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IMS Series 8000 (5000SX?) Project

I'm actually starting to suspect the floppy controller more and more (or the floppy controller's interaction/compatibility with the fd50to34, maybe?). I read somewhere that IMD could write a 500k 8" floppy image onto a 1.2MB 5.25" floppy. I tried it on the AT clone and it was unhappy, complaining about the FDC Interrupt. Then I stuck a 1.2MB floppy in the 486 and tried to use IMD to write the CP/M 2.2 image and the TDINST1 image to high density 5.25" floppy, and sure enough, it wrote both of them without any complaints. Having done this, I wasn't really expecting the computer to *boot* off of the floppies, but I'm running out of ideas and don't have much better to do. But when I moved the drive over to the IMS and hooked it up, I noticed that on power up, there was absolutely no sign of the heads moving. I think the track number cycle thing I was seeing on the gotek is just a glitch. It seems like the drive is being selected (light comes on), but the heads don't seem to be seeking or anything. This is true of the IPLALL ROM and the MiniMon9 with the proper floppy controller address. The CPM ROM, which didn't seem to be doing anything with the gotek, also comes up with the drive light on, but just sits there and spins, also without actually seeming to really seek.
 
Ah. Okay, to get the same behavior out of the physical floppy drive, I had to tie 'RDY' to ground. Now the physical floppy seems to be demonstrating the same behavior as the goteks seem to have, where it's just moving the head back and forth (between tracks 1 and 2, maybe?). (I think maybe the behavior I was seeing on the gotek wasn't a glitch, just that the gotek automatically pulls RDY and leaves it pulled.)
 
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Try this next set of disks, disk 1 is for booting. This is TurboDOS 1.41. I soldered up a copy of your 34 to 50 pin adapter yesterday and I will see if I can get any action out of my Gotek with Flash Floppy firmware.
 

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new_castle_j said:
Try this next set of disks, disk 1 is for booting. This is TurboDOS 1.41. I soldered up a copy of your 34 to 50 pin adapter yesterday and I will see if I can get any action out of my Gotek with Flash Floppy firmware.
Click to expand...
That one *definitely* behaves differently than the other ones in the flash floppy gotek. It Still doesn't boot, but jumps out to track 24 and checks it, then track 25, then track 26 before jumping back to track 0.
 
Ok, that behaves much more like how TurboDOS would boot, the boot file is not on the first tracks. I get the same Error 31 on my Flash Floppy gotek here with that image, but I don't have experience with the configuration options on gotek. This boot disk is an 8" floppy with:
77 tracks 2 heads 360 rpm and 8 sectors per track of 1024 bytes each, does that help?
 
That's error 31 with a raw image, right? Yeah, those don’t seem to work at all. The IMD format isn't supported by gotek, so you have to convert them to something that is, like HFE. That encodes some extra stuff like RPM, bitrate, etc. that the IMD image also has. The HxC emulator software (https://hxc2001.com/download/floppy_drive_emulator/) has a built in converter that converts from IMD to HFE. I also noticed that the disk image was double sided, but all of the tracks on the second side were just E5 E5 E5... I created a second diskette image that was defined as single sided. On the FD50to34, I've noticed that the tracks it jumps to if you unjumper the 2side block (i.e. force the adapter to report back single sided media to the controller) are 51, 52, and 53, not 24, 25, and 26. You can grab that software linked above and try the conversion yourself (I think they have windows, linux, and macOS versions in the single download), but I've attached my converted HFE for doubleside and the attempt to convert to single side (the _SS version).
 

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Now that I've bridged 'RDY' to ground, I'm also seeing the CP/M BIOS jump to track 1, and then track 2 with the CP/M disk image. This is on both power up and also reset. It gets stuck on track 2 the same way that the turbosdos image seems to be getting stuck on track 26 (or 53, depending on how you have the 2side jumper). It seems like RDY bridge is getting it further down the line, but not the complete solution.
 
Oh, looking at this diskette image (TurboDOS 1.4 Disk 1) again in the HFE editor, I can see that I was wrong. It actually does have data on both sides of the disk, which means that 'converted to single side' disk I added to that last attachment is useless.
 
I made a little progress over here. I booted my system from hard disk and then inserted the double sided HFE image that you provided. It can read the data from the HFE image using the Gotek and FlashFloppy firmware, but it can't write to it or boot from it. Interestingly if I format the HFE image, then it can read/write to it, but still can't boot from it. The Gotek also seems slower than a real 8" drive, this is new territory for me too, maybe need to get some help from the FlashFloppy Facebook group?
 
I just want to thank all involved in this particular post - I have an IMS 8000 microcomputer, owned it for about 15 years now. New_Castle very kindly game me some HD controller boards some years back, Im ashamed to say I got as far as copying the TurboDOS ROM code to an EEPROM and creating a TurboDOS floppy using one if my NEC APC drives. I also bought a new-still-in-box DSDD floppy drive, same type as in the APC, intending it to go in the IMS 8000, as it only has single sided Shugart drives. The bit that stopped me was creating an adapter for the cabling from the IMS HD card personality board to the edge connectors on my MFM hard drive - and then we planned on moving house and it all went into storage, for like 3 years.
The house move never happened and Im attempting to sort the mess in the Attic that was my vintage computer space, then I can get back on with it all. Anyhow, I just wanted to say Hi and express thanks for the knowledge, encouragement and ROM/disk images in these posts! No need to reply, just carry on with the discussion, it fascinates me!
 
Alan, so good to hear from you! I can't just leave your post dangling out there without being acknowledged. I remember the software disk you gave me "The Last One", a fascinating program generator that would write programs in BASIC, a kind of "AI" circa 1981. I never found a manual or figured out how to run it though, it's not intuitive.

Whenever you get back to your system, make a post about it. I'll be here to help.
 
So if you create an IMG.CFG in the root of the flash floppy USB, you can define the parameters for a raw image. This prevents the gotek from giving an error 31.

Code: 
## configuration for 8" shugart drive for IMS?
# 77 tracks 2 heads 360 rpm and 8 sectors per track of 1024 bytes each, does that help?

[ims]
cyls = 77
heads = 2
secs = 8
bps = 1024
rate = 500 
rpm = 360
iam = yes
mode=mfm

Having said this, I didn't have ANY luck getting a raw image exported from the IMD to get as far along as the LFTD14-1 image does. I tried using IMD on DOS, disk-analyse on macOS, and also the HxC floppy emulator utility to create raw files, and none of them really seemed to do much.

I also had mentioned earlier that I had manually bridged the RDY pin to ground and that got the tracks reading. It turns out that you don't have to do that with the gotek. In the FF.CFG file, also in the root directory (if you don't have one, you can get the default from the flash floppy page), you can specify how you want pin 2 and 34 to behave:

Code: 
# Pins 2 & 34 output (drive->host) manual configuration
# auto: Auto-configure from interface= setting
# nc: Unused/No Connection [eg. if pin is an input (host->drive) on your host]
# low: Always 0 volts (0v)
# high: Always 5 volts (5v)
# rdy: Drive ready (Ready = 0v)
# nrdy: Logical complement of above
# dens: Density mode (High Density = 0v)
# ndens: Logical complement of above
# chg: Disk changed (Changed = 0v)
# nchg: Logical complement of above
# Values: auto, nc, low, high, rdy, nrdy, dens, ndens, chg, nchg
pin02 = auto
pin34 = rdy

With this configuration set, the flash floppy on the unmodified fd50to34 accesses the heads the same way the modified one does. (I still needed to manually bridge it anyway, to get it to actually try and seek with the 5.25" drive hooked up.
 
alan8086 said:
Here's my rig anyhow...
Click to expand...
That's awesome. Is that the original case, or just something you had / found? I need to build a case for mine. I only have the card cage, the 12-slot motherboard, and the various cards. I'll need to build a custom case at some point, and my plan is to try to get it to look as close to the original IMS case as possible.
 
twmiller said:
That's awesome. Is that the original case, or just something you had / found? I need to build a case for mine. I only have the card cage, the 12-slot motherboard, and the various cards. I'll need to build a custom case at some point, and my plan is to try to get it to look as close to the original IMS case as possible.
Click to expand...
It's all original I think - I can give you pictures, measurements and details on how the side panels fit on to the case etc when the time comes if you like?
 
new_castle_j said:
Alan, so good to hear from you! I can't just leave your post dangling out there without being acknowledged. I remember the software disk you gave me "The Last One", a fascinating program generator that would write programs in BASIC, a kind of "AI" circa 1981. I never found a manual or figured out how to run it though, it's not intuitive.

Whenever you get back to your system, make a post about it. I'll be here to help.
Click to expand...
Now you mention it, I did didn't I! I intend to make modern copies on decent M3 disks of all the original owners work disks - something may turn up by way of instructions or an inference of how TLO is used? There are certainly programs he wrote from TLO on some disks I have.
 
twmiller said:
So if you create an IMG.CFG in the root of the flash floppy USB, you can define the parameters for a raw image. This prevents the gotek from giving an error 31.
Click to expand...
I forgot to mention that the way IMG.CFG works is that it looks for filenames with the bit in brackets to apply those settings to, so those particular settings would only work for a file with an extension of .ims.img (like lftd14-1.ims.img) and be ignored for .img files that don't have the .ims bit.
 
I added the interleave value to your img.cfg file and got the raw disk image to work in the FlashFloppy Gotek. It works the same as the HFE file though, it can be read/written to once the machine is booted via hard disk, but it can't be booted from the Gotek. The .img file also seems to read/write data faster than the HFE file. There must be some kind of debug mode that the Gotek can be put into to get an idea of why it hangs on boot. I'm attaching my image and config for you to play with. I'm using the same 34 to 50 pin adapter that you are, but I have none of the jumpers shunted.
 

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