CompuServe Thread

The Amiga Forum · Tool Box

#GRONNNNK!

6 messages in this thread

#11116From: Jez San @ Argonaut S/WMar 10, 1986 8:10 PM

Randy- No.. The Trackdisk.Device was written by Neal at Commodore Amiga. Tim King (at MetaComCo) wrote the HIGH LEVEL AmigaDOS, but the actual code that accesses the disk is NOT a Tim King program, thus talking to him about it would not solve matters. I havn't checked… but I believe the Amiga drives step at about 3ms, which is one of the fastest step rates possible. The reason for the noise is almost certainly due to the type of drive used, and NOT (as others believe) du e to a slow step rate. Time taken for the drives to step from track 0 to 80, is VERY fast, compared to all other drives I have seen. Reason for the horrible noise must therefore be a cheap mechanism. — Jez. * Reply: 11124

#11124From: Steve AhlstromMar 10, 1986 8:35 PM

Reason for the noise is simple — plastic runners on metal rails. They just need to be lubbed with a silicon based paste. (Like Dow Heat Sink compound). * Reply: 11129 * RR 11116 +

#11129From: Jez San @ Argonaut S/WMar 10, 1986 9:05 PM

Touche. — Jez. * RR 11116

#11171From: Larry MillerMar 11, 1986 12:01 AM

Bullroar, Jez. Stepper motors all have the characteristic that if you pick the stepping pulse rate correctly, it will step practically noiselessly. Faster than this, it misses steps. Slower than this, it makes a Full Stop (or nearly so) in between each step, causing lots of vibration –>noise. Actually, there is a RANGE of stepping rates that are quiet to varying degrees. the 3 ms might be real fast, but the Amiga stepper motors show every sign that they could run faster. This is not surprising, since the 3-1/2" drives have small parts and therefore low inertia (compared to a 5-1/4" drive, where 6ms is considered hot stuff). Even my big old 8-inch dreadnoughts step (quietly) at 3 ms.

#11190From: Jez San @ Argonaut S/WMar 11, 1986 7:15 AM

Larry- Tandon's and Mitsubishi's used to step quieter when at their maximum step rate. However, I've also seens types of drives that were *NOISIER* when stepped at their fastest step rate… your rule of thumb does not ALWAYS work… and I suspect the simple reason for noise on the Amiga drives, is PURELY mechanical, and not due to the step rate at all. I'll bet that they are already running at or near their maximum! — Jez.

#11260From: Bela Lubkin/SysopMar 12, 1986 5:49 AM

I don't care! I want to be able to diddle the step rate, and FIND OUT FOR SURE! – Bela