Hard Drive Buying Guide
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Access Time - How long it takes for a hard drive to find a piece of data.
ATA (Advanced Technology Attachment) - See IDE.
AT Bus - See IDE.
Bandwidth - The amount of data that can be transmitted in a fixed amount of time. Different measurement schemes include Hertz and bits per second.
Bit - A binary digit. The most basic representation of the basic binary code (0 or 1) with which the computer works.
Byte - 8 bits. Basically, a unit of measurement that is capable of storing one character.
Buffer - A temporary data storage area, usually in RAM, that helps keep frequently accessed data available without having to access the hard drive.
Cache - Pronounced cash. A section of conventional memory used to store data recently accessed from a hard drive.
Controller - A device that transfers information between the computer and peripheral devices. It can be found either on the motherboard, the interface card, or on the hard drive itself.
Device Drivers - Small programs that tell the computer how to communicate with a particular types of peripheral devices.
EIDE (Enhanced IDE) - A connection standard that's faster than IDE and cheaper than SCSI.
Fast ATA - See EIDE.
Fast IDE - See EIDE.
Fiber Optics - A wiring system that transmits light over a thin glass cable. This is less susceptible to interference and can be transmitted over greater distances than traditional cabling.
Fibre Channel - A high bandwidth data transfer protocol that takes advantage of high speed optical fiber cables. Usually found only in very high end servers.
FireWire - An extremely fast external connection standard used with high speed devices like hard drives and video cameras. FireWire supports simultaneous connections of up to 63 devices and transfer speeds up to 400 megabytes per second.
GB (Gigabyte) - 1,024 megabytes, or 1,073,741,824 bytes. The typical measurement used in describing a hard drive's storage capacity.
Hard Drive - A computer's primary storage medium. Essentially an incased disk drive that reads and writes data and transmits it back and forth to the computer over an interface.
Hz (Hertz) - A measurement of frequency equal to one cycle per second.
IDE (Integrated Drive Electronics) - A connecting standard that integrates the drive's controller chip and the drive itself. Some IDE varieties include:
ATA - Also known as basic IDE. It supports up t two hard drives and features a 16-bit interface. It can handle transfer speeds up t 8.3 MB per second.
ATA-2 - Also known as Fast ATA and EIDE (Enhanced IDE). These drives include a number of advancements and support transfer speeds up t 13.3 MB per second.
ATA-3 - This is a minor upgrade to ATA-2 and offers transfer speeds up to 16.6 MB per second.
Ulta-ATA - Also called Ultra-DMA, ATA-33, and DMA-33. These drives offer dramatic speed improvements, with transfer rates up to 33 MB per second.
ATA-66 - A version of ATA proposed by Quantum Corporation, and supported by Intel, that doubles transfer rate up to 66 MB per second.
ATA-100 - An upgrade to the ATA standard that supports transfer rates up to 100 MB per second.
ATA-133 - The latest version of the ATA standard. Found mostly in AMD based systems, it supports transfer rates up to 133 MB per second.
IEEE 1394 - See FireWire.
I.Link - See FireWire.
I/O Port (Input/Output Port) - A bi-directional port that allows data to be transmitted back and forth between devices.
Interface - A means of communicating between two different systems.
Jumper - A plastic plug and metal that is placed over different pins on a device in order to change operation parameters. On a hard drive a jumper is primarily used for setting the device to either primary or secondary.
KB (Kilobyte) - 1,024 bytes. A unit used to describe smaller amounts of memory.
Lynx - See FireWire.
MB (Megabyte) - 1,048,576 bytes. A basic measurement of computer memory.
MS (Millisecond) - One-thousandth of a second. The basic measurement of a hard drive's access speed.
MTBF (Mean Time Between Failures) - The average amount of time that a component works before failure.
Near Letter Quality - A description of advanced 9-pin and 24-pin dot matrix printers, where the text produced by the printer is hard to distinguish from a letter-quality daisywheel printer.
Network Interface Card - Usually abbreviated as NIC. An adapter card installed in a computer that enables it to connect to a network; most NIC's support several different types of networks and network cabling.
Network Printer - A printer available for use by workstations on a network. A network printer either has its own built-in network interface card, or it's connected to a printer on the network.
Plug-and-Play (PnP) - A configuration standard that allows a newly installed device to set itself up in an operating system automatically.
Port - The interface in which you hook-up components of a computer system. With hard drives it can be internal or external, and SCSI, IDE, or a number of other varieties.
Remote Capture - Refers to being able to take images under the control of a computer through use of software that is capable of remotely firing the camera (normally tethered to the computer).
Resolution - The number of pixels that are used to create an image.
RGB - Acronym for the colors: red, green, and blue.
Queue - A sequence of documents sent to a printer to be processed sequentially, usually in the order in which they sent by the computer. Some multi-operating systems such as Linux and Windows enable you to set privileges or delete print jobs from the queue.
R.A.I.D. (Redundant Array of Independent (or Inexpensive) Disks) - A type of disk drive controller that combines multiple drives for improved speed and redundant data storage.
RAM (Random Access Memory) - A temporary data storage found in computers and some of their components. It acts as a holding area for data that is waiting to be used.
Reliability - See MTBF.
Ribbon Cable - A flat cable containing numerous wires that is used to connect a hard drive to a port.
ROM (Read Only Memory) - A computer chip that contains permanent prerecorded data.
RPM (Revolutions Per Minute) - The basic measurement of a hard drive's rotation speed. Basically, how many times a disk performs a complete rotation per minute. The faster the rotation speed, the higher the data transfer rate.
SCSI (Small Computer System Interface) - Pronounced "skuzzy". A standard for connecting parallel port devices, such as certain hard drives, using a controller board. Different types of SCSI include:
SCSI-1 - These basic connections use an 8-bit bus, a 25-pin connector, and supports transfer rates up to 4 MB per second.
SCSI-2 - These drives use a 50-pin connector and support multiple devices. The transfer rate is the same as SCSI-1
Wide SCSI - As the name indicates, these drives feature a wider cable and a 68-pin connection that supports 16-bit data transfers.
Fast SCSI - While only using 8-bit bus, the Fast SCSI is able to transfer data at 10 MB Per second.
Fast Wide SCSI - These types of drives double both the bus (16-bit) and the data transfer rate (20 MB per second).
Ultra SCSI - Also known as Ultra Wide SCSI, it uses an 8-bit bus while transferring data at 20 MB per second.
SCSI-3 - These drives have a 16-bit bus and transfers data at 40 MB per second.
Ultra2 SCSI - Featuring an 8-bit bus and transfers data at a rate of 40 MB per second.
Wide Ultra2 SCSI - The latest standard, these use a 16-bit bus and support data transfer rates of 80 MB per second.
Seek Time - See Seek Time.
S.M.A.R.T. (Self-Monitoring Analysis and Reporting Technology) - A system and hard drive standard the monitors the drive's operation and looks for potential problems.
Spin Rate - How fast a hard drive's internal disk spins. The faster the speed the quicker data can be read, written, and transferred.
Transfer Rate - The measurement of how fast a hard drive reads data and transfers it to the system.
USB (Universal Serial Bus) - A Plug-and-Play external connection standard used to hook-up many different types of devices. It comes in two flavors:
USB 1.1 - Transfers data up to 1.5 MB per second and supports the simultaneous use of up to 127 devices.
USB 2.0 (Hi-speed USB) - Transfers data up to 60 MB per second and is backwards compatible with USB 1.1.
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