Runtime error on PC DOS 3.3 with 8088MPH

[Elendilon]

As discussed on vogons, here is a .vhd with the PC DOS 3.3 that causes an error with 8088mph. The demo is located at c:\demos\8088mph (but also occurs if you mount either of the included 8088mph floppy images).

8088 - 20MB ST-225 IBM PC DOS 3.3.zip

Note that this is not specifically being posted as a bug with MartyPC as it happens on real hardware - though there may be some not completely accurate thing as the error code given is different between real hardware and MartyPC.

On my actual machine I get:
Runtime error 002 at 0000:297.

On MartyPC I get:
Runtime error 003 at 0000:297.

The DOS on the machine reports its ver as:
IBM Personal Computer DOS Version 3.30

This is reported to me to be a period install - the guy I bought the computer from was the second owner and did not install the OS himself. He got it from the original owner, who had it sitting around for 20 years in storage and then replaced a memory chip to get it functioning. I do not have the DOS install disks so I can't check those.

The VHD is not a sector dump of the original hard drive because I was lazy. I used a picomem to copy the full file contents of the hard drive to a usb stick, and then created a vhd in pcem and copied them into that. I then sys-ed the vhd (in pcem) with a mounted floppy image of a disk I had sys-ed on the real pc.

[MobyGamer]

Hi, one of the 8088 MPH authors here. Turbo Pascal's runtime errors 0-99 are passed through from DOS, so error 2 on the actual machine translates to "File Not Found", and error 3 in MartyPC is "Path Not Found".

Do these errors occur if you place all of the demo files in C:\8088MPH? It's possible I didn't allow enough path/string space in the loader.

[Elendilon]

You guys (the 8088MPH authors) are really responsive!

Sorry, I should have linked the vogons thread I had referenced for more details:
https://www.vogons.org/viewtopic.php?p=1341526#p1341526

I have indeed tried running from C:\8088MPH, because I read (on pouet or a blog somewhere maybe? I don't remember exactly where sorry) that there was a fallback for that location when it failed to use some dos directory listing api. It displays the same error message regardless of the location though. I have also tried running it from a floppy, both on the real machine and on MartyPC.

The common denominator is the dos version. When I boot from a MSDOS 5.0 floppy on the real machine then the demo runs fine (including from the C:\DEMOS\8088MPH location). When booting MartyPC from the included HDD image, or any of the included boot images, or my own dumped MSDOS 5.0 image, it also works fine.

So this is more of a curiosity at this point; why does the DOS version (included on the VHD linked above), which reports itself as PC DOS 3.3, cause an issue?

[MobyGamer]

No idea. We had an issue with DOS 2.x which turned out to be a bug in the TP system unit. Should have worked in 3.3...