[Info-vax] VAX vs. MV/8000 [was Re: Hard links on VMS ODS5 disks]

[terry-...@glaver.org]

On Tuesday, August 22, 2023 at 10:16:51 PM UTC-4, Arne Vajhøj wrote:
> So you say that the Eclipse MV was "Eclipse compatible" instead 
> of having "Eclipse compatibility mode"? 

"NO mode bit!!!"

The hardware isn't as simple as Nova -> Eclipse -> Eclipse MV. The Nova 4 used an AMD 29xx bit-slice implementation very similar to the Eclipse S/140 hardware. Early Novas were hardwired logic. Later Novas and older Eclipsen were 181-based. The S/140 and later used a variety of implementations. Eclipse CPUs came in a variety of flavors. The original S-series, the C-series commercial machines, and the M-series with only one model (600) which was an attempt to market a maxed-out system dedicated to running AOS. There are a bunch of oddball internal differences that nobody but operating system programmers would care about between the S-series CPUs. I know about them because back in the day I created the "Frankenclipse" which was a S/230-class processor built out of a S/200. It passed all S/230 diagnostics (including EMORTL) if the hardware was slowed down, but would no longer pass the S/100 diagnostics. 64 interactive terminals on a 16-bit CPU.

DG wasn't quite as extravagant as DEC was when creating multiple operating systems and language implementations. But they had RTOS (magtape or core-resident), DOS (primitive), RDOS (very common), AOS (incompatible with RTOS/RDOS but gained in popularity) and AOS/VS (32-bit). They had an extended BASIC (XBASIC) and later on a commercial BASIC (CBASIC) which weren't really compatible. I think CBASIC was bought in from outside, but I never worked on it and didn't see the source code, so I can't say for sure.