TRS-80 Model 4 help requested

From: Tony Duell <>
Date: Thu Feb 27 18:23:45 2003

> On Wed, 26 Feb 2003, Al Hartman wrote:
> > For external drives, the drives are set to all
> > selects, and pins are pulled from the drive cable to
> > determine what position they are in.
> A minor complication with using DS drives, at least as external, . . .
> Didn't Radio Shack used pin 32 for drive select 3?
> Isn't that "side select"?

Yes, but the internal and external drive cables are electically totally
seprate, and the select lines for external drives appear on the DS0 and
DS1 pins of the external connector (only). That's why if you manage to
fit 4 half-height drives inside the M4, you have to run a cable to the
external connector on the FDC board also. There is no problem in having 4
DS drives on a M3 or M4

With the Model 1, all drives are external, and there's only one drive
connector. You're then limited to 3 drives if you have any DS ones.

Received on Thu Feb 27 2003 - 18:23:45 GMT

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