Yeah, I'm to blame. I knew that the DosBox FAT file writing code was less than perfect. For the most part, reading works just fine, its the writing and file modification thats hard. I didn't know how often this actual feature would be used, but now that I know there's demand for it, I'll pick it back up. Thanks for letting me know! 😀

canadacow wrote:

I didn't know how often this actual feature would be used, but now that I know there's demand for it, I'll pick it back up. Thanks for letting me know! 😀

Thanks 😀. Most of people of course use DOSBOX's emulated DOS, but there are reports from time to time on VOGONs about people using disc images/booting normal DOS. There are certainly some games which would not be runnable without it ...
I think also that this feature takes DOSBOX a bit further (emulating the whole computer...). There will be always some things which will be impossible to do in emulated DOS without disc images (e.g. low level disc access) or which will be thought as less important by developers.
If you need any things tested in future in this area (booting/disc images), just let me know.
BTW: I now remember two more problems:
- after using FDISK from MS DOS 5, creating partition, it ask to reboot after pressing a key. When the key is pressed DOSBOX end up with an error (I do not remember now the precise error - -I think some CPU error...). It is not fatal, just nuisance.
- formatting: I use MS DOS 5, which works fine. But I remember that some months ago I was using some other DOS version (?6.2 I do not remember now) and formatting did not work there.
I am a bit vague with these two bugs, because I did not expect to report them now. But seeing that you decided to restart the development ...

I will do more testing in future.

Mirek

@CANADACOW: I just want to ask how it goes on... If you check other forums, you probably noticed that there are occasionaly some questions about booting/images, so this feature is definitely being used (just a moment ago I wrote there in one thread a short explanation how to use HD images).
There are also supposedly problems with *some* booting images ( "imgmount" - yes, "boot" - no...). I did not test this yet (I usually work with my one MS DOS 5 image which worked for me almost ok since the beginning).

Mirek

canadacow told me that he fixed fat writing.
he will probably commit it once he is certain about it.

Thanks... I do not want to hammer, I can wait till it is finished.... I just posted the previous mail as a reminder of existing continual interest in this feature ...

Repairing copying between DOSBOX shell and HD images will greatly improve the usability (till now it was necessary to put larger things there by DiskExplorer).

Other ideas for future: access to CD ROM, access to mounted directories when another version of DOS is booted (I think CANADACOW talked some time ago about using "network redirector" or something like that).

Mirek

Ok. I've committed the fix to the CVS. Mind you it required only a single file to change (drive_fat.cpp) so if you just update that one you should be good to go. Still no DOS error codes... I plan to get those over the long Thanksgiving weekend. Take care everyone!

The repair seems to work almost ok, but nevertheless I got once into situation where the image file length was increased. I had 100 MB disc with the original file size 104 767 488 bytes, after one day of playing with images it has 105 282 560 Bytes. I do not know when it precisely happened and what caused it. 🙁
The disc image seems to work otherwise still ok.
At the end of the image file there are some binary data (I do not know whether it is a file or just some rubbish).

I wonder - how it can come to a situation when image file size is increased? IMHO whatever the situation is, FAT writing should never increase an image file size...
It should be probably possible to track down some situation in FAT writing code when (perhaps because of unexpected input) FAT writing wrongly increases image size (probably by writing at the end).
As I said - the image still works ok, but seeing that, I am afraid that sooner or later it could be corrupted by this bug ...

Mirek

There is some confusion with disc sizes in BXIMAGE and DOSBOX (which perhaps explains the bug mentioned above):

1. I created 100 MB disc by BXIMAGE.EXE
...
Enter the hard disk size in megabytes, between 1 and 32255
[10] 100
I will create a hard disk image with
cyl=203
heads=16
sectors per track=63
total sectors=204624
total size=99.91 megabytes
...
The file size was 104 767 488 Byte

2. I mounted it with these parameters in DOSBOX:
-size 512,63,16,203

3. I FDISKed and FORMAted:
Formatting 100.37M
...
105,027,584 bytes total disc space

??????!!!!????
The disc space is bigger than the image file in which it is stored... Either BXIMAGE or DOSBOX cannot count ...

Mirek

I think dosbox has not included overhead counts like FAT, and maximum
number of root entries. Then again in could be the old 1024 vs 1000 bytes
rounding.

canadacow wrote:

Still no DOS error codes... I plan to get those over the long Thanksgiving weekend. Take care everyone!

Any news about this? Or about that BXIMAGE/DOSBOX size problems as described above?

Mirek