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In article <5dnto7$ijl@nnrp1.news.primenet.com>, jason@primenet.com says...

>According to Ryan's MIPS page, Carrera offers a "Magnum" card for $315 and
>a "Jaguar" for $600+  Anyone know the differences / specs of each?

First a little history.

The secret, I guess, regarding the Magnum was that the MIPS/SGI Magnum 4000PC/SC systems were originally designed by engineers at Microsoft. The design was later purchased by MIPS Computer Systems (before their merger with SGI). It was chosen over an internal R4000-based workstation design that was well along at the time. The decision was based mostly on the fact that Microsoft had already done the NT driver support for their design (code named Jazz) and MIPS didn't wish to invest the resources necessary to write the necessary HAL and drivers for their internal design if there was already an R4000 design around at Microsoft. It also didn't help that the internal workstation design used the DEC Turbochannel expansion bus rather than the EISA bus used in Jazz and was something like six months later than than the Microsoft design.

The decision to scrap the internal design was an agonizing one for all involved. Until the R4000, all other MIPS processors had been brought up on internally designed MIPS systems. The R4000 turned out to be the first (and last) to be initially powered on with systems designed out-of-house. The internal workstation design was originally intended to be the bring-up vehicle for the R4000 (the project was code named Aftershock -- after several smaller Silicon Valley earthquakes that occured in the years before the 1989 Loma Prieta earthquake). Unfortunately, the design team, in retrospect, picked the wrong expansion bus and was later to the finish line than the lean-and-mean (and not thinking about high-volume) Microsoft team.

Once the design was purchased from Microsoft, a number of logic and mechanical changes were made to make the design volume shippable. (The original design was intended to be a low-volume platform for internal code developement only.) The only significant architectural change was to completely redesign the audio subsystem (that was my job :-). The only other significant change was to tweak the ASIC set in order to support the R4000SC with secondary cache (the original Microsoft design only supported the R4000PC). All other changes were minor component changes, a relayout of the board, and significant changes to the mechanical design.

With the design rights owned by MIPS, RISC/os was ported to the machine running in big-endian mode. The Magnum is the only machine ever built to my knowledge that was truly bi-endian. Indeed the two OSes supported used different endiannesses. The machine, on power-up, was little-endian. If the boot PROM was detected to be RISC/os, the machine reset itself and switched to big-endian. If it detected a little-endian NT ARC prom, it remained in little-endian and simply jumped to the PROM code.

Essentially, Windows NT was written on MIPS R4000 machines (no surprise here -- this has been somewhat general knowledge). What wasn't generally known was that the R4000 hardware on which the code development was done was designed by Microsoft themselves and not MIPS. Later, after the Magnum was shipped, Microsoft bought many of them to replace their then aging original Jazz hardware.

Surprisingly, I believe that until NEC and later NeTPower designd MP R4000MC systems, virtually all MIPS-based NT machines derived from this original Microsoft design. This included machines from MIPS, NEC, Olivetti and Carrera. The only single-processor design which booted NT I know of not derived from the original Microsoft design was Deskstation...

Now on to the question at hand:

The standard Magnum card was a tweaked version of the original Microsoft design (the RAMDAC was changed, for example, to a Brooktree part). It has a fixed resolution of 1280x1024x8bit at a refresh rate of 60Hz. It is supported by both UNIX (RISC/os, NetBSD, Linux) and NT. The Magnum connector is a 13W3 style (a la Sun). It will, obviously, work with multisync monitors but it does have a fixed sync and was able to drive older fixed sync SONY monitors.

Like the Magnum itself, the Jaguar card was designed by engineers at Microsoft but later licensed to Carrera (there may have been others). It has a proprietary ASIC which is capable of doing some 2D acceleration and bitblt. It is significantly faster than the standard Magnum card if only because the Magnum card was a simple frame-buffer.

To most users, the major advantage of the Jaguar card is that it supports a variety of resolutions and refresh rates between VGA (640x480) and 1280x1024. My Jaguar card, sporting the fastest RAMDAC speedgrade available, is running at 70Hz@1280x1024x8bit. The card would hold up to 4MB of video RAM, but unfortunately wasn't capable of doing 24/32-bit color at 1280x1024.

The card has a standard VGA video connector rather than the more expensive and less standard 13W3 connector of the Magnum.

As far as I know, the only OS which supports the Jaguar is Windows NT. It is supported out-of-the-box on the standard NT4.0 distribution just as the Magnum video card is.