Method for extraction of a variable length record from fixed length sectors on a disk drive

A memory media for enabling a host processor which employs variable length (VL) records to communicate with storage means which employs fixed length (FL) sectors for storage of said VL records, said memory media comprising:

• a) means for enabling an interface module to derive a first control data structure for an update VL record received from said host processor, said first control data structure including information describing segments of said update VL record;
• b) means for enabling a processor to determine a FL sector in a disk track wherein an old VL record commences that corresponds to said update VL record;
• c) means responsive to said old VL record commencing at other than a sector break of said FL sector, for causing said processor to derive a second control data structure for a portion of a prior VL record that immediately precedes said old VL record in said disk track and a third control data structure for said old VL record;
• d) means for causing said processor to substitute in said third control data structure, information regarding update segments of said update VL record from said first control data structure;
• and
• e) means for operating a disk controller and a disk drive to record in said FL sector determined by means c), data indicated by said second control data structure and at least a portion of said update VL record, through use of said third control structure as altered by means d).