Published by mgreene on 05/21/2008 – 00:00
My OS/2-eCS boot process notes using Bootable JFS.
My main point of curiosity is the operation of the os2ldr file and I found that it is hard to get far without understanding the steps getting to executing os2ldr. The point leading up to os2ldr is considered the “Black Box” because there are a number of ways to boot eCS-OS/2 for example FAT, IFS, or Remote IPL. The major issue is that the “Black Box” sets up the system and provides all information os2ldr requires.
Just for by own interest I pulled the MBR from my eCS 2.0 RC4 driving using DFSee and disassembled. What follows is the result and some comments from noted sources. Since I am not very good at reading decompiled code I went to the next level, trying to step through the boot using a MBR, BPB and os2boot running in Bochs on my one of my Linux systems.
I found an old 630 meg IDE hard drive and installed in the system. The system was booted using the current eCS 2.0 RC4 CD. I then ran LVM and made bootable compatible partition and wrote the MBR. Next, I did a long JFS format of the partition and then ran sysinstx.com against it to get os2boot installed. I did forget to set the partition active, but later corrected using DFSee. The hard drive was pulled and install in my LINUX system and I used dd to image the drive.
This image will boot through the running of os2boot, but will quit due to the lack of an os2ldr file. That will come later. So if anyone is interested the image can be downloaded here: harddrive.zip When setting up in Bochs the correct drive settings are 1240 cyl 16 heads 63 sectors. Here is a quick howto in getting started with Bochs.
This is a work in progress, subject to change daily. It is for my own information and if it helps or be an interest others then that would be a bonus.
Changes
21 May 2008:
I updated my Bochs image with the UNI os2ldr and os2krnl from the eCS RC4. These are not the latest but I can trace from boot through os2ldr. The file is 1.6 meg and unzips to 630 Meg and can be downloaded here: newdrive.zip.
Note!!! download DFSee iso and boot it as the CDROM to set the hard drive image active if it will not boot.