Jazz was the codename under which this family of systems was originally developed by Microsoft before it was sold off to MIPS Computer Systems, Inc. MIPS, Toshiba, Acer and various customers and licenses have developed a variety of architecturally very similar systems.
Most of these systems were running the ARC firmware and [NT]. Some systems made by MIPS were reconfigurable to big endian; in big endian mode a different set of firmware and some UNIX flavor such as RISC/OS in case of MIPS was being used.
Olivetti M700-10, MIPS Magnum 4000 and MIPS Millenium are based on the NCR 53C90.
All Jazz family systems come with an ARC firmware.
Linux/MIPS supports the Olivetti M700-10 almost since birth. Support is supposed to be stable in 2.2 and in various stages of bitrot after that. As of Linux 2.6 resurrection of support is being worked on. Not test results on other Jazz family systems are available.