Gotek on AT&T UNIX PC

[agentb]

Anyone tried hooking up a gotek to a UNIX PC (3b1)? I'm going to mess around with this at some point. I still don't fully understand the MO (motor enable) jumper on the gotek, do I want this jumpered for 3b1?

 

[agentb]

My best guess is the MO jumper is to be used if you want the gotek to respond when it sees the MO line active. Looking at the 3b1 schematic, I should just be able to use the Drive 0 Select line, so I'm just going to stick with the S0 jumper. Next up I'll flash the gotek with FlashFloppy, but waiting for my USB A-to-A cable that's needed to flash the newer Artery-based gotek's that don't use the STM32 chips anymore... Some info here: https://www.msx.org/forum/msx-talk/hardware/goteks-with-new-guts

 

[alejack12001]

UNIX used with the 7300, which I assume you have, is very primitive as oppose to Linux being used today. You will have to write your own driver to get the GoTek to work with the UNIX your using. The GoTek requires a very specialized driver to work with UNIX because of the reverse addressing little endian issue, so you can't plug and chug. I have tried GoTek 720 and 1.44 on a 6300 using DOS and it was a no go. However there is one member of the forum who did get the GoTek to work with DOS and he illustrated this in his video on you tube. https://www.youtube.com/watch?v=DxqSyNAMNFo I think he goes by lamda84 and you might try sending him a PM to see if he responds. In addition, you might try to get inn touch with Trixter or Chuck(G). Trixter has had extensive knowledge with AT&T platforms. Chuck(G) could help you with the programming since he has had a lot of Assembly experience.

 

[agentb]

Thanks for the info. I hadn’t considered the endianness issue, hmm. I’m planning to try the FlashFloppy firmware so I’ll have to see if there’s anything in the config about endianness- I haven’t looked into FlashFloppy yet.

 

[agentb]

Got the gotek working with FlashFloppy! I'm not sure about the "interleave = 2" line, but seems to work. Someone using HxC mentioned Interleave 2 so I'm going with it too.

Here is the IMG.CFG I made, pretty straightforward:
## IMG.CFG for AT&T UNIX PC / 3B1 / PC 7300

# NOTE: The tags match on filesize alone. If you wish to define an explicit
# tagname match, you can for example add '3b1' to the square-bracketed tags
# to limit matches to filenames of the form *.3b1.{img,ima,dsk}

# 3B1 (TEAC FD-55B: 2S DD 40T)
# DSDD 400 KB
[::409600]
cyls = 40
heads = 2
secs = 10
bps = 512
interleave = 2

[::368640]
cyls = 40
heads = 2
secs = 9
bps = 512

[::327680]
cyls = 40
heads = 2
secs = 8
bps = 512

 

[agentb]

To clarify, only one jumper used, and that's on S0.

 

[alejack12001]

First, I commend you for getting it to work. As I mentioned in my post, I couldn't get it to work under DOS 6.22 and ROM 1.43.
What size was your GoTek drive 720 or 1.44 Floppy? Did you replace your 360 K Floppy or use it as B drive?

The following is what I got from the testing of the GoTek 72 (720) Floppy Emulator
(Note: Drive 0 on Emulator set as Boot Disk MSDOS 6.22)

Settings not tried "J5, JC, JB, MO"

Jumper Setting	Drive Emulated	Floppy 360K Present	Machine Response
JA & S0	B	Yes	"Ready, ROM error"
JA & S1	B	Yes	Not ready on A. ROM Basic not available. Press reset (Note: Floppy A lamp lighted while emulator light out)
S0	B	Yes	Not ready on A. ROM Basic not available. Press reset (Note: Both LED's on Floppy A and the emulator are lighted)
S1	B	Yes	Not ready on A. ROM Basic not available. Press reset (Note: Both LED's on Floppy A and the emulator are lighted)
JA & S0	A	No	Not ready on A. Primary Boot Strap, flashing press restart to reboot." (Note: Emulator Lamp out before and after POST. LED thumb drive on for 1-3 sec used right button to load buffer before sequence of boot.0 shows buffer loaded from 0 also LED on thumb drive illuminated)
JA & S1	A	No	"Ready on A. Primary Boot Strap, flashing press restart to reboot." (Note: Emulator Lamp out before POST, however, Emulator Lamp on after POST for 1 sec. LED thumb drive on for 1-3 sec used right button to load before sequence of boot. D0 shows buffer loaded from 0 also LED on thumb drive illuminated)
S0	A	No	Not ready on A. ROM Basic not available. Press reset (Note: Emulator Lamp out before and after POST. LED thumb drive on for 1-3 sec used right button to load buffer before sequence of boot. D0 shows buffer loaded from 0 also LED on thumb drive illuminated)
S1	A	N0	"Ready on A. Primary Boot Strap, flashing press restart to reboot." (Note: Emulator Lamp out before POST, however, Emulator Lamp on after POST for 1 sec. LED thumb drive on for 1-3 sec used right button to load buffer before sequence of boot. D0 shows buffer loaded from 0 also LED on thumb drive illuminated)

I didn't know about the Flash Floppy. I will have to look into it again and see if I could get it to work.Thanks for the info on Flash Floppy. Some how I would have to get beyond the POST and the startup of the MSDOS.

 

[agentb]

I am using a 1.44 gotek. There is only one drive in the UNIX PC and only the S0 line is accessed by the hardware so can’t have two drives connected concurrently. So the gotek replaces the original floppy for me.

does the 6300 have the standard PC floppy cable with the twist to the connector at the end? If that’s the case, and you want to boot from the gotek, the gotek will need to be jumpered for S1 and at the end of the cable (after the twist) so it’s the A: drive. Looks like you already tried this though. I would also say maybe try the MO jumper in addition to the S1 but I don’t know if that will actually help at all.

i don’t know what the stock firmware is on the gotek, I just went straight to FlashFloppy and also added the 128x32 OLED screen as I knew that would be helpful for debugging and usage interface.

 

[rea5245]

Got the gotek working with FlashFloppy!

Awesome! I'm about to try the same thing with an AT&T Unix PC I recently found. It doesn't boot; I presume the hard drive is bad. On your Gotek's USB drive, what floppies do you have? If you have the diagnostics disk, or the operating system disks already set up, would you be willing to share your USB drive's directory tree with me?

Thank you,
Bob

 

[agentb]

Hi Bob. Cool that you have a UNIX PC! I was just playing around with it so only tested the diagnostics disk (disk 1 of the foundation set) and a dos image. For disk 1 I converted the .IMD to raw image using IMDU. You need to be careful which .IMD you use as I hear some are missing the first two blocks. I also tested without using a custom IMG.CFG but it’s possible flashfloppy stores the last used IMG.CFG in its brain as I believe that’s what it does with the other config file. If you need more help let me know. Does your gotek have the oled screen? That really helped me see what the heck was going on. I’ll look up the link for the proper IMD’s you want

 

[agentb]

It’s the bitsavers images you want not the unixpc.org ones.

 

[agentb]

If your hard drive is crapped out, David Gesswein’s MFM emulator is an awesome option. That’s what I’m using in my UNIX PC thanks to firebirdta84 David even provides a fully loaded HD to get you started: http://www.pdp8online.com/3b1/demos.shtml

 

[rea5245]

Thanks, agentb. I don't know how similar FlashFloppy is to HxC, which is what I have, but for HxC I need to convert floppy images into .HFE files. I've had bad luck doing that so far with IBM PC floppies, and I don't know if it's because I was using bad floppy images, or if I was doing something wrong.

So I was hoping to find some files that have already worked on a Gotek, on someone's Unix PC, so I could at least confirm that my Gotek was working, and that my Unix PC was working.

- Bob

 

[rea5245]

David even provides a fully loaded HD to get you started: http://www.pdp8online.com/3b1/demos.shtml

David's image is for a 3B1. I'm pretty sure I have a 7300 - there's a sticker on it saying 20MB, which implies I have a 7300 with an upgraded hard drive.

Do you know if a 3B1 disk image would work?

- Bob

 

[agentb]

Do you know if a 3B1 disk image would work?

Yes a “3B1” image should work in a 7300 - pretty much the same machine just with the space for a full height HD in the 3b1 model. However that image is 67MB and primarily intended for using with the FreeBee emulator or with his MFM emulator. I suppose it could be written to a physical 67MB HD - that may have been the original intent.

 

[agentb]

I haven’t used .HFE files - I’ll look into it.

 

[agentb]

I haven't used .HFE files before, but just tried using disk-analyse from https://github.com/keirf/Disk-Utilities for the file conversion.

'LD_LIBRARY_PATH=../libdisk ./disk-analyse -v 01.imd 01.hfe'

No idea if it worked properly. Output stated:
Found format "ibm"
PLL Parameters: period_adj=5% phase_adj=60%
T0.0-39.1: IBM-MFM DD (10 512-byte sectors, 5120 bytes)
T40.0-82.1: Unformatted
There should really only be 40 tracks for a 400k UNIX PC disk image so this .hfe is bigger than it should be. But it might work for you. I posted it here:
https://file.re/2021/05/30/01/
Link will disappear in 24 hrs so grab it now

 

[rea5245]

Thank you. I'll give it a try.

 

[agentb]

Hey Bob -- I tried the 01.HFE that I converted with disk-analyse on my Gotek running FlashFloppy firmware and appears to work fine. Hopefully you can get it working with your gotek.

 

[Svenska]

First, I commend you for getting it to work. As I mentioned in my post, I couldn't get it to work under DOS 6.22 and ROM 1.43.
What size was your GoTek drive 720 or 1.44 Floppy?

If you use the FlashFloppy firmware, there is no difference between 720 and 1.44 Goteks; they are identical from a hardware point of view.