So I have been (again) trying to properly archive old MS OS/2 SDKs. The version 1.02 SDK from December 1987 (corresponding to OS/2 1.0) turned out to be a bit of a poser.
The SDK came on both 3.5″ and 5.25″ media (unlike the older 1.00 and 1.01 SDKs, which as far as I can tell only existed on 5.25″ media). My Kryoflux tells me that the Install floppies were modified in both the 3.5″ and 5.25″ disk sets. Now, it’s very common for OS/2 install disks to be modified, because the installer writes an INSTALL.LOG file. But I could find no evidence of that happening.
Instead, it looked like Microsoft made some changes after mastering the disks, but exactly what those changes were is difficult to tell.
On the 5.25″ Install disk, Microsoft almost certainly updated the INSTAID.EXE file (the main installer executable). The allocation chain for INSTAID.EXE is not contiguous, which is a strong hint that it had been overwritten with a larger file. Yet the timestamp for INSTAID.EXE is the same as the other files (12/15/1987) and the entry for INSTAID.EXE is in the middle of the root directory, alphabetically sorted.
Okay, so that makes some sense. Microsoft made some last-minute installer change and had to update the already mastered disks. One might expect to find the same sort of change on both 3.5″ and 5.25″ media… but no.Continue reading