b-em a little help with mmf image please

[coopzone]

Hi everyone,

i'm using b-em on linux and for the most part all is well.

I tried to load the mmfs.rom thinking it would be needed to use a beeb.mmf file, having tried all sorts and nothing worked.

eventually I tried just loading the mmfs file with the stock DFS rom (i thought it stood no chance, but it works!) So I assume the mmfs code works independently of the ROM image.

Now my problem is - how do you select what disk image is in use out of the mmfs file ?

Derek

[Coeus]

There are couple of ways to work with these in B-Em.

1. Internal MMB emulation. If you have a MMB file, i.e. the container file that has SSD disks within it, you can load it into B-Em without any extra ROMs by choosing Disk->Load MMB File. What happens then is that B-Em internally implements the disk image management commands (*DIN etc.) and, once an image is selected with *DIN, B-Em makes it look like a floppy disc, just like if you had loaded the disk with Disc->Load Disc 0/2 etc. so ordinary DFS can access the contents.

2. You can use MMFS. For that you need the version that expects the memory mapped SD-card, not the user port one. See the MMFS build structure for more info. If you go that route and load the ROM into a suitable slot you would then load an SD-card image (including the FAT fileysstem) with Disc->Load SD Card. With this approach B-Em isn't looking to the container file at all - it is emulating an SD card adapter and the MMFS ROM is doing the work. How the SD card is formatted would need to be compatible with the version of MMFS, i.e. a FAT filesystem with single BEEB.MMB file for MMFS version 1 or a FAT32 filesystem with individual .SSD and .DSD files on it for MMFS v2.

EDIT: re-reading your post I think you are using option 1 from above, B-Em's internal support for MMB files. In that case you should be able to use the same commands as if you had MMFS, i.e. *DCAT to find which disk images are available and *DIN to "insert" one.

[coopzone]

Thanks for the help.

I am trying option 1 at the moment, ie loading the mmb file directly.

I can get DIN and DOUT to work, but any other commands seem to fail, for example DCAT and DDRIVE from give Bad Command.

Is there a doc for this feature somewhere, I have looked around the github site. But that seems to be a little behind on documentation, it that it does not even mention using MMB files except in the source files.

Thanks

Derek

[Coeus]

I can get DIN and DOUT to work, but any other commands seem to fail, for example DCAT and DDRIVE from give Bad Command.

The MMB access for B-Em was originally written to enable one of the MMB games menu to run (Tricky's?) and implemented only the commands used by that menu program. There is a new branch with the full set of commands at: https://github.com/stardot/b-em/tree/sf/mmb-mzone2

There isn't any separate documentation, though now the full set of commands is implemented the document for MMFS should now be applicable.

There are a couple of quirks, though. Because this uses unmodified DFS, it can't return an immediate error for "no disk in that drive". If an MMB file is loaded this takes over one or both drives depending on the boot disks selection inside the MMB file. If there is no boot disc for a particular drive, or of both discs are removed with *DOUT on that drive, DFS will then try to access to the real floppy. You can use this to advantage in being able to *COPY between SSD files stored directly on the host and SSD disks within the MMB file.

Any other questions do let me know.