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BASICS
SOFTWARE
.The human interface
...The ways we pass information between ourselves and the computers, must be effective.
...From the computer Sight makes up 80%, sound makes 11% so they must have high quality.
...To the computer we Key-in, point and click, speak, scan, all are fairly prone to error.
...Good interfaces are easy, friendly, enjoyable, -like having a conversation.
...Good interfaces must also be accurate, timely, and robust(solid performers).
.Computer types
...Mainframe computers, very powerful, huge networks with large bandwidth, used by Government
. . . multinationals, banks, and research science. They need a band of dedicated staff to operate.
...Mini computers, distributed smaller computers that usually form the backbone of a network
...Personal Computers, used in homes and business. Linked to the Net or stand alone and operated by the user.
.Keyboards
...The ugly interface, cause injury(RSI), prone to human error, difficult to master, evolved from type-writers.
...Newer ergonomic layouts available, extra function buttons help, but remains an awkward device
.Components and peripherals
...The computer has a CPU (central processing unit), Memory, and channels to pass the data (BUS), at the centre
...Going into the centre are input devices - keyboard, mouse, scanner, microphone, modem, etc.
...Linked to the centre are storage devices - Hard disks, floppy disks, CDs, DVDs, etc.
...Coming from the centre are output devices - Monitor screens, printers, speakers, LCD projectors, modem,etc.
.Types of interfaces.
...Command line - e.g. DOS where the user enters commands and the computer responds. The user must learn the commands
. . . and this is like learning a mini language. So it is not suited to the casual user.
...Graphical interface - e.g. Windows where the user points and selects. Uses more computer power to operate and
. . . but is not suited to data entry of text.
...Menu interfaces - e.g. filling out a screen form, name, address, order taking etc. Effective but disliked
. . . because they tend to drive the user, but the user likes to feel they are in charge.
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Programs are a list of instructions that the computer executes. The instructions are written in a computer language
Examples of languages are C++, COBOL, Visual Basic, ADA, Basic. Programs must be 100% accurate or they are said to have
BUGS in them. The bugs or mistakes will cause the program to "crash" (stop), produce wrong information, or annoy the user
Programs usually undergo many changes so they should be well structured and easy to maintain.
.Operating systems.
The operating system is the bottom level resident program that schedules, runs, controls, and manages the computers resources.
It usually includes utility code to perform common routines (error checking) and functions (copying files)
Examples are DOS, Windows 95, Windows NT, UNIX, OS/2.
.Application software.
Application software refers to the programs that the user runs. There are several categories.
..Business
. . . Accounting
. . . Sales ordering
. . . Stock recording
..Education
. . . Maths
. . . Geography
. . . Computer tutorials
. . . Science. etc
..Games/entertainment
. . . Cards
. . . Shoot-em down
. . . Mind puzzles
. . . Mazes. etc
..Graphics
. . . Drawing
. . . Photo cut/paste/change
. . . Desk top publishing
..Multimedia
. . . Animation
. . . Video
. . . Music and sound
..Program development
. . . program languages and compilers
. . . Automated program writers
. . . programming tools
..Utilities
. . . Special effects
. . . File management tools
. . . Communications
..Productivity - general purpose
. . . Office - Word processors, Spreadsheets, Databases, Planners and Organisers
.Ownership.
The writer of the programs or the company that the programer works for OWN the software.
They have a COPYRIGHT. No-one can use it without their permission.
They can get permission by buying a copy, licensing a copy, or being given a copy.
By making a copy freely available to anyone it is said to be in the PUBLIC DOMAIN.
SHAREWARE is half way in between, it is freely available but you are invited to see this as a sample
and to pay a small amount if you wish to continue to use it.
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