13 Jun
2001
13 Jun
'01
11:42 a.m.
Yep. Lots of elbow room. Eventually, I'll get my
KDA-50 up and all, but
for now, it's a nice MFM disk farm.
With a KDA50 a MicroVAX II should be a fairly sweet system, IF you can find
the disks. My MicroVAX III has one in it.
I would, too, if I had a 4000-class VAX. OTOH, I have
some stuff (like
COMBOARDs) that do not run on 4000-class VAXen because of timeout latency,
etc. I have recently run across a document I received from a DEC engineer
years ago where they describe what devices are not rated for use in a
VAX 4000 because the timeouts had lengthened over the years and over the
various models. I need to scan this in. We first noticed the problem
when a VAX 4000 w/TLZ04 and COMBOARD would lock up so tight that we had to
power off. Turns out the TLZ04 was starving us and the timeout recovery
mechanism that worked with MicroPDPs and uVAX-II and uVAX-III CPUs changed
enough with the VAX 4000 to cause serious wedging.
In my case the only 4000's I've got are VAXstation 4000's (VLC, 60, and 90),
but I've been wanting a nice VAX 4000 to replace my MicroVAX III. Now I'm
not so sure. If you get the document scanned in, I'd be *very* interested
in a copy.
I find _that_ to be the biggest limitation of the
uVAX-II - I have enough
MFM disks to keep my machines working, but since newer versions of VMS
don't like to fit on an RD54, I'm kinda trapped. I need the older stuff
for some reasons and I'd love to move to newer stuff for others (mostly
modern disks and communications devices).
In your case I'd recommend trying to find an ESDI controller, if you don't
already have one. Something like a WQESD/4 (my personal favorite) would
greatly increase your disk capacity. Of course it sounds as if you're
planning on eventually setting it up with a KDA50.
I have a BA123 that I'm currently setting up as a
uVAX-II because that's
my "biggest" Qbus machine. I expect to recycle its BA23 with a KDF11
CPU because that's my biggest Qbus PDP-11. Nobody has thrown a newer
VAX or MicroPDP my way yet (except for the Pro380/Console I rescued from
work when we dumped the VAX 8530 8 years ago).
My biggest VAX size-wise is my MicroVAX III, it's in a large 3rd Party rack
mount with two RA7x boxes (one has two RA72's the other two RA73's). It
also can have hooked up a pair of RL01's and a pair of RL02's. The downside
is it's currently in the back of my storage unit until I get a house. When
I was running it, it was my PDP-11 Archival system. My longrange plan for
it is to add SCSI and throw on a SCSI 9-Track I've got if possible (had to
give away my TU-81+ thanks to a serious lack of space). I'd planned on
upgrading this system to a VAX 4000 series machine when I got the chance,
now you've got me wondering if a RLV12 will work in a VAX 4000.
Zane