Paul Weissmann's OpenPA, the invaluable archive on anything related to the HP's PA-RISC architecture, devices, and operating systems, has branched off for a bit and started collecting information on RISC laptops.

Technical computing in the 1990s was mostly done on RISC workstations with Unix operating systems and specialized applications. For mobile use cases, some of the popular RISC vendors built RISC Laptops for mobile Unix use in the 1990s.

Often based on contemporary Unix workstations, these RISC laptops were often marketed for government and military uses such as command, technical analysis and surveillance.

↫ Paul Weissmann at OpenPA

OpenPA has always had content beyond just PA-RISC (like HP's Itanium machines), so this is not entirely surprising, and it also happens to be something that's sorely needed - there's remarkably little consolidated information to be found on these RISC laptops, and it's usually scattered all over the place and difficult to find. They were expensive and rare when they were new, and they're even rarer and often more expensive today.

What we're talking about here are laptops with PA-RISC, SPARC, (non-Apple) PowerPC, and Alpha processors, running some variant of UNIX, like HP-UX, SunOS/Solaris, AIX, and even Windows NT. A particularly interesting listing at the moment is the Hitachi 3050RX/100C, a laptop based on the Hitachi PA/50L PA-RISC processor that ran something called HI-UX/WE2, a UNIX from Hitachi I can't find much information about.

The most desirable laptop listed is the amazing Tadpole Viper, which was the most powerful SPARC laptop Tadpole ever made, and I'm pretty sure it's the most powerful SPARC laptop, period. It was powered by a 1.2Ghz UltraSPARC IIIi processor, and was also sold as the Sun Ultra 3, in 2005. I would perform some seriously questionable acts to get my hands on one of these, but they're most likely virtually impossible to find.

Anyone who can help Weissmann find more information - feel free to do so.