D.G. Nova update (boo f'ing hoo)

Date: Fri, 01 Apr 2005 09:51:13 -0800 From: jim stephens <jwstephens at msm.umr.edu> To: General Discussion: On-Topic Posts Only <cctech at classiccmp.org> ; Subject: Re: D.G. Nova update (boo f'ing hoo) In the Western Dynax variety of these drives, there was a signal called "funul" which was "function unload". When a power supply was sensed to be out of spec, or any other malfunction was detected, such as an out of range seek attempt, funul would be pulled to kill any write current. The heads would then have a connection made to a set of capacitors which had sufficent energy to retract them very quickly (faster velocity than a regular seek) back to the unload stops. This ensured an unload when the power cable was pulled. I had occasions where the heads were energized when the unload happened and you could see dead sectors in a spiral all across many tracks down to track 0, as the heads unloaded. If you can run a verify program, and see this sort of thing, just a sector or two / track, you may have had this happen. On our drives there was a few gates that could fail to cause this to happen. Jim Tom Jennings wrote: <snip>