"e.stiebler" <emu at e-bbes.com> wrote:
> Dave McGuire wrote:
>>> >> OTOH, they old ones show up on ebay frequently, and they are not that
>>> >> expensive.
>> > Not that expensive? I call $100-200 for a Qbus card pretty pricey.
>> > Unibus models go for many hundreds, upwards of $1000.
>
> Sorry, but the new one want be cheaper than that. That's why I don't
> call them expensive.
Indeed. If we talk $200 just for the board, and then you still have do
develop the firmware, then $200 for a actual, already tested and proven
SCSI controller is cheap.
And new SCSI disks can still be bought as well. And while not dirt cheap
perhaps, they are still not that expensive. Especially since you are not
interested in several hundred gig drives for a PDP-11 anyway.
Someone else asked about differences between a RQDX1 and RQDX3, from a
software point of view. There is none, except in the irrelevant parts,
such as the identity given by the controller, and version numbers and so
on. The controllers are both MSCP. In fact, they are no different
(either of them) from a KDA50, or UDA50 for that matter. Or any other
MSCP controller. That's the whole point of MSCP.
The controller always present the same interface to the computer. What
it does on the other side is hidden.
So, in fact, the device driver is the same for all these controllers, in
all operating systems.
MSCP is a great concept. Just wish it had survived. But, as with many
DEC designs - they were technically wonderful, but they weren't PC. And
PC became the de facto standard. No matter how lousy the hardware was/is.
Johnny
"Zane H. Healy" <healyzh at aracnet.com> wrote:
> On Wed, 10 Mar 2010, e.stiebler wrote:
>
>> > Zane H. Healy wrote:
>> >
>>>> >>> OTOH, they old ones show up on ebay frequently, and they are not that
>>>> >>> expensive.
>>> >>
>>> >> What "old ones" show up on eBay?
>> >
>> > The "usual" suspects like cmd, dilog, emulex ?
>> > OK, in all honesty I didn't check for more than a year, but they showed up
>> > before, that's why I canceled my design ...
>
> Okay, old 3rd party disk controllers. The problem with these is that they
> also require old hard drives. I'm also slightly surprised to hear mention
> of CMD controllers that aren't expensive, but then I've not looked for such
> things in years.
Huh? New SCSI disks works just as well.
The biggest problem might be that some OSes gets confused by really big
disks. With RSX for instance, the device driver used to have a bug so
that disks larger than 8 Gig didn't work right. The size got masked to
24 bits... With M+ 4.6, the system instead caps the disk size at 8 Gig
if the disk is larger, unless you switch to 32 bit LBNs.
The only other problem with SCSI disks is that you might need to get
adapters for the old style 50 pin connectors.
However, as long as we talk plain SCSI, and not differential, or
something else odd, it is still just fine being backward compatible...
> My PDP-11's are using 1" High 3.5" SCSI Hard Drives, it does wonders for the
> noise level, and helps with the power consumption, but I'm honestly a bit
> worried about their long term viability. At least I have a much larger
> supply of SCSI drives I can use than I do MFM Hard Drives (and yes, I have a
> few of those, and a couple ESDI drives).
I'm using second, or if it is third generation storage work disks for my
machines. Blue boxes. Pretty. And I can put seven of them in one unit.
Actually, I only have five in there, along with a DAT-3 tape unit, and
an Exabyte externally.
> Of course the other thing I worry about is power supplies. In fact that's
> what I've been loosing VMS boxes to. :-(
Power supplies for the PDP-11s? Yes, that is always a possible
problem... And a bigger one than disks, I'd say.
Johnny
I've got 3 different size wire wrapping tools.
My ICT1301 uses monster wire wrap posts, most of which are made in two halves. One half is part of a printed (or some are hand wired) circuit board and the other half is part of the rack it fits in. Bare 25 AWG tinned copper wire is wrapped around the two halves, up to 25 for each board to connect the board to the rack. No tails going off anywhere else. To swap a board all the wire wraps need to be undone before the board can be slid out. It does mean every logic pin is easily accessible for fault finding, and each one has a little hook for the scope probe to hang from. The solid one are used for connecting the cabinets together, same size tool but using sleeving on the wire. Up to 1500 connections between racks. There are ten electronic cabinets, not counting the two power supply and twelve peripherals cabinets. The tool fits in the smallest size of Stanley 'yankee' spiral ratchet screwdriver. Clockwise to wrap, anti-clockwise to unwrap.
I also have a similar slightly smaller one for back plane wiring of later ICL mainframes. Uses smaller pins and smaller wire otherwise identical.
The third one is the more modern standard wire wrap for integrated circuits. I'm currently using it to build a serial/parallel interface to my 1301 using 74 series TTL and a few C/N MOS chips. At work I used to have a tool for this from RS components which had a wrapper on one end and unwrapper the other end and a stripper in the middle. This has probably been chucked away and a replacement is incredibly expensive so I'm making do with wire stripping pliers and a much simpler wrapping tool I bought over the internet from the states along with a half dozen colours of insulated wire.
On Wed, 10 Mar 2010, Rob Jarratt wrote:
> There was a thread recently on the comp.sys.dec newsgroup which ended up
> with the suggestion from David Riley that he would be prepared to build an
> FPGA-based board with a QBUS interface on one side and an SD interface on
> the other which anyone could then program to emulate any disk/controller
> they like. I have been in touch with him to see how much interest he has
> had, because he needs a minimum number of about 10 to make it viable, but so
> far there has only been me and one other person showing an interest. David
> reckons they would come to a little over $200 each (possibly less if there
> is more interest). David is not yet on cctalk so he agreed to let me
> cross-post this to cctalk on his behalf, but I have cc'd him so you can
> reply direct.
>
> Regards
>
> Rob
>
I think it would be useful to include the RD51 and RD52 in the list of
supported drives. I believe it is MicroRSTS/E which expects something like
an RD51 or RD52 for a system disk.
Additionally would such a board support hardware partitioning? Something
like the old Webster WQESD/04 EDSI boards where you can partition a drive
into multiple drives that appear to be seperate physical drives to the OS?
This is especially useful when running multiple OS's on the same hardware.
This is something I would definitely be interested in, especially if the
price is right.
Another thought is, would it be possible to have it include a system clock
on the same board?
Zane
On Mar 10, 2010, at 8:19 PM, Chuck Guzis wrote:
>> I've been using a Roadrunner pen since my supply of (cheap) wire-wrap
>>
>> sockets dried up. Similar idea, but with enamelled copper wire
>> instead. You wrap the wire round a socket pin or component lead 2
>> or 3
>> times, then solder it, run it to the next lead, wrap, solder and
>> carry
>> on.
>
> Didn't Vector have a system that used tefzel-insulated wire called
> "Slit-N-Wrap" that used a wiring pen with a little spool of wire on
> top? I've seen tefzel wire offered on eBay, but it always seems to
> be tinned, not silverplated.
From:
Dave McGuire <mcguire at neurotica.com>
Yeah, I remember those ads. "Slit-N-Wrap...don't Just Wrap and
wonder if the post cut the insulation". They were competing with
the Just Wrap product, which is self-explanatory.
-Dave
I was looking at an old ad for Ok Tools' "Just Wrap" today. Are Just
Wrap or Vector's Slit N' Wrap around anymore? Were these not popular?
Seems like they would have been much easier than cut n' wrap.
- John S.
I don't normally like to mix work with pleasure, but (selfish plug) here
is an article I wrote today:
http://tinyurl.com/ykpd6bn
It's about the history of the IEEE LAN/MAN Standards Committe -- from
which we all got standardized Ethernet, WiFi, Bluetooth, etc*.
*< no shame > Slashdotting strongly encouraged. < / no shame >*
*
Ethan Dicks <ethan.dicks at gmail.com> wrote:
>On Tue, Mar 9, 2010 at 4:01 PM, Dave McGuire mcguire at neurotica.com> wrote:
>> On Mar 9, 2010, at 3:20 PM, William Donzelli wrote:
>>> Curious...
>>>
>>> Who here has a DECwriter I (LA30)? This is the original early 70s
>>> DECwriter made out of Flip Chips. Google for a picture.
>>
>> ?Not me. :-(
>>
>>> Who here would like a DECwriter I?
>>>
>>> No, I am not selling, just curious...
>>
>> ?Oh, I'd definitely drool over such a device. ?I've typed on no end of LA34s, LA36s, and LA120s, but never an LA30.
>Agreed - I have run miles of paper through the common models of
teleprinters, but have never seen an LA30 up close.
>-ethan
I bunch of years ago, I got an LA30 decwriter that was about to be "discarded". I got the prints as well, and I added lower case to it. I used the ADM-3A method of making the lower case characters up one dot to allow for "decenders" (the LA30 uses a 5x7 matrix). I took out the 2513 character generator, and re-wired it for a 2716 EPROM. It is in my "other" garage and works OK. Plugs into dataphone and all that. I was lucky that there was an extra pin on the character generator board (or I used the negative supply I don't remember right now).
The real modification I would like to do is add a FIFO chip or some such, as padding each line with a bunch of NUL characters is a pain.
I guess that connecting it to my SBC6120 would be a good retro thing. Got to get it (the SBC6120) working!!
For those with Xerox 820-II systems, Al has kindly posted a file on
bitsavers containing images of a large collection of 8" floppies primarily
for the 820-II (there are a few for other systems too) that I acquired a few
years ago and just finished archiving this week. There is also an excel
file with details on each floppy. These came from someone who worked as a
software developer in the late 70s/early 80s and many appear to contain
source code.
Richard
>which anyone could then program to emulate any disk/controller they like.
Ah, well, this is the hard part of the job, right? Building the board is
the easy part.
I'd buy a couple, at least, without exaggeration, if the Verilog or VHDL
to make them functional already existed.
Bob Armstrong