Browse Prior Art Database

System for Blocking Variable Length Records

IP.com Disclosure Number: IPCOM000079867D
Original Publication Date: 1973-Sep-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Ouchi, NK: AUTHOR

Abstract

The system described recognizes gaps placed within variable-length records recorded on a data track, for dividing the data track into blocks having a constant number of nongap bytes. It is assumed that the variable-length records are written in the count-key-data format. The count-field of any record includes a new field having a displacement value, indicating the distance in nongap bytes from the start of the count-field to the start of the fixed-block gap. It is possible that the displacement value will be a multiple byte number.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 58% of the total text.

Page 1 of 2

System for Blocking Variable Length Records

The system described recognizes gaps placed within variable-length records recorded on a data track, for dividing the data track into blocks having a constant number of nongap bytes. It is assumed that the variable-length records are written in the count-key-data format. The count-field of any record includes a new field having a displacement value, indicating the distance in nongap bytes from the start of the count-field to the start of the fixed-block gap. It is possible that the displacement value will be a multiple byte number.

In the instance where the displacement number is a multiple byte number, the low-order byte is the first byte within the displacement field and followed by successively higher order bytes. This is done to insure that the proper count will be written onto the disk during a write operation, and that the counter will be initialized to the proper value during a read operation when using the circuitry shown.

The system shown has a multibyte counter 4 which is initialized during the reading of each count-field. Counter 4 is stepped whenever a byte is read, written or clocked. The counter is also stepped through OR circuit 2 each time the high-byte field of the displacement field in the count-field being read is, in fact, read. .This is to provide a counter with the proper value during the read initialization process. Counter 4 is reset through 0R 3 by either the presence of index being sensed or up...