Computer Language Flashcards
Text based Interfaces
User types in commands as a series of words or abbreviations. All commands can be carried out using the keyboard. Characters and control keys (arrows, Return, Tab, etc)
Text based Interfaces - Use
Setting up a BIOS
Older business software e.g. accounts packages.
Text based Interfaces - Advantages
- Simple and accurate.
- Little processing power needed.
Text based Interfaces - Disadvantages
- Needs Keyboard
- Need to know commands in advance.
Forms Dialogue
Interaction is through a series of forms that are used to enter data and display results.
Many inputs may use drop down boxes, radio buttons and check boxes.
Forms Dialogue - Use
Setting configuration .
Forms Dialogue - Advantages
Familiar to paper forms, which might be familiar with.
Forms Dialogue - Disadvantages
May be restrictive.
Graphical User Interfaces (GUI)
Combination of windows, menus, icons and a pointer. (WIMP)
Graphical User Interfaces (GUI) - Benefits
(USUALLY)
- Easier to learn for novice.
- More intuitive to use once learned.
- Allows customization (desk-top, creating shortcuts).
- Similar to other packages with which users are familiar.
- No need to learn complex text commands
- Has good help systems, tutorials, wizards, etc.
Graphical User Interfaces (GUI) - Disadvantages
- Requires a lot of processing power.
- Requires hard disk space.
Dedicated Keys
A specific key or button has a function associated with it. May also refer to a key combination eg C for copy.
USE: As control buttons for devices with embedded computers eg cameras.
Soft Keys
Keys that can be programmed to perform specific functions.
USE: allocating frequently performed tasks to the function key on a keyboard.
Voice Synthesis - Use
- Automated announcements e.g. on board trains - will not be forgotten.
- Used with automated phone systems.
Voice Synthesis - Advantages
- Useful for blind, e.g. reading machine.
- useful when screen can not be used e.g satellite navigation systems.
Voice Synthesis - Disadvantage
- May sound very artificial, lacks expression.
- No use in noisy environments.
- No use for deaf.
Speech recognition
Device recognizes spoken words.
Speech recognition - Benefits
- Speeds up text input/ faster then typing.
- May help to avoid RSI.
- Hands free, user can do other tasks at the same time.
Speech recognition - Problems
- The System can’t tell the difference between homophones.
- The system can get confused between commands and dictation.
Handwriting Recognition
User uses a pad and writes as if with a pen on paper. Computer recognizes the characters written as if they were typed.
Handwriting Recognition - Benefits
It’s easier/faster for users than typing.
It’s more “natural” form of input.
Avoids use of bulky keyboard.
Design validation
Does it meet requirements?
Have the appropriate techniques been used? - Methods of implementation, hardware.
Is the user interface acceptable?
Feedback from prototypes
Design evaluation
Can the design be implemented with given resources?
Can the design be completed on time?
Is the design as simple as possible?
Can the design be completed within the given budget?
Algorithm
An algorithm is a sequence of steps designed to perform a particular task.
Types of algorithms
-Structured English.
-Pseudo code.
Flowchart.
Machine language
Instructions represented by patters of bits that the processor in a computer can understand.
What is Assembly Language?
Assembly Language is an abbreviation of machine language.
Semantics
The rules which govern the meaning of a word or phrase.
Syntax
The rules which govern the way in which words can be put together.
Language Levels
Computer languages are classified according to the way in which they interact with the hardware.
Low Level Languages: FEATURES
- Few data structures.
- Are concerned largely with operating on bits.
- Commands cover only simple operations such as shifts, additions, and transfer memory to a register.
- Commands interact directly with the hardware.
- Programs are difficult to transfer to different types of computer.
High Level Languages: FEATURES
- Commands are very similar to “English” therefore it’s easier to understand.
- Commands are more powerful than in a low level language.
- There are a variety of data structures available e.g. strings, arrays, records.
- If there are errors the translation process will identify many of them.
- The commands do not refer to hardware directly so they are easier to transfer from one type of machine to another.
Use low level language when
- Control of hardware directly is needed.
- maximum performance is needed.
- Resulting program can be very small.
Use high level language when
- Allow portability.
- Easier to write in.
- Whenever possible.
Procedural Programming (Imperative Languages)
Languages where a series of command loops, decisions and calculations are carried out in sequence.
Procedural Languages
Procedural languages are to do with actions, calculations and following a set of instructions. They are used for most programming tasks.