11 Jan
2004
11 Jan
'04
4:22 p.m.
I just noticed something for the first time in my
VARM.
According to table 11.1, the MicroVAX-I supports the VAX's
PDP-11 emulation mode. The only other models that also
support this are the 11/7xx series, the 82xx, 83xx, and 86xx
systems--and they're all rather larger than a MicroVAX-I.
My VARM states, on page 378 (in Appendix B, if you have a
different version) that the uVAX I does NOT have PDP-11
compatibility mode.
Mine's the 1987 version that has Figure 11.1 but no
Table 11.1. Chapter 11 is "Architectural Subsetting".
Regardless of what any book says, I'd be stunned if
they squeezed compatibility mode into the uVAX I.
AFAIK, none of the chip-based VAXen have compatibility
mode.
Also AFAIK, only the VAX-11/7xx series includes
compatibility mode (although you need to know that
the VAX 8600 was going to be the VAX-11/790 for
this simple rule to work :-)). The VAX 8200
(Scorpio) and the VAX 8800/8700/8500/8530
(Nautilus) do NOT include compatibility mode.
Finally, if you drop the right boards into a
BA123 to make a uVAX I, it's not *much*
smaller than a VAX-11/725 :-)
Antonio
--
---------------
Antonio Carlini arcarlini(a)iee.org