--- Chuck McManis <cmcmanis_at_mcmanis.com> wrote:
> Yup, that would be the DEC "standard" three loop current loop interface.
> (Tx loop, Rx loop, reader-run loop).
Is there a picture of the "standard" 20mA connector with pinout? I want to
test my ASR-33 up against a VT220 and I need at least to make a pin-swabbing
cable if I don't need a 12V power supply, too.
> >Yep. Unfortunately I dont have any peripherals. Except the one RL01, and
> >apparently I dont have an interface board for that.
>
> I don't believe DEC made a Quad RL controller. I've only seen the M8433
> which is a hex wide RL controller that plugs into the PDP-8/a.
That is the only RL controller I am aware of. OTOH, I like it a lot. I
got one when I could not get RK05 drives, but I could get RL01 drives for
around $100 plus shipping (over ten years ago). At that time, RL02's were
still many hundreds.
> >If the core memory doesnt work out, is the MOS memory actually affordable?
I can't say for quad MOS. I've only got hex MOS... I haven't paid over $50
a board for any of it.
> >Anyone willing to tell me some PDP parts suppliers that may have some
> >interface boards,
I have bought much from Continental Computers including an RL8A, KT8A and 128Kw
memory board (MM8A-?) but you have to know by handle number what to ask for. I
rattled off a list of boards and they only had two or three of the ones I was
interested in.
> > like whatever I need to hook up that RL01 (what exactly
> >is a RL01 anyways).
An RL01 is a 5Mb, single platter, embedded servo-style, removable drive. The
RL02 is a 10Mb version of the same technology. They aren't all that fast, but
they were plentiful, being available for the -8, -11 and various flavors of
VAXen. IMHO, there is much less to maintain than than with RK05s. The OS/8
driver for the RL01 defines three logical units per physical drive, 40%, 40%
and 20% of the capacity, but the third unit is slower because it fills the
nooks and crannies around the first two units. It's because of a physical
device size limitation in OS/8.
> Maybe I should be looking to add floppy drives, etc.
Floppies are nice if you have a stack of media with stuff on it. I have
a few games and such. I'd like to be able to back them up to a modern machine
and cut a CD-ROM of the disk images. To that end, I've just extracted a
Tandon TM-848 floppy from my DataRam Q22 box and need to see about a power
harness (six pin, H-shaped) and a 34<->50 pin cable to hook it up to an old
box to do media conversion.
> >OR, are people using IBM's as a terminal, and running some program that
> >pretends to be an attached paper tape reader/punch unit? That might do
> >for starters, though its not anywhere near as satisfying.
If you didn't have a teletype, I guess a TTY emulator on a PC would be
a way to go, but I don't know of any punch/reader emulating software, per
se. I guess you could adapt ProComm or something like it that can upload
and download data over the application.
> >From there you have several choices, perhaps the simplest is the ASR33 with
> paper tape software. As attendees to VCF can attest, it makes a loud but
> somehow comforting ratcheting sound to hear FOCAL or some other system
> being loaded at 10 CPS. On Highgate there is software for RX01's (OS/8 et al)
It's not comforting to load papertape basic and Star Trek at 10cps... that's
a *lot* of tape. I was glad to have a highspeed reader on the 12Kw -8/L.
> Lots of fun ahead,
> --Chuck
For sure!
-ethan
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Received on Wed Oct 06 1999 - 23:01:44 BST