Jayson Smith wrote:
Ah. I was just curious. I assume that means there's not a simple poke I can enter to change the time DOS moves the head in an I/O error condition? It's not really that I hate the noise, I just think DOS wastes a lot of time, since in most cases, moving back a few tracks would result in a valid track, unless the drive door is open, no disk is inserted, or the disk is damaged or not formatted.Jayson
You can change the number of tracks that recalibrate seeks back, but after it's done, DOS expects the drive head to be positioned at track 0, so there isn't much room to decrease the count. It would be possible to insert code to seek back just a little more than the current expected head position, but an I/O error can mean that the drive is not actually at the expected head position. ;-) Many types of I/O error do not involve head position uncertainty, but DOS funnels almost all errors into the same recovery--making the sound of recalibration the audible signal of an I/O error count being exceeded. ;-)
"Michael J. Mahon" <mjmahon@aol.com> wrote in message a4-dnXGourxKb9vWnZ2dnUVZ_o6dnZ2d@giganews.com">news:a4-dnXGourxKb9vWnZ2dnUVZ_o6dnZ2d@giganews.com...Jayson Smith wrote:On a somewhat related topic, I've always hated the way DOS 3.3 goes "BZZZZZZZZZZZ!" when recalibrating the drive after a read/write error. Is there any way to shorten the time DOS moves the head toward track 0, so as to possibly eliminate the buzzing in some circumstances? I much prefer the way ProDos does this, going back a few tracks instead of making absolutely sure the head is at track 0, and probably going way too far overboard in most situations.JaysonIt doesn't go that much "overboard", since the seek cam _could_ be up around "track 40" and you have to seek back far enough to hit the track 0 stop. Of course, you could always seek back until you found a track/sector mark that you could read, then go again from there.It would be possible to make a full recalibrate quieter, by half- stepping or even micro-stepping back against the stop, but it wouldtake more code space. But it really doesn't matter. The drive is absolutely not injured in any way by repeatedly stepping back beyond track 0. If you don't like the noise, get a half-height drive with a quieter stop or a track 0 switch that disables backward seeks. ;-)
-michael NadaNet and AppleCrate II: parallel computing for Apple II computers! Home page: http://home.comcast.net/~mjmahon "The wastebasket is our most important design tool--and it's seriously underused."