Last month I made a trivial little cable adapter PCB to use with the
Intel SBC 202 double-density M2FM floppy controller in an Intel Series
II or III MDS (normally part of an MDS 720 subsystem). The usual SBC
202 cabling has two DC37S connectors on the MDS back panel, one for
drives 0 and 1, and the other for drives 2 and 3. (There's a variant
that has a ribbon cable to the internal drive as 0, and only one DC37S
for drives 2 and 3.)
https://www.flickr.com/photos/22368471 at N04/albums/72157659736489274
Schematic and board layout in Eagle and PDF:
The adapter has no active electronics; it just wires a DC37P to a
50-pin header for a cable to one or two normal 8-inch floppies.
I just got around to testing it yesterday, and was pleasantly
surprised that my SBC 202 and the adapter worked on the first attempt.
The SBC 202 was of unknown provenance so I didn't actually have much
expectation of it working. I haven't yet tried more than one drive on
Intel used radial ready signals from the drives, so the drive(s) have
to be configured slightly differently than the factory defaults to be
fully compatible with the MDS 720.
I have one spare bare adapter PCB which can be made available for
$5.95 plus shipping from Colorado if anyone else needs such a thing. I
am NOT willing to source the connectors or assemble the boards.
You can also order them in increments of three pieces directly from OSH Park:
If there's demand for a few units, I can have a small run made in
China very inexpensively, probably under $4 each plus shipping from
Richard Main has made fancier adapter PCBs that also support 34-pin
cabling for the use of high-density 5.25 or 3.5 inch disks.
I finally fixed my H7864 PSU so I can now run my rtVAX 1000. However, I
think the machine is damaging memory boards. I checked the ripple and 5V
looks OK, but 12V looks suspicious. Is the 12V supply used by the memory?
Incidentally, as I have mentioned before, I have drawn out the schematics
for the H7864 PSU. The schematics are drawn illogically, with mistakes
almost certainly still there, but the Primary side I think is more
reasonable now. Is there a good place to post these?
> Date: Wed, 2 Dec 2015 12:40:08 +0000
> From: Rod Smallwood <rodsmallwood52 at btinternet.com>
> To: "General Discussion: On-Topic and Off-Topic Posts"
> <cctalk at classiccmp.org>
> Subject: TU-58
> Message-ID: <565EE6A8.2030004 at btinternet.com>
> Content-Type: text/plain; charset=utf-8; format=flowed
> Dear List
> While the silk screeners process the panels I have a
> couple of days for a little project
> I have a TU-58 and yes it had gooey drive wheels.
> Now it no longer has that problem but I have black and gooey fingers.!!!
> I know this issue has been addressed before.
> So I think somebody must know where I can get the right tubing to
> replace the degraded stuff.
> The drive hub is 0.42" and the rubber bit was 0.62" o/d
> A UK source would be nice,
I'm also intessted in this. I have a dual TU-58 that belongs to my VAX
11/730 that need new capstan rubber. European source...
CBM15 V012 has been released to CSDB, and is currently available for
CBM15 is a telecommunications software, that facilitates direct two-way
communications between a Commodore 64 computer and a Teletype Corp. M15KSR
(or any other compatible machine).
Note that CBM15 follows the 5/N/2 serial protocol, at a fixed line speed of
45.45 baud (22mS signalling period). As with any of these PC-to-TTY setups,
an external RS-232 to Current Loop converter is required. This is an
initial release, and upcoming releases will add new features and correct a
bug or two.
So.. am I the only one on the list(s) with a C-64 and an M15 on hand? If
you have the required hardware, please give it a try - so far, I've had no
feedback from any other 'real' M15 owner..
I used my PDP-8/e at home to test the RX8E controller and the RX01 floppies
that came with the PDP-12. Both worked OK.
We found a bad SP380 on a M7102 board in the DW8E the Omnibus expansion
chassis. This would not let the SKIP instructions work with the RX8E, RK05,
or PC8E. Once we replaced the SP380 we were able to boot OS/8 from an RX01
floppy. This may be the only PDP-12 to ever do that.
This is a funny cartoon and subsequent discussion thread from the
Multics discussion group about emacs.
Names and personal info edited out due to archival by unknown parties of
the list and that these folks might not want names and certainly not
email addresses archived. Mentioning that not as a criticism, just to
explain the format. I also edited the thread back to bottom posting.
Original XKCD cartoon link.
>> From: Multicians <snip>
>> Subject: Re: [multicians] Emacs humor
>>> Thanks, Gary. As an emacs diehart, I fully appreciate that. In
fact, there is a silly phrase that many emacs users use, when referring
to all the obscure key bindings that you get by default with emacs, or
can create. It.s called:
>>> I believe the history (someone can correct me if I.m wrong) is that
Emacs was developed at the MIT AI Lab (by Richard Stallman) and
initially written in Teco. It was developed on Lisp machines, which
sported lots of modification keys on its keyboard. These included
Control, Shift, Hyper, Meta, Super (and perhaps more). Naturally, emacs
took advantage of some of these . at least those that were available on
multiple terminals or could be emulated on lesser terminals. I remember
when I worked at MIT LCS (down the hall from MIT AI), we had a key
binding on our Lisp Machines that called the elevator to the 8th floor.
I don.t remember the key binding, but I.m sure it used a few of these
modification keys (and probably .e. for .elevator. as the modified key).
In any case, the class of these funky key bindings was referred to as
>>> I.m sure I.ve gotten some of the facts wrong, but I.m also sure
that at least someone on this list will correct me!
>>> . Eric
>> On Dec 1, 2015, at 11:30 AM, Ken <snip>> wrote:
>> I seem to recall that one of the Lisp machine keyboard modifiers was
"Top", and that the phrase was therefore
>> Where, of course, you were typing the "Cokebottle" key with the
Control, Shift, Meta, and Top modifier keys depressed.
>> I think the elevator hack involved the AI Lab PDP-6 (or maybe,
later, PDP-10), but I wouldn't be surprised if it migrated to the Lisp
machines, too The old -6, especially, had added hardware to enable it
to control the various robot devices the AI lab played with. Some AI
Lab hardware guys gained access to the machinery room on the 10th floor
and added some extra relay circuitry to one of the elevator controllers,
and it wasn't much of a stretch to run the control wires down to the 9th
floor machine room. IIRC it took a few years for whatever company was
responsible for maintaining the elevators to discover the unauthorized
modification and remove it.
>> How long it stayed removed is an entirely different question, of course.
>> MIT-LCS '72-'80
>> Multics ARPANET software
On 12/1/2015 11:42 AM, Eric <snip> [multicians] wrote:
> I just knew I had that facts wrong! Yes, you.re right. I remember the
Top key now.
> I do know that the elevator hack worked on Lisp machines, but I think
you.re right that it also worked on some other interfaces. I remember
getting frustrated when I.d be .ready to leave. (at 2am, or so), and
would call the elevator, and then I.d have to fix .one more bug., and by
the time I got to the elevator, I actually had to push the boring old
button to get the elevator doors to open! :-)
> . Eric