>< I believe that "mmg" is still used as a prefix in medical fields,
>< but here it means (as far as I can figure out) "millimicrogram".
>< Can someone correct me on this (I'm sure I'm wrong!)
>
>A friend is a toxicologist and with it isn't PPM it's picograms/liter.
>
In the environmental testing field PPM, PPB and PPQ for part per quadrillion
are standard. Also nanogram, picogram and even femtogram are standard terms
for Mass spec. injection amounts.
Current Mass spec. detection limits are in the VERY low femtogram
quantities.
Dan Burrows
dburrows(a)netpath.net
At 02:57 PM 10/18/98 -0700, you wrote:
>
>Yah! The Vintage Computer Festival was immortalized on television.
>
>It aired on CNET Central on the USA network this morning at 6:00am. You
>might be able to catch re-runs of it this week on local stations. Its the
>last segment of the show.
>
<snippage>
...also, (tho I have not seen the segment yet) CNET placed links to the VCF
website and my Computer Garage web site on the CNET Central site. (don't
know if the sites were specifically mentioned in the segment)
But, a LOT of people have been watching, at least if I can guage anything
by the number of emails I have received since yesterday mentioning the CNET
segment.
I suspect that I'm going to be referring a number of these people to the
list, since nearly every one of them has been asking about new homes for
old gear! (after I cull out the neat ones of course... B^} )
Overall... COOL!
-jim
---
jimw(a)agora.rdrop.com
The Computer Garage - http://www.rdrop.com/~jimw
Computer Garage Fax - (503) 646-0174
On a system/34, stick something through the slot, and pull the cover
off. The silver thing inside the slot is one end of a catch, which
attaches to the frame. Pushing on the silver thing swings the catch
away.
>
>I made my first major equipment move today. It was a System/34 system
>unit (5340), a System/36 system unit (5360), two band printers (3262),
and
>two tape drives (8809). About 5,000 lb. as near as I can figure.
Nothing
>fell over or hurt anybody- very encouraging for the next move (although
>now I'm out of room!)
>
>My biggest, burning question is this: How do you get those darn covers
on
>the side of the S/36 open? All it has is a little 1/4" long slot.
>Probing around inside was completely fruitless. I can see a black
plastic
>piece inside through the slot, but pushing, pulling, lifting, or
pushing
>down on it doesn't do anything.
>
>Any help would be much appreciated.
>
>Richard Schauer
>rws(a)ais.net
>
>
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Get Your Private, Free Email at http://www.hotmail.com
< But this doesn't explain why some units are not common even in scientifi
< fields. Like the millifarad, for example.
This is because that is an odd size 1000mF (10^-6) is rather uncommon
when standard values and notation came about. Back then a 50mF cap was
a large value! It was the advent of transistor circuits and their lower
voltage power supplies that 1000mF were common. Then again we see caps
now in the full Farad sizes.
Then again from a womans point of view, it may be that 1400mm sounds
bigger than 5 and a half inches. ;)
Allison
< Assuming each relay occupied a cubic inch, one million relays would
< occupy a cube 100 inches on each side, or just a bit over 8 feet on each
< Not ridiculously large.
The problem is not the size of the relay but the wires to interconnect
them. For each relay one can assume there would be a minimum 10% volume
overhead for interconnecting wires.
< Of course, real relays much smaller than a cubic inch are readily availa
< and a real computer of that density would have incredible cooling
< problems.
There are small units in the size of T05 (.325" dia, .265 tall) and
the crystal can sizes (1.25x1.00x.375). So small relays are common and
their power needs are very small. Also they cycle faster. These relays
also have the advantage of being sealed preventing contamination. The
later detail is real for larger systems.
I have used the crystal can relays for control systems (25 relays!) and
they are reliable fast and modest power. the units I used were Allied
Signal manufacture and at 26.5v only required 50mA (max) and had 5A DPDT
contacts. Each relay would use 1.325W... full scale machine using say
10,000 would use a fair amount of power. There are lower power relays
available as well. Using two cross coupled makes a fine flip-flop.
Allison
< Here in the US, it's rare to see nanoFarads used as a unit - it's
< far more common to see a 2.2nF capacitor referred to as a 0.0022uF
< or as a 2200pF unit. This is an extension of the days when
< "microFarad" was "mF", and the next subdivision was "micro-micro-Farad"
< or "mmF".
I have a lot of cap on drawing I've specified as nF and I switched to
pF (picofarards 10^-12) back in the late 60s.
< I believe that "mmg" is still used as a prefix in medical fields,
< but here it means (as far as I can figure out) "millimicrogram".
< Can someone correct me on this (I'm sure I'm wrong!)
A friend is a toxicologist and with it isn't PPM it's picograms/liter.
Allison
>> If one were to estimate the number of transistors in a penitum II
>> at 100 million (?), then if an exchange has ~three relays per number,
>More like a little more than a 1 million. With a 100 million transistor
>CPU I could rule the world!!!
Assuming each relay occupied a cubic inch, one million relays would
occupy a cube 100 inches on each side, or just a bit over 8 feet on each side.
Not ridiculously large.
Of course, real relays much smaller than a cubic inch are readily available,
and a real computer of that density would have incredible cooling
problems.
Tim.
>And the millifarad. If you want to get an odd look, go into an
>electronics shop and ask for a 2.2 millifarad capacitor. Nothing wrong
>with the unit AFAIK but nobody seems to use it other than me :-)
Here in the US, it's rare to see nanoFarads used as a unit - it's
far more common to see a 2.2nF capacitor referred to as a 0.0022uF
or as a 2200pF unit. This is an extension of the days when
"microFarad" was "mF", and the next subdivision was "micro-micro-Farad",
or "mmF".
I believe that "mmg" is still used as a prefix in medical fields,
but here it means (as far as I can figure out) "millimicrogram".
Can someone correct me on this (I'm sure I'm wrong!)
Tim.
I know being an old Apple zealot I'm supposed to bemoan Win95, but it
hasn't been a problem for us. Now 300 machines on our network with the
old Cat3 cable and dozens of old switches in the wire closets- that's a
problem, but nothing I can blame 95 for.
>
>On Sun, 18 Oct 1998 05:40:38 PDT "Eileen Backofen"
><backofene(a)hotmail.com> writes:
>
><Interesting perspective of computers in the classroom SNIPPED>
>
>>
>>The introduction of Windows 95 also did a lot to change encourage
>>education to change platforms.
>
><SMIRK>
>
>Yeah, I imagine it encouraged them to change back to the
>'Pencil and Paper' computing platform.
>
></SMIRK>
>
>
>
>___________________________________________________________________
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On Sun, 18 Oct 1998 05:40:38 PDT "Eileen Backofen"
<backofene(a)hotmail.com> writes:
<Interesting perspective of computers in the classroom SNIPPED>
>
>The introduction of Windows 95 also did a lot to change encourage
>education to change platforms.
<SMIRK>
Yeah, I imagine it encouraged them to change back to the
'Pencil and Paper' computing platform.
</SMIRK>
___________________________________________________________________
You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com
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