Hardware wise the Infoserver 150 is a MicroVAX 3100 Model 10. Software wise I never got any real chance to hack mine and ATM it's in my storage room along with a VXT1200 X-terminal, which was the reason the 150 existed in the first place - one of the popular DEC bundles of the day was an infoserver and 5 VXTs. The software uses the Local Area Disk protocol (LAD/LAST) for disk services which requires a client to be running on a VAX somewhere (SYS$MANAGER:ESS$STARTUP.COM). VXTs could boot using IP/BOOTP/TFTP. There must be more than just ROM changes to the hardware though. I used to think that the whole reason the 150 came about in the first place was that Digital had a small mountain of 3100/10s lying around so they did their usual trick of using old hardware for new tricks (viz: RL02s as console media for bigger VAXen (6xxx?), PRO380s as consoles for 8xxx's etc). The 150 was superceded by the Infoserver 1000, which was smaller than the RRD42s that it controlled.