It gives rights to data subjects to see a copy of their own personal data and to have it changed if it is incorrect. If an organisation breaks the law, they will be fined and made to pay compensation to the data subjects. 4. The Data Users must follow the following 8 principles:

• Data must not be processed unless there is a specific lawful reason to do so • Data must only be obtain and then used for specified purposes • Data should be relevant, adequate and not excessive for the specified use. • Data must be accurate and kept up to date • Data should not be kept longer than is necessary for the specified purpose • Data processing should meet the legal rights of the data subjects • Data users should protect the data against loss, theft or corruption by taking

appropriate security measures such e.g. files can be protected by passwords, files must be kept in a safe room, system can allow different levels of access for different users.

• Data must not be transferred abroad, except to certain European countries 5. There are exceptions to your right to see information held about you. You may not see information about you if it is kept in order to:

• Prevent or detect crime • Catch or prosecute offenders • Collect tax • Carry health and social work

Computer Misuse Act (1990) prevents illegal access to files. It is intended to protect all types of information stored on computer systems. One area which is covered by the Act is unauthorised access to computer files called Hacking. This includes altering data, deleting data, selling data to other companies. Illegal copying of programs is called software piracy. Another area is the writing and distribution of viruses. A virus is a program, which destroys data or causes computers to crash. Viruses are usually spread by people by copying disk from unofficial sites or by opening E-mails from strangers. Copyright, Design and Patent Act (1989) controls illegal copying. It makes it illegal to copy a file without permission from the owner or copyright holder. There are 3 ways that the law is often broken:

• Using software without the proper licence. • Downloading text, images, sound and videos from the Internet and using them without

saying where you got them or without the owner’s permission • Copying a program without permission from the copyright holder. • Several rules exist for copying of books, prints, music recordings, etc ….


General Purpose Packages – Integrated Packages What is an integrated package? Integrated packages are General Purpose Packages, which combine two or more different application packages in a single package such as Appleworks, which is a package made up of six packages (word processing, spreadsheet, database, painting, drawing and communication). What is it used for? Integrated packages provide a lot of features for a relatively low cost. They are often used by people on a small budget like schools and small businesses.

Advantages of Integrated Packages

• They have a common HCI - the different application packages communicate with the user in the same way: the commands, the shortcut keys and the menus are the same

• Documents of different types can be open at once. A word processing document can be open at the same time as a database and the user can switch between them.

• It is easy to transfer data between different types of document. You could take the data from a spreadsheet and a drawing you have produced with a graphics package and insert them into a word processing document.

• Cheaper to buy than separate packages. Disadvantages of Integrated packages • They lack features - the different application packages are often not as powerful as the

separate application packages. • The integrated package may be larger than each package separately. This will take up

more memory and leave less room to store documents. • Some packages might be redundant.

Static and Dynamic Linkage You can transfer data between the separate applications within the integrated package in two ways: Dynamic Linkage A change to the data in one file will automatically be carried over to the same data into any other files using that data i.e. mail merging, charting.

Static Linkage The data in each part of the integrated package is separate and changing it in one part will not affect any other files using that data i.e. copy/paste.

Integration between separate packages Most stand-alone packages are multi-purpose now. For example, modern word processing packages have drawing tools, a mail merge facility and spreadsheet facility.


Modern operating system will allow you to work with more than one program at the same time this is called multi-programming. However the two packages are not likely to have a common HCI which means that they use two different sets of commands and therefore integration might be more difficult.

General Purpose Packages – Desktop Publishing A Desktop Publishing package (DTP) is a package designed to set up professional looking pages such as magazine, leaflets, posters, books, newsletters or newspaper pages. The pages will contain text and pictures.

Wizard A wizard can be used to start a DTP document. It offers a choice of templates. The wizard will step the user through the process of completing the document.

Importing and scaling graphics Graphics can be scanned, downloaded from the Internet or from a digital camera and stored into your folder. They can then be imported into the document and scaled to any size. They could also be cropped to delete the unwanted areas.

Importing text Text boxes can be set up and positioned exactly where required. Then the text will be imported into the box. If the text file is too big for the text box, another text box can be set up and linked with the first one. The remaining text will flow in it. Wrapping text around your graphics Text can be wraped around a graphic. There are different ways of wrapping text around a graphic:


General Purpose Packages – Presentation/Multimedia Multimedia documents combine text, graphics, sound, animation and video clips. Multimedia authoring packages and presentation packages are both used to set up slideshows using all these types of data. Templates and wizards are used to help the user set up the presentation.

Assembling the elements of a presentation Before you start your presentation you need to gather all the materials you are going to use (sound files, video clips, pictures, animations….) and save them in a folder. Then you can begin to put the presentation together.

Inserting text

There are two ways of adding text • Typing it at the keyboard • Copying and pasting it from other documents. • Scanning it using OCR software and saving it into your folder.

Inserting graphics and scaling graphics There are several ways of adding graphics

• Using Clip Art • Using he Internet (Websites for pictures or Google images) • Using an encyclopaedia on CD • By inserting graphics that you have collected and stored in a graphics folder in your

own folder • By scanning pictures • By downloading pictures that you have taken with a digital camera or using a web cam • By drawing your own pictures with a painting or drawing package

Adding audio You can attach an audio file to your slides, or to an object on the slide (buttons). Again sound files can be:

• downloaded from a free sound file from the Internet • recorded a track from a CD • played from a musical instrument such as a MIDI keyboard • recorded directly using a microphone and for example Sound recorder from

Accessories • selected from a bank of sounds offered by the multimedia package.

Adding Video

Videos can be downloaded from the Internet or from a digital camcorder or a digital camera for short films.


Using Hyperlinks to link slides Once you have made up the slides you need to link them up. Some packages link your slides one after another and also allow you to set up the links yourself by creating buttons with hyperlink attached to them.

General Purpose Packages – Web Page Design The information on the Internet is in the form of billions of web sites. Each site is made up from different parts, like the pages of a book, and they are called web pages.

• Web pages are written in a language called HTML (Hypertext mark-up language). Every page you visit on the Internet is powered by HTML. Most application packages such as word processing and DTP packages, can convert documents into HTML format.

• A Hotspot is a screen area that is sensitive to mouse clicks, which trigger some action.

When the user clicks on a hotspot or sometimes only puts the pointer on it, some action is triggered ie. display a picture, run a video, or open a new window of information. When you put your pointer over a hotspot, the arrow changes shape (arrow change to a hand) and a message appears in the status bar at the bottom of the screen.

• Hyperlinks are the bits on a web page that you click on to go somewhere else.

• You can also get web-design applications that let you create a web page and save it as

an HTML file.

• To get a web page started, you can use a wizard, which will step you though the process. It might offer you a selection of templates to choose from

Well-designed Web sites? They have to follow the following rules:

• Test the design on the intended users. • Keep background simple and choose text formats that will contrast with it. This

makes the pages easier to read on the screen. • Keep the overall design simple. Use similar layout for all the pages so that it is easier

to navigate through the site. • Keep graphics to a minimum because they increase the file size and make download

time longer. • Keep the number of hyperlinks needed to a minimum. Hyperlinks are the bits on a web

page that you click on to go somewhere else. Ideally it should not take someone more than four links to get to anywhere on a web site.

• You can also create hotspots.


GPP test – Revision WIMP= Window Icon Menu Pointer A WIMP environment is an example of a graphical user interface (GUI) because it uses icons (small pictures) to represent different things on the screen. Menu Driven: The user chooses from a list of commands called menu Advantages: the user does not have to remember or type any commands. They are listed in menus. Disadvantage: It takes time to open the menus to find the right command. It is more user friendly. Command driven: The user has to type the command to make the computer do something. Advantage: Fast if you are experienced Disadvantage: The user has to remember which command to type in and type it correctly. Integrated Packages: made of several general purpose packages (word processing, database, painting, drawing, spreadsheet, communications) – for example Appleworks. Advantages:

Easy to transfer information between the different packages. They have a common Human computer interface (HCI) and therefore have a lot of

commands in common. They are cheaper to buy than several GPP packages

Disadvantages:

The programs that make up the different parts of the integrated package are less powerful than separate packages.

Use a lot of RAM when loaded. Dynamic and Static linkage: Dynamic linkage means that if the same data is used in different packages of the integrated package and you change it in one part, the change will be carried over into all the programs using the data – for example a mail merge. Storage of information: Backup copy: an extra copy of your work in case the original copy is lost or damaged. Data can be stored on floppy disc, the hard disc of the computer or server, CDs, magnetic tapes, memory sticks, ZIP discs. Teletext -Viewdata Teletext is a one-way information service – the user cannot interact with the system. Viewdata is a two-way information system. The user can receive and send information (Booking and paying a holiday)


Types of computers: Desktop – Laptop – Palmtop LCD=liquid crystal display Palmtop and laptop computers are useful because they are light, portable and run on batteries. Multimedia: When many media are being used The user of a multimedia system can insert videos, high quality pictures/ photos, music /sound into documents. Input devices needed: digital camcorders, digital cameras, scanners, microphones Output devices needed: speakers Virtual Reality A method of reproducing the outside world digitally within a computer system. To take part in virtual reality the user may need to wear a special headset and gloves rather than use a keyboard and monitor. Real time processing is needed because the information has to be processed immediately to make it more realistic. Voice recognition The user speaks to the computer using a microphone. To use voice recognition, the user must speak slowly and clearly. Networks Two main types: Local Area Network (LAN) usually used in an office, bank, building, school. Computers are linked by either cables (copper cables or fibre optic) or wireless transmission. Advantages of LANs:

Can share peripherals such as hard drive, printers, and web cameras Can share data files Communication between computers using E-mail

Wide area network (WAN) connects computer across large distances (link up cities or countries). It uses telecommunications links (telephone or satellite) Advantages of WANs:

People can communicate instantly worldwide Information can be centrally stored and accessed easily from anywhere – people can

work from home or anywhere and be in contact with the central office Working from home With computers and E-mail, lots of people are choosing to work from home. Advantages:

Less expenses such as petrol, train/bus ticket , working cloth, restaurant bills Can work when it is suitable. Ideal for a mother with a young family or with children at

school


Disadvantages: No contact with other workers either for help or for social purposes.

Setting up a new computer system Setting up costs or installation costs: New hardware, cables for network, furniture for new computing room, printers, software (applications and network software) Running costs: paper/ink or toner for printer, upgrade for software, maintenance, salary for computer operator Printer Driver: Allows the printer and the computer to communicate. Makes sure that what is on the screen is the same as what is printed out on paper.

General Purpose Packages General Purpose Packages are commercially available, fully tested software packages designed to allow the user to solve a range of problems. Examples:

• Word processing: to produce text documents such as letters, memos, essays, stories • Database: to store, search and sort data such as a telephone book • Spreadsheet: to store numbers and to perform calculations using formulae such as

bank accounts • Graphics: to produce graphics, animations, cartoons • Web page creation: to produce web pages and websites • Multimedia and presentations • Desktop publishing: to combine text and graphics • Expert Systems: to store and process the knowledge of an expert. They help people

to make decisions Some packages combine functions from other packages, for example: a word processing packages have drawing tools. Storing data in your GPP Types of data that can be entered and stored using GPPs:

• Numbers: In spreadsheets, numbers are used in formulae to do some calculations. Page numbering feature in word processing.

• Text: in word processing, spreadsheet (labels), databases, graphics • Graphics: in Painting and drawing but also in word processing, spreadsheet and

databases • Audio: Many packages can handle audio for example Multimedia and web page creation.

Audio can be stored on two ways: MIDI and as digital audio. A MIDI audio file stores


the instructions that tell the computer how to create the sound. A digital audio file stores samples of sound waves.

• Photos: in graphics, multimedia and presentation packages. • Animations: Many packages can handle animated graphics. Animations are a series of

graphics, which are displayed very quickly one after another to give the impression of movement. To get a fluent movement 24 pictures per second is needed. Animation file are therefore very large.

• Video: in multimedia and web page creation packages. To get a smooth video, video images have to be processed 40 frames per second and therefore file can be very large. They need to be compressed. They are usually store on DVDs.

Making Backups Computers may break down, disks can develop faults or you may delete things by mistake. It is important to take extra copies of your work and to store them in a safe place. Text documents can be saved in different file formats. The most common are ASCII , RTF (rich text format) and plain text. Using a standard file format means that you can be sure that the files will be accepted by a wider range of software. Advantages:

• ASCII stores information about the characters. It does not store information about styles, fonts, spacing. Files stored in ASCII are very portable.

• Plain text is identical to ASCII. Stores text but no formatting. • RTF stores the information about the text, paragraphing, indentation, styles, font and

sizes. Human-Computer Interface (HCI) The HCI is the part of the computer system that people use to communicate with the computer. GUIs (Graphical User Interface) use graphics to control the computer’s actions. A WIMP HCI uses Windows, Icons, Mouse and pull-down menus. WIMP HCIs are user friendly. They are easier to learn. The commands are listed in menus and therefore the user does not have to remember them. No typing skills are required. Can have more than one window open at one time. Customising the HCI means that you change it to suit your own needs. You could change the appearance of the icons, choose the buttons you want to see on the toolbars, the speed and appearance of the pointer, the colour of the desktop or wallpaper.

Keyboard shortcuts Experienced users often find it quicker to use the keyboard instead of selecting commands from menus. For example Ctrl+B for bold


Help on the computer • On-line Help and On-line tutorial

On-line help is a help feature available within the package. On-line tutorial teaches you how to operate a package.

• Templates: They are skeletons of a document, headings, colour, fonts, tables, text boxes are already set up.

• Wizard: A wizard is a feature in a package that guides you through a complicated task.

GPPs in the workplace

Jobs Some jobs may be lost. New jobs are created. Staff needs IT skills and constant training to make full use of the packages.

Paperless world? Although computers communicate electronically and data is stored on CDs and DVDs, we use more and more paper because of junk mail.

Initial costs, replacement costs and running costs • Initial costs involve paying for computer systems, application packages, training

courses, cabling for networks. • Replacement costs involve more powerful computers, software update, worn out

printers. • Running costs involve maintenance and repairs, printer toner or cartridges, internet

connections.

The Law

Data Protection Act 1998 It protects the rights of people when personal information is stored on computers. Businesses and organisations must make sure that they comply with the DPA. Data must be: • obtained legally • held only for lawful purposes • adequate, relevant, accurate and not excessive • accurate and kept up to date • held no longer than necessary • secure and • data subjects should be allowed to access the information held about them and to have it

changed if it is wrong. Exceptions: Police, security forces, Inland Revenue. Data subject: people who have data held about them


Data User: Authorised user within an organisation who is given an ID and password to access data Data Controller: person or organisation controlling the collection, contents and use of personal data. The Copyright, Designs and Patents Act 1989 It protects the interests of companies and individuals whose work was being copied. It is an offence to: • copy or steal software • upload, download or reproduce information without permission of the owner • run purchased software on several computers at the same time without the appropriate

license. The Computer Misuse Act 1990 It is an offence to: • hack • modify or damage information (viruses)

General Purpose Packages – Expert systems

An Expert System is a package that holds a body of knowledge and a set of rules on a subject that has been gained from human experts. An expert system helps the user make decisions by asking questions and then based on the user’s answers and the knowledge it holds offering advice. It can also explain to the user how it arrived to the solution. Purpose of Expert Systems: They help people make decisions in a whole range of situations:

• In the financial world for investment • In hospitals to help doctors diagnose illnesses and suggest treatments • In industry to maintain and repair equipment

Advantages:

• They make expert knowledge available through a computer system • They combine the knowledge of lots of experts. • People from remote areas can have expert help at any time • People can learn by asking questions and reading the answers.


Programming F/G/C

CLEAR ( To clear the screen of all text)

END (To mark the end of a program)

PRINT (To output data on screen) PRINT “Hello” PRINT TAB(20,10);”Hello” PRINT “3+7=”;3+7

INPUT PROMPT (To ask the user for data and store it in a variable)

INPUT PROMPT “Please enter the length in metres and press <<return>>: ”:length INPUT PROMPT “Please enter your name and press <<return>>: ”: name$

LET (To assign a value to variables) LET name$=”Mrs Hennessey” LET mark1=34 LET counter=counter+1 LET average=(mark1+mark2+mark3)/3

Programming G/C

READ…..DATA (To read data that has been written inside the program just

before END) AND FOR…. NEXT (To repeat statements a fixed number of times)

IF……THEN……ELSE……ENDIF (to make decisions) IF mark>=50 THEN

PRINT “You have passed ELSE

PRINT “You have failed” ENDIF

A FOR loop is needed to read the three DATA lines at the end of the program

FOR people=1 TO 3 READ name$,age

NEXT people

DATA John,15 DATA Mary,13 DATA Sue,16 END


DO…..LOOP UNTIL……(To repeat statement until a condition is realised) Do

INPUT PROMPT “Please enter the length of the rectangle – must be between 0 and 10 metres”:length IF length<0 OR length>10 THEN

Print “Wrong data- must be between 0 and 10” ENDIF

LOOP UNTIL length>=0 AND length<=10

Programming C

ARRAYS1. To set up arrays 2. To enter data in an array:

3. To display data : FOR people=1 to 10

INPUT PROMPT “Enter name:”:name$(people)

INPUT PROMPT “Enter age: “:age(people) NEXT people

FOR people=1 to 10 PRINT name$(people),age(people) NEXT people

DIM name$(10),age(10)


AUTOMATED SYSTEMS 1. NEED FOUNDATION Robots and machines work faster than human beings: products made faster and on time; they can work in hazardous environments: no one gets injured (no fatalities); they can do repetitive tasks: they can work 24/7 without getting bored or making mistakes; GENERAL Robots and machines are very efficient: many products can be made accurately (to one thousandths of a millimetre!), quickly and with very little waste (rejected components). CREDIT Robots and machines are adaptable: their end-effectors can be changed and are reprogrammed to perform other tasks. 2. HARDWARE and SOFTWARE FOUNDATION A robot can be either stationary or mobile. The basic anatomy of a robot consists of a waist, shoulder, elbow and wrist to which an end effector/ tool (spray gun, 2/3 finger gripper, drill, shearer, magnet, suction cups, etc…) is attached. The joints can move using either motors or hydraulics. Mobile robots move using wheels or caterpillar tracks (like tanks). Robots have sensors on them to detect the environment. Examples of sensors include temperature, pressure, proximity (distance to an object), light, magnetic, etc… Sensors send data back to the computer. This data is called feedback. The computer controlling the robot can then tell the robot what to do next. CAD/CAM : Computer Aided Design and Computer Aided Manufacture. Computers are used in the design of products using expensive software, e.g. AutoCad, Floorplan, etc… These software can draw products in 3d and allow it to viewed from various angles. Pre-defined shapes and measurements make the designers job very easy. Parts of the product can be changed very quickly in front of the customer. Computers also aid in the manufacture of products. They are fed with the instructions of how to make them and then instruct the robot or lathe to make the product. This saves time and money as less people are employed; less wastage of materials; faster delivery of products; increased customer satisfaction; all this leading to more customers, which means more money. GENERAL Sensors are not part of the robot and have to be connected to them. This requires an interface which allows the computer to communicate with the sensor.


A sensor detects the environment which has a range of values (analogue). These analogue values are converted (analogue input) into digital signals so that the computer can understand them. The computer sends digital signals that need to be converted into analogue signals (analogue output) so that the robot/ machine/ motor can understand them, e.g. turn left or open a window. A mobile robot can be guided using 2 methods : magnetic and light. Magnetic guides : electric cables/ wires are laid under the ground. Magnetic sensors on the robot detect the magnetic radiation from the cables and follow them. The advantage of this is that no one can trip on them or disturb them in anyway. Disadvantages are that it is expensive to install (dig up) and difficult to change the pathways. Light Guides : white lines are painted on the ground. The robot shines a bright light on the ground and picks up the reflection of the light using its light sensor. The advantage of this is that paths can easily be changed. Disadvantages are that the lines can dirty and covered by various materials making a path difficult to follow, i.e. maintenance of the lines would have to be high. Robots can be programmed using High Level Instructions, using English type words like in programming (True Basic). Simulation plays a big part in the final production of products. Simulation helps manufacturers see the result of a product being tested under various conditions using a computer. E.g. a bridge can be subjected to various weights of traffic or winds, etc… to see if it will perform and maintain its shape. E.g. a building is set on fire and if the safety features have been designed correctly (smoke alarms, fire extinguishers, fire escapes and fire escape signs are correctly displayed, then people will be able to get out of the building on time with no loss of life. E.g. traffic light simulation under various conditions of traffic load and directions before installing traffic lights at a junction. Virtual Reality allows the user to immerse/ enter a computer generated 3D world. The user wears a body suit (that measures the body’s movement (input) and displays them on screen); special gloves (input) that manipulate objects on the screen (like opening doors, pressing buttons); and a headset (consisting of speakers, microphone(input) and a screen). The movement of the headset can indicate which way the camera moves in the virtual world; or the visor can track the movement of the eyes and the program can respond accordingly. The computerized images can be simulated in any environment making you feel like you're really there. VR can have various applications for fun or for serious applications. E.g. training pilots, soldiers, getting the ‘feel’ of a building when you walk inside it; training surgeons, etc… Operating robots, running simulations and virtual reality programs require real-time processing (data is processed immediately) otherwise things can go wrong if there are any delays. E.g. turning down the temperature; or putting out a fire.


Check these websites for VR devices : http://www.vrealities.com http://www-vrl.umich.edu/intro/index.html http://coe.sdsu.edu/eet/articles/VRApps/start.htm And VR applications : http://www.quest3d.com/index.php?id=152 http://www.quest3d.com/index.php?id=153 http://www.quest3d.com/index.php?id=148 CREDIT Analogue to Digital (A to D) Converters are used when sensors give analogue signals (feedback) to the computer so the computer can understand the signals. E.g the temperature of a room. Digital to Analogue (D to A) Converters are used when a computer sends digital signals to a robot to do something which need to be converter into an analogue signals so the robot can ‘understand’ what to do. E.g. a motor is given a signal to turn clockwise or anti-clockwise A robot is programmed using High Level languages in a special form called a control language. This language is easy to learn and simple to command a robot. E.g. RT 90 (turn right 90 degrees); FD 100 (forward 100). Robots’ software is sometimes stored in ROM (Read Only memory). This is because the robots software runs as soon as it is switched on and the program cannot be accidentally or deliberately deleted. The disadvantage is that the program cannot be changed easily. Embedded Systems are machines that contain computer technology (computer chips) integrated in it with specialised software to run it to perform a dedicated function. E.g. antilock braking system or fuel injection system in a car; airplanes; manufacturing equipment; washing machine; microwaves; medical equipment, (most digital appliances), cameras; toys; vending machines; mobile phones; etc…. These systems are part of a larger system (e.g. a car) and are expected to function without human intervention. Intelligent Robots are machines or embedded systems that can analyse data (e.g. vision systems that allow a robot to recognise an object) and make decisions. i.e. a machine that can simulate human intelligence (reasoning, recognition, planning and adapting). See http://www.ornl.gov/info/ornlreview/rev26-1/net526.html for an interesting article on smart cars of the future. 3. IMPLICATIONS FOUNDATION People now need to be retrained in their jobs, e.g. to operate robots or to maintain them. GENERAL Job losses occur when robots can do the work of many people. Job gains occur when people are hired to make, program, maintain and operate the robots and automated systems.


People who work in automated systems have more leisure time as they don’t work as hard and for so long. Their jobs become less dangerous, perhaps more boring or perhaps more interesting/ exciting working with new modern technologies, depending on a persons point of view. The workplace has to be safe when humans and machines work together otherwise there can be serious injuries and law suits. Starting an automated system requires a high initial cost for the design and implementation of the workplace and for the machinery. However, long term savings are made as a robot can replace several people saving money on salaries; high production rates with minimum faulty products (wastage of resources) and increased growth due to customer satisfaction. There will always be cost such as replacement cost and maintenance. CREDIT The design of the workplace is done with the intention of making the automation very efficient and safe. E.g. assembly lines are continuous and fully automated where possible. E.g. robots are fitted with flashing lights and sirens to warn people of their approach. E.g. Robots are fitted with bump sensors and proximity sensors so that they can stop and avoid causing damage to humans and themselves. E.g. areas are designated for robots and humans to keep them apart.


Communications And Networks Networks A network is when two or more computer systems are linked together. This allows data to be shared and messages to be sent between them. A standalone computer is a computer, which is not part of a network. A LAN is a local area network. LAN’s cover a small area such as a room or a building. Each computer on a LAN is called a station. The computers are joined together using cables or wireless transmitters A WAN is a wide area network. WAN’s cover large geographical areas connecting computers and individual networks. WANs use telecommunications links. Advantages of LAN’s

• Data and programs can be shared between computers connected to the LAN. • Peripherals such as printers can be shared between everyone who has a computer

attached to the LAN. • Electronic mailing can be operated. • Passwords can help network security. • Different levels of user access will reduce unauthorised interference. • A network user may access their data from any computer connected to the network.

Advantages of WAN’s People can communicate worldwide. This method of communication is cheaper than phone calls. Users can send email, send data files, carry out financial transactions, carry out research and teleworking which is working from home while being in contact with the central office. Network Connections

• Stations on a LAN can be connected using cables or wireless signals as the connection medium. Two types of cable are copper cabling such as coaxial cabling and unshielded twisted pair cabling (UTP) and fibre-optic cabling. Wireless networking includes infrared communication (Bluetooth, Wireless Fidelity Alliance (WiFi) and satellite links.

• WAN’s use telecommunications links to transmit and receive data. Telecommunication is a general term that describes the communication of information over a distance.


A client and server network is a method of network organisation in which network stations (clients) make use of the resources available on one or more servers, e.g. our school network. A file server provides disk storage for programs and users data. Desktop computers are the most common type of client computer. Multi access computers allow many users to access the system at the same time and to:

• share the systems processing power • share the systems memory • share the data stored on the system

A network interface card (NIC) is required for a computer or a device such as a printer to connect to a LAN network. It allows data to be communicated between the server and other computers and stores the IP address.

Security • Network information should be secured to prevent information being hacked, deleted

copied or changed. • Physical security includes installing locks on networks computers, using security locks

on computer rooms and ensuring network computers have no CDROM or floppy drives. • Software security includes the use of ID’s and passwords, which are required to

access the network. Passwords should be changed regularly and should be difficult to guess.

• Encryption is also used to encode data held on the system. Encryption means putting data into code to prevent I being understood by unauthorised users.

Electronic communication Electronic communication is the process of sending and receiving electronic messages. Electronic mail, text messaging and file transfer are examples of electronic communication. Electronic mail is a way of sending messages from one computer to another. To access email users require access to the Internet via an ISP (Internet Service Provider) or a private network, an electronic mail address or mailbox, a computer and an email client program (e.g. Outlook Express) or a web based email system such as schoolmaster. Netiquette is short for network etiquette. Netiquette is a set of rules governing acceptable standards when people are using email.

Advantages of Email • Email is faster and cheaper than sending a letter by post. • Email can be checked from any location in the world. • Email cuts across time zones. • Identical copies of your email can be sent to many different people at the same time. • Paper is not necessary.


Disadvantages of Email • You must check your mailbox regularly to avoid problems. • The person being mailed must have a mailbox (email address). • Email may not be suitable for official documents. Such documents may require paper

copies • Email can be perceived to be impersonal. • Email is not as secure as the postal system. • Viruses can be attached and spread through email. • Junk email (spam) is a considerable problem. • Spam is unsolicited email, this is email you do not want or ask for. • Filtering software and email addresses which are hard to guess are ways users can try

to reduce spam. Text messaging is electronic communication by means of a mobile phone. SMS means short message service. File transfer involves sending attachments by email. Some viruses are transmitted through email attachments. The Internet

What is the Internet? The Internet is a system, which allows computers and networks worldwide to connect with each other using a range of telecommunication systems.

Internet Uses & Services • The Internet makes vast amounts of information available worldwide. • The Internet has three main services: The World Wide Web(WWW), electronic mail

and file transfer. • Ecommerce, research, playing games (entertainment), on-line banking and on-line

shopping are major uses of the Internet. How Does the Internet Work? Information on the Internet is stored on web pages at locations called web sites. Hyperlinks are links between web pages, documents or files. Web pages are prepared in HTML. A browser is a piece of software, which fetches and displays web pages. Examples of browsers include Internet Explorer and Netscape Navigator. Connecting to the Internet


An Internet ready computer consists of a computer system, a modem and communication software such as a browser and an email client program. When computers connect to the Internet through a phone line, a modem is required at each end of the link. Modems transfer the signals into a suitable format. Dial-up and broadband are two ways to connect to the Internet. On-line to the Internet means being connected to the Internet. Off-line from the Internet means being disconnected from the Internet. Searching the Internet A search engine is a site on the Internet, which is designed to help people find information. A simple or basic search allows users to enter one or more keywords into an entry box. Users then click a button to begin the search. A complex or advanced search allows users to refine their search. Examples of complex searches include restricting the search to only parts of the web or by choosing an option from a menu. A complex or advanced search uses OR, AND or NOT.

Downloading Downloading is the process of saving a file from a network onto a computer. Downloading takes place when files are being received. Uploading is when a file is being sent. Three types of software may be downloaded, freeware, shareware and commercial software.

Freeware, Shareware and Commercial Software Freeware is software, which is totally free. Freeware is distributed freely for use on computers systems. Shareware is not free. Shareware allows users a free trial period to evaluate the software. Users must then either pay for the software or delete it. Shareware relies on people being honest. Commercial software is not free and normally payment is made up front for a licence.

Internet Service Providers (I.S.P.) ISPs are companies who provide access to the Internet. Users connect to the ISP host computer. Additional Internet Services Chat, instant messaging, streaming video and video conferencing are all available through the Internet. Mobile Internet technologies include laptop (notebook) computers, palmtop(PDA) computers and mobile phones.


Video conferencing is the use of communications links to conduct meetings between people who are geographically separated.

The Law Some people disregard others’right to privacy and use network to send unvanted e-mails, chain letters, adverts, junk mail or spam. The laws which may affect the use of computers include:

• the Computer Misuse Act, • the Copyright, Designs and Patents Act • and The Data Protection Act.

Ethics Ethical issues are concerned with people’s perceptions of what is right or wrong. Ethical issues relating to networks include invasion of personal privacy, censorship and freedom of speech.


Computer Systems 1. SYSTEMS SOFTWARE GENERAL 1. Common features of high level languages (HLLs)

o Easy to write/ code. Instructions use words, numbers and mathematical symbols and signs

o They must be translated into machine code. o finding mistakes and debugging is easier than with machine code o Programmers do not need to how the computer works.

2. Purpose of High Level Languages To allow programmers to overcome the difficulties when programming in binary code (1’s and 0’s) 3. Need for Translation Computers only understand machine code, therefore the HLL has to be converted/ translated into machine code which the computer understands CREDIT 1. Types of translator A COMPILER first translates the whole program (source code) into machine code, and then executes the object code. The 3 advantages are :- this makes the program RUN faster; and the object code can be saved as an executable file so that the compiler is not necessary to run the program again. Once the compiler translates the program it is removed from RAM, giving the system more memory resource. The disadvantage is that errors are found after the program has been translated. An INTERPRETER translates each lines of code and then executes it. The advantage is that it finds mistakes as you write each line. The disadvantages are that it runs slowly, and that the interpreter is always in RAM. 2. Portability of software Portability refers to how easy it is to RUN a program/ software package on different type of computer systems/ platforms. The more platforms it can be used on, the more portable it is. 2. OPERATING SYSTEMS FOUNDATION 1. An Operating System (OS) is a collection of program which controls all the functions and actions that help the computer to run, from switching on to switching off! The OS is stored


on disc (DOS) and then loaded into RAM. Sometimes the OS is stored on ROM chips which means the OS runs the instant you turn it on, and you cannot accidentally delete it. 2. Directory/ folder Files (program and data) are stored in some sort of order in folders. Directories are set up and the File Manager has to keep a details about all the files (where, how big, etc…) and maintains the directory. GENERAL 1. An Interactive System is when a human being is actively using a system to process data, e.g. a an ATM or when doing word processing. 2. A Real-Time System is when data is processed immediately without any time delays, either with or without a human being present. Any delay could result in fatal accidents or money being lost. For e.g. auto pilot, baby incubators, nuclear shut down facility, holiday and cinema bookings 3. There are 2 types of files. Program files contain instructions of how to do a particular task; and Data files are what is produced by a program file. E.g. .doc, .xls. .pub, .ppt, etc… CREDIT 1. Operating System has to communicate with the user so it provides a Human Computer Interface (HCI) which allows the human to communicate via a GUI (WIMP) interface. Commands are issued via pointing devise and via keyboard. Output is displayed on the monitor or by sound. Three other functions of an OS are :-

o Memory management : makes sure that programs and data loaded in Ram do not overlap or program crash

o File management : keeps track of where all files are stored and responsible for copying, deleting, renaming, loading and saving of files held on backing storage media

o Error reporting : communicates to the user any errors generated by users or by devices as messages on screen and by sound, e.g. files not found, insert disc, etc…

2. Interactive systems with background job capabilities Some interactive systems wastes the time of the processor as the CPU has to wait for the user to finish what they are doing. Instead it can do other tasks while waiting for the users inputs. For e.g. while a user is word processing (pausing between typing, and the time between keystrokes), the CPU can send data to the printer. Otherwise the user can only do word processing till after the document is printed. Hence interactive processing (word processing) with background job capabilities (printing while CPU not busy)! 3. Device Drivers


Every device operates in a different way from the CPU. A special program called a driver instructs the CPU how to send/ receive data to/ from it. E.g. printer, scanner, mouse and monitor drivers. 4. Hierarchical Filing system All files can be kept flat i.e. on one plain i.e. no grouping/ folders or hierarchically. Files can be organised into a hierarchical structure. The main or ROOT directory contains all the other sub-directories/ folders. So we have files within folders within folders. The advantages are :- naming files is simple; files can have the same name; and it is easier to find a file. (with Flat filing systems file names have to be different so naming them can get very complicated and hence difficult to find). 5. Sequential and Random/ Direct Access to data When data is accessed only after going through data before it, it is know as sequential access to data. E.g. accessing song 5 on a cassette, requires the device (cassette player) to fast forward through the first 4 songs. When data can be accessed immediately by the read/ write head of the device jumping to the appropriate position on the media, it is know as random/ direct access to data. E.g. accessing song 5 on a CD, the position of the read/ write head of the device (CD player) jumps directly to the start of song 5. (it can also jump randomly to any song if told to do so). Devices that use discs as their media use random/ direct access to data. Computer memory also uses random access to data to read or write data to or from memory. 3. LOW LEVEL MACHINE FOUNDATION 1. A Stored Program is when a HLL is used to write a program and then the instructions are saved on backing storage media like a disc. In the early days, the program would be erased from memory when the power was switched off and hence could not be stored. Therefore it would have to be tediously re-written. 2. Measurements A Bit is the smallest piece of data, a 1 or a 0. A Byte is a combination of 8 bits. A single character on the keyboard is represented by 8 bits. A Kilobyte is 1024 bytes. A Megabyte is 1024*1024 bytes (or 1,048576 bytes) A Gigabyte is 1024*1024*1024 bytes (or 1024 Megabytes) A Terabyte is 1024*1024*1024*1024 bytes 3. Main Memory Size. The size of RAM ranges from 256 Mb to 1024 Mb (=1 Gb)


4. Input, Process, Output (IPO). Data flows from Input devices to the CPU. The CPU process data and sends data to the Output devives. The bcaking storage devices receives and sends the CPU data. This is called Writing (saving/ receiving data) and Reading (loading/ sending data). The Central Processing Unit (CPU) contains the Processor and Main Memory (= RAM and ROM) GENERAL 1. Concept of machine code. The computer only understands/ uses 2 states of electricity, either high voltage or low voltage, a 1 or a 0. A combination of 1’s and 0’s allows the computer to communicate and function. 2. Representation of :-

o positive whole number : represented by binary code which uses the following weighting :-

128 64 32 16 8 4 2 1 Number

0 0 0 1 0 1 1 0 22 1 0 1 0 1 0 1 0 170 0 1 0 1 0 1 0 1 85

o text : each character is represented by ASCII (American Standards code for

Information interchange) o b/w bit-mapped graphics : each dot/ pixel (picture element) in a graphic produced by

for e.g. a paint program , is either black or white, on or off, 1 or 0. (Therefore, only 1 bit is used to represent 1 pixel). So, bit-mapped graphics is represented by binary code, 1 bit per pixel

3. Storage location : memory (RAM and ROM) is divided up into areas where data is stored. Each area is called a location.

CREDIT 1. Calculation of storage requirement of b/w bitmap EXAMPLE :- an image is 5 inches width and 4inches tall (5 x4). The resolution (quality) of the picture is 300 dpi (dots per inch). ANSWER :- “Each pixel is either on or off, black or white, therefore each dot/ pixel needs 1 bit to represent it”

5 * 4 * 300 * 300 (multiply the dpi twice) = 1,800,000 bits 180,000,000 bits/ 8 = 225000 bytes 225000 bytes / 1024 = 220 Kilobytes

2. Processor Structure


o Control Unit (CU) : is responsible for coordinating all activities in the processor o Arithmetic Logic Unit (ALU) : does all the arithmetic and logical operations o Registers : temporary data storage (memory) within the processor

3. Word : the number of bits a processor can process in one go. The bigger the word, the more bits can be processed. E.g. a 32 bit Playstation can process 4 times more than an 8 bit Spectrum. 4. Concept of Addressability : Each location in memory has a unique address. Therefore, data that has to be accessed from (or put into) memory can be located/ found very quickly. 4. HARDWARE FOUNDATION 1. A Microprocessor is found in modern automatic devices and appliances that makes them ‘smart’. eg. a microwave oven controls the cooking time and temperature. eg. an automatic camera senses the light level at several points of the viewing screen, average the light, and computes and sets the correct lens opening and shutter speed. They also control computers and any digital device. 2. Chip A chip is has thousands of very small complicated circuits on a small piece of silicon. This is made possible by circuits being microscopic, hence microchip! 3. Main Memory is where all data and programs (including the OS) is loaded into. This allows data to be edited/ processed before it can be output or saved. Main Memory is made up of RAM (Random Access Memory) and ROM (Read Only Memory) 4. Backing storage refers to where data and programs are held permanently on. E.g. disc, tape, memory sticks (USB pens/ Flash drives) 5. Types of Computers : Desktops are used on desks. They have a larger monitor and keyboard, and to have various pointing devices. Laptops/ notebook have their own power source (rechargeable battery) and are light and compact enough to carry about to do work on trains, buses, etc… Palmtops are small enough to fit in your palm. They can do a few applications like word processing, databases, spreadsheets, memos, diary, etc… They have a touch sensitive screen and uses a stylus with a tiny keyboard. (can also converts what you write on the screen into word processed text) 6. Current Input devices : mouse, trackball, trackpad, graphics tablet, touch sensitive screen, keyboard, joystick 7. Current Output devices : printer (laser, inkjet), plotter, monitor (VDU)


8. Current Backing Storage devices : magnetic tape, floppy disk, hard disk, CD-ROM, DVD-ROM GENERAL 1. Mainframe : they are very big in size and have basically the same as a desktop but more of it. i.e. more processors 9100), gigabytes of Ram, several types of backing storage; and can support 100 users. They are used for large business and co-operations like banks and universities. 2. Capacity of backing storage Magnetic Tape : stores data magnetically like a cassette stores music magnetically. They are erasable, reusable, cheap, and durable and used for backup copies as they can hold a lot of data. They can easily be catalogued and stored in a tape library. For example,

o Reel-to-Reel tape (reel is 10.5 inches in diameter, tape is 2400 feet long, .5 inch wide) holds about 40 megabytes of data.

o Cassette tape is small and holds little data. o Cartridge Tape is about half the size of a video cassette and holds about 20000

pages of information. Floppy Discs : store data magnetically. They can hold more data on a small space from 720 Kbytes to 1.44 Mbytes. Hard Discs are made from Aluminum and are not flexible. Because it is hard it can rotate at thousands of times a minute, data can be read and written to very quickly. Data can also be packed more densely, allowing for more data to be stored. They can store anything from 20 Gigabytes to over 200 Gigabytes of data. CD-ROM (Compact Disc-Read Only Memory). Optical Laser Discs range in size from 4.72 to 14 inches. Microscopic pits and lands are used to represent data (1’s and 0’s) and are read by lasers. There are suited for data that does not change. The laser technology (not magnetic) gives these devices tremendous capacity for storage. e.g. a 9 million word (20 volume) encyclopedia, is stored on a compact disc, with room to spare (~720 Mbytes). (A 14’ disc can store up to 20 reel-to-reel tapes!!). There are also CD-R (WORMS, Write Once Read Many times) and CD-RW (re- writeable/ reusable). DVD (Digital Versatile Disc). Can store more data than CD-ROMs and store data on more than one layer and some on both sides of the disc. 2 whole movies can be stored on one DVD! 3. Current Input devices : scanner, digital still camera, digital video camera, webcam, microphone 4. Current Output devices :- (Loudspeakers +)


o Liquid Crystal Display (LCD). AN electric current is passed at set locations behind the screen at which points the liquid crystal changes property and allows shapes to be made on screen.

o Thin Film Transistor (TFT). Each pixel on the screen is control by a transistor. It

controls the level of quantity and intensity of each of the 3 primary colours Printer comparisons :- Type of Printer Resolution (dpi) Speed (pages

per minute) Cost (£s) Cost of Ink /

toner Laser upto 2400 x

1200 4 to 32 ppm 200 to 2000 30 to 200

Inkjet upto 2880 x 1200

8 to 15 ppm 60 to 300 10 to 30

5. Current Backing Storage devices :-

DRIVE CAPACITY TRANSFER SPEED

(megabits per second)

DRIVE COST MEDIA COST

Floppy Disc 1.4 MB 0.04Mbps £5 ~10p / disc Hard Discs 80 to 200Mb 100 Mbps >=£50 NA Tape 30 GB 10Mbps £370 £2 to £30 CD-RW 700 MB 30Mbps £25 13p for -R

40p for _RW DVD-RW 9GB 30Mbps £70 £1.50 -/+ R

£2.50 -/+ RW Flash up to 1GB 1Mbps ~£60 NA CREDIT 1. Sequential and Random/ Direct Access devices DEVICE TYPE of

ACCESS MEDIA Main Use/s Other

Tape player Sequential (slow access to data)

Magnetic tape Back up Expensive/ holds lots of data

Floppy disc drive Direct (slow) Floppy disc Back up Cheap/ phasing out for USB pens

Hard disc drive Direct (very fast but not portable)

Hard Disc Stores programs and data that changes often

Holds lots of data


CD-ROM drive Direct (fast) CD-ROM Multimedia programs

CD-R and CD-RW cheap + backups

DVD-ROM Drive Direct (fast) DVD Multimedia, movies

Several versions (and -R and -RW) Lots of data

Flash Drive Direct (fast) USB pen Back up, holds lots of data, very portable

cheap

2. Specialised input devices

o Disabled users : voice recognition to give commands and dictate letters; special clicking devices; devices that follow eye movement, larger keyboards (only lower case)

o Virtual reality : trying to create a 3d-world on a computer. Immersive VR is when you

feel as if you are in the simulated world. For this you need a special headset (to sense direction and movement of head); gloves to manipulate objects ; treadmill to simulate movement forwards/ backwards; joysticks.

o Use of a variety of input devices for multimedia : scanner, digital camera, digital

video camera, microphone

o Sound card : microphone connects to it to sample CD/ radio quality sound converting sound data (analogue) into digital format. The sound card helps the processor by processing and storing sound data temporarily so as to allow the processor to do other more important tasks, thereby speeding up the system.

3. Specialised Output Devices

o Disabled users : voice output so users can her what is going on; o Virtual Reality : headset (screen to output scene and loudspeakers to output sound);

motors and hydraulics to simulate motion o Use of variety of output devices for multimedia : printer, high resolution monitors,

speakers o Sound card : the loudspeakers are connected to it to reproduce high quality sound at

CD/ Radio quality changing data from digital to analogue format o Graphics card : calculates and processes all the data for reproducing graphics on the

screen. It has its own processor and memory to allow the main CPU to do its job, thereby making the display of multimedia very fast and at high resolution


4. Current Backing Storage devices :- See 1. Sequential and Direct/ Random Devices above.

COMMERCIAL DATA PROCESSING 1. NEED FOUNDATION Computers play an essential part in businesses and industries. This is because of the huge volumes of data and documents. Computers can process data extremely fast (millions of instructions per second); can access and store data almost instantly; and they can do repetitive task without getting bored or making mistakes. CREDIT Computer software analyse data and provide managers with relevant information so that they can make correct decisions. E.g. when to sell Christmas items based on sales from the previos years. E.g. what items to sell in summer. 2. DATA PROCESSING CYCLE FOUNDATION Data Collection -> Data Preparation -> Input -> Processing -> Storage -> Output GENERAL Data is just numbers and letters that don’t make sense. E.g. 7, rainbow. E.g. a spreadsheet table. Information is data in context, or that makes sense. E.g. we can see 7 colours in a rainbow. E.g. a fully labelled chart made from a spreadsheet table. 3. DATA COLLECTION, PREPARTION and INPUT FOUNDATION Data is first collected and then prepared (sorted/ grouped) for input into the computer. This process can take time so a direct data entry can speed up the process. Such methods include bar codes, mark sense cards and magnetic stripes. Reading a Bar Code give the computer information about what the item name is, the country of origin and the manufacturer of the item. Bar codes can be found on almost all items on sale.


Mark Sense Cards allow cards/ paper to be marked (e.g. by pencil) and then read. E.g. a cross in a box for a multiple choice paper. E.g. a line in a box to choose a number on a lottery ticket. Magnetic Stripes are found at the back of credit and debit cards, loyalty cards, driver's licenses, telephone calling cards, parking tickets, airline tickets and membership cards. They contain information that is useful or specific to a specific person. GENERAL Magnetic Ink Character Recognition (MICR) : Magnetic ink is used to print letters and numbers on documents, e.g. bank cheques. Each character has a different amount of magnetic ink in comparison to each other. A MICR reader can tell what letter or number is read by the amount of magnetism each gives out. MICR is expensive but a document can still be read even if it is crumpled or dirty. A Check Digit is found at the end of a bar code. It comes from by doing calculations on the previous numbers on the bar code. When a bar code is read, the computer perform a calculation on the all the numbers but the last. If it comes up with the same number as the check digit, then that item is accepted (e.g. a beep is heard in a supermarket till). If not, the operator will have to rescan the bar code. Types of check (validation) :- Length check : an entry must be of a certain length (more or less will not be accepted). E.g. a Postcode must have not more than 8 characters. Range check : data entered must be between 2 numbers. E.g. between 16 and 65. Check Digit : see above. CREDIT Smart Cards : a plastic card that contain a microchip. This chip can either store data like a magnetic stripe (but more secure) or have some processing power. They can store data like personal medical history, bank details, etc… Smart cards can also be used as electronic purses, where the card can be filled up with money and then used. Optical Character Recognition (OCR) : Computer software can read the characters from a document that is scanned and then save it as a word processed file. This will save time re-typing all the details. Validation is when the computer is programmed to accept certain values. Verification is when a human being decides if data entered is correct or not. E.g. double entry (by the same operator or by 2 operators; if both pieces of data entered are the same, the data is accepted, else re-enter data again. E.g. the computer will ask if you want to “Save”, “Delete”, “Exit”, “Shut Down” (y/n)?


4/5. PROCESSING, STORAGE and OUTPUT FOUNDATION Data are stored in databases. Database files are made up of fields and records. These files have to be updated regularly and backed up on a regular basis. Information can be output on screen or on paper. GENERAL Interactive Processing is when a human being is involved in the data input. E.g. cinema/ airline booking system; ATMs; word processing, etc… CREDIT Sequential Access is when data is accessed serially, e.g. a song on magnetic tape is accessed by forwarding the previous songs first. Random/ Direct Access is when data can be accessed immediately anywhere on the media. Devices like Floppy Discs, Hard Discs, CD and DVD ROMS, memory sticks, (RAM/ ROM), etc… are all random access media. Multi-User Database : more than one person can access the same database at the same time. The database, which is centrally stored, makes updating and backing up of the database very simple and easy. Information can be output to a File for later use. 6. HARDWARE and SOFTWARE FOUNDATION Most big businesses use Mainframe computers. They are very large computers in size, have several fast processors, Terabytes of RAM (lots on memory), several types of backing storage (and lots of it); and can support 1000 users. Connected to mainframes are Terminals. These terminals are either dumb (have no processor, just a mouse, keyboard and monitor); or have their own processor. AN ATM is an example of a terminal that is connected to a mainframe computer. 7. IMPLICATIONS FOUNDATION Social : business can prosper due to increase amount of work being down by fewer people. Jobs are lost as well as created (more managers). Technical : E-commerce is the buying and selling of products electronically, e.g. via the internet. Advantages are that there are reduced cost (no buildings/ rooms to buy or rent; less people needed) and prices can thus be competitive; and no travelling for the customer. Disadvantages are that people cannot try out the goods before buying; returning of goods is not easy and can take a long time; no social contact; and security of financial data can be at risk. On-line banking also provides the customer to save time and money but security of usernames and password must be good.


Economic : There are always high initial costs to set up a business, i.e. buying of hardware, software and training. However, by buying in bulk (lots of products), prices are cheap and hence lots of people buy from your business. E.g. IKEA. This is known as Mass Market. Security and Privacy : Information must be made and kept accurate as computers just follow instructions. People can get upset or get in trouble if data about them is not correct or up-to-date. E.g. paid incorrectly. E.g. extremely high bills. All personal data must be kept private and must not be given to other companies unless people have given permission to do so. GENERAL Social : Many jobs are created. E.g. Programmer : codes and implements a solution. E.g. Systems Analysts : looks at the current systems and decides if it can be improved by computerisation/ updating or just to leave it as it is. E.g. Engineer : makes sure that all hardware and software is operational and functional. E.g. Network manager : makes sure that network is working, sets up security and access rights, monitor and record all activity Technical : Electronic Funds Transfer (EFT) : a persons bank card is wiped. The shops computer phones the customers bank and finds out if they have sufficient funds to pay the bills. If so, money is debited from the customers account and transferred to the shops bank account. Otherwise the transaction is cancelled. Advantages are that the shops are guaranteed to get paid; less money are in the tills so less incentive for thieves and short queues. Point of Sale (POS) is where items are scanned electronically (direct input) into the computer. This saves time entering data and shortens queues. Mistakes are less likely to be made and price changes can be done easily (once) by computer. Economic : Running costs usually involve paper, ink, discs, consumables and some maintenance costs. Security and Privacy : Data is kept secure is several ways : physical restriction to data / computers (locked doors, security personnel); user names and passwords; software encryption (data is encoded and needs a password/ key to unlock the code); and removing and storing data, e.g. data stored on disc and the disc locked up in a safe). Some companies sell customer lists to other companies who may be interested in certain customers. Again, customers must give consent first. CREDIT Computer Crime and Fraud : examples include hacking into secure systems; conning people to give them their bank details; stealing and use of bank cards, etc… Interesting articles are available on the net about the various types of computer crime : http://www.parliament.uk/documents/upload/postpn271.pdf


http://www.crime-research.org/news/26.11.2005/1661/ 8. ADVANTAGES FOUNDATION Computerised systems, compared to manual systems are faster at inputting, storing, accessing and updating data. Data is more secured and more than 1 person can view records. Records are not misplaced nor lost and can be easily sorted and searched, usually within seconds. Backup copies can also be made easily and all this takes up less space than a manual system. GENERAL Databases can do automatic searches and issue letters to customers at appropriate times for various reasons (product review, billing, etc…) Computerised databases can find records almost instantly and can send letters automatically to various customers using standard letters via the process of mail merge CREDIT Records about customers are only entered once into a database system. A customers record can then be accessed and used by many employees many times for may purposes within a business or organisation = Single Entry, Multiple Use

************ THE END

************ There are plenty of websites that can help you study for Computing Studies in more details. Just type in any aspect of the course in a search engine. There are plenty of interesting material about computing (past, present, future). The following 2 websites have more course notes will enhance your learning through different examples, different viewpoints and experiences and different explanations. http://www.bbc.co.uk/scotland/education/bitesize/standard/computing/ http://www.balfronhigh.org.uk/index.htm

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