25 Nov
2009
25 Nov
'09
1:36 p.m.
On 11/25/09, allison <ajp166 at verizon.net> wrote:
Right. It's just a bunch of ROMs and clock chips pretending to be a
PR8E-like papertape reader.
I should probably make a post there about my new-to-me VT78. It
checks out so far, but I don't have a copy of OS/78 to do anything
"fun" on it yet. I was hoping someone here would respond to my query
about what's out there for the MR78
The MR78 was only used for the booter. I believe there were at least two booters, RX01, RX02.
I've found reference for those as well as a mention of a diagnostic
ROM set. I would like to be able to put together a box with 4x or 8x
the normal ROM, use modern ROMs and burn all known booters rather than
hack on my one-and-only MR78. Fortunately, it hangs off of a DB25, so
it should be trivial to redesign and build in the same space.
OS/78 you need to find it on the net, then copy to
RX01
formatted 8" floppy.
I've seen OS/278 from the DECUS collection. I must not be looking
into the right places for OS/78. Writing the RX01 floppy is no big
deal - with what I have sitting around the house, the shortest path is
probably to throw an RXV11 or RXV12 into a Qbus box and use vtserver
to move the disk image. The second shortest path would be to get
around to assembling a 34-to-50-pin cable and using an old PC to write
the image. Fortunately, I have multiple 8" drives and several boxes
of still-in-the-shrinkwrap 8" disks, most (but not all) already
formatted in IBM 3740 format.
-ethan