John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote in
news:i5gtkhhjtkr7lhajfo4mg16ag294ped50q@4ax.com:

> On Tue, 18 Oct 2022 14:55:00 -0000 (UTC),
> DecadentLinuxUserNumeroUno@decadence.org wrote:
>
>>John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote in
>>news:smdtkhhofnb1ckdj29jofegoo2f6mce7k2@4ax.com:
>>
>>> On Tue, 18 Oct 2022 14:16:07 -0000 (UTC),
>>> DecadentLinuxUserNumeroUno@decadence.org wrote:
>>>
>>>>John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote in
>>>>news:vf9skhph0rqm0g05ehgd9f9u5nrrab1f70@4ax.com:
>>>>
>>>>>
>>>>> Rack panels are standard and look strange if they are thicker
>>>>> than their neighbors. The heavy stuff needs trays or slides of
>>>>> course.
>>>>>
>>>> You have obviously never seen a rack populated with devices
>>>> from
>>>>multiple vendors.
>>>
>>> Probably not more than 10,000 times.
>>
>> All cheap chassis shit like the one you are going to use?
>>
>>> I don't think I've ever seen
>>> a panel that wasn't 1/8 thick. It would look weird.
>>
>> I think that until this thread, you were oblivious to it. Until
>> I
>>was critical of your choice. Especially ina a 4U design.
>>
>>>>The thickness of the front panel is (and should
>>>>be) dependent on what the weight of the gear is it supports.
>>>
>>> Do NOT cantelever heavy stuff off the front panel!
>>
>> Bullshit. The spec is that the device MUST be able to be
>> supported
>>by said front panel and by that alone. The designer cannot know
>>if there will be another device or stack of devices below it.
>
> What spec? Who enforces it?

Use some common sense. AND ask the dopes you are buying that POS
thin faced turd from. No matter what you think, the front panel
carries all the weight of the unit, just as the specs state, and the
ONLY exception is when "drawer slides" have been mounted.

> If a heavy unit is cantelevered off the front panel,

For one thing, that is not even the correct term. Any rack device
will be stable if only held in place by the bottom two screws,
because the entire faceplate is held fast against the rack by the
weight of the device itself hanging behind the faceplate.

> it will be a
> hazard to install and remove.

You have obviously not spent much time populating racks, much less
examining rack equipment, and obviously particularly not for a
military contractor.

> As you install it, it will scrape on
> the unit below and scratch it up.

More bullshit. The spec also includes NOT having ANY protrusions
on the top and bottom face of your product. Like screw heads on the
bottom OR the top of your unit. So "sliding one out" after the front
panel has been detached ALWAYS has its weight on the unit below it.
If there is no unit there, one must hold the weight as the screws are
removed to keep it horizontally oriented. They are specifically made
to be able to be slid into place on top of an existing unit, and ALL
properly designed rack mount devices have ZERO protrusions on the top
or the bottom. One must use countersunk, flush or below flush
fasteners in one's design. There are also not supposed to be any
venting on the top or bottom of a unit.

You said you "saw" thousands of units. I INSTALLED (and
uninstallled) thousands of units over several years time and those
racks are in place in over 50 cities around the world. They were ALL
100% fully disassembled after the build and the cabling and rack
units and the racks were shiped to the site and then fully reloaded
and rewired up. Every last one... literally thousands of units
Some 3U and up units do get slides installed. Some do not. Again,
the specification is that the unit must be able to reside in the rack
only held by the front panel with no rear attachment (slide mount
points). Granted many if not most folks incorporate rear attached
slides that support the weight as well, but that is a prefernce, not
a requisite. The spec remains. The only exception are server
chassis, which are typically many more U than a 3 or 4. They ALWAYS
get slides installed.

A good example is rack mounted UPS units. They have very thick
front faces. Because they follow the spec. Not every one gets
installed in the bottom of the rack or gets slides added, and those
that do... oh looky... nothing below to support them. There are
many other heavy devices with thick front panels. Why? Because that
is the spec.

> When someone later loosens the
> front panel screws, all its weight will flop onto the unit below,

No shit. And no, it does not "flop", like your argument here has.
You are sporting 100% flawed logic. It sits on what is below it and
if there is no unit below it, it should be sitting on the tech's hand
as the front panel fasteners get removed. And it has been that way
since the onset of the use of this type chassis which we all know of
as racks.

> which already had its own weight to support.

Racks typically, but not always get populated from the bottom up.
Been that way forever. The stack of still installed units below the
one being serviced are supposed to be able to support such weight.
Been that way forever. The bottom unit has no support below it.
Some get slides and some do not.

> The whole stack of
> units could collapse.

More flawed, non-factual horseshit.
> Users can't know, years later, if this will happen or if the unit
> below can bear the weight of both.

A tech pulling a unit from a rack will normally have access to the
rear of the rack to remove cabilng AND to examine the circumstance
under which they are performing the servicing. More flawed, non-
factual logic on your part... for years running.

> Don't do it. Nobody competant does.

All the folks in industry that use racks who know how to spell the
word competent do.

On Tue, 18 Oct 2022 19:08:44 -0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

>
>> When someone later loosens the
>> front panel screws, all its weight will flop onto the unit below,
>
> No shit. And no, it does not "flop", like your argument here has.
>You are sporting 100% flawed logic. It sits on what is below it and
>if there is no unit below it, it should be sitting on the tech's hand
>as the front panel fasteners get removed. And it has been that way
>since the onset of the use of this type chassis which we all know of
>as racks.
>

So one tech uses his hand, from the back of the rack, to support the
box while another tech pushes the heavy box into the rack and fastens
the front panel screws? Hire really strong techs. Or one with really
long arms.

Try that with this gradient driver amp:

https://www.dropbox.com/s/qbpws16c29asaxc/PP5.JPG?raw=1

John Larkin <jlarkin@highland_atwork_technology.com> wrote in
news:if2ukh1fdd78e23c5sc7aj80gnqqg93qg9@4ax.com:

> On Tue, 18 Oct 2022 19:08:44 -0000 (UTC),
> DecadentLinuxUserNumeroUno@decadence.org wrote:
>
>>
>>> When someone later loosens the
>>> front panel screws, all its weight will flop onto the unit
>>> below,
>>
>> No shit. And no, it does not "flop", like your argument here
>> has.
>>You are sporting 100% flawed logic. It sits on what is below it
>>and if there is no unit below it, it should be sitting on the
>>tech's hand as the front panel fasteners get removed. And it has
>>been that way since the onset of the use of this type chassis
>>which we all know of as racks.
>>
>
> So one tech uses his hand, from the back of the rack, to support
> the box while another tech pushes the heavy box into the rack and
> fastens the front panel screws? Hire really strong techs. Or one
> with really long arms.
>
> Try that with this gradient driver amp:
>
> https://www.dropbox.com/s/qbpws16c29asaxc/PP5.JPG?raw=1

Before I built all those satellite baseband gateways for all those
US and Aussie cities, I built the simulator for the F-35. Several
racks full of GHz level RF modules... And then another... and then
a third. They were several racks of 9 units. 8 4U 16 channel units
with one 5 or 6U center modules, which were the combiners for those
with a back panel loaded with 64 SMA ports that resolved down to 16.
I built those modules. But none of them had a behemoth like that in
them. They all were Chem etched Aluminum though like that chassis. I
hand built every single module and *then* installed them all into the
racks.

So after months of building units and tying them all together using
same length cables, etc. They all went into a classified lab that
after I placed and wired together all the racks, including a monster
inch diameter welding cable that grounded all of them together that
would be placed in the field in the drop floor when it got to the
Hughes Anechoic facility in Texas. After I got them all wired
together, they program all of the racks for timing so that all 1024
channels were gathering signals that all then got the same timestamp,
and calibrated the offsets down to microseconds (or even faster).
Once we got all that done, I was no longer allowed in that lab, wired
it with white noise generators over the door to the lab and was
literally no longer allowed in the lab because I did not have the
clearance for the final programming segment. A lab you were not even
allowed to take a piece of paper into or any kind of writing
instrument. It became a secret level classified lab. There was a
small wooden box on the wall outside the lab for cell phones. The
door had an electronic lock on it that looked like the dial on a bank
vault. And a sign in / out sheet.

I literally built every module from flat panels and side panels
with angled edges for rigidity. They were pretty thick Aluminum
chassis. Each of the 4U modules had 16 variable phase, variable gain
modules from General Microwave at first. Those were how they all got
calibrated together for matched arrival times on signals. They had
several tens of units (at like $800 each) that would not perform the
370 odd degree span of the electroninc phase control.
Apparently the vendor's in house calibrator looked at the two ends
of the spectrum and called them good to go, but in actual use they
puked on wheeling the phase around the full 360 degrees much less
370. So they ALL got rejected and a new vendor used. The real PITA
was having to take the rack modules all apart to replace the 16 units
in each one with the new vendor's modules. They worked nice and were
a lot lighter weight than the hobbed out chassis of the originals,
but I had them alter the chassis design to make that rear of the rack
bank of mixers and phase shift modules "serviceable". Because that
replacement chore was a real pain. They agreed. So now, they could
be serviced without having to disassemble practically the entire
module. Two central trays instead of just one. I have probably seen
and used more semi-rigid SMA cables than you have, so many that we
got really good prices from the makers and then there were a huge
number of sheathed SMA cables for all the back of the rack links to
that the center splitter / combiner in each rack had. But inside
there were a hundred small diameter "solder wetted" of the unsheathed
semi-rigid variety. Various same length links. My shtuff looked
like that Quantum computer they make that gets lowered down into a
liquid Nitrogen tank. And the splitter combiner was a mad house of
links inside. 16 sets of 8 way splitter combiners inside to make the
giant 64 channel center modules. So they were timed together very
good, and the phase shift / attenuator modules had less of a chore to
do to get them all synched up. Making any detected event carry
proper microsecond timed stamps on them for the events that were
simulated in the anechoic chamber in order to calibrate the sensors
on the F-35 they had hanging there in the chamber with all of my
racks full of channels. Fake a missile launch radio event in the
chamber and get all the sensors in the bird calibrated out correctly.
I wish I had been able to go down to Hughes to seee it in place, but
did not have the clearance yet.

But none of the rack devices I built that were 6+U like that had a
hunk of laminated mass in them like that though! The 4 inch wide
slides, right? Dang, dude.

They all used linear supplies because swtchers introduce glitches
ticks and noise into the high frequency events. So bigger than a
switching supply but still small potatoes compared to that monster.
Your gonna need a bigger overhead lift. That looks dangerous for
that amount of weight. How many did you have to make of those? And
you WANT to be a power supply maker... so funny. You move from
small Hi Freq devices to big PS stuff. I question your logic again.
Hehehe...

The biggest we produced when I was at the power supply company
weight wise on this side of the pond was one that had two 2kVA
transformers sitting in the bottom of it, and it looked like a big
server on casters. Like a Weeble, one could not knock it over. All
the weight was down there at the bottom.

But back at the telecom place (F-35 Stimulator) every unit used
slides and they were ALL suspended units that did not touch the unit
above or below, even though the racks were all fully populated from
top to bottom. Any unit could be pulled out and serviced at the
bench easily. They were fairly light.

But when I did the satellite baseband gateway series of racks some
were packed in like sardines, and all were packed with millions worth
of our gear and network switching gear from Cisco and Juniper.
Quadruple redundant. High speed, properly terminated Ethernet links,
and high speed optical links all throughout. All tagged by a whole
crew of girls that came in after I built out the racks. Then ran
power to them and then the software engineers would come in and
install many many sessions of boot / and run VDMs on all the items
that had operating systems or firmware that operated them...
quadruple redundant... oh, did I say that already? Then, the girls
break all the wiring down and put it in a giant box on a pallet.
Each end tagged of course. And I would the place every item back in
the boxes they came in and the only thing that remained in the racks
were the power strips and the big server card chassis. And any blank
slot covers.

Once on site, there were two 8 meter dishes being constructed to
point at the bird in the sky with. And they reset all of the racks,
without their soft shipping pads, and add a couple Ka band RF racks,
which we did not need in the network side series of racks I built,
and put all the cables back in and fired them up for a series of
startup testing... and voila! Satellite baseband gateway. 21 US
cities and 17 cities in Australia, and a couple colleges in the
middle east. Theirs was the most scrutinized, believe that.
One rack was filled top to bottom with high speed hard drive arrays.
None of ours or Australia's had that.

On Tue, 18 Oct 2022 08:15:28 -0700, John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote:

>On Tue, 18 Oct 2022 14:55:00 -0000 (UTC),
>DecadentLinuxUserNumeroUno@decadence.org wrote:
>
>>John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote in
>>news:smdtkhhofnb1ckdj29jofegoo2f6mce7k2@4ax.com:
>>
>>> On Tue, 18 Oct 2022 14:16:07 -0000 (UTC),
>>> DecadentLinuxUserNumeroUno@decadence.org wrote:
>>>
>>>>John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote in
>>>>news:vf9skhph0rqm0g05ehgd9f9u5nrrab1f70@4ax.com:
>>>>
>>>>>
>>>>> Rack panels are standard and look strange if they are thicker
>>>>> than their neighbors. The heavy stuff needs trays or slides of
>>>>> course.
>>>>>
>>>> You have obviously never seen a rack populated with devices from
>>>>multiple vendors.
>>>
>>> Probably not more than 10,000 times.
>>
>> All cheap chassis shit like the one you are going to use?
>>
>>> I don't think I've ever seen
>>> a panel that wasn't 1/8 thick. It would look weird.
>>
>> I think that until this thread, you were oblivious to it. Until I
>>was critical of your choice. Especially ina a 4U design.
>>
>>>>The thickness of the front panel is (and should
>>>>be) dependent on what the weight of the gear is it supports.
>>>
>>> Do NOT cantelever heavy stuff off the front panel!
>>
>> Bullshit. The spec is that the device MUST be able to be supported
>>by said front panel and by that alone. The designer cannot know if
>>there will be another device or stack of devices below it.
>
>What spec? Who enforces it?
>
>If a heavy unit is cantelevered off the front panel, it will be a
>hazard to install and remove. As you install it, it will scrape on the
>unit below and scratch it up. When someone later loosens the front
>panel screws, all its weight will flop onto the unit below, which
>already had its own weight to support. The whole stack of units could
>collapse.
>
>Users can't know, years later, if this will happen or if the unit
>below can bear the weight of both.
>
>Don't do it. Nobody competant does.

There are customers that do care, and test for it by full-scale
vibration tests on whole cabinets to MIL-S-901. A front-cantilevered
heavy components would break free and fly across the room.

Small equipment rates a 500-pound hammer, and medium rates 2000
pounds.

..<https://en.wikipedia.org/wiki/MIL-S-901>

The barge test is a sight to behold.

Joe Gwinn

On Thu, 20 Oct 2022 14:18:57 -0400, Joe Gwinn <joegwinn@comcast.net>
wrote:

>On Tue, 18 Oct 2022 08:15:28 -0700, John Larkin
><jlarkin@highlandSNIPMEtechnology.com> wrote:
>
>>On Tue, 18 Oct 2022 14:55:00 -0000 (UTC),
>>DecadentLinuxUserNumeroUno@decadence.org wrote:
>>
>>>John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote in
>>>news:smdtkhhofnb1ckdj29jofegoo2f6mce7k2@4ax.com:
>>>
>>>> On Tue, 18 Oct 2022 14:16:07 -0000 (UTC),
>>>> DecadentLinuxUserNumeroUno@decadence.org wrote:
>>>>
>>>>>John Larkin <jlarkin@highlandSNIPMEtechnology.com> wrote in
>>>>>news:vf9skhph0rqm0g05ehgd9f9u5nrrab1f70@4ax.com:
>>>>>
>>>>>>
>>>>>> Rack panels are standard and look strange if they are thicker
>>>>>> than their neighbors. The heavy stuff needs trays or slides of
>>>>>> course.
>>>>>>
>>>>> You have obviously never seen a rack populated with devices from
>>>>>multiple vendors.
>>>>
>>>> Probably not more than 10,000 times.
>>>
>>> All cheap chassis shit like the one you are going to use?
>>>
>>>> I don't think I've ever seen
>>>> a panel that wasn't 1/8 thick. It would look weird.
>>>
>>> I think that until this thread, you were oblivious to it. Until I
>>>was critical of your choice. Especially ina a 4U design.
>>>
>>>>>The thickness of the front panel is (and should
>>>>>be) dependent on what the weight of the gear is it supports.
>>>>
>>>> Do NOT cantelever heavy stuff off the front panel!
>>>
>>> Bullshit. The spec is that the device MUST be able to be supported
>>>by said front panel and by that alone. The designer cannot know if
>>>there will be another device or stack of devices below it.
>>
>>What spec? Who enforces it?
>>
>>If a heavy unit is cantelevered off the front panel, it will be a
>>hazard to install and remove. As you install it, it will scrape on the
>>unit below and scratch it up. When someone later loosens the front
>>panel screws, all its weight will flop onto the unit below, which
>>already had its own weight to support. The whole stack of units could
>>collapse.
>>
>>Users can't know, years later, if this will happen or if the unit
>>below can bear the weight of both.
>>
>>Don't do it. Nobody competant does.
>
>There are customers that do care, and test for it by full-scale
>vibration tests on whole cabinets to MIL-S-901. A front-cantilevered
>heavy components would break free and fly across the room.

>
>Small equipment rates a 500-pound hammer, and medium rates 2000
>pounds.
>
>.<https://en.wikipedia.org/wiki/MIL-S-901>
>
>The barge test is a sight to behold.
>
>Joe Gwinn

Yes. We tested some marine control consoles. They were installed in a
barge in a pond and explosives were detonated in the water. All sorts
of buttons and knobs flew off, imaged by a high speed movie camera.

They used some sort of magnesium lights for the camera, and that set
some stuff on fire, but that didn't count against us.

在 2022年10月21日星期五 UTC+8 10:08:43，<John Larkin> 写道：
> On Thu, 20 Oct 2022 14:18:57 -0400, Joe Gwinn <joeg...@comcast.net>
> wrote:
>
> >On Tue, 18 Oct 2022 08:15:28 -0700, John Larkin
> ><jla...@highlandSNIPMEtechnology.com> wrote:
> >
> >>On Tue, 18 Oct 2022 14:55:00 -0000 (UTC),
> >>DecadentLinux...@decadence.org wrote:
> >>
> >>>John Larkin <jla...@highlandSNIPMEtechnology.com> wrote in
> >>>news:smdtkhhofnb1ckdj2...@4ax.com:
> >>>
> >>>> On Tue, 18 Oct 2022 14:16:07 -0000 (UTC),
> >>>> DecadentLinux...@decadence.org wrote:
> >>>>
> >>>>>John Larkin <jla...@highlandSNIPMEtechnology.com> wrote in
> >>>>>news:vf9skhph0rqm0g05e...@4ax.com:
> >>>>>
> >>>>>>
> >>>>>> Rack panels are standard and look strange if they are thicker
> >>>>>> than their neighbors. The heavy stuff needs trays or slides of
> >>>>>> course.
> >>>>>>
> >>>>> You have obviously never seen a rack populated with devices from
> >>>>>multiple vendors.
> >>>>
> >>>> Probably not more than 10,000 times.
> >>>
> >>> All cheap chassis shit like the one you are going to use?
> >>>
> >>>> I don't think I've ever seen
> >>>> a panel that wasn't 1/8 thick. It would look weird.
> >>>
> >>> I think that until this thread, you were oblivious to it. Until I
> >>>was critical of your choice. Especially ina a 4U design.
> >>>
> >>>>>The thickness of the front panel is (and should
> >>>>>be) dependent on what the weight of the gear is it supports.
> >>>>
> >>>> Do NOT cantelever heavy stuff off the front panel!
> >>>
> >>> Bullshit. The spec is that the device MUST be able to be supported
> >>>by said front panel and by that alone. The designer cannot know if
> >>>there will be another device or stack of devices below it.
> >>
> >>What spec? Who enforces it?
> >>
> >>If a heavy unit is cantelevered off the front panel, it will be a
> >>hazard to install and remove. As you install it, it will scrape on the
> >>unit below and scratch it up. When someone later loosens the front
> >>panel screws, all its weight will flop onto the unit below, which
> >>already had its own weight to support. The whole stack of units could
> >>collapse.
> >>
> >>Users can't know, years later, if this will happen or if the unit
> >>below can bear the weight of both.
> >>
> >>Don't do it. Nobody competant does.
> >
> >There are customers that do care, and test for it by full-scale
> >vibration tests on whole cabinets to MIL-S-901. A front-cantilevered
> >heavy components would break free and fly across the room.
>
>
>
>
> >
> >Small equipment rates a 500-pound hammer, and medium rates 2000
> >pounds.
> >
> >.<https://en.wikipedia.org/wiki/MIL-S-901>
> >
> >The barge test is a sight to behold.
> >
> >Joe Gwinn
> Yes. We tested some marine control consoles. They were installed in a
> barge in a pond and explosives were detonated in the water. All sorts
> of buttons and knobs flew off, imaged by a high speed movie camera.
>
> They used some sort of magnesium lights for the camera, and that set
> some stuff on fire, but that didn't count against us.
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