• Please review our updated Terms and Rules here

IBM 5150 Won't Boot Anything But 180K Disk Images On Gotek

MajorMar

Member
Joined
Mar 25, 2019
Messages
32
Location
SF Bay Area
I have been working on a problem for the past few weeks and I haven't been able to find a solution. Essentially, I can't get my 5150 to boot from a Gotek drive with FlashFloppy except for 180K disk images (i.e. IBM-DOS 2.11). I have read in the forums that even newer versions of DOS should run on the 5150. More details below.

The situation:
I recently picked up my first IBM 5150. (Woohoo!) I have gotten it to a working state (except for this problem) by replacing memory, cleaning and restoring drives, power supply, etc. It has The BIOS has the IBM part number of "1501476" printed on it which I believe is the third-gen from 1982. It came with two Teac FD-55BV-36-U which seem to be working fine. Is also has a Seagate st225 hard drive which I am not using for now. However, I have no software or other older PCs that I could hook one of these floppies to in order to make some physical boot media.

- I connected a Gotek drive with FlashFloppy firmware as the drive after the twist replacing one of the Teacs.
- I can boot IBM-DOS 2.11 which is a 180K disk image.
- I can format a physical disk to 360K on the Teac drive after booting into 2.11.
- I cannot boot any image larger than 180K (i.e. 360K or 720K) from the Gotek. I get "Disk Boot Failure" from IBM-DOS 3.3 and "Non-system disk ..." from anything newer than that.
- The system scans the Gotek drive like it's reading it, but then returns the errors above.

What I have tried:
- The system originally had a PC's Limited clone of the standard IBM floppy controller. I switch this out with a standard IBM one.
- I have checked the switches on SW1: 7 is OFF, 8 is ON.
- I have checked the cable and the Gotek drive on my TRS-80 M3. So at least I know they are working if I have the right settings for the right machine.
- I have tried custom IMG.CFG on the Gotek with settings for 360K drive geometry explicitly stated.
- I have tried .hfe versions of the floppy images using HxC floppy emulator.
- I have unplugged all other cards in the system besides the video card and floppy controller.
- I have tried multiple boot images from multiple versions of DOS (both IBM and MS). I have gotten most of these from winworldpc.com.

Does anyone have any other ideas? Can anyone confirm that they can boot from a gotek drive on a 5150 with 360K images? If so, were you using HxC firmware or FlashFloppy? I would appreciate any suggestions. I have learned a lot from this forum over the past few weeks!

Thanks!
 
I am able to boot my 5150 from a Gotek (using HxC firmware) using a 360K disk image of MSDOS 3.x and 5.x.

However, this is with use of a slightly newer clone (still based on the 8272 chip) of the original PC floppy controller card. For reasons unclear to me, I was unable to read/boot from the Gotek using the original PC floppy controller provided with the 5150. My suspicion is that the newer clone card, which is also designed to support 1.2M 5.25" drives, has improved timing and/or interface circuitry compared to the original PC controller card and hence is a better match for the Gotek design.
 
Last edited:
I am able to boot my 5150 from a Gotek (using HxC firmware) using a 360K disk image of MSDOS 3.x and 5.x.

Thanks for confirming those details. I might try loading the HxC firmware and trying it instead although FlashFloppy has worked so well for me on other machines it's hard to imagine it wouldn't work here.
 
I don't have a gotek (floppies forever! :p ) but what I would to to sanity check things: try formatting a bootable 360k system disk using DOS 2, don't forget to copy command.com and other files. Then switch the floppy drive so it is "A" and try booting that disk. It it boots, that would at least point to an issue with the gotek. If not, I would suspect a problem with the cable connector since double sided does work as "B".

However, this is with use of a slightly newer clone (still based on the 8272 chip) of the original PC floppy controller card. For reasons unclear to me, I was unable to read/boot from the Gotek using the original PC floppy controller provided with the 5150. My suspicion is that the newer clone card, which is also designed to support 1.2M 5.25" drives, has improved timing and/or interface circuitry compared to the original PC controller card and hence is a better match for the Gotek design.
My suspicion is the Gotek may be serving up the images as high density instead of low density. Yes, that will boot and read. You could verify that with a tool like ImageDisk to see what datarate the controller is communicating at.
 
My suspicion is the Gotek may be serving up the images as high density instead of low density. Yes said:
To be specific the controller I am using is the first revision Compaticard, which has no onboard firmware and when installed in a 5150 will only support 360K drives unless additional driver software is loaded.
Furthermore, by design a Gotek with HxC firmware will only communicate with the controller at DD data rates (as it should) if it has loaded a 360K PC format DSDD disk image.
So... in my setup the Gotek is communicating with the controller at the data rate of a standard 360K DD drive, and works just fine doing so.
 
Last edited:
I use a FlashFloppy firmware based Gotek, can boot 160,180,320,360,720 (anything DD) on a PC or PC XT just fine.
Then I can move that same Gotek and same USB stick to a newer machines and use HD images just fine without updating the config.

I keep on one the bench with a card edge adapter so it's ready to go in to any machine I'm building.

I'm not sure if they've updated it, but when I got my Gotek the firmware and provided software were absolute garbage.
 
I use a FlashFloppy firmware based Gotek, can boot 160,180,320,360,720 (anything DD) on a PC or PC XT just fine.
Then I can move that same Gotek and same USB stick to a newer machines and use HD images just fine without updating the config.

I keep on one the bench with a card edge adapter so it's ready to go in to any machine I'm building.

I'm not sure if they've updated it, but when I got my Gotek the firmware and provided software were absolute garbage.

I agree with all your comments - it is pretty amazing what the Gotek is able to do. I also use the same Gotek with non-IBM PC computers - all one needs to do is select a disk image (from the front panel) compatible with the computer/controller the Gotek is plugged into, and the Gotek reconfigures itself for the appropriate drive rotation speed and data rate. On the other hand, the Gotek web site is very disorganized and even after many revisions the software provided to create disk images is far from intuitive.
 
I don't have a gotek (floppies forever! :p ) but what I would to to sanity check things: try formatting a bootable 360k system disk using DOS 2, don't forget to copy command.com and other files. Then switch the floppy drive so it is "A" and try booting that disk. It it boots, that would at least point to an issue with the gotek. If not, I would suspect a problem with the cable connector since double sided does work as "B".

Well, I did format a 360K drive with "format b:/s", made sure command.com was on there and it booted from the floppy just fine.
 
SpidersWeb, could you send me your ff.cfg file so I can compare it to mine? Also, what are your jumper settings when you use it on a PC?
 
Thanks to everyone for your help so far! As I am new to the forum, my posts are being moderated. As soon as I can post more I will give you an update on my progress.
 
Update: I was able to find my old K10N750SLI motherboard which supports 360K all the way through 2.88M floppy drives. (Gotek with 360K disk image works fine with it BTW) I connected one of the TEAC floppy drives to it and loaded up MSDOS 6.22. I burned a 360K disk image of MSDOS 5 to the actual drive and then reinstalled the TEAC in my 5150 and it boots fine from the actual drive. So, the problem is definitely related to the Gotek somehow. Next, I am going to test the card edge to 34 pin converter I am using when connected to the 5150 as that is something I haven't tried yet.
 
Update2: (Solved) It turns out the problem was in the card edge to 34 pin header converter I was using. After testing it on my "newer" PC with similar results it was obviously down to a problem on that converter board. Turns out pin 32 was not making a good connection. Which makes sense in retrospect since that is the "head 1 select" pin. After installing a bodge wire, everything is now working fine. IMG_20200629_153315.jpg
I would have never suspected that a simple board like this would have any issues, so I didn't bother to check it before now.

Thanks to everyone that responded with ideas and suggestions!
 
The gotek is capable of being configured for many different types of computer. It's possible there is some jumper that controls the behaviour of the side select line? Or the thing has a jacked up configuration in the firmware on it
 
Back
Top