This is a new solution for booting OS/2 from multiboot compliant bootloaders. It can be compared with another OS/2 booting technologies, like memdisk by Veit Kannegieser (used by eComStation boot CD's) or memfiles in OS/2 kernel developed by OS/4 team. The FreeLDR first pre-loads a number of files to memory, as multiboot modules, then these files are served to os2ldr and os2krnl. They are loaded on-demand from there to their final position.

This way of OS/2 booting is somewhat difficult to configure and requires still many manual steps to configure so far (it can be automated by scripts, in future). But this way has some advantages. For example, it is universal and works for any filesystem supported by FreeLDR (or other multiboot compliant bootloader). The files which are usually loaded by uFSD and mFSD (os2ldr, os2ldr.msg, os2logo, os2dbcs, os2dbcs.fnt, os2ldr.ini, all BASEDEV drivers, initial IFS, a dozen of initial DLL's) are pre-loaded as multiboot modules (so, the bootloader creates a memdisk-like structure, but with no filesystem). Then these files can be retrieved from in-memory structure to their final positions.

1. This can be used with any filesystem supported by FreeLDR (or any other multiboot-compliant bootloader, like GRUB).
2. Multiple OSes can be loaded from each filesystem, no need in separate partitions
3. No existing IFS drivers modification is needed. Our approach can be potentially used with any IFS.
4. OS/2 can be booted from a CD using no emulation boot, no memdisk or floppy image in memory is needed.
5. OS/2 can be loaded from SCSI (Currently, bootjfs in eComStation can only load from IDE/SATA drives, int 13 without extensions is not supported by bootjfs)
6. It gets a drive letter from DLA tables, unlike bootjfs, which has a drive letter hardcoded in its bootblock.
7. Booting from flash disks can be automated. OS/2 can load from PRM flash sticks only by using danidasd,dmd DASD manager by Daniela Engert. Other DASD managers cannot assign a drive letter to a PRM removable and the user gets a famous “OS/2 is unable to operate your hard disk…” message. A danidasd disadvantage is that a drive letter must be hardcoded in config.sys in danidasd command line and the user must each time correct the drive letter with each machine he tries to boot flash disk on. Our OS/2 booter has a special feature to autodetect the drive letter.
8. OS/2 can now booted with IFSes which have not previously been to be bootable ones. We have successfully tried to boot OS/2 from FAT32 and VFAT.
9. It can boot OS/2 with no regard of I13X flag set in MBR – it can set this flag itself.

1. The OS/2 booter cannot be used with FAT filesystem. It can be only used with installable file systems, not in-kernel FAT driver.
2. It can be more difficult to configure by inexperienced user.

• OS/2 booter configuration
• Technical details