On 7/19/20, emanuel stiebler <emu(a)e-bbes.com> wrote: By the early 1980s it was apparent that some of the more complicated VAX instructions weren't worth the space they took up in firmware. Especially POLY and EMOD, which turned out to be both slower and less accurate than coding them up as subroutines. And the PL/I and COBOL compilers were implementing packed decimal using decimal shadowing. Chucking out those instructions and doing them by emulation in the OS freed up enough chip real estate to allow the remaining VAX architecture to be implemented on a chip. All the later VAXen supported only the MicroVAX subset architecture in hardware/firmware. I don't recall which was the last VAX to support the whole architecture in hardware/firmware. Perhaps the VAX 8200/8300 (Scorpio)? That was a single-board implementation. It could be paired with a high-end Evans & Sutherland 3D graphics monitor. DEC tried unsuccessfully to use that combination to compete with Apollo in the workstation market, but it was too little too late. One reviewer said that coupling the E&S graphics to the VAX 8200 was like turbocharging a lawn mower. Did Unix support that configuration, or was it VMS-only? -Paul W.