Re: Problem with Universal Disk Controller

[David Wilson <mcs6502@gmail.com>]

On Feb 28, 2:53 am, AppleCPM <a...@wilserv.com> wrote:
>     As long as we're discussing the UDC, I thought I'd see if I could
> clear up some of my confusion about the card.

> Do they need to be in any particular order?  Yes.

> Will a 1.44 MB drive work with the card?  Only as an 800KB drive.

> How about early Mac drives like the M0130 (I think that's the model number)?

No. The 400KB drive is not supported. I have used the original 800KB
Mac drive successfully but it is much slower than the Apple 3.5 drive
on the UDC.

Here are the 13 valid configurations listed in the UDC manual. Format
is J1, J2.

1) 3.5
2) 5.25
3) 3.5, 3.5
4) 3.5, 5.25
5) 5.25, 3.5
6) 5.25, 5.25

7) 3.5+3.5
8) 3.5+5.25
9) 5.25+5.25

10) 3.5+5.25, 5.25
11) 3.5+5.25+5.25
12) 3.5+3.5+5.25
13) 3.5+3.5+5.25+5.25

Like the IIgs, 3.5" drives must precede 5.25" drives in the daisy
chain.

Daisy chains longer than two drives are not recommended due to signal
noise/degradation.

The rules of which drive is S5,D1 S5,D2 S2,D1 and S2,D2 get
complicated with options 10-13 - I will have to scan the manual.