Re: Did Commodore cheat with the quad density floppies?

----- Original Message ----- 
From: "Michał Pleban" <lists@michau.name>
To: <cbm-hackers@musoftware.de>
Sent: Monday, January 07, 2019 10:12 AM
Subject: Re: Did Commodore cheat with the quad density floppies?


> 8" disk drive motors do not stop when started once. The idea that the disk should stop spinning and start again when needed came only with 5.25" drives.

Many of the early 8" drives did indeed run the drive motor constantly, often powered from the AC line.

However, later drives like the  Tandon TM-848 actually had a quite extensive set of motor control options; you could for instance turn each of four motors on and off independently, you could turn them on and off with the drive select (with optional turn-off delay), run them constantly, etc.

Depending on how the controller handles it you might be able to move a jumper to turn off the motor when not in use if that's what you want.

There's a fairly extensive manual for the TM-848 here (see p. 1-22):

http://www.bitsavers.org/pdf/tandon/TM848_service_1982.pdf

Note that there was a later TM-848E with a reduced parts count and a direct-drive instead of belt-drive motor. I have both types and they are quite different; if anyone needs the -E manual I might be able to help.