Browse Prior Art Database

Media Control Records in Hard Disk Environment

IP.com Disclosure Number: IPCOM000043961D
Original Publication Date: 1984-Oct-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Aiken, JA: AUTHOR [+3]

Abstract

This article describes a concept of using a modified version of the 5-l/4-inch diskette interchange architecture in a hard disk environment to make dual software support for diskettes and hard disks much simpler. With the concept, it is also possible to partition a physical hard disk into many smaller logical volumes and to identify each of the logical volumes. Most internal hard disk-based systems do not have a volume media control record because they are internal to the base systems and do not require a unique volume identification of the media for data interchange.

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Media Control Records in Hard Disk Environment

This article describes a concept of using a modified version of the 5-l/4-inch diskette interchange architecture in a hard disk environment to make dual software support for diskettes and hard disks much simpler. With the concept, it is also possible to partition a physical hard disk into many smaller logical volumes and to identify each of the logical volumes. Most internal hard disk- based systems do not have a volume media control record because they are internal to the base systems and do not require a unique volume identification of the media for data interchange. However, with the advent of a removable hard disk for use in small systems, it turns out desirable to use a volume media control record to provide dual software support for the hard disk and diskettes so that data and programs are interchangeably retrieved from either the hard disk or the diskettes. Another factor to be considered is that, in the hard disk sharing environment, a single hard disk is shared by a number of program products. Thus, a unique volume identification is needed for each logical volume. For the purpose of satisfying the above needs, the present arrangement uses a modified version of the 5-1/4-inch diskette media control record described in [*]. This is because the hard disk has more cylinders, heads and sectors than the 5-1/4-inch diskette. Thus, within the header (HDR 1) record located at the second 128-byte part of the diskette media control record, various address fields such as Beginning of Extent (28), End of Extent (34), End of Data Address (74) and Beginning of Diskette Table of Contents (112) are expressed in hexadecimals instead of one EBCDIC byte as in the 5-1/4-inch diskette interchange architecture. In accessing the internally fixed or removable hard disk, the read- o...