Input and Output

Ergonomic Keyboard

It is a keyboard that separates the keys into two halves shaped like a wide "V." Some keyboards have a fixed layout, while others are movable. To the touch typist, the layout feels odd at first, it puts less stress on the hands and wrist. It also winds up being comfortable for most people.






Inkjet Printer

Inkjet printers are the most common type of consumer printers. The inkjet technology works by spraying very fine drops of ink on a sheet of paper. These droplets are "ionized" which allows them to be directed by magnetic plates in the ink's path. As the paper is fed through the printer, the print head moves back and forth, spraying thousands of these small droplets on the page.

While inkjet printers used to lack the quality and speed of laser printers, they have become almost as fast as laser printers and some can even produce higher-quality images. Even low-budget inkjet printers can now print high-resolution photos. The amazing thing is, as the quality of inkjet printers has improved, the prices have continued to drop. However, for most people, refilling the inkjet cartridges a few times will often cost more than the printer.




Laser Printer

A printer that uses a laser and the electrophotographic method to print a full page at a time. The laser "paints" a charged drum with light, to which toner is applied and then transferred onto paper (see electrophotographic for more details). Desktop laser printers use cut sheets like a copy machine. Large printers may use paper rolls that are cut after printing.

Magnetic-ink Character Reader (MICR)

As an Optical Character Reader (OCR) is not perfect at converting standard printed text into electronic form, there is a more reliable system available. It is called the magnetic ink character reader.

Advantage:

• Very reliable, low errors
• High speed
• Not so sensitive to grubby paper.

Disadvantage:

• The ink technology is relatively expensive
• The font has to be specific.

Optical-Character Recognition (OCR)

Often abbreviated OCR, optical character recognition refers to the branch of computer science that involves reading text from paper and translating the images into a form that the computer can manipulate (for example, into ASCII codes). An OCR system enables you to take a book or a magazine article, feed it directly into an electronic computer file, and then edit the file using a word processor.






Optical-mark Recognition (OMR)

Optical Mark Recognition (also called Optical Mark Reading and OMR) is the process of capturing human-marked data from document forms such as surveys and tests.  Many traditional OMR (Optical Mark Recognition) devices work with a dedicated scanner device that shines a beam of light onto the form paper. The contrasting reflectivity at predetermined positions on a page is then utilized to detect the marked areas because they reflect less light than the blank areas of the paper.

Secondary Storage

File Compression
File compression is the practice of packaging a file or files to use less disk space. The File Compression category includes software programs that will archive your files and extract archived files such as ZIP and RAR files. Many products in this category let you manage files and protect them with encryption. Notable titles include WinZip, WinRAR, and 7-Zip.




Hard Crash

When a hard drive spins, the head that reads and writes the magnetic data floats just above the surface of the platter. Originally, the term hard drive crash referred to the head literally crashing into the platter, causing serious damage to your hardware and data.
An abrupt halting of operations by a computer due to a malfunction, allowing the users or operators of the computer little or no time to minimize its effects.







Internet Hard Drive

The sole purpose of an Internet hard drive is to offer a means of accessing your computer files (pictures, documents, music, videos, etc.) from any computer, as long as that computer has access to the Internet. Similar to depositing money into your bank account, and later withdrawing that same money from any ATM machine, an Internet hard drive will allow you to "deposit" your computer files into a remote hard drive, and then later access those very same files from any other computer.

Optical Disc Drive

In the real world, "optical" refers to vision, or the ability to see. In the computer world, however, "optical" refers to lasers, which can "see" and read data on optical discs. These discs include CDs and DVDs, which are made up of millions of small bumps and dips. Optical drives have lasers that read these bumps and dips as ones and zeros, which the computer can understand.

Some common types of optical drives include CD-ROM, CD-RW, DVD-ROM, DVD-RW, and Blu-ray drives. CD and DVD writers, such as CD-R and DVD-R drives use a laser to both read and write data on the discs. The laser used for writing the data is much more powerful than the laser that reads the data, as it "burns" the bumps and dips into the disc. While optical drives can spin discs at very high speeds, they are still significantly slower than hard drives, which store data magnetically. However, because optical media is inexpensive and removable, it is the most common format used for distributing computer software.

Solid-State Storage

Solid-state storage is a nonvolatile, removable storage medium that employs integrated circuits (ICs) rather than magnetic or optical media. It is the equivalent of large-capacity, nonvolatile memory. Examples include flash memory Universal Serial Bus (USB) devices and various proprietary removable packages intended to replace external hard drives.

The System Unit

 Flash memory

               A computer chip with a read-only memory that retains its data when the power is turned off and that can be electronically erased and reprogrammed without being removed from the circuit board, often used in fax machines.

 

Graphic cards

      Your graphics card (also called a video card) is the hardware that actually creates the images shown on your monitor. For three-dimensional applications like the Second Life Viewer, this card does much of the work involved in actually calculating and drawing the 3D world. As a result, your graphics card plays a very important part in your Second Life experience.

Sound cards

            

Integrated circuit that generates an audio signal and sends it to a computer's speakers. The sound card can accept an analog sound (as from a microphone or audio tape) and convert it to digital data that can be stored in an audio file, or accept digitized audio signals (as from an audio file) and convert them to analog signals that can be played on the computer's speakers. On a personal computer, the sound card is usually a separate circuit board that is plugged into the motherboard.

Network interface card (NIC)

 


Often abbreviated as NIC, an expansion board you insert into a computer so the computer can be connected to a network. Most NICs are designed for a particular type of network, protocol, and media, although some can serve multiple networks.
 

Plug and Play

            

(1) The ability to add a new component to a system and have it work automatically without having to do any technical analysis or manual configuration. See definition below, UPnP and Plug-and-play TV.
(2) (Plug and Play) A standard from Intel for peripheral expansion on a PC. On starting up the computer, Plug and Play (PnP) recognizes the attached peripheral devices and adjusts the appropriate internal settings, namely configuring the IRQ, DMA and I/O address. See IRQ, DMA and PC I/O addressing.

Bus Line

        
A collection of wires through which data is transmitted from one part of a computer to another. You can think of a bus as a highway on which data travels within a computer. When used in reference to personal computers, the term bus usually refers to internal bus. This is a bus that connects all the internal computer components to the CPU and main memory. There's also an expansion bus that enables expansion boards to access the CPU and memory.

HDMI

             Short for High-Definition Multimedia Interface, it is the first industry-supported uncompressed, all-digital audio/video interface. It's a single cable and user-friendly connector that replaces the maze of cabling behind the home entertainment center. HDMI provides an interface between any audio/video source, such as a set-top box, DVD player, or A/V receiver and an audio and/or video monitor, such as a digital television (DTV), over a single cable. 

 

Cache memory

           
 A memory cache, sometimes called a cache store or RAM cache, is a portion of memory made of high-speed static RAM (SRAM) instead of the slower and cheaper dynamic RAM (DRAM) used for main memory. Memory caching is effective because most programs access the same data or instructions over and over. By keeping as much of this information as possible in SRAM, the computer avoids accessing the slower DRAM.