uhclem@trsvax.UUCP (07/18/88)
<> B>I'm attempting to get MultiDOS (Model III version) to run more quietly B>on our Model IVPs. Using the config (I believe that is the command) B>I can choose a step rate from 6 to 40 ms. To get the quietest drive B>access, I was told I should use 6 ms. for the 4P drives. If I do this, B>will errors in reading/writing appear more frequently? The Tandon TM-50-1 drives used in the Model 4P should be run at 6msec. They *MUST* NOT be run at 12msec. (TRSDOS 06.01.01 was released to force the DOS to do restores at the same speed as seeks. Previously it went one speed slower on restores.) The problem is that Tandon went and used an 80 track stepper motor and double-steps it at about 3msec intervals. At a 12msec CPU-supplied step rate, the double-stepping sets up some sort of harmonic in the drive motor/head assembly and the drive will actually step the wrong way! I have watched these drives exhaust all 254 step pulses during a restore and never make it to track 0 on a 40 track drive. The heads just wander back and forth and quite often end up at track > 40. 20 and 30msec do not exhibit this problem, but do generate noise. If you haven't pulled out those Tandon drives and replaced them with TEAC FD54 or FD55 drives, I would suggest you do so. The drives will cost you $160-$180 for a pair, but they will work at any step rate, and you will get double sided capability if your DOS supports it. The reliability will also be so much higher. TM50's do occupy space reliably, and could help you save water by placing them in your toliet tank. <This information is provided by an individual and is not nor should be construed as being provided by Radio Shack or Tandy Corp. Radio Shack/Tandy Corp has no obligation to support the information provided in any way. What am I saying? My employer doesn't use Tandon drives anymore, and the Model 4P does not have the same shortcomings as the IBM PC, and therefore it does not exist, so this letter can't exist.> "Thank you, Uh Clem." Frank Durda IV @ <trsvax!uhclem> ...decvax!microsoft!trsvax!uhclem ...convex!infoswx!hal6000!trsvax!uhclem ...sys1!hal6000!trsvax!uhclem Hope you aren't on "The Edge Of ihnp4!"