Storage Technology Corporation

James William Wolf

Richard A Gill

Benjamin Joseph Baron

Donovan M Janssen

Christian Allen Todd

Keith Gary Boyer

James C Cates

Lynn C Jacobs

Servo tracks for magnetic tape storage are written using two opposite polarities, rather than the one polarity normally used in servo tracks. Timing continues to be performed using only pattern members of like polarity, due to physical restraints, but the use of two polarities allows additional information to be encoded in the pattern more efficiently.

Polarity encoded pattern for timing based servo

A method and a mechanism enabling the method are described to aid in distinguishing new information from old information on a medium. A new variable called a Master Write Pass Count is created for the medium. The Master Write Pass Count is initialized once, advanced on each occasion that new information is written in the medium, and it is never reinitialized or regressed. During each write session the Master Write Pass Count is copied into a Write Pass Count variable associated with each block receiving the new information. The Write Pass Counts may be stored in the header or trailer of the associated block, or external to the block. When the blocks are read from the medium, the Write Pass Counts may be used alone, or in combination with other information associated with the blocks, such as a block identification number, to aid in distinguishing new information from old information.

Method and mechanism to distinguish valid from outdated recording blocks in a tape drive

The coaxial reel tape cartridge uses a lengthy tape path within the tape cartridge to reduce the stresses on the tape medium as it is transported between the two reels. The tape is drawn from each reel around a corresponding rotating guide element which is coplanar with the tape reel. The tape is then transported along one side of the tape cartridge exterior housing to a corresponding hydrostatic bearing which is located at a corner of the tape cartridge adjacent the tape access opening. The hydrostatic bearing is coplanar with the tape guide, but at a slight angle with the vertical to thereby impart a slight twist to the tape as it traverses the length of the tape cartridge. The two hydrostatic bearings are located inside of and at opposite ends of the tape cartridge exterior housing, flanking the tape access opening. The two hydrostatic bearings are attached to a base plate which maintains the hydrostatic bearings coplanar with respect to each other. The base plate itself is angled with respect to the horizontal plane of the tape cartridge exterior housing so that the tape, as it traverses the path between the two hydrostatic bearings, changes elevation from the plane of the first reel to the plane of the second reel. The tape is only subjected to a twist along one segment of the tape path while remaining coplanar along this segment of the tape path, and is subjected to an elevation change in a manner that involves neither twist nor bending.

Coaxial reel tape cartridge with reduced tape forces

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Loveland, CO, United States of America

James William Wolf