[Simh] Interdata OS/32 - adding disks

[Don Stalkowski]

On Mon, Feb 01, 2016 at 10:14:23PM -0500, Davis Johnson wrote:
> 
> There were two SMD controllers, older "MSM" and newer "IDC". The IDC
> controller relaxed some of the restrictions on mixing drives in the same
> string.

I had an MSM300 and 2 MSM80 drives configured so the controller
shouldn't have been an issue.

> 
> Try configuring multiple identical disks. I know that I've done that with
> SIMH.

I configured 3 MSM80 drives and the results surprised me.

dm0 remained on DSC4 and dm1 was on DSC3 and dm2 on DSC5. I would have
thought dm0 would have been allocated to the first MSM80 drive, DSC3.

The new drives formatted ok.

Ah, I just got it: DSC4 is address FC, DCS3, FD, and DSC5, FE. The
simh drives are assigned by address.

Ok, I went back to my previous sysgen and set/attached the drives
properly and it worked. The problem was that I was getting the drives
all mixed up!

Thanks for the suggestion about using 3 identical drives - it got me
going in the right direction.

Don