Disk drive

(Or "hard disk drive", "hard drive", "floppy disk drive", "floppy drive")

A disk drive is a peripheral device that reads and writes hard disks or floppy disks. The drive contains a motor to rotate the disk at a constant rate and one or more read/write heads which are positioned over the desired track by a servo mechanism. It also contains the electronics to amplify the signals from the heads to normal digital logic levels and vice versa. In order for a disk drive to start to read or write a given location a read/write head must be positioned radially over the right track and rotationally over the start of the right sector. Radial motion is known as "seeking" and it is this which causes most of the intermittent noise heard during disk activity. There is usually one head for each disk surface and all heads move together. The set of locations which are accessible with the heads in a given radial position are known as a "cylinder". The "seek time" is the time taken to seek to a different cylinder. The disk is constantly rotating (except for some floppy disk drives where the motor is switched off between accesses to reduce wear and power consumption) so positioning the heads over the right sector is simply a matter of waiting until it arrives under the head. With a single set of heads this "rotational latency" will be on average half a revolution but some big drives have multiple sets of heads spaced at equal angles around the disk. If seeking and rotation are independent, access time is seek time + rotational latency. When accessing multiple tracks sequentially, data is sometimes arranged so that by the time the seek from one track to the next has finished, the disk has rotated just enough to begin accessing the next track. The disks may be removable disks; floppy disks always are removable hard disks were common on mainframes and minicomputers but less so on microcomputers until the mid 1990s(?) with products like the Zip Drive. A CD-ROM drive is not usually referred to as a disk drive. Two common interfaces for disk drives (and other devices) are SCSI and IDE.

Contact Us

support@handybackup.net

sales@handybackup.net

+1 (707) 703-13-11

Term of the Day

  • Digital Pictures
    “Recently digital pictures have begun to obtain a great deal of popularity. Digital cameras are no longer only the means of the wealthy and now...”

Backup Software Glossary

Current glossary explains various terms that you may come across while working with Handy Backup or other backup software.

Handy Backup is a backup utility for Windows Servers and PCs that is famous for its flexibility and ease of use.

The glossary contains 222 terms. The current section Storage Media contains 39 terms.

Other “Storage Media” Terms

  • MMC Memory Card
    “A flash memory card that provides storage for cellphones, PDAs and other handheld devices. Introduced in 1997 with a 4MB capacity, the 32x24x1.4mm...”
  • Memory Stick
    “Yet another standard, set by Sony but now also manufactured by others such as Lexar Media. The main drawback is that there are fewer cameras using...”
  • Removable hard disk
    “A removable hard disk is a type of disk drive system in which hard disks are enclosed in plastic or metal cartridges so that they can be removed like...”

Who uses our backup software?