While recovering from shoulder surgery, I watched a lot of retro-computing videos from YouTube (especially Usagi Electric) and it made me all
nostalgic for the kind of hacking I used to do. So I dug my Davidge
DSB-4/6 (DSB-4000 rev. B) out and resumed GIDE hacking.

I now have it booting from the hard disk. I've read the work Armin
Diehl did with a VHDL implementation of GIDE on his Prof80 ECB system
and liked it enough that I'm trying to transition my naive disk-handling
to his partitioning scheme.

I was hoping to read/write Davidge floppies w/22DISK and have disk
definitions for them, but 22DISK operates 3.5-inch floppies at 300kbps
in DD mode so it can't read a disk produced on the Davidge nor can the
Davidge read a disk written by 22DISK. The closest I've come is to
image a Davidge disk w/IMD and re-write it using 250k->300k conversion. Conversely, format a disk with 22DISK and my Davidge disk definition,
image it with IMD and re-write it using 300k->250k conversion.

I assembled what I consider a minimum viable system disk and imaged it
with IMD, but a copy written from that image has a bad sector in the
last sector (18) on track 0 (3.5/5.25, 18 128-byte SD sectors). The
DD/MFM data area is intact, however.

--
|/"\ John D. Baker, KN5UKS NetBSD Darwin/MacOS X
|\ / jdbaker[snail]consolidated[flyspeck]net OpenBSD FreeBSD
| X No HTML/proprietary data in email. BSD just sits there and works!
|/ \ GPGkeyID: D703 4A7E 479F 63F8 D3F4 BD99 9572 8F23 E4AD 1645

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Sat, 19 Jul 2025, John D. Baker wrote:

I now have it booting from the hard disk. I've read the work Armin
Diehl did with a VHDL implementation of GIDE on his Prof80 ECB system
and liked it enough that I'm trying to transition my naive disk-handling
to his partitioning scheme.

I should mention that for anyone interested, it is currently available
at "ardiehl.de". Alas, the published email address on the site is no-
longer valid.

After seeing what little there is on the Davidge machines (only photos
and ROM images on bitsavers and only a couple of videos on YouTube of
the "1538A.BIN" ROM image being executed under MAME), I think I may have
the most complete, working Davidge DSB-4/6 in the world right now,
so I'm hoping to put things together to preserve the knowledge.

(There's a LOT of similarity between the DSB-4/6 implementation and the
CCS 2422/2810 FDC/CPU combination. Even the floppy formats are the
same although for 3.5/5.25 DD, I'm using all 80-track hardware rather
than 35 or 40 tracks.)

--
|/"\ John D. Baker, KN5UKS NetBSD Darwin/MacOS X
|\ / jdbaker[snail]consolidated[flyspeck]net OpenBSD FreeBSD
| X No HTML/proprietary data in email. BSD just sits there and works!
|/ \ GPGkeyID: D703 4A7E 479F 63F8 D3F4 BD99 9572 8F23 E4AD 1645

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

Is this the same John D. Baker of Applicard fame? I built the high
speed serial daughter card for the Applicard, originally based on
schematics and data from an old website you had. I did a how-to blog on
it a few years back. Best CP/M card ever made! https://planemo.org/2012/07/29/high-speed-serial-port-for-the-apple-ii-pcpi-applicard/


Eric


On 7/19/25 8:08 PM, John D. Baker wrote:

While recovering from shoulder surgery, I watched a lot of retro-computing videos from YouTube (especially Usagi Electric) and it made me all
nostalgic for the kind of hacking I used to do. So I dug my Davidge
DSB-4/6 (DSB-4000 rev. B) out and resumed GIDE hacking.

I now have it booting from the hard disk. I've read the work Armin
Diehl did with a VHDL implementation of GIDE on his Prof80 ECB system
and liked it enough that I'm trying to transition my naive disk-handling
to his partitioning scheme.

I was hoping to read/write Davidge floppies w/22DISK and have disk definitions for them, but 22DISK operates 3.5-inch floppies at 300kbps
in DD mode so it can't read a disk produced on the Davidge nor can the Davidge read a disk written by 22DISK. The closest I've come is to
image a Davidge disk w/IMD and re-write it using 250k->300k conversion. Conversely, format a disk with 22DISK and my Davidge disk definition,
image it with IMD and re-write it using 300k->250k conversion.

I assembled what I consider a minimum viable system disk and imaged it
with IMD, but a copy written from that image has a bad sector in the
last sector (18) on track 0 (3.5/5.25, 18 128-byte SD sectors). The
DD/MFM data area is intact, however.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Fri, 25 Jul 2025, ECNeilson wrote:

Is this the same John D. Baker of Applicard fame? I built the high speed serial daughter card for the Applicard, originally based on schematics and data from an old website you had. I did a how-to blog on it a few years back.
Best CP/M card ever made! https://planemo.org/2012/07/29/high-speed-serial-port-for-the-apple-ii-pcpi-applicard/

After looking at the above link, yes, that's me! When I finished school
back in 1996, I lost access to Usenet newsgroups (or it was ridiculouly cumbersome to even _start_ a newsreader). I was looking around and found
out about "eternal-september.org" and that's one account I didn't mind
setting up.

Still have all the gear--it's just blocked by all manner of other stuff
so I can't actually get to it to operate any of it. I was recently disassembling the copies of ZMP I customized for the Davidge DSB 4/6 as
the one for the designated modem port _didn't_ use interrupt-driven
receive while the ones for the nominal printer port and aux port _did_,
but my "ZMP Install Disk" didn't have their sources--only the earlier polled-I/O versions. The interrupt-driven ones must be on 8-inch
floppies, but I don't have room to set up any of the 8-inch drives.
Likewise, my QTerm disk for the Davidge must be 8-inch as I only have
the final executables on the hard disk and the one for the modem port
doesn't do interrupt-driven receive while the ones for the printer and
aux port do.

There's only one public-facing web server I have access to, but I
never put any of my older stuff up there before. I've been working
on fixing it up and hope to get it there soon-ish.



--
|/"\ John D. Baker, KN5UKS NetBSD Darwin/MacOS X
|\ / jdbaker[snail]consolidated[flyspeck]net OpenBSD FreeBSD
| X No HTML/proprietary data in email. BSD just sits there and works!
|/ \ GPGkeyID: D703 4A7E 479F 63F8 D3F4 BD99 9572 8F23 E4AD 1645

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

Sorry I can't help you on your DSB-4/6 project. I am such a fanboy of
your and Steve Hirsch's work on the PCPI Applicard. I have all of your published documents, and have CP/M and NZCOM booting on my CF3000 flash
drive on my Apple //e.

Good luck on your DSB endeavors.

Eric
KE5EN


On 7/25/25 3:49 PM, John D. Baker wrote:

On Fri, 25 Jul 2025, ECNeilson wrote:

Is this the same John D. Baker of Applicard fame? I built the high speed
serial daughter card for the Applicard, originally based on schematics and >> data from an old website you had. I did a how-to blog on it a few years back.
Best CP/M card ever made!
https://planemo.org/2012/07/29/high-speed-serial-port-for-the-apple-ii-pcpi-applicard/

After looking at the above link, yes, that's me! When I finished school
back in 1996, I lost access to Usenet newsgroups (or it was ridiculouly cumbersome to even _start_ a newsreader). I was looking around and found
out about "eternal-september.org" and that's one account I didn't mind setting up.

Still have all the gear--it's just blocked by all manner of other stuff
so I can't actually get to it to operate any of it. I was recently disassembling the copies of ZMP I customized for the Davidge DSB 4/6 as
the one for the designated modem port _didn't_ use interrupt-driven
receive while the ones for the nominal printer port and aux port _did_,
but my "ZMP Install Disk" didn't have their sources--only the earlier polled-I/O versions. The interrupt-driven ones must be on 8-inch
floppies, but I don't have room to set up any of the 8-inch drives.
Likewise, my QTerm disk for the Davidge must be 8-inch as I only have
the final executables on the hard disk and the one for the modem port
doesn't do interrupt-driven receive while the ones for the printer and
aux port do.

There's only one public-facing web server I have access to, but I
never put any of my older stuff up there before. I've been working
on fixing it up and hope to get it there soon-ish.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)