21 Sep
2021
21 Sep
'21
9 a.m.
The RD53s in both Microvax 2000s are dead. I'm reluctant to buy more 30+ year old
rotating media.
If I'm going to buy a disk emulator, I'd much prefer SCSI to MFM, for the obvious
performance reasons.
Reseller price for a Maxtor XT-2190 (RD54) is just over US $1000. Disk Emulators are
significantly cheaper.
Thirty years ago I did 4.3BSD-Tahoe kernel hacking on a Vaxstation-II/RC with two RD53s.
One of the spindles was very noisy, I think from the bearing. I really like the quiet of
scsi2sd in my DECstation 5000s (and soon, Alpha 3000/500s and a /700).
One of the reasons I got the 2000s is to format MFM drives for an RQDX3 (I don't have
any PDP-11 CPUs). I have a CMD CQD-420 Qbus SCSi controller, and an MTI almost-equivalent.
I've seen Glen Slick's reverse engineering of the PLD for the CDQ-200. I hope the
newer MTI board "just works"; but if not, MFM is a fallback.
On Tuesday, September 21, 2021, 08:44:11 AM PDT, Chris Zach via cctalk <cctalk at
classiccmp.org> wrote:
He could also just fix the RD53 and boot off that, then transfer to the
much faster SCSI. I still keep the RX02's around on my pdp11 because I
can boot BRU64k for tape backups. It works. :-)
On 9/21/2021 10:39 AM, Peter Coghlan via cctalk wrote:
If you want to try other options, maybe you could put
some minimal boot
code on a MOP server and have your MV2000 boot from that over the network
before it tries to access your SCSI disk?? Or put some code on a floppy disk
and boot from that?? If you have a suitable adapter cable, you can plug a
5.25in HD floppy drive into your MV2000 provided it can be jumpered suitably
to look line an RX33.? My experience with random PC drives says some can
and some can't.? A 3.5in drive can also be used but the ROMs are expecting
an RX33 so an RX33 disk image should be written to the 3.5in floppy.
Regards,
Peter Coghlan.