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MEMDISK can boot (some) ISO's now.

Posted: Tue Aug 04, 2009 4:51 am
by Icecube
MEMDISK can boot (some) ISO's now, just like Grub4Dos.

The following code (new preferred syslinux syntax):

Code: Select all

LINUX /boot/syslinux/memdisk
APPEND iso raw
INITRD /g4u.iso
does the same as:

Code: Select all

KERNEL memdisk
APPEND iso raw initrd=/g4u.iso
(raw is needed on the append line for G4U on some PCs, raw is not needed for most other iso's)

G4U, Offline NT Password and Recovey Tool and DBAN will be booted with ISO emulation in the next release of UBCD.

Edit on 20 November 2009: The PLoP iso (floppy emulation) and Dell Diagnostics iso (hard disk emulation) work now.

The ISO is mapped to BIOS drive 0xE0 (same drive as drive (hd96) in grub4dos). If 0xE0 already exists (is your normal CD drive for example, this drive is shifted upwards (becomes 0xE1) and the emulated iso will be available as 0xE0. So if you boot several ISO's after each other (ISO's in ISO's) with MEMDISK the old CD drives will shift one BIOS drive up.

Currently only memory mapping is implemented. Direct mapping might be added in the future.

All iso's that can be booted with grub4dos iso emulation (memory mapped), can probably be booted with MEMDISK too (if you have enough ram of course). Note: not all ISO's can be booted with MEMDISK or GRUB4DOS, see ... topic=5041 for working ISO's.

The same limitations as for grub4dos iso emulation are true for memdisk iso booting.

See also: ... topic=8258

Edit on 8 June 2010:
UBCD50 and higher have the ISO booting capable MEMDISK.

Get Syslinux 3.86 or higher to get the last version:

Posted: Sun Oct 11, 2009 9:01 pm
by W3ird_N3rd
Forgive me for being a complete idiot, but what's the advantage of this over the current method? (I'm not saying it shouldn't be done, I'm just curious what this means)

Posted: Mon Oct 12, 2009 12:35 pm
by Icecube
Offline NT Password and Recovey Tool and DBAN come packed in an ISO.
In previous versions on UBCD, the needed files (kernel and initrd) where extracted and added to UBCD. When you boot those entries from the UBCD menu, they didn't look the same than when you boot the original ISO's because some help text files weren't added (in ubcd50b12 they where added). When you want to add the help text files, you have to correct the paths used in the config files for Offline NT Password and Recovey Tool and DBAN for all files (kernel, initrd, help text files). This makes it a bit difficult to easily update those programs (if you forget to change the config file, it won't work) and clutters the directory layout.
By using the ISO booting method, only one file needs to be updated, so it makes live a bit easier :D .

Posted: Mon Oct 12, 2009 4:09 pm
by W3ird_N3rd
Thanks for explaining, I understand it now. :) I'm looking forward to this being included in the UBCD. :)

Posted: Fri Nov 20, 2009 8:16 am
by Icecube
Uploaded a new MEMDISK version (from Syslinux 3.84-pre4 + 2 patches):

The PLoP iso (floppy emulation) and Dell Diagnostics iso (hard disk emulation) work now.