14 Oct
2000
14 Oct
'00
4:27 a.m.
From: Jerome Fine <jhfine(a)idirect.com>
Actually, since I am not a VAX/VMS person, I was
thinking more along
the lines of a PDP-11 and RT-11. But since I know that a Qbus host
adapter such as a CMD 220/M (CMD) and a SQ706A (Dialog) both
function for either PDP-11 CPUs or uVAX II CPUs on any OS which
uses the MSCP interface, I guess that I am too out of touch with the
problems of what an IDE Qbus controller might have difficulty with.
The key is MSCP is not a trivial protocal and the underlying hardware
to do that requires muscle in the form of a fast cpu.
IDE is fairly stupid and easy to interface as PIO, DMA would not be that
bad for vax or PDP11 but you would pay for it by needing drivers as
there are none.
And in particular, I was sort of referring to using an
IDE Qbus
controller
with John Wilson's adaptation of the Russian
HD(X).SYS that he has
so conveniently made available in E11. There has been some discussion
about producing an IDE/SCSI version of a Qbus controller which would
be able to be a REAL Qbus PDP-11 controller with an RT-11 software
device driver identical in code to the HD(X).SYS used with the E11
I think I was part of that discussion too.
RT-11 and the overlay TSX-11 are easy compared to something like VMS.
Unix sources permitting would be doable.
Anyone out there who wants to try? I would be very
pleased to
swap some of my time for a couple of SCSI 32 GByte hard drives
to test out the software. The only problem is that the only SCSI
host adapters I have are the 50 pin type (CQD 220/M), so there
I've run my PDP11 with SCSI CQD already as it's MSCP, Same
for VAX/VMS (it's in my MVII).
It's limited to 4 or 8gb and SCSI-II so forget the reall monster drives.
might be a problem if there are no drives larger than 8
Gbytes which
have the old SCSI-2 50 pin interface. On the other hand, if
Its pretty easy to fine drives inthe 2-9gb range still and they are
cheap.
The idea of such huge drive with RT11 and friends is that is wasted.
I use D540s (31mb) and swap them like carts as I have a bunch of em
and they are plenty big enough. Drives in the 120-400MB range are
plentyful for me, one 200mb drive would take all the binaries and
sources I have with room to spare that aren't already on Tims CD.
Whats the point?
The value of IDE on Qbus is cheap easy to find drives in the sub
(at the time) 1gb class.
Allison