Lesson 3: Input/Output and Storage Devices

Storage medium

("media" is the plural) is the physical material on which items are kept.

Optical Character Recognition

(OCR) software to automatically convert scanned text into a text file instead of a bit-mapped image.

Solid-state drive

(SSD) has the same functionality as traditional magnetic hard disks but instead of magnetic coating on top of platters; the data is stored on flash memory chips that retain the data without the presence of power. A solid-state drive has no moving parts.

Virtual machine

(VM) is application software used to create a virtual environment, which is referred to as 'virtualization'. With a virtual machine, a user can run multiple operating systems on one computer at the same time.

External Hardrive

An external, or portable hard drive sits outside the main computer tower in its own case. External hard drives can be used to backup your primary internal hard drive, and to provide additional storage.

Digital camera

A digital camera is a one that takes video or still photographs by recording images. Most cameras sold today are digital and are included in most mobile phones.

Disk cache

A disk cache, usually included as part of the hard disk, however, can also be a portion of RAM, is a tool for improving the time it takes to read from or write to a hard disk.

Dual boot

A dual boot is the ability to boot (start) your computer from different operating systems. This can be achieved by partitioning the hard disk.

Partitions

A hard disk, or hard drive can be divided into separate areas, called partitions, each of which functions as if it were a separate hard disk drive.

Disk fragmentation

Disk fragmentation occurs when files are not located in continuous sectors, which slows access time.

Redundant array of independent disks

RAID system integrates two or more hard disks, duplicating data, instructions, and information to improve data reliability. RAID is a way of storing the same data in different places on multiple hard disks.

Storage

also referred to as secondary storage, holds items such as data, instructions, and information for future use; storage holds these items while they are not being processed. Storage is non-volatile, which means the items in storage are retained even when power is removed from the computer.

Access arm

also referred to, as an actuator arm (part of the hard disk) is similar to the arm of a record player. As the platter spins, the access arm moves the read/write heads to the location information needs to be read, written, or deleted.

Flash memory cards

are solid-state portable storage systems capable of storing as much as 64 GB of data. They are commonly used with MP3 players, digital video cameras, and smartphones.

LED (light emitting diode) and LCD (liquid crystal display)

are today's most common monitor type. LED and LCD monitors are based on the same basic technology for image display, but differ in the kind of back-lighting used. While these monitors use cold cathode fluorescent lamps for back-lighting, the latter use light emitting diodes. This is the prime difference between the two display technologies. Therefore, LED monitors are in actuality, a type of LCD monitors, or an improvement over them, which generally result in a higher cost.

Arrow keys

are used to move the insertion point, represented by a symbol on the screen that indicates where the next typed character will display.

Reading

is the process of transferring items from a storage medium into memory. For instance, when you open a file that is stored on your hard drive, that process is reading. The computer is reading the file from the hard drive into memory.

Writing

is the process of transferring items from memory to a storage medium. If you are saving a file to your hard drive, the file is essentially being written to the hard drive.

Access time

is the time between initiating a request and obtaining the first data character from a disk. Simply stated, access time is the time required to find a file.

Latency

is the time it takes for the sector containing the data to rotate under the read/write head.

Seek time

is the time it takes the access arm on the hard disk with the read/write heads to position itself over the track.

Cluster

Two or more sectors form a cluster, which is reserved for data.

Toggle keys

allow a change between two different states. For example, Caps Lock is a toggle key. Pressing it will enable all capital letters, while pressing again will enable all lower-case text.

Monitor

also called a display device, is a screen that displays data and processed information referred to as output.

Random access

also referred to as direct access, is the ability of a device to jump directly to the file.

Compact disc

A compact disc (CD) is a flat, round, portable metal optical storage medium that is usually 4.75" in diameter.

Data transfer rate

Data transfer rate is the speed at which data transmits from one device to another. Essentially, how fast can a file be read (from a disk) or written (to a disk) once it's been found.

Blu-ray disc

One of the newest forms of optical storage, also known as BD-ROM, was developed to enable recording, rewriting, and playing back of high-definition (HD) video, as well as storing large amounts of data.

Cylinder

The same track on multiple platters together form a cylinder.

Form Factor

The size, configuration, or physical arrangement of a computer hardware object is referred to as form factor.

Tracks

The surface of disk is formatted into (invisible) bands called tracks where data is stored magnetically.

Wireless

The term "wireless" actually covers the whole range of wireless technologies, including Wi-Fi, Bluetooth,

Scanner

copies anything that's printed on a sheet of paper and converts the input into a graphic image for the computer. Because the scanner does not recognize the type of material it scans, everything is converted into a graphic bitmapped image, which is composed of a grid of dots called picture elements (pixels).

Sheet-fed scanner

feed the document through a slot in order to scan them, similar to fax machines.

Dot-matrix printer

has rows of electromagnetic pins that move to strike the ribbon of ink to form letters and punctuation symbols.

Function keys

have two primary functions: they are programmed to issue commands and accomplish certain tasks; they also act as shortcuts.

Platter

in a hard disk is made of aluminum, glass, or ceramic, and is coated with a material that allows items to be recorded magnetically on its surface. Each platter has two read/write heads, one for each side.

Hardware

in computer terms refers to the physical components that make up a computer system.

Solid-state storage

which consists of a non-volatile, removable storage medium that employs integrated circuits (ICs) rather than magnetic or optical media.

Projector

is a device that can project images from your computer onto a wall or screen, and is used in diverse environments.

Windows Explorer

is a file management application program used to manage drives, folders, and files.

Sequential access

is a method of accessing data on a tape drive where the drive must move the tape forward or backward until it reaches its destination.

Laser printer

is a non-impact printer that creates images using a laser beam and powdered ink, called toner. Laser printers are commonly used in offices; however, with the decrease in cost they have become quite common in home computing.

Thermal printer

is a non-impact printer that generates images by pushing electrically heated pins against heat-sensitive paper. Although the print quality of standard thermal printers generally is low, two special types of thermal printers, thermal wax-transfer printers and dye-sublimation printers, have a much higher print quality. Thermal printers are commonly used in retail for printing receipts.

Ink-jet printer

is a non-impact printer that sprays drops of ink onto a piece of paper. Ink-jet printers are commonly used in home computer systems.

Flash memory

is a nonvolatile computer storage technology that can be electrically erased and reprogrammed. It is primarily used in memory cards and USB flash drives for general storage and transfer of data between computers and other digital products.

Joystick

is a pointing device used to move objects in any direction on-screen. Although you can use joysticks as pointing devices, they are most commonly used to control the motion of on-screen objects in computer games.

Pointing stick

is a pressure-sensitive small nub used like a joystick. It's usually found on laptops embedded between the G, H, and B keys.

Internet hard drive

is a service on the Internet that provides online storage to computer users.

Bluetooth

is a short-range, wireless standard that allows devices to quickly and securely communicate with each other.

Trackball

is a stationary pointing device consisting of a ball housed in a sensor-lined opening designed to detect rotation of the ball, similar to an upside-down mouse.

Laser mouse

is a type of computer pointing device that uses a laser beam rather than a ball to track the movement of the user's hand.

Hand scanner

is a type of scanner that is physically held in a user's hand, and works by manually moving the scanner in consecutive sections over the document.

Wi-Fi

is a type of wireless networking protocol that allows devices to communicate without cords or cables. Wi-Fi is technically an industry term that represents a type of wireless local area network (LAN) protocol based on the 802.11 IEEE network standard.

Line printer

is an impact printer in which one line of text is printed at a time. They are widely used in the automotive, logistic, and banking world for high speed and bar-code printing.

Pointing device

is an input device allowing control of movements of the on-screen pointer. The pointer is an on-screen symbol, usually an arrow, that shows the current location of the on-the-screen activity.

Microphone

is an input device that converts sound waves into electrical signals that the computer is able to process. Microphones are commonly used with speech or voice recognition software; which converts spoken words into computer text.

Touch screen

is an input, and display device commonly used on smart-phones, tablet PCs, iPods, ATM machines, airport kiosks, retail point-of-sale terminals, car navigation systems, and medical monitors.

Non-impact printer

is an output device that forms characters and graphics without actually striking the paper. Non-impact printers give both higher print quality and faster printing speed than impact printers.

Printer

is an output device that produces text and graphics on a physical medium such as paper or transparency film.

Input device

is any peripheral device used to provide data to a computer system. Input devices fall under the category of hardware.

Throughput

is how long will it take to move the file from a disk into memory (RAM). In this case, lower numbers indicate lesser time.

Storage device

is the computer hardware that records and retrieves items to and from a storage medium. Storage devices can be the source of both input and output.

Resolution

is the number of pixels in a given area. It also refers to the clearness and sharpness of an image and is controlled by the number of pixels on the screen.

Formatting

is the process of preparing the disk for reading and writing; and enables you to install programs on the disk.

Mouse

which is a pointing device used to move a cursor on the screen allowing objects to be selected, moved, and manipulated using the buttons.

Keyboard

like a typewriter, is used for entering characters (such as letters, numbers, and symbols), and is essential in allowing us to enter commands into the computer.

Impact printer

works by striking or impacting a pin against ink covered cloth ribbon, which leaves an impression on the paper.

Tape

one of the first storage media used with mainframe computers, is a magnetically coated ribbon of plastic capable of storing large amounts of data and information at low cost. Libraries and large organizations use microfilm and microfiche to archive relatively inactive documents and files.

Headset

or earbuds are an output device used to produce sound that fit over the user's ears in order to avoid distracting other people.

Hard disk

or hard disk drive, consists of several non-flexible, circular platters that store items electronically. Traditionally hard drives are magnetic that contain magnetic hard disks, read/write heads, and an access mechanism, and is the primary storage device of the computer.

Touchpad

or track pad is a flat surface that can detect finger contact. It's a stationary pointing device, commonly used on laptop computers.

Speakers

provide the ability to output sound, therefore they are an output device.

Sectors

refer to the number of fixed-size areas (imaginary pie slices) that can be accessed by one of the disk drive's read/write heads, in one rotation of the disk.

Speech recognition

refers to the ability of a computer to understand spoken words.

Cloud storage

services are a type of online storage, which provides additional services over a traditional Internet hard drive. A primary benefit is the ability to synchronize a user's hard drive to the online storage.

Microfilm and microfiche

store microscopic images of documents on roll or sheet film. They are commonly used for archiving data in organizations and libraries.

Optical media

such as the compact disk (CD) are storage media that hold content in digital form that are written and read by a laser; these media include all of the CD and DVD

Optical mouse

uses an LED light to track the mouse movement in relation to the surface it passes over without the use of a ball.

Flatbed scanner

usually found on a desktop, enables you scan a document by placing it flat against a glass panel. This is the most common type of scanner.