Input and Output Devices

Flashcards of Vocabulary for Input and Output Devices and related topics.

Analogue Data

Data that is constantly varying, such as sound waves.

Digital Data

Discrete data made up of only two values: 0 and 1.

ADC (Analogue to Digital Converter)

A device that converts analogue data to digital data.

DAC (Digital to Analogue Converter)

A device that converts digital data to analogue data.

Input Device

Device used to enter data into a computer system.

Keyboard

An input device used to type in data (text, numbers, and symbols).

Optical Mouse

An input device used to control a pointer/cursor on a screen using laser and optical sensor to detect movement.

Microphone

An input device used to input sound to a computer.

Digital Camera

Input device used to capture digital photographs using a lens and a sensor to capture light.

Voice Recognition

Software used to identify a known user from their voice.

Speech Recognition

Software that recognizes spoken words.

2D Scanner

An input device used to convert hardcopy images/documents into a digital format.

OCR (Optical Character Recognition)

Software that scans text from a document to be converted into a text file format.

OMR (Optical Mark Recognition)

Software is used to detect the presence of marks in certain positions on a paper form.

3D Scanner

An input device used to scan solid objects and produce a 3D digital model.

Barcode

A series of black and white lines of varying thickness used to represent numeric digits or characters.

Barcode Scanner

Input device used to scan barcodes, using laser and sensors to convert barcodes to binary values.

QR Code

Matrix of black and white squares that can link to websites, videos, text, etc.

QR Code Scanner

Input device used to scan QR codes, using a red laser and sensors to convert QR codes to binary values.

Touchscreen

An input device that allows simple touches to carry out many of the functions of a pointing device (such as a mouse).

Capacitive Touchscreen

Touchscreen that operates by using the conductive properties of the object/finger that is used to touch the screen.

Resistive Touchscreen

Touchscreen that makes use of two layers; when the top layer is touched, the top layer and the bottom layer complete a circuit at the point of touching.

Infrared Touchscreen

Touchscreen that uses sensors and infrared beams; sensors detect the point of touching through a break in a beam.

Output Device

A piece of hardware that produces the processed data to the user.

LED Screen

A screen that is made up of tiny LEDs; LED brightness can vary by varying the electric current sent to each LED.

LCD Screen

A screen that is made up of tiny liquid crystals and backlighting.

LCD Projector

A projector that uses LCD screens and a special prism to project an image.

DLP (Digital Light Projector)

A projector that is composed of millions of micro mirrors on a small DMD chip.

Inkjet Printer

A printer that uses liquid ink and a moving printing head to print out data.

Laser Printer

A laser printer uses toner and static electricity to print out information.

3D Printer

Output device used to produce 3D solid objects; the solid objects are built up layer by layer using materials such as powdered metal, paper, or plastic.

Actuator

A mechanical output device that produces movement; they can rotate, close, push, and pull an object.

Firmware

A piece of software that runs directly on the hardware.

Primary Memory

Main memory inside the computer that is directly accessible by the CPU.

Secondary Storage

Non-volatile storage that is not directly accessed by the CPU.

Magnetic Storage

Data is stored in the form of magnetic dots. Examples: Hard disk drive (HDD), portable hard disk drive, magnetic tape drive.

Optical Storage

Data is represented on disks as pits and land. Examples: CD, DVD, Blu-ray disc.

Pit

An indentation on the surface of an optical disk used to represent data.

Land

The raised surface between two pits on an optical disk.

Solid-state storage

Uses NAND/NOR chips are used to store data, Made of transistors that are laid out in a grid. Examples: Solid-state drive (SSD), Portable SSD, SD Card, USB Flash Memory, RAM.

Cloud Storage

Online storage platform where data is stored in a remote physical location using hundreds of interlinked data servers.

File Compression

It reduces the file size.

Lossless Compression

Method of compression that loses no data in the process, for example: Code, Text file, Database file.

Run-length encoding (RLE)

The repeated patterns of characters/pixels/samples are identified, then encoded into two values: The number of identical characters in the run (run count) and the value of the pattern (run value).

Data Dictionary

The repeated characters/pixels/samples are identified, then indexed (put in a table), and then replaced by their index. The number of occurrences and The position of repeated characters/pixels/samples in the file is stored in the table

Lossy compression

Method of compression where redundant details are permanently removed from the file without significantly affecting the quality of the file, for example: Images, Audio files, Video files

Sensor

An input device used to measure the physical properties of the surrounding environment.

Automated Systems

A combination of software and hardware designed and programmed to work automatically without the need for any human intervention.

Microprocessor

A type of integrated circuit contained on a single chip.

Volatile

The contents of the memory are lost when the power to the RAM is turned off

Von Neumann Architecture

Often referred to as the stored program concept where Programs are stored on a secondary storage device, Data and instructions are moved to RAM and stored in it, Instructions are fetched, decoded, and executed one after another by the CPU

RAM

Made up of partitions. Each partition consists of an address and its contents. It is used to store data/files currently in use, to store software/programs/instructions/parts of OS currently in use, to store data temporarily, to speed up the fetch stage of the FDE cycle

Central Processing Unit (CPU)

A type of integrated circuit contained on a single chip that is used to process the instructions. The structure consists of an Arithmetic and Logic Unit (ALU), Control Unit, and registers. To perform an FDE cycle / To process an instruction

Registers

A small fast memory location within the CPU, to store data/address/instruction temporarily. Examples: Program Counter (PC), Current Instruction Register (CIR), Memory Address Register (MAR), Memory Data Register (MDR), Accumulator (ACC)

Buses

Pathways to transmit data, addresses, and control signals between the internal components of the CPU. Examples: Data bus, Address bus, Control bus

Interrupt

A signal sent from a device or software that informs the CPU that its attention is required with different priorities. To inform the CPU that its attention is required, to deal with vital tasks immediately based on their priority, enables multi-tasking to be carried out on a computer

Interrupt Service Routine (ISR)

A piece of software that is that contains the code that handles the interrupts, it a part of the operating system

Core

A unit on a CPU that is made up of an ALU, control unit, and registers, to perform an FDE cycle, process an instruction. Increasing the number of cores allows the CPU to process multiple instructions at the same time

System clock

A component that regulates the number of FDE cycles the CPU can perform in a second.

CPU Cache

A type of storage that stores frequently used data/instructions, to speed up access as it is faster to access than RAM

Embedded Systems

Performs a single/limited function, as a microprocessor, has dedicated hardware, uses firmware. Example: Domestic appliances, Cars, Security Systems, Lighting Systems, Vending Machines

Application Software

Programs that provide the services that the user requires to perform tasks. Examples: Spreadsheet, Word Processor, Database, Web browser, Image-editor, Game

System Software

Programs that provide the services that the computer requires to manage/maintain the hardware. Examples: Operating System, Utility software, Compiler / Interpreter / Assembler

Operating System

A piece of system software that performs many basic tasks and allows the user to communicate with the computer hardware. Tasks: provides a platform for running applications, memory management, managing peripherals and drivers, manage multitasking, handling interrupts

Utility software

A program that performs a specific task required for the operation of a computer system. Examples: Antivirus, Disk repair, Backup software, Screensaver

High-level language

A type of programming language that is close to human language. Machine-independent (a portable language), has built-in functions which save time when writing a program

Low-level language

A type of programming language that is close to the native language of the computer, Machine-dependent (code is specific to the type of computer), Allows direct manipulation of memory.

Machine Code

The binary instructions that a computer understands and executes directly.

Assembly Language

A form of low-level language that uses mnemonics, an assembler is needed to translate an assembly language program into machine code

Instruction Set

A list of all machine code commands that can be processed by a CPU, used to define the commands that can be carried out by the CPU

Language translators

Software used to convert programming language code to machine code to be executed by the computer. Examples: Compiler, Interpreter, Assembler

IDE (Integrated Development Environment)

Software that provides useful functions for a programmer writing a computer program, such as: Code Editor, Run-time environment, Translator, Error Diagnostics, Auto-completion, Auto-correction

Serial transimission

It refers to data being transmitted one bit at a time over a single wire. Examples: Wi-Fi, USB

Parallel transimission

It refers to the transmission of multiple bits of data over multiple wires all at the same time. Examples: RAM, Integrated circuits (IC)

USB (Universal Serial Bus)

Data transmission method that uses serial transmission to transfer data between a computer and several devices, allows both half-duplex and full-duplex data transmission

Network Interface Card (NIC)

A component in a device that enables it to connect to a network, contains the MAC Address of the computer generated at the manufacture stage

Router

A device that sends data packets to a specific destination on a network, can assign IP Addresses, can connect a local network to the internet

MAC (Media Access Control) Address

A unique address that identifies a device on a network, allocated by the manufacturer

IP (Internet Protocol) Address

A unique address that identifies a device on a network, allocated by the router/network provider, can be static or dynamic. There are two versions: IPv4 and IPv6

Data Packets

A small part of a message/data that is transmitted over a network, consists of three sections: Packet header, Payload, Trailer

Parity Check

An error-checking method that relies on counting the number of 1s in each byte of data received and comparing it to the agreed parity

Checksum

A value is calculated from the block of data using an algorithm. The checksum is transmitted with the block of data and The receiver re-calculates the checksum to compare

Echo Check

A copy of the data is sent back to the sender, returned data is compared with the original data by the sender’s computer

ARQ (Automatic Repeat Request)

Uses positive and negative acknowledgments and timeout

Check digit

A digit that is calculated from all the other digits and then appended to the number.

Internet

Worldwide collection of interconnected networks, relies on physical infrastructure that allows devices to connect to other networks and devices

WWW (World Wide Web)

The collective name for all the web pages available, part of the internet that users can access using a web browser

Web page

A web document written in HTML.

Website

A collection of related web pages.

Web server

A computer that stores web pages, receives requests from clients and returns the requested web page

Web browser

Software used to display web pages by rendering HTML. Provides an address bar, navigation tools, Stores bookmarks and favorites, Stores user history.

DNS

A server that stores URLs and their matching IP addresses.

Uniform Resource Locator (URL)

A unique text-based address for a web page, contains the protocol, the domain name, and the filename

HTTP

The main protocol that controls the transmission of data to and from web servers.

HTTPS

A protocol used to control the transmission of data to and from web servers, It uses encryption, It uses SSL

Cookies

Small text files that are created and sent by a web server, are stored on a user’s computer by the web browser

Session Cookie

A cookie that is stored temporarily on a computer, it is deleted when the browser is closed or the website session ends, It is stored in temporary memory

Persistent Cookie

A cookie that is stored permanently on the user’s hard drive, it is only deleted by the user or when the cookie expires, it is stored on the user’s secondary storage.

Malware

Programs installed on a user’s computer with the aim of deleting, corrupting, or manipulating data illegally