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Magnetic Bubble Domain Storage Structures for Sequential Files

IP.com Disclosure Number: IPCOM000082736D
Original Publication Date: 1975-Jan-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 4 page(s) / 86K

Publishing Venue

IBM

Related People

Chang, H: AUTHOR [+2]

Abstract

Insertion of new records or removal of old records from a sequential file in a static storage, such as a magnetic tape, always requires the copying of the entire file. The structure shown employs magnetic bubble domain devices for storage of information to provide a structure, in which insertions and deletions of information can be achieved without requiring copying of the entire file.

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Magnetic Bubble Domain Storage Structures for Sequential Files

Insertion of new records or removal of old records from a sequential file in a static storage, such as a magnetic tape, always requires the copying of the entire file. The structure shown employs magnetic bubble domain devices for storage of information to provide a structure, in which insertions and deletions of information can be achieved without requiring copying of the entire file.

The storage consists of shift registers each of which stores a record of data. The storage structure (Figs. 1A and 1B) is serially connected but divided by the I/O stations (read/clear and write stations) into two areas. These areas provide the background and foreground of the information. Two corresponding groups of conversion switches S are provided which are controlled by two separate conductors. The read/clear station is located at the leading bit position of the first record in the background area, while the write station is located at the trailing bit position of the last record in the foreground.

Deletion of a record is shown in Fig. 1A. The record is brought to the position including the clear station by advancing or backspacing the foreground and background simultaneously. At this time, the background data is advanced to be cleared, while the foreground data is held to idle in the shift registers. To achieve this, switches S3 and S4 of the background are set in the down positions, so that information is advanced from one background shift register to the next. At the same time, switches S5 are in the up positions while switches S6 are in down positions. This means that information in the foreground shift registers continues to recirculate in these registers, without advancing from one register to the next.

Fig. 1B shows a line insertion operation. To insert a new record between records A and B where record B follows record A, the records in the background and foreground areas are advanced or backspaced simultaneously, such that record A is placed in the shift register which contains the write station and record B is placed in the shift register which contains the read/clear station. The background data is then held idle by setting switches S3 in the up position, while switches S4 are in the down position. The foreground record is advanced to make room for insertion of new records by setting switches S5 and S6 in their down positions.

Simultaneous advancement or backspacing of the foreground and background information can be accomplished by this structure, as is apparent from Figs. 2A, 2B and 2C. Fig. 2A shows the idle operation in which information just recirculates in the various shift registers. To achieve this, the switches on the left-hand side of the registers remain in their up positions, while the switches at the right-hand side of the registers remain in the down positions. In this mode, each shift register will continue to recirculate its information, and the storage is ...