More information from Bob
This computer and OS was the predecessor of the IBM RS/6000. The last OS
that ran was AIX 2.2.1, and the actual AIX V3 that was released on the
RS/6000 was compiled on an RT.
The machine had many upgrades to what you list here, it had 4, and 8 MB
memory boards, an enhanced processor, then the final advanced enhanced
processor with 16MB of memory and some cache on the board. Disk options
were a 10MB, then 40MB then the final 310MB EESDI drives. The 6150 could
hold 3 drives, and the 6151 could only hold 1.
It had a 'megapel' graphics option, that allowed it to run 8 bit graphics
on the IBM 5080 display. Also available was a 5081 graphics engine
adapater for CAD applications (orginally designed to run off of IBM
channel based mainframes).
Several companies also developed graphics boards for it.
In its final days there was a crude SCSI controller, and a HUGE disk drive
that you could hook up (weighed a ton).
During the early years of the internet (NSFnet) where the universities
were acting as hubs, we all had racks of RT 6151's connected together with
token ring, running AOS (it was BSD Unix). They provided the routing for
what we now call the internet.
I still have one that actually runs, has 3 310 MB drives, boots up AIX
2.2.1 (fully patched), on the 16MB AE processor, with a megapel graphics
card, and ethernet. It even has X11 R5 installed..
The RT could also run PC applications
using emulator software - not the DOS shell. Once installed the software
could be fired up by command, and offered DOS 4.0, not a lot of good, but
quick at it as it used the RISC processor not a 286 DOS board. The
limitations to this were that you could upgrade the DOS4 to later DOS5,
but the machine hung as the memory manager on DOS5 grabbed all available
memory, which hung the machine - no memory left. Also the VRM was like a
DOS BIOS, but not chip based, instead loaded onto disk before the S/W
install - from 2 x 5.25" diskettes.
Lastly the final processor was and Advanced Enhanced processor with 32MB
od onboard memory, and pretty quick it was too for it's time.
(My machine had a an IBM 5081 screen which allowed me to run X10,
About recent RISC processor usage, well the AS/400 has been using them
since 1993 ish when they went from the white cupboard size to the black
cocktail cabinet size - that was from 8 bit to 64 bit architecture in one
fail swoop. Also I remember a lot of the IBM mainframes use RISC
technology, so it's far from dead or dying. plus the PowerPC architecture
machines are the latest versions of the 6150.