Odd bug with RPCEmu, or ADFS???

[geraldholdsworth]

Here is an odd bug I've found, while running some tests with Disc Image Manager. At first I thought I had a bug in my application, so I created an ADFS E disc image (reformatted it) and copied the same file onto the image, using my RPCEmu (Recompiler, 0.9.3 on macOS) running RISC OS 5.28. But, I got the same result. I even then tried again, and created from scratch an ADFS E image, and copied the same file onto (with RPCEmu). Same result.

The problem does not occur when you copy the file onto the image, but rather when you copy the file off the floppy image onto a directory in HostFS. I've been getting Abort on Data Transfer errors, then when I try and do anything get a Filecore in Use error, and even got, a couple of times, a Bad Mode 20 from RPCEmu itself, before it closed down. The worst I got was the entire screen displaying green garbage, which the only way out was to close down RPCEmu.

I've checked the macOS folders I'm using for HostFS have the appropriate permissions - I even set 'Staff' and 'Everyone' to Read and Write (and on enclosed items), just in case.

I've attached the three images, plus the file I have been using (which is a PNG image, not that it should matter as we are just copying the file from one place to another).

[paintings]

I'm seeing the same on RISC OS 5.28 (RPCEmu-Recompiler, v0.9.3a, macOS Catalina). Running the same test on RISC OS 3.71 works.

When I try RPCEmu-Interpreter, the test works on RISC OS 5.28. I think this indicates it's an RPCEmu bug, albeit an easy one to sidestep.

Incidentally, I noticed another problem with RPCEmu-Recompiler. When you use Configure to increase the number of floppy discs, the floppy disc icon does not appear on the icon bar - you have to shut down and restart RPCEmu. With RPCEmu-Interpreter, the floppy disc icon appears as soon as you click on "Set" and acknowledge the warning message.

[geraldholdsworth]

That's funny - I tried with Interpreter, after I'd posted this, and that crashed also. I'll dig out my Windows laptop later on and try that. But I don't think it's worth a bug report...different if it happened to all files being copied off a floppy.

[paintings]

That's funny - I tried with Interpreter, after I'd posted this, and that crashed also. I'll dig out my Windows laptop later on and try that. But I don't think it's worth a bug report...different if it happened to all files being copied off a floppy.

I only tried RPCEmu-Interpreter with one of the .adf images to begin with, so I went back and tried all 3 disc images. Results were as follows:

Image 1: Test (written by ADFS) - File copy worked
Image 2: Test (written by DIM) - "Abort on data transfer" from RISC OS
Image 3: Test 2 (written by ADFS) - "Bad mode 20" from RPCEmu

I re-ran the test a few more times with the first (previously-working) .adf image and now that has started to fail as well. I suspect that the emulator is reading from uninitialised memory and the success/fail depends on the memory contents.

[geraldholdsworth]

I've found that this happens with other files too. Not particularly big ones either.

Just done a few tests, copying files of varying lengths onto an ADFS F image, then copying back to another directory. Only the smallest of the files (about 1000 bytes) copied OK. The others crashed the system, in different ways.

But, works OK with the same RPCEmu install but running 4.39 (as pointed out above, with an earlier OS).

Might try upgrading RISC OS to the latest daily build to see if that still does it.

EDIT: RISC OS 5.29, from last night, still crashes.

[sirbod]

I’d suggest testing on tin and then reporting on either the ROOL RPCEmu or Bugs forum as appropriate, as it’s only occurring under RO5.