The interesting NABU was IMHO not these, but the NABU 1200. An early 8086 Unix machine. I got one at a garage sale in 1993 or so. It worked, and the Microsoft Xenix 1.0 was a direct port of V7 Unix from Bell Labs and quite educational in this respect precisely because it was still simple and understandable, compared to to the work station OS's of the time.<p>Proprietary no-source OS's were still common then, so binary patching the kernel to put in a different hard disk parameter table (to use a luxuriously large 20MB drive in place of the ST412 the machine came with - precious! Must not mess with the irreplaceable original OS image) was undaunting, especially with a .h file handy that gave the structure. Compiling "elvis" to get vi in the absolutely stripped down Minix mode, that used 63Kbytes of the maximum 64K of code space that executables could use... fun times. Of course back then you still had a hope of compiling current C with ancient pre-ANSI K&R C compiler. Most stuff that I ran on the machine didn't need much porting.