> From: Mouse
> they require that I subject myself to the Web.
> I recognize that few people share this attitude.
Well, I sorta understand; the modern 'active content' mania causes me to
grind my teeth, too.
But the non-active Web has major benefits. E.g. I read this list via the
(entirely non-active :-) archive page, so my mailbox doesn't get cluttered up
with the dross.
Noel
In a message dated 8/26/2016 8:51:16 A.M. US Mountain Standard Time,
phb.hfx at gmail.com writes:
On 2016-08-26 12:37 PM, Eric Christopherson wrote:
> Years ago I bought two HP 9000/715s. I've barely done anything with them,
> so I don't remember for sure if they even came with keyboards. That
unit's
> keyboards are supposed to be HP-HIL, and I know there was a breakout box
to
> use a PS/2 *connector* on such a keyboard; but I'm wondering about the
> particulars of that.
>
> I have run across one HP keyboard in my stash, which has a PS/2
connector.
> It only partially works on a PC -- certain keys don't register at all.
What
> I'd like to know is: is it certain that this is just a broken beige box
PC
> keyboard? The alternative I'm pondering is that it's really an HP-HIL
> keyboard with a PS/2 connector that just coincidentally seems to
partially
> work on a PC. That's unlikely, I know, but I just want confirmation to
rule
> it out.
>
It is probably just a broken PC keyboard the communication protocols on
PS/2 and HP-HIL are very different.
and.... the HP HIL keyboad has a TOTALLY different connector also...
Years ago I bought two HP 9000/715s. I've barely done anything with them,
so I don't remember for sure if they even came with keyboards. That unit's
keyboards are supposed to be HP-HIL, and I know there was a breakout box to
use a PS/2 *connector* on such a keyboard; but I'm wondering about the
particulars of that.
I have run across one HP keyboard in my stash, which has a PS/2 connector.
It only partially works on a PC -- certain keys don't register at all. What
I'd like to know is: is it certain that this is just a broken beige box PC
keyboard? The alternative I'm pondering is that it's really an HP-HIL
keyboard with a PS/2 connector that just coincidentally seems to partially
work on a PC. That's unlikely, I know, but I just want confirmation to rule
it out.
--
Eric Christopherson
>On 26/08/2016 06:26, Warner Losh wrote:
>> 10base5 also had rules for minimum bend radius
>
>True, because bending the cable alters the geometry and introduces
>impedance discontinuities, though (to be picky) the allowable bend
>radius varies between cable manufacturers because the precise cable
>construction dictates the tightest bend that wouldn't upset the
>impedance. What I recall from the standard is that cables must support
>a bend radius of 254mm /or less/ in order to be flexible enough for
>reasonably easy installation. A sort of "maximum minimum bend radius".
>
>> as well as tap locations to be at the maxima of the reflection point.
>
>Actually it's to /avoid/ maxima and thereby to ensure things are out of
>phase, minimising adverse interference effects. The node positions are
>at 2.5m intervals, a distance which is chosen so that taps and
>terminators are very unlikely to be exact wavelengths apart and hence
>will /not/ be at maxima, so conflicting signals will be out of phase.
>IIRC correctly it's deliberately not quite 1/19th of the wavelength.
>
>For the same reason, cable sections are supposed to be odd multiples of
>the half-wavelength of the signal (23.4m, etc).
>
>> For early gear, failure to
>> put it at a vibration node would often result in unreliable behavior,
though
>> I can't recall if that included collisions or not.
>
>--
>Pete
>Pete Turnbull
Yes, the whole reflection thing could get into a bit of a complex
discussion involving transmission line theory, but I am an electrical
engineer, so here goes:
Yes, you need proper termination at either end, or else you get the wrong
voltages on the line and cause 'collisions' (well, detect collisions
anyway, though there aren't really any until the first reflection comes
back from the cable end).
And yes, you're supposed to put the nodes 2.5m apart. With only a two node
network, and with a really short coax (<1m in my case here), the problem
this solves is practically nonexistant.
In theory, a properly terminated cable should have virtually no reflections
at either end of the cable. In reality, imperfections in the cable,
tolerances in your terminators, etc. can cause a small bit of reflection,
but it should be mostly negligible. At each node, however, the transceiver
places a small load on the coax, and some (small) amount of reflection will
occur here. The reason you want the 2.5m spacing is so that you stop any
nodes from being a perfect wavelength apart (23.4m minimum) and having
their reflections build on each other enough to cause a problem with the
signal levels and corrupt data (and trigger a collision).
Also, the wavelength of ethernet signalling is 23.4m. This is a full
wavelength, not a half as pete said. Ethernet is 10Mbit/second (more
accurately, also 10Mbaud), which means normally that the maximum frequency
of the raw data signal would actually be 5MHz, but since ethernet uses
manchester encoding, there are sequences of bits which can produce a 10MHz
signal, as well as sequences of bits which can produce a 5MHz signal. The
minimum propagation speed of 802.3 compliant 10BASE5 coax is (IIRC) .78C (C
being the speed of light, 3E8 m/s), so taking .78C/10MHz = 23.4m
Regards,
Joe Zatarski
Tuesday night, I got a small 2 node thicknet segment going between my DEC
VXT2000 and my laptop. I took a quick demo video,
https://youtu.be/A5T2GlAN2N4
The hardware setup is as follows: I have a twisted pair (10BASET) to AUI
converter (a Lantronix LTX-C) (not to be confused with a 10BASET MAU) which
is connected to (and driving) a Cabletron coax MAU with 10BASE5 vampire
tap. This is connected to a small piece of 10BASE5 coax, which is
terminated with a 47 ohm resistor pushed into each end. This coax runs over
to an identical MAU with vampire tap, and an AUI cable connects it to my
DEC VXT2000.
Anyway, I hope to demo a larger 10BASE5 network at VCF MW, but I need
outside help since I only have two AUI capable devices (the LTX-C and my
VXT2000). So if you're going to be at VCF MW, and you've got some gear with
AUI on it, bring it along and I can hook you up. I have about 50m of cable
I think, and plenty of MAUs, but I'm short on AUI cables with both ends on
it, so bring along any you have if you'd like to connect.
Regards,
Joe Zatarski
I can not wait to get back to the back of some of the rooms I have not
been in for 20 to 30 years where I would stash away anything that
looked like a single board computer... who knows... there may be gold in
them thar stacks! #Ed
In a message dated 8/25/2016 4:10:31 P.M. Pacific Daylight Time,
billdegnan at gmail.com writes:
On Thu, Aug 25, 2016 at 6:57 PM, Cameron Kaiser <spectre at floodgap.com>
wrote:
> > > Over on the Vcfed forum Evan reports:
> > > The pre-production Apple 1 sold via CharityBuzz and displayed at VCF
> > > West closed today at $815,000.
> > >
> > > So, which is it?
> >
>
>
I would be curious to know the weight of the celebration Apple I, to see
what it's dollar per gram ratio is. Help put things in perspective.
Bill
In a message dated 8/25/2016 4:10:31 P.M. Pacific Daylight Time,
billdegnan at gmail.com writes:
On Thu, Aug 25, 2016 at 6:57 PM, Cameron Kaiser <spectre at floodgap.com>
wrote:
> > > Over on the Vcfed forum Evan reports:
> > > The pre-production Apple 1 sold via CharityBuzz and displayed at VCF
> > > West closed today at $815,000.
> > >
> > > So, which is it?
> >
>
>
I would be curious to know the weight of the celebration Apple I, to see
what it's dollar per gram ratio is. Help put things in perspective.
Bill
I have a MicroVAX II which has started garbling and losing characters output
to the console. It had seemed that re-seating the processor board would fix
it, but that no longer seems to be the case.
I was just wondering if anyone else has ever come across this failure mode?
Regards
Rob
so, what was the vcf's take?
In a message dated 8/25/2016 12:49:29 P.M. US Mountain Standard Time,
ian.finder at gmail.com writes:
Wow, how extraordinary a price for such a boring (in terms of design if not
impact), well-understood, easy-to-replicate computer.
You can be sure it wasn't a vintage computer enthusiast as much as a
business enthusiast who got it... :)
Sorry I'm such a hater, I've just never understood the Apple 1 thing very
much.
On Thu, Aug 25, 2016 at 12:18 PM, Evan Koblentz <cctalk at snarc.net> wrote:
> The pre-production Apple 1 auctioned via CharityBuzz and displayed at VCF
> West closed just now for $1,210,000. Blows away the old record of
> $900-something. Amazing!!!
>
--
Ian Finder
(206) 395-MIPS
ian.finder at gmail.com
