my Data General Nova 4/X RDOS installation...

From: Tom Jennings <>
Date: Fri Feb 25 18:38:45 2005

Just a few notes to tell what happened last night, putting a disk
OS on for the first time.

First, I powered the machine on a full two hours before I used it.
No tape problems this time! Though, the servos seem to drift a
lot. The tape loop in the column is supposed to ride at the
center mark, but it starts out far too shallow, and gets deeper as
it warms up. I doubt this is normal. It's very smooth and
predictable, and seems stable when power is on for 4+ hours.

With the machine came a few OS tapes, including RDOS 6.60 (fairly
old), so I booted that. Followed SOP (see, new) basically it came up without

The 6070 disk drive is a top loader -- one platter in a large
removable cartridge (10MB), another fixed in the drive. I'll take
photos this weekend. There are four heads on a single voicecoil
drive. The drives are DP0 and DP0F (Disk Pack 0 (zero), F=fixed).
Typically you boot from the removable.

A bootstrap and a "starter" RDOS system is written on the disk,
the starter having enough drivers to support the hardware.
Utilities (editor, assembler, etc) are loaded from the distro
tape. One of the utilities is SYSGEN, the system generation

SYSGEN didn't work for me, most of the way through it stopped
early, then complained of missing library files. The filenames
imply some operator error (eg. looking for MRDOSA.LB, missing, but
there's ARDOSA.LB, ZRDOSA.LB, ...), presumably this is solvable.

In the mean time I can run just fine with BOOTSYS.SV, the starter
system. I hope the tuned one runs faster than this one does! I
should borrow a camcorder, mike the disk, maybe that would help
convey the Model-T-ness of it all. Though it's 1980, RDOS started
long before that, and though it's a reasonably modern internal
paradigm, the user interface (CLI) and hardware speed with the
starter system is pretty slow, on par with my CP/M-80 dual-floppy
system, subjectively. Of course this thing has real hardware with
data-channel (DMA) and big software, can be tuned, etc.

This weekend I'm going to load up one of the platters with some of
the random-seeming tapes and see what's on them.

For the record: I realize this wasn't a heroic restoration; it was
actually fairly easy. I haven't had to replace a single bad chip
(so far...), it came with it's own manuals and tapes, and though
the disk platter transplant was rather extreme, the problem [head
crash] ws basically caused by me being an idiot. The PDP-1
restore, that's Real work! The tape drive did require actual
hardware debuggery and rebuilding those vacuum switches, but even
that was pretty straightforward.
Received on Fri Feb 25 2005 - 18:38:45 GMT

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