Browse Prior Art Database

Reduction of Optical Drive Bring Up Time

IP.com Disclosure Number: IPCOM000108923D
Original Publication Date: 1992-Jul-01
Included in the Prior Art Database: 2005-Mar-23
Document File: 1 page(s) / 48K

Publishing Venue

IBM

Related People

Fennema, AA: AUTHOR [+4]

Abstract

An optical drive that is used as a library device needs to come ready (bring-up time) as fast as possible. This article describes one technique for reducing the bring-up time.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 67% of the total text.

Reduction of Optical Drive Bring Up Time

       An optical drive that is used as a library device needs
to come ready (bring-up time) as fast as possible.  This article
describes one technique for reducing the bring-up time.

      An optical drive has many hardware calibrations that are used
to reduce the effects of manufacturing tolerances and media
tolerances.  Therefore, these calibrations are performed every time
the media is changed.  One of the calibrations (focus acquire) needs
to be performed at the inner crash stop to prevent accidental damage
to customer data.  The typical approach for getting the head to the
inner crash stop is to simply move the head in slowly for a minimum
time that will guarantee that the head is really at the inner crash
stop.  Many optical drives do not incorporate position sensors for
the head because these are usually expensive parts that require
critical alignment.  Therefore, the head must be moved in slowly to
prevent the shock of banging into the inner crash stop (which could
damage the head).  This slow movement inward can take a substantial
amount of time, which lengthens the bring-up time.

      This invention proposes a seek close to the disc inner diameter
as soon as a media eject request is received.  Then, while the media
is spinning down, the head is biased inward slowly to move the rest
of the way to the inner crash stop.  A mechanical brake engages when
the loader tray moves to the unloaded position. ...