[syslinux] nopassany parameter causing trouble

Gene Cumm gene.cumm at gmail.com
Mon Dec 19 12:41:14 PST 2011

On Dec 19, 2011 3:07 PM, "Bernd Blaauw" <bblaauw at home.nl> wrote:
> Op 19-12-2011 4:22, Gene Cumm schreef:
>> I'd expect nopassany to hide everything except the new disk.  CD
>> drives are HDD-like and should be hidden by nopassany.
> Ouch, as they're not mounted by default by any kernel anyway but require
device driver (UIDE.SYS) and an installable filesystem driver

It could be worth noting in doc/memdisk.txt (like a footnote) that CDs are
in the HDD device range (0x80 - 0xFF) and normally 0xE0.  The issue would
be making it noticeable but not obtrusive.

>> nopassany on memdisk #1 should hide the FDD/HDD (including CD) but not
>> using nopassany in the second should make eltorito.sys pick the ISO.
>> Under this condition, I'd expect the ISO could easily be assigned
>> "C:".
> Scenario:
> 1 : boot from CD, use as LiveCD (with hidden harddisks)
> 2 : boot from CD, use as InstallCD (visible harddisks)
> 3 : boot from CD, boot ISO from CD, use as LiveCD (hidden hdds)
> 4 : boot from CD, boot ISO from CD, use as InstallCD (visible hdds)
> Your suggestion allows [3] but prevents [4] as the harddisk gets hidden
during ISO loading time. [1] is not possible as hiding harddisk also hides
CD, according to your comments.

This is achievable if you use two separate LABELs in the CD (live,
install).  With cmd.c32, you could even specify MEMDISK and the ISO once in
the config.  If MEMDISK had the command line somewhere and it could be
exposed to a COM32 (lua.c32 or something like ifmemdsknopassany.c32), this
may ease things eventually.

This would be interesting for the moment: ifmemdsk.c32 that works like
ifcpu.c32.  Look for flag and have 3 possible commands, if flag present, no
flag, no memdisk.  Probably better in lua.c32 in the end.

>> I'm guessing from the "cmdline" statements that you didn't try moving
>> the nopassany to the MEMDISK for the ISO and not the MEMDISK for the
>> FDD.
> See above. Duplicating ISO could be possible but isn't my favourite
> My last resort is relying on the DOS PCI IDE/SATA CD-driver called UIDE
by Jack R Ellis, but that's limited to PCI IDE/SATA thus instead of
ELTORITO.SYS 's controller-independent hooking into non-emulation CDs on
for example USB CD drives.


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