Re: VCFMW

[Jason T via cctalk]

VCFMW13 Talks & Presentations videos are up!  Here's a YouTube
playlist with all of them for this year:

https://www.youtube.com/playlist?list=PLE-Iywr9LQERoM2Iy6EeO9ln5SdFnmnsW

Fall cleaning - 9-track drives available

[Bob Rosenbloom via cctalk]

I have four 9-track tape drives, and a dirty DEC rack, that I need to 
get rid of.


Two of the drives are HP 7970B's. One has the door unattached. Then 
there's a Kennedy 9100 800/1600 bpi drive.
Very heavy.  As found, none tested by me. Just don't have time to play 
with them.


Last is a CDC drive complete with an AST clone PC with an Overland Data 
controller and software. This
was running a few years ago but has not been used since. Has Media 
Master format conversion software also.


There's also a smallish DEC rack. Could use the top painted but 
otherwise not too bad. Includes four sets of rack

slides.

All are located in Santa Cruz, CA and need to be gone soon, I need the 
room in my hangar. Come get them!


Photos here: http://dvq.com/fall_cleaning/

--
Vintage computers and electronics
www.dvq.com
www.tekmuseum.com
www.decmuseum.org

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[Noel Chiappa via cctalk]

> From: Alexandre Souza

> What about a nuclear bomb?

OK, if we're going to start being _really_ silly. drop them into a
singularity! :-)

The best part is that you'll get to watch them being ripped apart and
destroyed by tidal forces _forever_ (since time dilation means that as they go
over the event horizon, their local time seems to stop compared to ours).

Noel

Re: DEC H744 +5 supply

[Brent Hilpert via cctalk]

On 2018-Sep-21, at 4:03 PM, Noel Chiappa via cctalk wrote:

>> From: Brent Hilpert
> 
>> In typical "down-converters" there are additional current paths in the
>> supply, paralleling the input path, that can provide the 'additional'
>> electron flow rate. ... the whole rationale of a switching supply is to
>> use time (varying switching periods) and temporary energy storage to
>> change that EI relationship from input to output without energy loss.
> 
> So, two more questions (if you have the time):
> 
> I can see that there's a nice synergy between the switching concept and the
> buck converter (since the switch does exactly what the buck converter needs,
> in terms of turning the input current off and on), _but_ - are there switching
> supplies that operate the way I described (up-convert the frequency, then use
> a transformer to get directly to more or less the right voltage)? I.e. without
> needing to use a buck converter to do the conversion from low current at
> higher voltage to higher current at lower voltage? (Although I guess the coil
> for the buck might be cheaper than the transformer - even though the use of a
> high frequency would reduce the size of the latter - making the buck approach
> superior.)
> 
> To put it another way, there's no _necessary_ connection between the switching
> concept, and the buck converter is there? Does that mean it is in theory
> possible to stick a buck converter on the output of a linear supply to do the
> V1I1-> V2I2 conversion? (Although I know it's probably a stupid design, 
> because
> you'd still need some sort of switcher for the buck converter, so the linear
> supply would be basically pointless.)

There are a thousand configurations for power supplies possible depending on 
what needs to be accomplished: circuit isolation (e.g. mains from load), EI 
conversion up or down, degree of regulation, economy tradeoffs, etc.

An example that perhaps fits what you're thinking of is the old motor-generator 
setups which convert 60Hz to 400Hz, the 400Hz then being used as input to a 
variety of supplies.

It's useful to keep in mind that regulation and EI conversion are different 
objectives but they can be achieved either separately or in concert.
What we commonly refer to as a "linear power supply" does EI conversion (and 
circuit isolation) in one stage (the transformer), followed by an independent 
regulator stage.
Your common modern generic switching supply integrates EI conversion, 
regulation and circuit isolation into one feedback loop across one transformer 
(switching at high frequency).

A buck converter is inherently a switching converter, the buck operation 
requires the switching to function.
There is a corresponding boost converter with a different circuit topology 
around the inductor, for . .  boosting voltage.
There are also boost-buck converters.

Dropping 5V to 3.3V or 1.xV for ICs is often accomplished with little on-board 
buck converters which you may not have realised were there, to avoid the losses 
and heat of a linear regulator.
 

> 
>> If the heatsinks seem huge compared to modern day supplies, that's more
>> likely the result of technology improvements - faster devices, and
>> moving from bipolar switching transistors to mosfets. Bipolar
>> transistors have a near-fixed voltage drop which can't be reduced
> 
> Right, I knew bipolars had the fixed drop, but I hadn't made the connection
> to that being the cause of the large amount of heat needing to be dumped.
> Useful enlightenment!
> 
> 
>> If you supply a link & location to a schematic I'll take a look
> 
> Here:
> 
>  http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/jpg/H744.tif
>  http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/jpg/H744.jpg
> 
> Thanks to everyone for taking the time and energy to reply!
> 
>   Noel

Re: DEC H744 +5 supply

[Brent Hilpert via cctalk]

On 2018-Sep-21, at 4:03 PM, Noel Chiappa via cctalk wrote:
>> From: Brent Hilpert
> 
>> If the heatsinks seem huge compared to modern day supplies, that's more
>> likely the result of technology improvements - faster devices, and
>> moving from bipolar switching transistors to mosfets. Bipolar
>> transistors have a near-fixed voltage drop which can't be reduced
> 
> Right, I knew bipolars had the fixed drop, but I hadn't made the connection
> to that being the cause of the large amount of heat needing to be dumped.
> Useful enlightenment!

To clarify, bipolars have a fixed MINIMUM drop, which can be used in a 
switching supply to as much advantage as possible with bipolars, but have a 
varying drop in a linear regulator (that's where the 'linear' comes from) which 
results in the large losses and inefficiency of linear regs.

Re: DEC H744 +5 supply

[Brent Hilpert via cctalk]

On 2018-Sep-21, at 3:20 PM, Noel Chiappa via cctalk wrote:

>> From: Mattis Lind
> 
>> The H744 is a buck converter. You can read about buck converters here:
>> https://en.wikipedia.org/wiki/Buck_converter
> 
> Wow, that was incredibly hard to read; no clear and simple explanation of the
> basic concept of how it works, before getting into the details!
> 
> If I understand it correctly, it stores part of the incoming energy of a block
> of current in the field around the inductor; later, switches change state to
> create a loop that includes the inductor, and it uses the stored energy to
> cause electrons to flow around the new (temporary, because of the switch)
> circuit. Is that about right?

Yes, that's a basic part of the operation.


> The H744 manual doesn't really talk much about that aspect of the circuit's
> operation (at least in terms of 'we use this trick to get all the energy out
> of the incoming current flow'); it just describes the stuff around the coil as
> "an LC filter". It says "This type circuit is basically only an averaging
> device", which I wouldn't say is really on point - that would describe my
> (incorrect) prior description as well as the correct one.
> 
> And just to make it even more confusing, it says "most of the input voltage is
> absorbed across the emitter-collector of Q5", but I looked, and Q5 is tiny,
> and I eventually figured out that that only applies to the +15V needed to run
> the voltage regulator.


Q5 is functioning as a common-base stage in the driver chain (base tied to 
fixed +15V).

It is not part of the +15V supply to the 723, that is provided by R2, zener D2, 
C2.

Q5 'voltage isolates' the 723 from the higher voltages around Q4-3-2 while 
nonetheless providing a control signal path from the 723 to the drivers.

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[Alexandre Souza via cctalk]

What about a nuclear bomb?

2018-09-21 20:05 GMT-03:00 dwight via cctalk :

> I'd think a nice blast with a oxy-acetylene  torch should do what is
> needed. Even if it doesn't melt the disk, it will surely exceed the Currie
> point and all data is gone.
>
> Dwight
>
>
> 
> From: cctalk  on behalf of Jerry Weiss via
> cctalk 
> Sent: Friday, September 21, 2018 2:49:30 PM
> To: General Discussion: On-Topic and Off-Topic Posts
> Subject: Re: Advice requested on proper disposal of Seagate ST3000DM001
> disk drives
>
> On 9/21/18 1:06 PM, Fred Cisin via cctalk wrote:
> > On Fri, 21 Sep 2018, Eric Smith via cctalk wrote:
> >> That's way too good for these 

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[dwight via cctalk]

I'd think a nice blast with a oxy-acetylene  torch should do what is needed. 
Even if it doesn't melt the disk, it will surely exceed the Currie point and 
all data is gone.

Dwight



From: cctalk  on behalf of Jerry Weiss via 
cctalk 
Sent: Friday, September 21, 2018 2:49:30 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Advice requested on proper disposal of Seagate ST3000DM001 disk 
drives

On 9/21/18 1:06 PM, Fred Cisin via cctalk wrote:
> On Fri, 21 Sep 2018, Eric Smith via cctalk wrote:
>> That's way too good for these 

Re: DEC H744 +5 supply

[Noel Chiappa via cctalk]

> From: Brent Hilpert

> In typical "down-converters" there are additional current paths in the
> supply, paralleling the input path, that can provide the 'additional'
> electron flow rate. ... the whole rationale of a switching supply is to
> use time (varying switching periods) and temporary energy storage to
> change that EI relationship from input to output without energy loss.

So, two more questions (if you have the time):

I can see that there's a nice synergy between the switching concept and the
buck converter (since the switch does exactly what the buck converter needs,
in terms of turning the input current off and on), _but_ - are there switching
supplies that operate the way I described (up-convert the frequency, then use
a transformer to get directly to more or less the right voltage)? I.e. without
needing to use a buck converter to do the conversion from low current at
higher voltage to higher current at lower voltage? (Although I guess the coil
for the buck might be cheaper than the transformer - even though the use of a
high frequency would reduce the size of the latter - making the buck approach
superior.)

To put it another way, there's no _necessary_ connection between the switching
concept, and the buck converter is there? Does that mean it is in theory
possible to stick a buck converter on the output of a linear supply to do the
V1I1-> V2I2 conversion? (Although I know it's probably a stupid design, because
you'd still need some sort of switcher for the buck converter, so the linear
supply would be basically pointless.)


> If the heatsinks seem huge compared to modern day supplies, that's more
> likely the result of technology improvements - faster devices, and
> moving from bipolar switching transistors to mosfets. Bipolar
> transistors have a near-fixed voltage drop which can't be reduced

Right, I knew bipolars had the fixed drop, but I hadn't made the connection
to that being the cause of the large amount of heat needing to be dumped.
Useful enlightenment!


> If you supply a link & location to a schematic I'll take a look

Here:

  http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/jpg/H744.tif
  http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/jpg/H744.jpg

Thanks to everyone for taking the time and energy to reply!

Noel

Re: DEC H744 +5 supply

[Brent Hilpert via cctalk]

On 2018-Sep-21, at 1:03 PM, Noel Chiappa via cctalk wrote:
> Oh, one thing I forgot to include:
> 
>> a lot of the incoming power in that 30V AC has to be thrown away, in
>> producing +5V.
> 
> So, if my understanding is correct, the 'switching' H744 really isn't much
> better than a classic linear supply. It still wastes a very large amount of
> the input power, and it still has a massively heavy transformer in it. Yes?

No, it's much better than a linear supply.
With the given 20-30VAC input (do I have that right?) - lets take a 
conservative 25VDC after rectification and filter - if input to a linear 
regulator producing 25A @ 5V,
that's a loss of (25-5)V * 25A = 500W, to produce a usable 125W.
That heatsink isn't sinking 500W and DEC wouldn't be producing a supply that 
inefficient.

A glance at the schematic (as Eric provided the ref to) you might think it's 
just a linear regulator: AC input, rectification, cap filters, pass 
transistors, filter choke, with a 723 IC regulator controlling it, all the 
standard elements are there.

But it's not: L1 is the bucking inductor - it's not just a filter choke.
Diode D5 provides the current path for L1 to supply energy to the load when the 
source is switched off.

The subtle thing about designs like this is where does the switching 
oscillation come from?, as there is no obvious oscillator present.
I think what's going on is:
- Q1/R4 are sensing current from the source via voltage drop across R4.
- As that current goes up Q1 starts to conduct, eventually tripping SCR 
Q7 hard on.
- This raises the voltage at E1.4, the error amp sense input.
- This fools the regulator into thinking it's seeing way too high an 
output voltage so it hard shuts down the Q5-4-3-2 chain,
   disconnecting the source from L1 and the output, and shutting off 
the source current.
   E1.4 is now back to sensing the output voltage via the V-SENSE 
feedback.
- With source current off, L1 now starts supplying energy to the load 
through D5, as it's magnetic field starts to collapse rather than build.
   As that energy peters out and the output voltage droops, E1.4 via 
the V-SENSE line now sees too low an output voltage and turns
   Q5-4-3-2 back on so the source can supply current, and energy into 
L1 and the load.
- repeat. Hence oscillation.

There is still a sizeable 60Hz transformer (step down to 20-30VAC) because the 
switching is taking place after the transformer rather than straight off the 
mains, this allows the switcher design to be simpler and get away with using 
much lower voltage semiconductors.
The transformer is nonetheless much smaller than it would be in a straight 
linear regulator design because the secondary current it has to supply is 
several factors lower than for a comparable linear reg.


> So I wonder what exactly the advantage was in going to the switching approach?

Improved power efficiency.
Improved material economics.


> Yes, it keeps the output voltage steadier then a pure linear supply could -
> but I'll bet there are analog approaches that can do the same. (They'd need
> something that can produce a steady reference voltage, but the switching
> approach needs, and has, the same thing.)

In addition to reference stability, the basic error factor in a regulator is 
the loop gain of the error amplifier, and applies to both linear and switching 
regs.
Neither produces a perfect output, it just reduces the the variation by some 
factor (the gain factor).
If you think about it, if the output were perfectly stable how would the 
regulator know to provide correction?


> Maybe the main output transistors
> are happier being full-on or full-off, or something like that?

Yes, that is one of the benefits of switching regulator over a linear 
regulator. It keeps the in-regulator losses to a minimum.

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[Steve Malikoff via cctalk]

Noel said
> > From: Eric Smith
>
> > That's way too good for these 

Re: DEC H744 +5 supply

[Noel Chiappa via cctalk]

> From: Mattis Lind

> The H744 is a buck converter. You can read about buck converters here:
> https://en.wikipedia.org/wiki/Buck_converter

Wow, that was incredibly hard to read; no clear and simple explanation of the
basic concept of how it works, before getting into the details!

If I understand it correctly, it stores part of the incoming energy of a block
of current in the field around the inductor; later, switches change state to
create a loop that includes the inductor, and it uses the stored energy to
cause electrons to flow around the new (temporary, because of the switch)
circuit. Is that about right?


The H744 manual doesn't really talk much about that aspect of the circuit's
operation (at least in terms of 'we use this trick to get all the energy out
of the incoming current flow'); it just describes the stuff around the coil as
"an LC filter". It says "This type circuit is basically only an averaging
device", which I wouldn't say is really on point - that would describe my
(incorrect) prior description as well as the correct one.

And just to make it even more confusing, it says "most of the input voltage is
absorbed across the emitter-collector of Q5", but I looked, and Q5 is tiny,
and I eventually figured out that that only applies to the +15V needed to run
the voltage regulator.

Noel

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[Jerry Weiss via cctalk]

On 9/21/18 1:06 PM, Fred Cisin via cctalk wrote:

On Fri, 21 Sep 2018, Eric Smith via cctalk wrote:
That's way too good for these 

Re: DEC H744 +5 supply

[Eric Smith via cctalk]

>
> * If you supply a link & location to a schematic I'll take a look, I don't
> feel like wading around in bitsavers pdfs to try to find it right now.


page 207 of:
http://bitsavers.trailing-edge.com/pdf/dec/pdp11/1140/PDP-1140_System_Engr_Drawings_Rev_P_Jun74.pdf

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[dwight via cctalk]

All the molten lava is done. You could still smash it with a lava rock.

Dwight



From: cctalk  on behalf of Chuck Guzis via 
cctalk 
Sent: Friday, September 21, 2018 11:36:25 AM
To: Fred Cisin via cctalk
Subject: Re: Advice requested on proper disposal of Seagate ST3000DM001 disk 
drives

Anyone headed for Hawaii?  It'd be interesting to see what some molten
lava would do to one...

--Chuck

Re: DEC H744 +5 supply

[Eric Smith via cctalk]

On Fri, Sep 21, 2018 at 1:38 PM, Noel Chiappa via cctalk <
cctalk@classiccmp.org> wrote:

> My understanding is that, without using a transformer (which creates an
> independent circuit loop - more below), there's no way to increase the
> _amperage_ out of circuit over what's fed into it: since amps are
> electrons/second, the electrons/second out more or less have to equal
> electrons/second in, since one can't easily 'create' electrons - at least,
> in
> normal electonic gear!
>

No, a switching buck converter can definitely have more current out than
in. In fact, that's common. The buck regulator on your PC board may supply
100A at around 1V to your CPU, but doesn't draw anywhere near that many
amps from its 12V input.

Although it works differently than a stepdown transformer, it does the same
job, converting power at a higher voltage but lower current to a lower
voltage at a higher current.

Re: DEC H744 +5 supply

[Brent Hilpert via cctalk]

On 2018-Sep-21, at 12:38 PM, Noel Chiappa via cctalk wrote:

> So there's something about the H744 I'm not sure I understand; hopefully those
> with more analog-fu will set me straight if I'm confused.
> 
> This supply runs off 20-30V AC. It takes the input AC, rectifies it, and runs
> it through a cap to filter out the ripple. What's next is that it's an early
> switching supply; i.e. the electronics inside switches that newly-created main
> DC off and on very quickly to keep the output voltage at around +5V.
> 
> However...
> 
> My understanding is that, without using a transformer (which creates an
> independent circuit loop - more below), there's no way to increase the
> _amperage_ out of circuit over what's fed into it: since amps are
> electrons/second, the electrons/second out more or less have to equal
> electrons/second in, since one can't easily 'create' electrons - at least, in
> normal electonic gear! (Transformers, by creating a whole new circuit loop,
> can 'create' more electrons/second in the new loop; since they tie the 'out'
> of the new circuit back to its 'in', they can recirculate the 'extra'
> electrons.)
> 
> And to the extent that the output is at lower voltage, the energy differential
> has to be dumped; hence the huge heat sinks - a lot of the incoming power in
> that 30V AC has to be thrown away, in producing +5V. Right?
> 
> My (possibly confused) understanding is that later switching supplies take the
> incoming 60Hz wall AC, transform it to a higher frequency, run _that_ through
> a transformer (which can be a lot smaller, since it's at a higher frequency,
> and the higher the frequency, the smaller the transformer you can use - hence
> the use of high frequency AC in airplanes, to allow use of smaller - and thus
> lighter - transformers). That then turns out a massive amount of amps in the
> output loop (since with a transformer, energy out is roughly energy in, modulo
> resistive losses; and with constant power, if V goes down, I goes up).
> 
> So the losses are a lot lower - N amps at 110V in produce ~20N amps out at
> +5V. (Well, depending on all the losses, ~20.) And the whole works is a lot
> lighter, to boot.
> 
> Did this programmer get all that analog stuff correctly?


No. You don't need a transformer to increase the current  ('electrons/S') in 
the output above that of the input.

In typical "down-converters" there are additional current paths in the supply, 
paralleling the input path, that can provide the 'additional' electron flow 
rate.
There are the parallel filter capacitors, and in the typical 'bucking 
converter'  - which, while I'm not familiar with the H744 design*, I suspect it 
probably is - there will be what looks like a reverse-biased diode across the 
(switched) input which allows 'arbitrary' current levels to flow out of a 
series inductor which previously stored energy from the source, and deliver 
that current through the load.

The energy differential from the voltage reduction is not being dumped as a 
power loss, it was converted by the supply to a different EI relationship 
between the input and output.

The forgotten factor in your analysis is time: the whole rationale of a 
switching supply is to use time (varying switching periods) and temporary 
energy storage to change that EI relationship from input to output without 
energy loss.

If the heatsinks seem huge compared to modern day supplies, that's more likely 
the result of technology improvements - faster devices, and moving from bipolar 
switching transistors to mosfets. Bipolar transistors have a near-fixed voltage 
drop which can't be reduced and thus present an increasing power loss as 
current goes up, while mosfets can be designed for lower 'insertion' losses.

* If you supply a link & location to a schematic I'll take a look, I don't feel 
like wading around in bitsavers pdfs to try to find it right now.

GE2149G206 Bit slice CPU??

[Holm Tiffe via cctalk]

Hi all,

I've got an VME Bus sized CPU or GPU Board out of ebay a while before,
it is equipped with 4 pcs of AM29203 Slices and an AM2910A Sequencer.
It sems to be a german Product.
The Sticker on one of the DIN 96 Connectors states: 

GE2149G206 WNr. 10488 Grund- Baugruppe

Does anyone know what it is or where is it coming from?

Kind Regards,

Holm
-- 
  Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe, 
 Freiberger Straße 42, 09600 Oberschöna, USt-Id: DE253710583
i...@tsht.de Fax +49 3731 74200 Tel +49 3731 74222 Mobil: 0172 8790 741

looking for out-of-print computer book

[billr--- via cctalk]

Hi folks,

 

I am trying to find an out-of-print tech book for a research project I'm
doing. The book is called Porting Macintosh Applications to Windows 95 and
NT by Greg Stone, dated December 1996, ISBN 0471118516, published by Wiley.

 

It's listed on Amazon but not available; I've searched on
 usedbooksearch.net and even WorldCat, with no
luck. Wondering if anyone has any ideas how I could find a copy? 

 

Figure someone on this list could point me in the right direction. Would
love any help.

 

Thanks,

 

*   Bill.

 

 

Bill Rosenblatt

GiantSteps Media Technology Strategies

157 Columbus Ave., Suite 409

New York, NY 10023

(212) 956-1045

Skype: billrosenblatt

Twitter: @copyrightandtec

Blog: https://copyrightandtechnology.com/

LinkedIn: https://www.linkedin.com/in/billrosenblatt/ 

Forbes: https://www.forbes.com/sites/billrosenblatt/

 

 

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[Fred Cisin via cctalk]

5) as a test suite for development of thermite  (Does Amazon sell pre-made
thermite?)


On Fri, 21 Sep 2018, Eric Smith via cctalk wrote:

Mostly #6, and a little bit of #5. I'd be delighted to offer "retaliation
in kind for the SS damage of drives of Steve Jackson Games", but I don't
think destroying my own drives provides that.


You hadn't previously explicitly mentioned that they were yours.

Let us know how your homemade recipe does on the Kilo-Seagate measurement 
scale.

Re: DEC H744 +5 supply

[Mattis Lind via cctalk]

The H744 is a buck converter. You can read about buck converters here:
https://en.wikipedia.org/wiki/Buck_converter

You have a good description there.

Den fre 21 sep. 2018 kl 22:03 skrev Noel Chiappa via cctalk <
cctalk@classiccmp.org>:

> Oh, one thing I forgot to include:
>
> > a lot of the incoming power in that 30V AC has to be thrown away, in
> > producing +5V.
>
> So, if my understanding is correct, the 'switching' H744 really isn't much
> better than a classic linear supply. It still wastes a very large amount of
> the input power, and it still has a massively heavy transformer in it. Yes?
>
> So I wonder what exactly the advantage was in going to the switching
> approach?
> Yes, it keeps the output voltage steadier then a pure linear supply could -
> but I'll bet there are analog approaches that can do the same. (They'd need
> something that can produce a steady reference voltage, but the switching
> approach needs, and has, the same thing.) Maybe the main output transistors
> are happier being full-on or full-off, or something like that?
>
> Noel
>

Re: DEC H744 +5 supply

[Noel Chiappa via cctalk]

Oh, one thing I forgot to include:

> a lot of the incoming power in that 30V AC has to be thrown away, in
> producing +5V.

So, if my understanding is correct, the 'switching' H744 really isn't much
better than a classic linear supply. It still wastes a very large amount of
the input power, and it still has a massively heavy transformer in it. Yes?

So I wonder what exactly the advantage was in going to the switching approach?
Yes, it keeps the output voltage steadier then a pure linear supply could -
but I'll bet there are analog approaches that can do the same. (They'd need
something that can produce a steady reference voltage, but the switching
approach needs, and has, the same thing.) Maybe the main output transistors
are happier being full-on or full-off, or something like that?

Noel

DEC H744 +5 supply

[Noel Chiappa via cctalk]

So there's something about the H744 I'm not sure I understand; hopefully those
with more analog-fu will set me straight if I'm confused.

This supply runs off 20-30V AC. It takes the input AC, rectifies it, and runs
it through a cap to filter out the ripple. What's next is that it's an early
switching supply; i.e. the electronics inside switches that newly-created main
DC off and on very quickly to keep the output voltage at around +5V.

However...

My understanding is that, without using a transformer (which creates an
independent circuit loop - more below), there's no way to increase the
_amperage_ out of circuit over what's fed into it: since amps are
electrons/second, the electrons/second out more or less have to equal
electrons/second in, since one can't easily 'create' electrons - at least, in
normal electonic gear! (Transformers, by creating a whole new circuit loop,
can 'create' more electrons/second in the new loop; since they tie the 'out'
of the new circuit back to its 'in', they can recirculate the 'extra'
electrons.)

And to the extent that the output is at lower voltage, the energy differential
has to be dumped; hence the huge heat sinks - a lot of the incoming power in
that 30V AC has to be thrown away, in producing +5V. Right?

My (possibly confused) understanding is that later switching supplies take the
incoming 60Hz wall AC, transform it to a higher frequency, run _that_ through
a transformer (which can be a lot smaller, since it's at a higher frequency,
and the higher the frequency, the smaller the transformer you can use - hence
the use of high frequency AC in airplanes, to allow use of smaller - and thus
lighter - transformers). That then turns out a massive amount of amps in the
output loop (since with a transformer, energy out is roughly energy in, modulo
resistive losses; and with constant power, if V goes down, I goes up).

So the losses are a lot lower - N amps at 110V in produce ~20N amps out at
+5V. (Well, depending on all the losses, ~20.) And the whole works is a lot
lighter, to boot.

Did this programmer get all that analog stuff correctly?

Thanks!

Noel

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[allison via cctalk]

On 09/21/2018 12:19 PM, Eric Smith via cctalk wrote:
> On Fri, Sep 21, 2018 at 6:04 AM, Bill Gunshannon via cctalk <
> cctalk@classiccmp.org> wrote:
>
>> Or just throw it in the garbage.
>
> That's way too good for these 

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[Zane Healy via cctalk]

> On Sep 21, 2018, at 11:16 AM, Eric Smith via cctalk  
> wrote:
> 
> On the other hand,
> 
> 1) Reduce the likelihood that they will end up on eBay as "Seller
>> Refurbished" or "New, other".
>> 1b) to put on eBay as "New, other" or "seller refurbished", WITH PICTURES,
>> as a commentary on eBay condition descriptions.
> 
> 
> maybe after application of thermite I might sell them as "Seller
> Refurbished".
> 
> Eric

At that point, sell them in an Art Gallery.

Zane

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[Noel Chiappa via cctalk]

> From: Eric Smith

> That's way too good for these 

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[Chuck Guzis via cctalk]

Anyone headed for Hawaii?  It'd be interesting to see what some molten
lava would do to one...

--Chuck

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[Fred Cisin via cctalk]

Do any of the rifle ranges near Vegas rent use of a Browning 50 caliber 
machine gun?

(or artillery?)


Maybe a VERY high powered laser cutter, to cut the letters N F G THROUGH 
the drives.


Convince North Korea that there would be special symbolism to attaching 
one to the nosecone of each of their nuclear missiles.

Or:
Convince North Korea that those are what they need to improve the data 
processing of their nuclear program.



If they were mailed anonymously and unlabelled to various TLAs, how much 
effort would be wasted in the attempts to read them?

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[Chris Elmquist via cctalk]

On Friday (09/21/2018 at 11:42AM -0600), Eric Smith via cctalk wrote:
> On Fri, Sep 21, 2018 at 11:28 AM, Fred Cisin via cctalk <
> cctalk@classiccmp.org> wrote:
> 
> > Put it in a gift-wrapped box next to you on the bus.
> > Whoever steals it will get just what they deserve.
> >
> 
> :-)
> 
> But actually I wouldn't wish ST3000DM001 drives on my worst enemy!

Ship them across town by FedEx,

https://www.youtube.com/watch?v=WCGBNj-aSwA

-- 
Chris Elmquist

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[Eric Smith via cctalk]

On Fri, Sep 21, 2018 at 12:06 PM, Fred Cisin via cctalk <
cctalk@classiccmp.org> wrote:

> Eric hasn't specified [and shouldn't have to] as to WHY,
> but here are some idle speculations:
>

Mostly #6, and a little bit of #5. I'd be delighted to offer "retaliation
in kind for the SS damage of drives of Steve Jackson Games", but I don't
think destroying my own drives provides that.


> 5) as a test suite for development of thermite  (Does Amazon sell pre-made
> thermite?)
>
> 6) Maybe Eric just wants to vent some anger over problems he had with them



On the other hand,

1) Reduce the likelihood that they will end up on eBay as "Seller
> Refurbished" or "New, other".
> 1b) to put on eBay as "New, other" or "seller refurbished", WITH PICTURES,
> as a commentary on eBay condition descriptions.


maybe after application of thermite I might sell them as "Seller
Refurbished".

Eric

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[Fred Cisin via cctalk]

On Fri, 21 Sep 2018, Eric Smith via cctalk wrote:

That's way too good for these 

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[Peter Corlett via cctalk]

On Fri, Sep 21, 2018 at 12:04:39PM +, Bill Gunshannon via cctalk wrote:
> Or just throw it in the garbage. [...]

More satisfying: write "Bitcoins" on it before leaving it lying around
somewhere it's likely to get stolen.

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[emanuel stiebler via cctalk]

On 2018-09-21 13:42, Eric Smith via cctalk wrote:
> On Fri, Sep 21, 2018 at 11:28 AM, Fred Cisin via cctalk <
> cctalk@classiccmp.org> wrote:
> 
>> Put it in a gift-wrapped box next to you on the bus.
>> Whoever steals it will get just what they deserve.
>>
> 
> :-)
> 
> But actually I wouldn't wish ST3000DM001 drives on my worst enemy!

Keep them for "Independence Day III" ;-)

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[Eric Smith via cctalk]

On Fri, Sep 21, 2018 at 11:28 AM, Fred Cisin via cctalk <
cctalk@classiccmp.org> wrote:

> Put it in a gift-wrapped box next to you on the bus.
> Whoever steals it will get just what they deserve.
>

:-)

But actually I wouldn't wish ST3000DM001 drives on my worst enemy!

Re: Buy Herman's house!

[Peter Corlett via cctalk]

On Fri, Sep 21, 2018 at 07:13:48AM -0700, Donald via cctalk wrote:
> Mr. Hollerith's house is available.

Is it... a house of cards?

Thank you, I'll be here all week.

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[Fred Cisin via cctalk]

On Fri, 21 Sep 2018, Bill Gunshannon via cctalk wrote:

Or just throw it in the garbage.  Do you really think people are going
thru your  stuff looking for data?


Put it in a gift-wrapped box next to you on the bus.

Whoever steals it will get just what they deserve.

Re: HP 2000 /2100 emulator ?

[Ed Sharpe via cctalk]

yea   doing the  same  here  at  SMECC  at  some point we have a  2000 
access system  but   probably needs  work and and a  disck  drive and besides  
who wants to power and cool it  24/7?


 
I  need a  couple  extra  front panels I make  blink (  do not  want to mess  
with the  ones  belonging  to system.. )) and st the  33 or  35  in front t of 
it.
 
 
would  love a  2883  disk  drive?  even willing to ship its  500 lb mass across 
 country
 
 
ed sharpe archivist for smecc
 
In a message dated 9/21/2018 9:50:45 AM US Mountain Standard Time, 
cctalk@classiccmp.org writes:

 
On Fri, Sep 21, 2018 at 8:18 AM, Pete Lancashire via cctalk <

cctalk@classiccmp.org> wrote:

> emulate an HP 2000 or even in modern 2100 my goal is nothing serious I'd
> love to be able to do HP basic and find the version of Star Trek I think
>


> If I could have my dream come true the emulator would be on a little SBC
> running Linux t
>

SIMH can do that and runs just fine on a Raspberry Pi, or probably on any
other Linux SBC.

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[Guy Sotomayor Jr via cctalk]

If I wanted to reduce a drive to slag, I’d just put it in a propane furnace 
(actually the drive would
go into the crucible).  They generate up to 2700F (~1500C) and they’re for 
melting gold, silver, copper,
etc.  So I suspect it would do the job.  ;-)  Plus you’d a nice molten mess 
that you can pour out.

TTFN - Guy


> On Sep 21, 2018, at 9:43 AM, Ed Sharpe via cctalk  
> wrote:
> 
> Hmmm...  OK   take a  giant  sledge and beat the living  hell out  of  it
> 
> 
> Great  physical release and   data  pretty well   toast... and the sound 
> is glorious!
>  
> And  besides you get  some  exercise!
>  
> Ed#
>  
>  
>  
>  
>  
>  
> In a message dated 9/21/2018 9:20:25 AM US Mountain Standard Time, 
> cctalk@classiccmp.org writes:
> 
>  
> On Fri, Sep 21, 2018 at 6:04 AM, Bill Gunshannon via cctalk <
> 
> cctalk@classiccmp.org> wrote:
> 
>> Or just throw it in the garbage.
> 
> 
> That's way too good for these 

Re: HP 2000 /2100 emulator ?

[Eric Smith via cctalk]

On Fri, Sep 21, 2018 at 8:18 AM, Pete Lancashire via cctalk <
cctalk@classiccmp.org> wrote:

> emulate an HP 2000 or even in modern 2100 my goal is nothing serious I'd
> love to be able to do HP basic and find the version of Star Trek I think
>


> If I could have my dream come true the emulator would be on a little SBC
> running Linux t
>

SIMH can do that and runs just fine on a Raspberry Pi, or probably on any
other Linux SBC.

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[Ed Sharpe via cctalk]

Hmmm...  OK   take a  giant  sledge and beat the living  hell out  of  it


Great  physical release and   data  pretty well   toast... and the sound is 
glorious!
 
And  besides you get  some  exercise!
 
Ed#
 
 
 
 
 
 
In a message dated 9/21/2018 9:20:25 AM US Mountain Standard Time, 
cctalk@classiccmp.org writes:

 
On Fri, Sep 21, 2018 at 6:04 AM, Bill Gunshannon via cctalk <

cctalk@classiccmp.org> wrote:

> Or just throw it in the garbage.


That's way too good for these 

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[Eric Smith via cctalk]

On Fri, Sep 21, 2018 at 6:51 AM, systems_glitch via cctalk <
cctalk@classiccmp.org> wrote:

> Burning of potassium permanganate to manganese greensand will often get it
> going. You are on your own for figuring out how to do that.
>

Multiple sources, including Robert on this list, tell me just to use
magnesium ribbon. I just looked it up; it's inexpensive and should be very
easy to use.


> Thermite is not the ultimate destructive force some people seem to think it
> is. If you're trying to totally liquefy the platters you'll probably need
> to remove them from the drives and put them in something capable of
> containing the thermite for at least a little while (e.g. graphite
> crucible). The usual, "put it in a flower pot" will likely either result in
> a mess or a smallish hole through the platter, which really isn't any
> better than running a drill through it.
>

All the more reason to experiment with it!

Elsewhere it's been suggested that somewhere between 0.25 and 0.5 kg of
thermite ought to do the job without needing to disassemble the drive
first. I've got sixteen drives to experiment with.

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[Eric Smith via cctalk]

On Fri, Sep 21, 2018 at 6:04 AM, Bill Gunshannon via cctalk <
cctalk@classiccmp.org> wrote:

> Or just throw it in the garbage.


That's way too good for these 

Re: Beckman DU600 MC68332 SBC (Was: HP CPU32 Emulation Adapter)

[Joseph Zatarski via cctalk]

That board came out of the instrument it belongs to (a Beckman DU600), 
which came out of the trash here. I've put quite a bit of time into 
reverse engineering the hardware as well as porting and writing some 
software. The most recent thing I've done with it is port an old version 
of minix.



https://youtu.be/s8kXpKJqy9U


https://imgur.com/a/JGS0X


On 09/21/2018 05:04 AM, Carlo Pisani wrote:

But, I've got one of these:
https://hackaday.io/project/6150-beckman-du600-reverse-engineering

hi
where did you find it?
here I have an EVS board, by motorola :P

HP 2000 /2100 emulator ?

[Pete Lancashire via cctalk]

I will soon have a teletype model 35 all cleaned up and running
Why like is some suggestions for something I can put in the base and
emulate an HP 2000 or even in modern 2100 my goal is nothing serious I'd
love to be able to do HP basic and find the version of Star Trek I think
that was the name of the game just show I can demonstrate the friends how
cool these machines were.

If I could have my dream come true the emulator would be on a little SBC
running Linux t
Or even a simple OS that upon being powered up it would display login or
was that log on on the teletype pretty much having the coat hard-coated but
still having an area for saving files.

Thanks and thanks for all the previous assistance members of this group of
this list have given me

Buy Herman's house!

[Donald via cctalk]

Mr. Hollerith's house is available.

 

https://www.wsj.com/articles/forgotten-tech-pioneers-d-c-estate-asks-almost-
19-million-1537456578?emailToken=bb675bfcb9f6274f6e8c1b05ae28f2344xumjbywJXs
AwzIJYvBg3RJlRIZHZMV6ZNib7ahvK98qrcXxNgBADqPZCBCTTSWKSViH7isyQ4Ra78fLGOUMQtm
bpNzGJ7UynZ+6QLN+6DJX7vdRFal288hJJHrIqDHw

=article_copyURL_share

 

 

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[Nemo via cctalk]

On 20 September 2018 at 23:20, Eric Smith via cctalk
 wrote:
> Anyone have advice on making thermite? Ingredients, sources, proportions?
>

NIST SP 800-88 Rev. 1?  There is some milspec about sanding the
platters that actually specified what grit to use but I do not
remember the title.

N.

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[drlegendre via cctalk]

Take them up to the 'range, around Virginia or Eveleth MN, and pay one of
the demo crews to stick the drives at the bottom of their next borehole.

Ka-blooey! Nothing left but an artificial bauxite deposit.

On Fri, Sep 21, 2018, 7:10 AM Bill Degnan via cctalk 
wrote:

> I can only assume someone is paying you to do this for insurance or legal
> purposes.  There is a good poem, "John Barleycorn Must Die" which has a lot
> of useful suggestions.
> bill
>
> On Fri, Sep 21, 2018 at 8:04 AM Bill Gunshannon via cctalk <
> cctalk@classiccmp.org> wrote:
>
> > Or just throw it in the garbage.  Do you really think people are going
> > thru your
> >
> > stuff looking for data?
> >
> >
> > bill
> >
> >
> >
> > On 09/20/2018 11:37 PM, drlegendre via cctalk wrote:
> > > If you're that intent on firey destruction, it would be much simpler &
> > > safer to use an oxyacetylene cutting torch, or a plasma cutter.
> > >
> > > On Thu, Sep 20, 2018, 10:20 PM Eric Smith via cctalk <
> > cctalk@classiccmp.org>
> > > wrote:
> > >
> > >> Anyone have advice on making thermite? Ingredients, sources,
> > proportions?
> > >>
> > >> The internet seems to think that just using aluminum powder with
> ferric
> > >> oxide is relatively hard to ignite, and that some manganese dioxide
> > would
> > >> help with that.
> > >>
> > >> Without spending too much time shopping, it looks like I can get:
> > >> * aluminum powder, 5 micron, 2 lb for $34
> > >> * ferric oxide, 10 lb for $27
> > >> * manganese dioxide, 1 lb for $39
> > >>
> >
> >
>

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[systems_glitch via cctalk]

Burning of potassium permanganate to manganese greensand will often get it
going. You are on your own for figuring out how to do that.

Thermite is not the ultimate destructive force some people seem to think it
is. If you're trying to totally liquefy the platters you'll probably need
to remove them from the drives and put them in something capable of
containing the thermite for at least a little while (e.g. graphite
crucible). The usual, "put it in a flower pot" will likely either result in
a mess or a smallish hole through the platter, which really isn't any
better than running a drill through it. The suggestion of using an
acetylene torch is far more practical, if you for some reason are really
needing to turn platters into blobs.

Thanks,
Jonathan

On Fri, Sep 21, 2018 at 8:45 AM Robert via cctalk 
wrote:

> If my memory of O Level chemistry classes is anything to go by, the
> idea was that you used a piece of Magnesium ribbon to ignite it. I
> don't recall Manganese Dioxide being part of the recipe.
> On Thu, Sep 20, 2018 at 10:20 PM Eric Smith via cctalk
>  wrote:
> >
> > Anyone have advice on making thermite? Ingredients, sources, proportions?
> >
> > The internet seems to think that just using aluminum powder with ferric
> > oxide is relatively hard to ignite, and that some manganese dioxide would
> > help with that.
> >
> > Without spending too much time shopping, it looks like I can get:
> > * aluminum powder, 5 micron, 2 lb for $34
> > * ferric oxide, 10 lb for $27
> > * manganese dioxide, 1 lb for $39
>

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[Bill Degnan via cctalk]

I can only assume someone is paying you to do this for insurance or legal
purposes.  There is a good poem, "John Barleycorn Must Die" which has a lot
of useful suggestions.
bill

On Fri, Sep 21, 2018 at 8:04 AM Bill Gunshannon via cctalk <
cctalk@classiccmp.org> wrote:

> Or just throw it in the garbage.  Do you really think people are going
> thru your
>
> stuff looking for data?
>
>
> bill
>
>
>
> On 09/20/2018 11:37 PM, drlegendre via cctalk wrote:
> > If you're that intent on firey destruction, it would be much simpler &
> > safer to use an oxyacetylene cutting torch, or a plasma cutter.
> >
> > On Thu, Sep 20, 2018, 10:20 PM Eric Smith via cctalk <
> cctalk@classiccmp.org>
> > wrote:
> >
> >> Anyone have advice on making thermite? Ingredients, sources,
> proportions?
> >>
> >> The internet seems to think that just using aluminum powder with ferric
> >> oxide is relatively hard to ignite, and that some manganese dioxide
> would
> >> help with that.
> >>
> >> Without spending too much time shopping, it looks like I can get:
> >> * aluminum powder, 5 micron, 2 lb for $34
> >> * ferric oxide, 10 lb for $27
> >> * manganese dioxide, 1 lb for $39
> >>
>
>

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[Bill Gunshannon via cctalk]

Or just throw it in the garbage.  Do you really think people are going 
thru your

stuff looking for data?


bill



On 09/20/2018 11:37 PM, drlegendre via cctalk wrote:
> If you're that intent on firey destruction, it would be much simpler &
> safer to use an oxyacetylene cutting torch, or a plasma cutter.
>
> On Thu, Sep 20, 2018, 10:20 PM Eric Smith via cctalk 
> wrote:
>
>> Anyone have advice on making thermite? Ingredients, sources, proportions?
>>
>> The internet seems to think that just using aluminum powder with ferric
>> oxide is relatively hard to ignite, and that some manganese dioxide would
>> help with that.
>>
>> Without spending too much time shopping, it looks like I can get:
>> * aluminum powder, 5 micron, 2 lb for $34
>> * ferric oxide, 10 lb for $27
>> * manganese dioxide, 1 lb for $39
>>

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[Robert via cctalk]

If my memory of O Level chemistry classes is anything to go by, the
idea was that you used a piece of Magnesium ribbon to ignite it. I
don't recall Manganese Dioxide being part of the recipe.
On Thu, Sep 20, 2018 at 10:20 PM Eric Smith via cctalk
 wrote:
>
> Anyone have advice on making thermite? Ingredients, sources, proportions?
>
> The internet seems to think that just using aluminum powder with ferric
> oxide is relatively hard to ignite, and that some manganese dioxide would
> help with that.
>
> Without spending too much time shopping, it looks like I can get:
> * aluminum powder, 5 micron, 2 lb for $34
> * ferric oxide, 10 lb for $27
> * manganese dioxide, 1 lb for $39

Hitex ICE for Motorola 68hc11

[Carlo Pisani via cctalk]

hi
has anyone ever used  Hitex ICE for Motorola 68hc11?
if so, with which software?

cheers

Re: HP CPU32 Emulation Adapter

[Carlo Pisani via cctalk]

> But, I've got one of these:
> https://hackaday.io/project/6150-beckman-du600-reverse-engineering

hi
where did you find it?
here I have an EVS board, by motorola :P

Re: Advice requested on proper disposal of Seagate ST3000DM001 disk drives

[Wayne S via cctalk]

Be aware that a cheap way of making fairly pure oxygen is just by heating up 
manganese dioxide, which will cause anything that is a like a flame to burn 
much hotter. I remember doing an experiment in grade school where you heat up a 
tablespoonfull of MD in a test tube with an  alcohol burner or (even a match 
under the tube), then slowly insert a popsicle stick with a glowing ember (you 
light the stick with a match then blow it out to get the glowing ember). The 
result is that the stick bursts into flame rather violently.

Just saying "BE CAREFUL".





Wayne


> On Sep 20, 2018, at 9:39 PM, Alexandre Souza via cctalk 
>  wrote:
> 
> Have you heard about a pointy hammer? :)
> 
> 
> 2018-09-21 0:37 GMT-03:00 drlegendre via cctalk :
> 
>> If you're that intent on firey destruction, it would be much simpler &
>> safer to use an oxyacetylene cutting torch, or a plasma cutter.
>> 
>> On Thu, Sep 20, 2018, 10:20 PM Eric Smith via cctalk <
>> cctalk@classiccmp.org>
>> wrote:
>> 
>>> Anyone have advice on making thermite? Ingredients, sources, proportions?
>>> 
>>> The internet seems to think that just using aluminum powder with ferric
>>> oxide is relatively hard to ignite, and that some manganese dioxide would
>>> help with that.
>>> 
>>> Without spending too much time shopping, it looks like I can get:
>>> * aluminum powder, 5 micron, 2 lb for $34
>>> * ferric oxide, 10 lb for $27
>>> * manganese dioxide, 1 lb for $39
>>