Browse Prior Art Database

Initializing Diskettes Without Index and Sector Pulses

IP.com Disclosure Number: IPCOM000046703D
Original Publication Date: 1983-Aug-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Dix, GL: AUTHOR [+3]

Abstract

The normal procedure used to initialize a diskette is to look for the index pulse to start writing the first sector and thereafter writing successive sectors when sector pulses are detected. When neither index pulses nor sector pulses are present, the physical length of the sector is not available and reinitializing a diskette could leave extraneous fields on a track in the gap between the end of the last sector and the beginning of the first sector. The lack of a sector pulse is overcome by a hardware counter which is run to indicate the starting point for each sector. A gap field (all ones) is written arbitrarily at the time the command is received. Following a fixed time, depending on the counter setting, sectors 1 through n are written.

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Initializing Diskettes Without Index and Sector Pulses

The normal procedure used to initialize a diskette is to look for the index pulse to start writing the first sector and thereafter writing successive sectors when sector pulses are detected. When neither index pulses nor sector pulses are present, the physical length of the sector is not available and reinitializing a diskette could leave extraneous fields on a track in the gap between the end of the last sector and the beginning of the first sector. The lack of a sector pulse is overcome by a hardware counter which is run to indicate the starting point for each sector. A gap field (all ones) is written arbitrarily at the time the command is received. Following a fixed time, depending on the counter setting, sectors 1 through n are written. The counter is programmable by the system to allow data records of varying predetermined lengths. The complete track on the diskette is written in three revolutions. During the first revolution the diskette ID is written using the counter as a reference. The logical ID is written on the second revolution using the diskette ID as a reference. On the third revolution the data is written using the logical ID as a reference. The extraneous fields between the last sector and the first sector are eliminated by first writing ones on the diskette for a length greater than the gap between the end of the last sector and the beginning of the first sector. Immediately following the on...