[Intel-devsys] IMAGEDISK for MDS 8" SSSD disks

Bill Beech (NJ7P) nj7p at nj7p.info
Sat Feb 22 16:15:12 MST 2020


On 2/20/2020 8:06 PM, Roger Arrick wrote:
> Happy 2020 MDS crew!
Yes, indeed!
> I need some help - It concerns SSSD formats on 8" disks MDS225.
> My latest project is to build an IMAGEDISK system on my PC to write .IMD
> files for various machines like Altos and Xerox 820.
So you build a "Dunfield" box.  I am also in the process of building one.
> I have the adaptec AHA-1542CF controller which can do SD on a PC.
> I've succeeded in writing SSSD 5.25" disks for my FLEX9 SWTPC system.
> So lots of things are working.
Interesting.  I have written a FLEX9 Simulator in SIMH.  What software 
do you have for for FLEX9?
> Now I have an SA800 8" drive going through a DBIT adapter which 
> generates the T43 write comp signal.
> I can read a standard CPM disk (SSSD, 
SSSD is 26 sectors...
> 28 sectors, 128 byte sectors, 77 tracks).
> This CPM disk will also read in my MDS225 running CPM using the 
> systems SD integrated drive.
Okay, so we have a starting point...
> But the disk I write out of imagedisk, which is a copy of this CPM 
> disk, will NOT read in my MDS.
> I can view this disk on the PC using IMDV and can see the CPM 
> directory but I can see that some of the interleaves are different.
Interleave will effect how fast you can read or write a disk, but should 
not stop a system from reading the disk...
> So, what would stop the MDS from reading an apparently good CPM disk.
There must be a error in the formatting of the written disk.  I have 
played with the GAP lengths using both an i8272 and a WD1791 to place 
more sectors on the disk, and not run into reading problems.
> IMD has a setting for R/W gap and Format gap.
> I've tinkered with these a bit but no success.
I would not expect any.  Lot of room for adjustment.  Can you do a track 
read on any track of written disk with Dave's tools?  Need to look at 
the actual format written on the written disk.
> Any ideas?
> _______________________________________________
> Roger Arrick
> Roger at Arrick.com
> Tyler, TX
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