DG S/130 progress

shadoooo shadoooo at gmail.com
Wed Oct 14 15:44:00 CDT 2015

I'm almost sure that the DG dual 8" uses hard-sectored floppies with 32 
sectors (33 holes).
The internal logic will generate sync signals for 8 sectors starting 
from the 32 on the floppy.
So industry standard hard-sectored floppies should be fine.
You need to use formatted disks, DG supplied floppies already formatted, 
and the OS cannot format it.
But: the drive itself has a format mode, so using a special formatter 
program (available at least on paper tape),
you can format disks.

Interesting thing (I think):
as I have a Nova 3 with 6030 floppy, which I would restore when time 
will allow me to,
and as I have no media to start the machine from, I searched a way to 
write new media from PC.
Then I developed a tool to connect it to PC via serial, using the 
console port;
this tool is somehow similar to VTserver for PDP11 realm, but more 
Basically, you can do memory transfers between Nova and PC (both 
directions), and
execute almost *ANY* I/O instruction on the Nova, under the strict 
direction of the PC.
On the PC, a tool developed in Python is used to bootstrap a special 
binary program (using Program Load feature on Nova),
and then to execute special scripts, prepared for particular disk and/or 
tape peripherals, to dump a device to image file (compatible with SIMH),
dump an image file to device, format a disk, and so on...
As all these procedures are controlled remotely by the PC, on the Nova 
always sits the very same small binary code,
thus supporting new peripherals should be very easy, once one 
understands how the whole stuff works.

I already developed (and debugged using an emulated Nova3 on SIMH) all 
is needed to read/write/format disks on 6030.
I think the very same code should work on the S/130, so if you want you 
could give a try.



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