US 5,210,851 A · High capacity tape drive transparently writes and reads large packets of blocked data between interblock gaps

Abstract

A tape packet assembler/disassembler (TPAD) for a tape drive accumulates host-transmitted records, which may or may not be blocked by the host. The accumulated host-transmitted records are combined into packets comprising a data portion made up of data blocks and of a trailer portion made up of table entries describing how to disassemble the packet. Host-transmitted commands to write a tape mark are intercepted by the TPAD and replaced by corresponding information in the trailer. Packets are accumulated in a buffer in the TPAD, and are written to the tape drive when the buffer becomes full, or upon a command from the host to reposition the tape, such as rewind. The interblock gaps that would ordinarily separate the host-transmitted records now separate packets, resulting in a considerable increase in the efficiency of tape utilization. The TPAD maintains in the trailer various pointers to assist in forward and back spacing by file and records. It also can automatically and adaptively compress and decompress the user's data. To assist in this it also maintains in the trailer information identifying data blocks containing a dictionary reset.

Claims8

Dependent claims

A method of storing information on a sequentially accessed mass storage device comprising the steps of:

sending to the sequentially accessed mass storage device a plurality of collections of information delimited by first signals that cause the mass storage device to separate consecutive collections of recorded information;
determining where in the plurality of collections any first signals occur;
preventing first signals located by the determining step from reaching the mass storage device;
storing in an index portion of a memory indications of where amongst the plurality of collections the first signals occurred;
storing in a predetermined location in the index portion a count indicative of the number of entries in the index portion;
storing in a data portion of the memory the plurality of collections of information;
writing on the medium of the sequentially accessed mass storage device a packet comprising the concatenated contents of the data and index portions of the memory;
and
delimiting the packet with first signals sent to the mass storage device.

6 more elements

Dependencies are inferred from the claim text.

High capacity tape drive transparently writes and reads large packets of blocked data between interblock gaps

Life of this patent

High capacity tape drive transparently writes and reads large packets of blocked data between interblock gaps

Life of this patent

Abstract

Claims8