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Record Updating Using a Reference Track

IP.com Disclosure Number: IPCOM000073378D
Original Publication Date: 1970-Dec-01
Included in the Prior Art Database: 2005-Feb-22
Document File: 3 page(s) / 37K

Publishing Venue

IBM

Related People

Day, KB: AUTHOR [+2]

Abstract

Digital data recorded on a magnetic media, such as tape, strips, disks, and the like, are usually formatted as a series of spaced-apart blocks of recorded signals. The spacings may contain no recordings, special or control recordings, or a mixture of the above. In many tape systems, re-recording updated data requires reading, processing and re-recording many of these blocks of signals if not all signals re-recorded on one tape or strip. Through-put of such systems is enhanced when any block of recorded signals can be updated without affecting any other block of recorded signals.

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Record Updating Using a Reference Track

Digital data recorded on a magnetic media, such as tape, strips, disks, and the like, are usually formatted as a series of spaced-apart blocks of recorded signals. The spacings may contain no recordings, special or control recordings, or a mixture of the above.

In many tape systems, re-recording updated data requires reading, processing and re-recording many of these blocks of signals if not all signals re-recorded on one tape or strip. Through-put of such systems is enhanced when any block of recorded signals can be updated without affecting any other block of recorded signals.

Difficulties in repeatedly updating data records in place on a moving media include the actual recorded signals drifting along the media causing readback difficulties, if not obliteration, of adjacent records. Also, media speed variations during updating operations for a fixed number of data entries result in varying record lengths. Prior attempted solutions to the above-stated problems include placing special character records logically and physically intermediate adjacent data record areas (in IBG); tachometer signals to meter record lengths and padding data record lengths for accommodating record length variations. These solutions have an adverse affect on data through-put rates.

Precise and repeated updating in place of any given block of recorded signals is made possible by prerecording a spaced-apart marker or reference sets of signals along the length of the media. These sets of reference signals define data recording areas. Conceptually, these reference sets of signals A, B, and C are transversely aligned with corresponding areas A', B', and C' adapted to receive data signals. When the media is manufactured, the reference sets of signals may be precisely recorded, never to be later erased. Alternatively, the reference sets of signals may be recorded during or before signal recording operations in a user installation. Such sets of reference signals can be re- established during successive signal recording operations.

The length of each block of signals A''-C'' is set by the location of the reference signals. Also, the spacing between adjacent blocks of rerecordable signals is determined by the reference signals. The reference signals in each set may include permutations usable as address indicia for the corresponding data recording areas. Alternately, the indicia could also identify the immediately adjacent upstream and downstream recording areas. Preferably, the number of signal positions in...