BSD/OS 2.0 for Intel, published by Berkeley Software Design Incorporated.

2 ISO9660 CD-ROM images, install may/may not be bootable from CD.  Boot floppy images are in the root of the binary install ISO. The system uses old-style UFS so it won't cleanly work with drive sizes over 4GB or so.

The source ISO is corrupted beyond repair, this is a fault of the original disc.  In my favorites, there will be another upload of BSD/386 2.0 which has the source code available if you need it or want to peruse it.

(if the installer asks for a serial, enter fc+j =VEa +L7m for 64 users)