| A | B |
|---|
| 40-pin ribbon cable | PATA cable used to attach EIDE devices (such as hard drives) or ATAPI devices (such as optical drives to a system. |
| 80-wire cable | PATA cable used to attach fast EIDE devices (such as ATA/100 hard drives) or ATAPI devices (such as optical drives) to a system. |
| advanced technology attachment (ATA) | Type of hard drive and controller designed to replace the earlier ST506 and ESDI drives without requiring replacement of the AT BiosÑhence, AT attachment. These drives are more popularly known as IDE drives. |
| advanced technology attachment packet interface (ATAPI) | Series of standards that enable mass storage devices other than hard drives to use the IDE/ATA controllers. Popluar with optical drives. |
| ATA/133 | This refers to what is probably the final extension to the parallel ATA connection standard. Allows a top data transfer rate of 133 megabytes per second. |
| ATA/ATAPI-6 | Also known as ATA-6 or "Big Drive." Replaced the INT13 extensions and allowed for hard drives as large as 144 petabytes (144 million GBs). |
| cylinder | Single track on all the platters in a hard drive. Imagine a hard drive as a series of metal cans, nested on inside another; a single can would represent a cylinder. |
| disk duplexing | Type of disk mirroring using two separate controllers rather than one; faster than traditional mirroring. |
| disk mirroring | Process by which data is written simultaneously to two or more disk drives. Read and write speed is decreased but redundancy in case of catastrophe is increased. |
| disk striping | Process by which data is spread among multiple (at least two) drives. Increases speed for both reads and writes of data. Considered RAID level 0 because it does not provide fault tolerance. |
| disk striping with parity | Method for providing fault tolerance by writing data across multiple drives and then including an additional drive, called a parity drive, that stores information to rebuild the data contained on the other drives. Requires at least three physical disks: two for the data and a third for the parity drive. This provides data reduncdancy at RAID levels 3-5 with different options. |
| DMA modes | Technique that some PC hardware devices use to transfer data to and from the memory without using the CPU. |
| Enhanced IDE (EIDE) | Marketing concept of hard drive-maker Western Digital, encompassing four improvements for IDE drives, including drives larger than 528 MB, four devices, increase in drive throughput, and non-hard drive devices. |
| external SATA (eSATA) | Serial ATA-based connector for external hard drives and optical drives. |
| geometry | Numbers representing three values: heads, cylinders, and sectors per track; define where a hard drives stores data. |
| hard disk drive (HDD) | Data-recording system using solid disks of magnetic material turning at high speeds to store and retrieve programs and data in a computer. |
| head actuator | The deivce used to position the head arms to diferent tracks on the surface of the platter. |
| heads | Short for read/write heads; used by hard drives to store data. |
| host bus adapter (HBA) | Connects SATA devices to the expansion bus. Also known as the SATA controller. |
| integrated drive electronics (IDE) | PC specification for small- to medium-sized hard drives in which the controlling electronics for the drive are part of the drive itself, speeding up transfer rates and leaving only a simple adapter (or "paddle"). |
| Interrrupt 13 (INT 13) extensions | Improved type of BIOS that accepts EIDE drives up to 137 GB. |
| logical block addressing (LBA) | Translation (algorithm) of IDE drives promoted by Western Digital as a standardized method for breaking the 504-MB limit in IDE drives. Subsequently adopted universally by the PC industry and now standard on all EIDE drives. |
| parallel ATA (PATA) | Implementation that integrates the controller on the disk drive itself. |
| Partial Response Maximum Likelihood (PRML) | Advanced method of RLL that uses powerful, intelligent circuitry to analyze each flux reversal on a hard drive and to make a best guess as to what type of flux reversal it just read. This allows a dramatic increase in the amount of data a hard drive can store. |
| PIO modes | Series of speed standards created by the Small Form Committee for the use of PIO by hard drives. Modes range from PIO mode 0 to PIO mode 4. |
| redundant array of independent (or inexpensive) disks (RAID) | A system of using multiple hard drives for sharing or replicating data among the drives. |
| SATA bridge | Adapter that allows PATA devices to connected to a SATA controller. |
| SCSI chain | Series of SCSI devices working together through a host adapter. |
| SCSI ID | Unique identifier used by SCSI devices. No two SCSI devices may have the same SCSI ID. |
| sector | Segment of one of the concentric tracks encoded on the disk during a low-level format. A sector holds 512 bytes of data. |
| sectors per track (sectors/track) | Combined with the number of cylinders and heads, defines the disk geometry. |
| sector translation | Translation of logical geometry into physical geometry by the onboard circuitry of a hard drive. |
| serial ATA (SATA) | Serialized version of the ATA standard that offers many advantages over PATA (parallel ATA) technology, including thinner cabling, keyed connectors, and lower power requirements. |
| Self-Monitoring, Analysis, and Reporting Technology (S.M.A.R.T.) | Monitoring system built into hard drives. |
| small computer system interface (SCSI) | Powerful and flexible peripheral interface popularized on the Macintosh and used ot connect hard drives, CD-ROM drives, tape drives, scanners, and other devices to PCs of all kinds. Normal SCSI enables up to seven devices to be connected through a single bus connection, whereas WideSCSI can handle 15 devices attached to a single controller. |
| solid-state drive (SSD) | Data storage device that uses solid state memory to store data. |
| stepper motor | One of two methods used to move actuator arms in a hard drive. |
| termination | Using terminating resistors to prevent packet reflection on a network cable. |
| track | Area on a hard drive platter where data is stored. A group of tracks with the same diameter is called a cylinder. |
| Ultra DMA | Hard drive technology that enables drives to use direct memory addressing. |
| voice coil | A type of motor used to move the access arm of a disk drive in very small increments. Like the voice coil of a speaker, the amount of current determines the amount of movement. |
