Understanding Computer Systems

computer system

is a combination of all the components required to process and store data using a computer. Every computer system is composed of multiple pieces of hardware and software.

Hardware

The machines, wiring, and other physical components of a computer or other electronic system

software

written programs or procedures or rules and associated documentation pertaining to the operation of a computer system and that are stored in read/write memory

program

Provide a computer or other machine with coded instructions for the automatic performance of a particular task.

logic

is the complete sequence of tasks that lead to a problem's solution.

Application software

computer software created to allow the user to perform a specific job or task

System software

software responsible for the general operation of a computer system, including the operation of hardware, running application software, and file management

operating system

the software that supports a computer's basic functions, such as scheduling tasks, executing applications, and controlling peripherals.

Input

describes the entry of data items into computer memory using hardware devices such as keyboards and mice.

Data items

the text, numbers, and other information processed by a computer.

Processing

working with data items, such as organizing them, checking them for accuracy, or performing mathematical operations on them.

central processing unit (CPU)

the computer hardware component that processes data.

Output

describes the operation of retrieving information from memory and sending it to a device, such as a monitor or printer, so that people can view, interpret, and work with the results.

information

processed data.

storage device

a hardware apparatus that holds data or information for later retrieval.

cloud

remote computers accessed through the Internet.

programming language

a language, such as Visual Basic, C#, C++, Java, or COBOL, used to write programs.

program code

a set of instructions written in a programming language.

coding the program

the act of writing the statements of a program in a programming language.

syntax

the rules of a language.

syntax errors

errors in a language's usage, including spelling and grammar.

computer memory

the temporary, internal storage within a computer.

Random access memory (RAM)

Temporary memory a computer uses to store information while it is processing.

volatile

a characteristic of internal memory in which its contents are lost every time the computer loses power.

nonvolatile

describes storage that retains its contents when power is lost.

machine language/binary language

a computer's on/off circuitry language; the low-level language made up of 1s and 0s that the computer understands.

source code

the readable statements of a program, written in a programming language; they are later translated into object code.

object code

program statements that have been translated into machine language.

compiler

A computer program created to read an entire program and convert it into a lower-level language and ultimately to assembly language used by the processor.

interpreter

software that translates the statements in a high-level programming language one at a time into machine language and identifies syntax errors. Contrast with compiler.

runs

to have a computer use a written and compiled program; also called execute.

executes

to have a computer use a written and compiled program; also called run.

scripting language

A computer programming language that is typically interpreted into a language the computer can understand without the need of a compiler.

logical errors

errors that occur when incorrect instructions are performed, or when instructions are performed in the wrong order.

program development cycle

the steps that occur during a program's lifetime, including planning, coding, translating, testing, producing, and maintaining the program.

users

people who work with, and benefit from, computer programs; see also end users.

end users

people who work with, and benefit from, computer programs; see also users.

desk-checking

the process of walking through a program solution on paper.

debugging

the process of finding and correcting program errors.

Conversion

the set of actions an organization must take in order to switch over to using a new program or system.

Pseudocode

an English-like representation of the logical steps it takes to solve a problem.

flowchart

a pictorial representation of the logical steps it takes to solve a problem.

terminal symbols

lozenge-shaped symbols used at the beginning and end of a flowchart; also called start/stop symbols.