[HECnet] Drives for a VAX-11/730

[Johnny Billquist]

Been away a few days, so late into the game. But anyway...

On 2013-07-15 16:21, Bob Armstrong wrote:
    My 11/730 is not happy     the electronics work great and are even
fairly easy to fix, but keeping disk drives on the thing working is
proving to be a challenge.   Right now it has two RA81s and one has quit
completely (   servo fine position error   ) and the other is flaky.   The
original R80 on the RB730 had the HDA die years ago and I   ve never been
able to find a replacement.

Saw the talk about the R80. I believe that either an RA80 or RM80 could provide the bits for the R80, but finding either would be difficult today.
RA81 is probably easier to deal with, but those are also getting rare.

    I have several vintage SMD drives, including a couple of nice CDC
9715 drives, that I was thinking about using to replace the RA8x
drives.   I have not one but two UNIBUS SMD controllers     an Emulex SC21
and a Spectra Logic 121     that I thought would do the job, but after
reading the fine print yesterday that turns out not to be true.   Both
controllers emulate RH11s with RM0x drives attached, which is fine if
you   re a PDP-11 but VMS has never supported that configuration.

Right.

    [Before anybody says    Wait     RM05s are supported by VMS,    that   s only
partly true.   VMS supported MASSBUS disks on a RH750 or RH780
controller, but VMS has never supported the RH11.   Emulex actually sold
a special VMS driver for their card, but I don   t have it and besides,
VMB still wouldn   t support it.   The Spectra Logic manual only talks
about PDP-11 OSes and carefully avoids ever mentioning VMS.]

Not surprising, since the RH11 do not really fit into the world of VAXen very well.

    I   ve got some RA7x drives, but there   s no easy way to mount them or
supply power to them.   I   m not sure if there ever was a rack mount
chassis for RA7x drives.   There was for RA9x drives, but those I don   t
have.     I also have two RC25 drives and several AZTEC controllers, but
those drives were horribly unreliable even when they were new.   Neither
works, and fixing them or getting removable media for them is hopeless.

Others already mentioned the rack box for RA7x drives. Nice hardware, if you can find it. It is the same size as the RA9x drives, but fits four RA7x drives each. With RA73 drives, you'll pack a whopping 8G on each rack location. Fairly impressive for its day. You just needs plenty of controllers... :-)

    Does anybody have any other ideas?   Who else has an old UNIBUS VAX?
What are you doing to disk drives?

SCSI has already been mentioned. On the 8650 I "have", there is UDA-50 with RA92 and RA73 drives, and CI, which in the end leads to more SCSI disks....

But you can't hook CI to a 11/730 either...

    I   ve actually had the 11/730 for about fifteen years now     I restored
it out of parts from two different 730s that were scrapped.   It   s been
fairly easy to keep running except for the drives, and although it   s
admittedly a bit slow, it   s a cool machine.

It is horribly slow... :-)

	Johnny