A Disk pack is a layered grouping of hard disk platter

Hard disk platter

A hard-disk platter is a component of a hard-disk drive: it is the circular disk on which the magnetic data is stored. The rigid nature of the platters in a hard drive is what gives them their name . Hard drives typically have several platters which are mounted on the same spindle...

s (circular, rigid discs coated with a magnetic data storage

Data storage device

thumb|200px|right|A reel-to-reel tape recorder .The magnetic tape is a data storage medium. The recorder is data storage equipment using a portable medium to store the data....

 surface). A disk pack is the core component of a hard disk

Hard disk

A hard disk drive is a non-volatile, random access digital magnetic data storage device. It features rotating rigid platters on a motor-driven spindle within a protective enclosure. Data is magnetically read from and written to the platter by read/write heads that float on a film of air above the...

 drive. In modern hard disks, the disk pack is permanently sealed inside the drive. In many early hard disks, the disk pack was a removable unit, and would be supplied with a protective canister featuring a lifting handle.

The protective cover consisted of two parts, a clear plastic shell, with a handle in the center, that enclosed the top and sides of the disks and a separate bottom that completed the sealed package. To remove the disk pack, the drive would be taken off line and allowed to spin down. Its access door could then be opened and an empty top shell inserted and twisted to unlock the disk platter from the drive and secure it to the top shell. The assembly would then be lifted out and the bottom cover attached. A different disk pack could then be inserted by removing the bottom and placing the disk pack with its top shell into the drive. Turning the handle would lock the disk pack in place and free the top shell for removal. The first removable disk pack was invented in 1965 by two IBM engineers, Thomas G. Leary and R. E. Pattison.

Examples of a hard disks with removable disk packs are the IBM 1311, and the Digital

Digital Equipment Corporation

Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...

 RP04.

See also

• disk cartridge
  Disk cartridge
  Disk cartridge has several meanings related to computer storage.-1960s storage medium:An early disk cartridge was a single hard disk platter encased in a protective plastic shell...
  
  ,
• history of hard disk