Shift register buffer apparatus

Claim 2

Buffer apparatus adapted for connection to sources of read and write requests and to input means supplying variable length record data, said apParatus comprising a shift register store having an input and an output and adapted to be initialized with a unique code entry and blank code entries stored therein, means forming a first path from the output to the input normally effective for recirculating entries in the store, means forming a second path from the output to the input and including storage means for extending the effective length of the store, means for detecting the unique code entry, means for detecting the first blank code entry following the unique code entry, means controlled by the unique code entry detecting means and the blank code entry detecting means when a write request occurs for storing input record data entries into the store starting at the position of said first blank entry and including means for rendering said first path ineffective during said storing, and means controlled by the unique code entry detecting means when read requests occur for rendering the second path effective and the first path ineffective to insert blank code entries into the store preceding the unique code and for rendering the first path effective and the second path ineffective to remove data entries, equal in number to the inserted blank code entries, from the store in a sequence related to the order in which the record data was stored, whereby record data entries are maintained in the store immediately following the unique code entry and free of blank code entries therebetween.

Claim 3

The combination set forth in claim 1 wherein each entry is a character represented in the shift register store by a plurality of logical bits, said shift register store comprising a plurality of parallel operated shift registers, one for each logical bit of a character, for storing the entries serial by character and parallel by bit.

Claim 4

Buffer apparatus, adapted for connection to sources of read and write requests and to means making variable length record data and corresponding class identity data available to the apparatus, comprising a shift register store having an input and an output and adapted to be initialized with a unique code entry and blank code entries stored therein, means forming a first path from the output to the input normally effective for recirculating entries in the store, means forming a second path from the output to the input and including storage means for extending the effective length of the store, means for detecting the unique code entry, means for detecting the first blank code entry following the unique code entry, means controlled by the unique code entry detecting means and the blank code entry detecting means when a write request occurs for storing available record and class identity data entries into the store starting at the position of said first blank entry and including means for rendering said first path ineffective during said storing, and additional means for detecting class identity data entries, means controlled by the unique code entry detecting means and by the additional means, for each class identity data entry of a requested class when a read request occurs for alternately rendering (1) the second path effective and the first path ineffective to insert a selected number of blank code entries into the store preceding the unique code entry and (2) the first path effective and the second path ineffective to remove an equal selected number of requested class entries from the store in the sequence in which the entries of the requested class were stored, whereby record and class identity entries are maintained in the store immediately following the unique code entry and free of blank code entries therebetween.

Claim 5

Buffer apparatus, adapted for connection to sources of read and write requests and to means making variable length record data and corresponding class identity data available to the apparatus, comprising a shift register store having an input and an output and adapted to be initialized with a unique code entry and blank code entries stored therein, means forming a first path from the output to the input normally effective for recirculating entries in the store, means forming a second path from the output to the input and including storage means for extending the effective length of the store, means for detecting the unique code entry, means for detecting the first blank code entry following the unique code entry, means controlled by the unique code entry detecting means and the blank code entry detecting means when a write request occurs for storing available record and class identity data entries into the store starting at the position of said first blank entry and including means for rendering said first path ineffective during said storing, and additional means for detecting class identity data entries, means controlled by the unique code entry detecting means and by the additional means, for each class identity data entry of a requested class when a read request occurs for alternately rendering (1) the second path effective and the first path ineffective to insert a selected number of blank code entries into the store preceding the unique code entry and (2) the first path effective and the second path ineffective to remove an equal selected number of requested class entries from the store in the sequence in which the entries of the requested class were stored, whereby record and class identity entries are maintained in the store immediately following the unique code entry and free of blank code entries therebetween.

Claim 6

The combination set forth in claim 3 wherein each entry is a character represented in the shift register store by a plurality of logical bits, said shift register store comprising a plurality of parallel operated shift registers, one for each logical bit of a character, for storing The entries serial by character and parallel by bit.

Claim 7

In a data processing system adapted to receive record data randomly by class and having utilization means requiring said record data grouped by class, a serial buffer mechanism comprising a recirculating shift register store having a plurality of storage positions, means for storing each record and unique class identity data for said record into the store in sequence as each record becomes available randomly by class, means for maintaining the record and class identity data in contiguous positions of the store free of blanks therebetween, means for detecting the class identity data of a desired class as it is recirculated through the store, and means controlled by the class identity data detecting means for retrieving each of the records of the desired class from the store in the sequence in which the records of the class are entered into the store

Claim 8

In a data processing system adapted to receive record data randomly by class and having utilization means requiring said record data grouped by class, a serial buffer mechanism comprising a recirculating shift register store having a plurality of storage positions, means for storing each record and unique class identity data for said record into the store in sequence as each record becomes available randomly by class, means for maintaining the record and class identity data in contiguous positions of the store free of blanks therebetween, means for detecting the class identity data of a desired class as it is recirculated through the store, and means controlled by the class identity data detecting means for retrieving each of the records of the desired class from the store in the sequence in which the records of the class are entered into the store

Claim 9

The combination of claim 5 wherein the lastmentioned means includes a first data path normally effective to recirculate data from the register output to the register input, and a second data path including a storage device effective during record retrieval for recirculating data preceded by blanks to maintain record and class identity data contiguous in the store.

Claim 12

The method of claim 7 wherein the steps of gating data from the store and gating blank codes into the store comprise extending the length of the store when the unique code is at the store output to permit the gating of blank codes into the store preceding the unique code, and shortening the length of the store when the data to be gated from the store has been shifted in the lengthened part of the store to thereby effectively remove the latter data from the store.

Claim 15

The method of claim 9 wherein the compacting step comprises extending the length of the store, when gating of data from the store is requested, to gate blank code data into the store preceding the unique code, and shortening the length of the store to gate from the store an amount of requested record data equal to the blank code data inserted.