On 10 Apr 2002 22:48:26 -0600, Eric W. Biederman wrote: >As for RECALIBRATE it is probably a good idea to get it out of there. >Skiming throught the draft ata standards I have: > ata-1 RECALIBRATE seeks to the start of the disk. > ata-3 RECALIBRATE is an optional command with vendor defined behavior > ata-6 no mention of RECALIBRATE. >
In a past job we had a system that did some full-duplex audio (record & play @ same time) work on an IDE drive. At the time drive speeds were no where near what they are today. To keep from getting drop outs in the stream we had to use what were called AV drives or Audio Video drives. A normal IDE drive perodically recalibrates the head movement system to compensate for drift from mechanical wear and temperature. If this recalibrate interval hit while streaming data we would get drops. An AV drive did the calibrations on-the-fly and wouldn't drop out. I believe the RECALIBRATE command forces this to happen. In fact I seem to remember a Maxtor engineer telling me that if we didn't want to use AV drives (they were expensive) we could perhaps issue RECALIBRATE at regular intervals in non-critical sections and keep the drive from doing it on its own. We opted for AV drives. You don't see any AV drives anymore so I'm guessing that everybody does the on-the-fly calibration now and its not necessary which perhaps explains the lack of the command in ata-6. -- Richard A. Smith Bitworks, Inc. [EMAIL PROTECTED] 501.846.5777 x204 Sr. Design Engineer http://www.bitworks.com
