30 Mar
2015
30 Mar
'15
4:57 p.m.
On Mar 30, 2015, at 7:50 PM, Christopher Parish
<christopher.parish at parishcomputers.com> wrote:
...
Second, I've noticed that the drive seems to mis-seek on occasion. I command the
drive to walk forward or back a single track, and the heads move but sometimes land on the
same starting track. This results in duplicate data for the next 10kB or so, and is
heavily pack dependent. Some packs don't exhibit it, others do. I imagine this is
related to the drive/pack runout condition described in the manual. Until I figure out
more, my plan is to add additional verification to the incoming data, checking the track
it landed on and re-commanding the difference if necessary.
As I recall, RL01/02 have embedded servo (one of the first DEC drives to do so). That
would suggest you have a marginal servo mechanism. As for wrong data, isn?t there a track
(cylinder) number in the headers? I would expect there to be one, so a wrong seek should
be detectable.
paul