compsci chapters 1+2

program

a set of instructions that a computer follows to perform a task, commonly known as software

programmer

a person who can design, create, and tests computer programs, also known as software developer

hardware

the physical devices that make up a computer

5 major components of a computer

central processing unit (CPU), main memory, secondary storage devices, and input and output devices

central processing unit

the part of the computer that actually runs programs

microprocessors

the CPUs located on small chips

main memory

where a computer stores a program while program is running, and data used by the program

random access memory

volatile memory used for temporary storage while program is running; contents are erased when computer is off

secondary storage

holds data for long periods of time; programs are normally stored here and loaded to main memory when needed

3 major types of secondary memory

solid state drive, disk drive, flash memory

disk drive

loads magnetically encoded data onto a spinning circular *****

solid state drive (SSD)

faster than disk drive, no moving parts, stores data in ********* memory

flash memory

portable drive, no physical disk

input

data that the computer collects from people and other devices

input device

the component that collects the data and sends it to the computer

output

data that is produced by the computer for other people or devices

output device

any device that presents data from the computer

software

a program or instructions that give directions to the computer and controls it

application software

programs that make computer useful for everyday tasks (ex: word processing, email, games, and web browsers)

system software

programs that control and manage basic operations of a computer (ex: operating system, utility program, and software development tools)

operating system

controls operations of hardware components

utility program

a “________” performs specific task to enhance computer operation or safeguard data

software development tools

used to create, modify, and test software programs

byte

enough memory to store letter or small number; divded into 8 bits

bit

an electrical component that can hold positive or negative charge, like on/off switch

binary number

this is how data stored in the computer must be stored

ASCII

most important coding scheme, defines codes for only 128 characters

digital data

any device that stores data as binary numbers

fetch-decode-execute

3-step CPU program cycle

assembly language

uses short words (mnemonics) for instructions instead of binary numbers

assembler

translates assembly language to machine language for execution by CPU

low-level language

a language which is close to machine code, and is closely related to the design of the machine.

high-level language

a language that is human readable and allows simple creation of powerful and complex programs

keywords

predefined words used to write program in high-level language

operators

“_________” perform operations on data and/or actions that take the problem from one state to another

syntax

a set of rules to be followed when writing program

statement

an individual instruction used in high-level language

compiler

translates high-level language program into separate machine language program

interpreter

translates and executes instructions in high-level language program

source code

statements written by the programmer

syntax error

prevents code from being translated and running

algorithm

set of well-defined logical steps that must be taken to perform a task

pseudocode

code not meant to be compiled or executed, and is used to create model program

flowchart

diagram that graphically depicts the steps in a program

computer's typical 3-step process

Receive input, perform some process on the input, produce output

function

piece of prewritten code that performs an operation

argument

data given to a function

string

sequence of characters that is used as data

string literal

string that appears in actual code of a program

end-line comment

appears at the end of a line of code, typically explains the purpose of that line

variable

name that represents a value stored in the computer memory

assignment statement

used to create a variable and make it reference data

garbage collection

removal of values that are no longer referenced by variables