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Key Ring Protection of Magnetic Tapes

IP.com Disclosure Number: IPCOM000043081D
Original Publication Date: 1984-Jul-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 3 page(s) / 32K

Publishing Venue

IBM

Related People

Powell, S: AUTHOR

Abstract

This article describes a mechanism for protecting the data on magnetic tapes in computer installations. Currently a write permit ring (WPR) is used for fail-safe physical protection by the tape drive. This article shows how this write permit ring can be compatibly extended to provide security for the owner of a much higher standard by requiring the protection ring and the tape spool to match before they can be fitted together. The WPR is a simple ring (of plastic usually) that fits in the tape spool. When the tape is mounted on the drive, the presence of the ring is determined mechanically and used to permit the execution of data write commands by the tape controller on that particular drive. Since all WPRs are identical, then inadvertent insertion of a ring is easy and can be overlooked.

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Key Ring Protection of Magnetic Tapes

This article describes a mechanism for protecting the data on magnetic tapes in computer installations. Currently a write permit ring (WPR) is used for fail-safe physical protection by the tape drive. This article shows how this write permit ring can be compatibly extended to provide security for the owner of a much higher standard by requiring the protection ring and the tape spool to match before they can be fitted together. The WPR is a simple ring (of plastic usually) that fits in the tape spool. When the tape is mounted on the drive, the presence of the ring is determined mechanically and used to permit the execution of data write commands by the tape controller on that particular drive. Since all WPRs are identical, then inadvertent insertion of a ring is easy and can be overlooked. Thus, tapes can be over-written even though the owner requested the ring to be removed. Errors are easy to make in the machine room. Particularly valuable data are at risk, so a second level of protection is desirable. The disadvantages are overcome when the WPR mechanism and ancillary equipment are extended so that the rings should not be capable of interchange between spools. This enables the owner of a tape to retain the ring and be virtually certain that no other can be inserted accidentally. The new type of ring described here is a compatible extension of the existing WPR so that with the new ring in place the WPR is still required for write permission, thus allowing tapes with the new rings to co-exist in a tape library and computer room with the older type, and serve exactly the same purpose with the new ring in place. The new ring is called a Key ring or a Key for short. The only component that needs changing to allow use of the Key is the tape spool itself - the tape drives, controllers, tapes and systems software components all remain unchanged. The spool is shown in Fig. 1. The Key is positioned in the same place as the current WPR on the tape spool, but it is wider so that the WPR cannot replace it. That is, the usual WPR will not fit into the groove reserved for the Key without falling out. The non-interchangeability is achieved by indentations around the circumference of both edges of the Key, and compatibility is achieved by having the WPR mounted directly on the Key, thus requiring both t...