dan@rna.UUCP (10/25/83)
Well these aren't rumors, and sorry to bother you if you know this stuff but... From DEC sales brochures... MicroVAX I: - two quad height Qbus boards which apparently use the new Q22 block-mode memory transfer protocol and (is wasn't clear) may require a C-D type Qbus backplane. - implements a proper subset of the VAX instruction set, missing PDP-11 compatibility mode, decimal arithmetic, certain string, D and H floating point and a few other instructions. The string move instructions MOVC3/5 are implemented. There is a vague statement that implies that missing instructions may be included by choice of the user (presumably some limited amount of WCS left). I am not very familiar with the code output of the UNIX VAX C compiler, can anyone comment on the effect of these missing instructions on the porting of UNIX to the MicroVAX I ? (DEC will provide it as MicroVAX ULTRIX). - in the same performance class as the 11/730 and 11/44. - pricing for a MicroVAX I system similar to the MicroPDP11 is $20000 (same disk and floppy), and $10000 without disks. This implies that a board alone is about $7000. VAX 11/725: - as someone else said, it is a re-packaged 11/730 with a 52 Mb disk (half fixed, half removable), with Unibus (4 free slots). - designed to work in an office environment - smaller, quiet and cool. - base price system with 52Mb disk and 1Mb memory - $25000. - first ship - 11/83, volume - Q3/FY84 I hope this helps... Dan Ts'o ...cmcl2!rna!dan
guy@rlgvax.UUCP (Guy Harris) (10/27/83)
- implements a proper subset of the VAX instruction set,
missing PDP-11 compatibility mode, decimal arithmetic, certain string,
D and H floating point and a few other instructions. The string move
instructions MOVC3/5 are implemented. ... can anyone comment on the
effect of these missing instructions on the porting of UNIX to the
MicroVAX I ? (DEC will provide it as MicroVAX ULTRIX).
The VAX-11 PCC doesn't generate PDP-11 instructions (obviously), decimal
arithmetic, or H floating point. It uses D floating point because of
the way C does floating point calculations (everything in double precision).
(That was *D* and H? I would have suspected G and H, myself, as I don't
know whether DEC Fortran can be told not to generate any double-precision
instructions, and because I suspect D and F floating point share more than
F and G do.) It does generate movc instructions for structure copies/calls/
returns.
Furthermore, the kernel does make use of a number of other string instructions
which are either in the assembly language support or are put in there by
"sed" scripts massaging compiled C code. I suspect that there may not be
too many problems, as VMS probably also uses a lot of those instructions.
The subset was probably designed around VMS and those VMS programs they
expected to run on the MicroVAX. Then again, they could all be #ifdefed
out if the kernel was built to support a MicroVAX.
Guy Harris
{seismo,mcnc,brl-bmd,allegra}!rlgvax!guy