module 2 - digital devices

computer

A device that accepts input, processes data, stores data, and produces output according to a stored program.

input

As a noun, the information that is conveyed to a computer. As a verb, to enter data into a digital device.

output

The results produced by a computer (for example, reports, graphs, and music).

process data

A systematic series of actions that a computer performs to manipulate data; typically represented on a DFD by a rounded rectangle.

central processing unit

(CPU) The main processing circuitry, or "chip," within a computer that contains the ALU, control unit, and registers.

microprocessor

An integrated circuit that contains the circuitry for processing data. It is a single-chip version of the central processing unit (CPU) found in all computers.

memory

The computer circuitry that holds data waiting to be processed.

storage

The area in a computer where data is retained on a permanent basis.

computer program

A detailed set of instructions that tells a computer how to solve a problem or carry out a task.

software

The instructions that direct a computer to perform a task, interact with a user, or process data.

stored program

A set of program statements that resides on a storage device, such as a hard drive, and can be loaded into computer memory and executed.

application software

Computer programs that help users perform a specific task such as word processing. Also called application programs, applications, or programs.

app

Short for application; popularly used to refer to applications available for the iPhone, the iPad, and other mobile devices.

system software

Computer programs, such as an operating system or utility software, that help the computer carry out essential operating tasks.

operating system

The software that controls the computer's use of its hardware resources, such as memory and disk storage space.

development tools

A software classification used to create software; examples include programming languages and scripting languages.

integrated circuit

Electronic circuitry etched on a base of silicon to form a microchip.

semiconductors

Substances, such as silicon or germanium, that can act as either a conductor or an insulator. Used in the manufacture of computer chips.

system board

The main circuit board in a computer that houses chips and other electronic components.

form factor

The configuration of a computer's system unit; examples include tower, mini-tower, and cube.

system unit

The case or box that contains the computer's power supply, storage devices, main circuit board, processor, and memory.

oleophobic

The characteristic of smartphone screens that resists oils.

lithium ion

The type of battery technology used in many of today's portable electronic devices.

discharge rate

In the context of battery life, the speed at which energy stored in the battery is released.

supercomputer

The fastest and most expensive type of computer, capable of processing trillions of instructions per second.

mainframe

A large, fast, and expensive computer generally used by businesses or government agencies to provide centralized storage, processing, and management for large amounts of data.

server

A computer or software on a network that supplies the network with data and storage.

personal computer

A microcomputer designed for use by an individual user for applications such as Web browsing and word processing.

desktop computer

A computer that is small enough to fit on a desk, runs from a wall outlet, and is built around a single microprocessor chip.

portable computer

A computer, such as a laptop, tablet, or smartphone, that runs on battery power.

laptop computer

A small, lightweight, portable computer that usually runs on batteries. Sometimes called a notebook computer.

Chromebook

A clamshell-style laptop computer that uses Chrome OS as an operating system and a thin client for Web access.

tablet computer

A small, portable computer with a touch-sensitive screen configured in a slate form factor.

slate tablet

A computer form factor in which the screen covers most of the system unit and there is no physical keyboard

2-in-1

A personal computer form factor that can be used as a tablet or with its attached keyboard.

smartphones

Cellular phones that have a high-resolution color screen, a browser, and the ability to run apps.

PDA

A device or software that helps track appointments, contacts, and notes.

wearable computers

Computers that are designed to be worn as clothing rather than to be carried.

microcontrollers

Special-purpose microprocessors that are built into the device they control.

compatible

In the context of digital devices, the situation when two devices use interchangeable software and peripherals.

x86

A family of microprocessors manufactured by Intel Corporation that defines the PC platform.

ARM

A RISC-based instruction set used as the basis for microprocessors in tablet computers and smartphones.

instruction set

The collection of instructions that a CPU is designed to process.

programming language

A set of keywords and grammar (syntax) that allows a programmer to write instructions that a computer can execute.

machine language

A low-level language written in binary code that the computer can execute directly.

ALU

) The part of the CPU that performs arithmetic and logical operations on the numbers stored in its registers.

registers

A sort of "scratch pad" area of the microprocessor into which data or instructions are moved so that they can be processed.

control unit

The part of the microprocessor that directs and coordinates processing.

instruction cycle

The steps followed by a computer to process a single instruction: fetch, interpret, execute, and then increment the instruction pointer.

instruction pointer

A component of the CPU that keeps track of sequential program execution.

microprocessor clock

A timing signal that sets the pace for executing instructions in a microprocessor.

gigahertz

(GHz) A measure of frequency equivalent to 1 billion cycles per second.

multi-core processor

A microprocessor that contains circuitry for more than one processing unit.

serial processing

Processing data one instruction at a time, completing one instruction before beginning another.

pipeline processing

A technology that allows a processor to begin executing an instruction before completing the previous instruction.

parallel processing

The simultaneous use of more than one processor to execute a program.

CPU cache

Special high-speed memory providing the CPU with rapid access to data that would otherwise be accessed from disk or RAM.

word size

The number of bits that a CPU can manipulate at one time, which is dependent on the size of the registers in the CPU and the number of circuits in the data bus.

CISC

(complex instruction set computer) A general-purpose microprocessor chip designed to handle a wider array of instructions than a RISC chip.

RISC

(reduced instruction set computer) A microprocessor designed for rapid and efficient processing of a small set of simple instructions.

RAM

(random access memory) Computer memory circuitry that holds data, program instructions, and the operating system while the computer is on.

capacitors

Electronic circuit components that store an electrical charge; in RAM, a charged capacitor represents an "on" bit, and a discharged one represents an "off" bit.

volatile

A term that describes data (usually in RAM) that can exist only with a constant supply of power.

dynamic RAM

Random access memory that requires a power source to hold data; used as main memory on most computers.

virtual memory

A computer's use of hard disk storage to simulate RAM.

ROM

(read-only memory) Refers to one or more integrated circuits that contain permanent instructions that the computer uses during the boot process.

boot loader

A program, usually stored in read-only memory, that starts the boot sequence, which loads the operating system into RAM.

local storage

Devices such as disk drives that store data within a computer or smartphone system unit, rather than on a network or in the cloud.

magnetic storage

A technology for recording data onto disks or tape by magnetizing particles of an oxide-based surface coating.

hard disk drive

A storage device that contains a large-capacity magnetic storage surface sealed inside a drive case. Typically used as the primary storage device in desktop and laptop computers.

hard disk platter

The component of a hard disk drive on which data is stored. It is a flat, rigid disk made of aluminum or glass and coated with magnetic oxide.

read-write head

The mechanism in a disk drive that magnetizes particles on the storage disk surface to write data, or senses the bits that are present to read data.

head crash

A collision between the read-write head and the surface of the hard disk platter, resulting in damage to some of the data on the disk.

access time

The estimated time for a storage device to locate data on a disk, usually measured in milliseconds.

SATA

(Serial Advanced Technology Attachment) The interface that transfers data from a drive to the main circuit board.

data transfer rate

The amount of data that a storage device can move from a storage medium to computer memory in one time unit, such as one second.

CDs

(compact discs) A useful method of archival storage for documents, music, and photos.

DVDs

(digital video discs) A useful method of archival storage for documents, music, and photos.

optical storage

A technology that records data as light and dark spots on a CD, DVD, or other optical media.

read-only

Storage media that can only be read from, but not recorded on.

recordable

The devices and standards that allow computers to write data permanently on CDs and DVDs, but do not allow that data to be changed once it has been recorded

rewritable

The devices and standards that allow users to write data on a storage medium and then change that data.

solid state storage

A technology that records data and stores it in a microscopic grid of cells on a non-volatile, erasable, low-power chip.

non-volatile

Any electronic component that does not require a constant supply of power to hold data.

memory card

A small, flat, solid state storage medium; frequently used to store data on cameras and handheld devices.

card reader

A device that can be used to read and record data on solid state storage devices, such as flash memory cards.

solid state drive

A data storage device that utilizes erasable, rewritable circuitry.

USB flash drive

A portable solid state storage device nicknamed "pen drive" or "keychain drive" that plugs directly into a computer's USB port.

remote storage

Any storage device that is not directly connected to a computer, but rather is accessed over a network.

cloud storage

A storage area that is located on a remote server, usually on the Internet, rather than on a local storage device.

backup

A duplicate copy of a file, disk, or tape. Also refers to a Windows utility that allows you to create and restore backups.

recovery drive

A storage device containing all the operating system files and application software files necessary to restore a computer to its original state.

file synchronization

A method for backing up data by copying any additions, changes, or deletions made on one storage device to another storage device.

disk image

A bit-by-bit copy of the contents of a disk; created for backup, archiving, or duplication of data.

peripheral device

Components or equipment, such as printers, that expand a computer's input, output, or storage capability.

expansion ports

Sockets into which the user plugs a cable from a peripheral device, allowing data to pass between the computer and the peripheral device.

data bus

An electronic pathway or circuit that connects electronic components (such as the processor and RAM) on a computer's system board.

hot-plugging

The ability of a component, such as a USB flash drive, to connect to or disconnect from a computer while it is running; also referred to as hot-swapping.

USB hub

A device that provides several auxiliary USB ports.

Bluetooth

A short-range network technology, typically used to transmit data between a peripheral device and a computer or handheld digital device.