[syslinux] Possible memdisk issue

Ady ady-sf at hotmail.com
Tue Jul 8 11:26:15 PDT 2014


> I'm having trouble getting memdisk 6.03pre18 to boot large floppies and 
> wondering whether I'm doing something incorrectly.
> 
> 1) Download http://www.fdos.org/bootdisks/autogen/FDOEM.144.gz
> 2) gunzip FDOEM.144.gz
> 3) newmkfloppyimg.sh 8 FDOEM144.img fdoem_8mb.img
> 4) newmkfloppyimg.sh 9 FDOEM144.img fdoem_9mb.img
> 5) Use following pxelinux.cfg:
> 
> LABEL works
> LINUX syslinux/memdisk
> INITRD fdoem_8mb.img
> APPEND floppy pause
> 
> LABEL infinite_memdisk_loop
> LINUX syslinux/memdisk
> INITRD fdoem_9mb.img
> APPEND floppy pause
> 
> With the latter, after memdisk asks me to press a key, boot sector code 
> execution seems to start (I do get "FreeDOS" on the screen), but then 
> somehow memdisk takes over again and starts over from scratch, so I get 
> this loop:
> 
> MEMDISK 6.03 6.03-pre18  Copyright 2001-2014 H. Peter Anvin et al
> e820: 0000000000000000 [snip]
> [...]
> Loading boot sector... press any key to boot... booting...
> FreeDOSMEMDISK 6.03 6.03-pre18  Copyright 2001-2014 H. Peter Anvin et al
> e820: 0000000000000000 [snip]
> [...]
> Loading boot sector... press any key to boot... booting...
> FreeDOSMEMDISK 6.03 6.03-pre18  Copyright 2001-2014 H. Peter Anvin et al
> e820: 0000000000000000 [snip]
> [...]
> 
> I can provide screenshots if seeing the specific numbers would help 
> isolate the issue. If memdisk is behaving as intended and I'm supposed 
> to provide memdisk additional parameters once the floppy gets above a 
> certain size, I'd appreciate some pointers on what I should try.
> 
> Thanks,
> Alex
 
It's interesting that you ask this, because every document related to 
newmkfloppyimg.sh specifically recommends adding:

 floppy c=$CYLINDERS s=$SECTORS h=$HEADS 

to the MEMDISK arguments.

You might also want to add "raw" too.

There is a chance the resulting floppy image is not adequate anyway, 
but I have not tested it.

Regards,
Ady.


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