Computing "Key Terms"

Computer

Device receiving data to process using instruction set producing processed data as result.

Computer architecture

Computer design & function, including computer parts design, organisation, connection.

Data

Computer program information. (s: datum)

Bit

Binary digit with 1 or 0 value.

Byte

8 bits forming a binary number.

Arithmetic logic unit (ALU)

Processor part processing data through basic mathematical & logical operations.

Central processing unit/processor

Computer part processing data & following instructions.

Control unit

Processor part following instructions, deciding data management (storage, receiving, transmission) by different computer parts.

Execute

Follow or perform instruction.

Software

Instruction set for specific task performance on computer.

Address

Byte numerical locator in memory.

Memory

Immediate use data storage device in computer.

Hard disk/drive

Secondary storage, rigid rotating disks coated with magnetic material, storing data.

Volatile

Lost during power supply interruption.

Bus

Wire collection transporting data between 2 parts of computer.

Bi-directional

Goes in 2 directions.

Data bus

Transports data between memory & processor.

Address bus

Specifies memory address information. Goes from processor to memory.

Uni-directional

Only goes in 1 direction.

Input (Computer architecture)

Computer received data/instructions to process.

Output (Computer architecture)

Computer produced intermediate/final results in processed data form.

Hardware

Computer physical part.

Input device

Hardware device allowing data & instructions entered into computer by user.

Output device

Hardware device displaying, projecting or printing computer processed data.

Secondary storage

Storing large data amounts unaffected by power supply interruption (non-volatile).

Algorithm

Problem solving set of step-by-step instructions.

Input (Algorithm)

Algorithm used data affecting correct output requirement.

Output (Algorithm)

Algorithm produced results.

Solution

Algorithm only provided with valid inputs always giving correct outputs.

Decomposition

Complex problem broken down into smaller more manageable parts.

Sub-problem

Problem whose solution culmulates into the solution of larger problem.

Pattern recognition

Similarity identification between multiple items.

Generalisation

Replacing similar problems/solutions with singular problem/solution.

Variable (Flowchart & pseudo-code)

Named storage space for changeable value used by algorithm.

Initialise

First instance of variable storage/assignment.

Flowchart

Algorithm visual presentation demonstrating steps sequence flow.

Flow line

Arrow indicating step order.

Symbol (Flowchart)

Special shape representing flowchart action/step.

Construct

Algorithm structure with only 1 entry & 1 exit point.

Sequence construct

Construct with multiple consecutive instructions performed in strict order.

Branch

Instruction sequence diverted from main flowchart due to decision symbol.

Selection construct

Construct picking between branches based on certain condition.

Iterate

Repeat.

Iteration construct

Construct repeating instructions while a condition is fulfilled.

Dry run

Process running through steps set manually.

Test data

Input data for performing dry run.

Trace table

Tabulating variable changes & algorithm outputs during dry run.

Pseudo-code

Algorithm description using mixture of natural language & constructs (sequence, selection, iteration).

Instruction set

Basic command/instruction set understood directly by processor represented in byte form.

Machine code

Instructions run directly on computer processor.

Program

Instructions set computers use performing specific tasks.

Programming language

Human communicate instructions to computers language.

Source code

Instructions in programming language both humans & computers can understand.

Syntax

Rules determining words & symbols arrangement in valid instruction.

Syntax error

Incorrect source code not following language rules.

Compiler

Code translator program completely translating source code into machine code before running it.

Interpreter

Code translator program translating source code into machine code & running it simultaneously.

Command line interface

Medium of interaction with program with commands represented as lines of text.

Graphical user interface

Medium of interaction with program with commands represented as visuals.

Syntax highlighting

Display of different source code parts differently using different colours & fonts according to programming language rules to ease difficulties in reading.

Interactive mode

Python feature allowing entering of source code line by line to immediately run & show results.

Comment

Part of source code explaining program but not translated or run.

Identifier

Character sequence following specific rules that may be used as variable name.

Keyword (Programming)

Specific words reserved by programming language for running code & cannot be used as identifier.

Variable (Python)

Name with assigned value that may be modified while program runs.

Constant (Programming)

Name with assigned value that cannot be modified while program runs.

Naming convention

Guidelines on how identifiers & names should be chosen.

Floating-point number (float)

Data type representing numbers with decimals.

Integer (int)

Data type representing whole numbers.

Literal

Value represented directly in source code.

String (str)

Data type representing text as sequence of characters or symbols.

Escape code

Character sequence inputted difficult to type out as literal or creates syntax errors if not treated uniquely.

Type casting

Conversion process between 2 data types.

Boolean (bool)

Data type representing True or False.

Array

Sequence of same sized items arranged consecutively in memory. Sometimes interchangeably used with list.

List (programming)

Data type storing multiple sequencial values.

Argument

Additional value used as input for function call.

Function

Reusable instructions set assigned to a name.

Function call

Process assigning arguments to new variables & running instructions assigned to function.

Nested function call

Resultant value of function call used as argument for another function call.

Return value

Function output, or presumed function call value after its assigned instructions are completed.

Body (functions)

Statements sequence in user-defined function.

Indentation

Spaces number in front of each source code line.

User-defined function (UDF)

Programming language user provided function.

Parameter

UDF special variable with argument assignment when UDF is called.

Signature (programming)

UDF first line specifying UDF name & its parameters.

Return instruction

Instruction immediately ending function treating subsequent value as provided return value.

Local variable

Variable internally created in UDF & can only be used within UDF.

Global variable

Variable externally created outside & before UDF & is usable both inside & outside UDF.

Binary operator

Operator only taking 2 inputs as values.

Operator

Performing instructions symbol using different syntax from function.

Floor division

Division operator rounding down result to nearest integer.

Sequence

Any data type storing multiple sequencial values.

Concatenation

Joining 2 sequences forming longer sequence.

Slice operator

Operator returning extracted sequence from longer sequence.

Index

Integer value representing value sequence position.

Index operator

Operator returning value from within sequence.

Immutable

Unchangeable from creation.

Mutable

Can be changed even after creation.

Control flow statement

Programming instruction changing instructions run order.