Memory module identification

Hi Aleksander,

On 9/3/2014 4:23 AM, Aleksandar Kuktin wrote:

>> Most non-profits/charities are understaffed (paid or unpaid).  Here,
>> I think the only one that has an abundance of staff (volunteers) is the
>> food pantry.  And, the tasks there are all essentially menial ones --
>> filling boxes with foodstuffs, keeping the floors clean, etc. So,
>> virtually every volunteered hour can be effectively used.
>>
>> At the opposite extreme, I know of a group that provides free dental
>> care.  Hard to imagine them needing many people that are NOT dentists!
>
> Interesting problems... I probably would have still optimized the
> opposite way, but never mind. Evolution will take its course. We'll see
> if it works out or not.

You often have perverse "market forces" at play in these organizations.
I.e., if you can't identify all of the memory modules that you have,
you don't *use* them all!  You "serve" fewer clients.  But, that doesn't
mean you have a competitor who gobbles up the remaining clients.
Rather, it just means you "do less good".

You "fail" when you can no longer attract enough volunteer labor
(perhaps because you aren't "doing ENOUGH good").  And, in the
event of failure, there isn't, necessarily, a "new vendor" who
steps in and takes your place.  That market ("Mission") may simply
no longer be addressed!

On 9/3/2014 2:44 AM, Aleksandar Kuktin wrote:
> On Tue, 02 Sep 2014 12:36:43 -0700, Don Y wrote:
>
>> Out of fear of getting sucked into a "growing problem", I just begged
>> off:  "Gee, sorry, but I can't help you with that..."
>>
>> (More interesting things to do with my time!  :>  )
>
> Probably an optimal solution, taking into account that whole "trained
> monkeys" thing you wrote about..

The problem will self-limit... as many memory modules as they have
labor to identify will get identified and used.  The balance will
be recycled.  Next week, the problem will repeat.  (never a shortage
of donated kit!).  Sometimes you get lucky -- reach into a bin and
find some modules with nice, human readable labels!  Then, dig
around looking for it's siblings:  "Ah, four identical modules!
Yippee!"

In sci.electronics.design Don Y <this@is.not.me.com> wrote:
> On 9/2/2014 12:42 AM, mroberds@att.net wrote:
>
>> You might be able to roll your own connectors by machining a chunk of
>> flat nylon or polycarbonate or something.
>
> This would be broken in a matter of weeks!

One of the frustrating things about Usenet sometimes is having to wait
for all the requirements to come out.  So far, in various posts, the
following have been proposed and discarded...

   Commercial module sockets -> Possibly too fragile.
Roll-your own module sockets -> Possibly too fragile.
  Chip clip direct to EEPROM -> Unskilled operators, error likely.
      Elastomeric connectors -> Possibly too fragile.

You're kind of running out of ways to connect to modules, unless you
have an idea in mind already and are waiting for someone else to suggest
it.

About the best thing I can think of at this point is to go back to the
original idea of harvesting commercial sockets from scrap motherboards.
Get several of each socket configuration (most motherboards have at
least two the same) and replace them when worn.  Also, even a socket
that is electrically worn may still have value as a mechanical sorting
tool: "If it fits this socket, drop it in the yellow bucket" and then
take another pass through the yellow bucket once you get another test
socket.

Matt Roberds

Hi Matt,

On 9/3/2014 10:21 PM, mroberds@att.net wrote:
> In sci.electronics.design Don Y<this@is.not.me.com>  wrote:
>> On 9/2/2014 12:42 AM, mroberds@att.net wrote:
>>
>>> You might be able to roll your own connectors by machining a chunk of
>>> flat nylon or polycarbonate or something.
>>
>> This would be broken in a matter of weeks!
>
> One of the frustrating things about Usenet sometimes is having to wait
> for all the requirements to come out.

Until you hash out an idea, you often don't *realize* what many
of the requirements might *be*!  I.e., did *you* know that memory
module sockets had such low durability figures -- *when* they are
published (i.e., "count them on a few hands")?

My initial assumption was that I could salvage parts from the
hundreds of motherboards to which I'd have access -- sacrifice
one (or six!) "to the cause" (in much the same way that other
bits of equipment have been cobbled together over the years at
these sorts of places -- "Ribbon cable used to connect the hundreds
of disk drives to the disk duplicator failed?  No problem!  Just
grab another one and toss the old one in the 'wire recycling' bin!").

But, if you're doing this on a *daily* basis (25 insertions?) it's
not a practical solution ("Gee, I wonder how much abuse these
DIMM sockets saw *before* the PC came here?")

> So far, in various posts, the
> following have been proposed and discarded...
>
>     Commercial module sockets ->  Possibly too fragile.
> Roll-your own module sockets ->  Possibly too fragile.
>    Chip clip direct to EEPROM ->  Unskilled operators, error likely.
>        Elastomeric connectors ->  Possibly too fragile.
>
> You're kind of running out of ways to connect to modules, unless you
> have an idea in mind already and are waiting for someone else to suggest
> it.

My solution is to step away from the problem  :>  Let someone with
more time on their hands come up with a strategy -- that *they* can
maintain.  They may run the calculus that it's "cheaper" to just
cherry pick the "easily recognizable" modules out of the bins and
discard anything that looks like it would require some effort to
determine it's identity/utility.

> About the best thing I can think of at this point is to go back to the
> original idea of harvesting commercial sockets from scrap motherboards.
> Get several of each socket configuration (most motherboards have at
> least two the same) and replace them when worn.  Also, even a socket
> that is electrically worn may still have value as a mechanical sorting
> tool: "If it fits this socket, drop it in the yellow bucket" and then
> take another pass through the yellow bucket once you get another test
> socket.

For most DIMMs, this is probably no more effective than taping a
sample DIMM to the front of each bin (i.e., the current approach).
It may have some merit with SO-DIMMs -- though I think the small
differences in keyway geometries may just encourage folks to "force"
parts into the "gauge".

The best solution is to invest in better tools and/or staff.  But,
with the abundance of donated kit, I doubt there is much incentive to
be efficient in salvaging a high percentage of it!

(e.g., the medical equipment tends to see far more attention as it
represents higher value items -- and in much scarcer quantities!)

On 9/4/14, 3:04 AM, Don Y wrote:

> My initial assumption was that I could salvage parts from the
> hundreds of motherboards to which I'd have access -- sacrifice
> one (or six!) "to the cause" (in much the same way that other
> bits of equipment have been cobbled together over the years at
> these sorts of places -- "Ribbon cable used to connect the hundreds
> of disk drives to the disk duplicator failed?  No problem!  Just
> grab another one and toss the old one in the 'wire recycling' bin!").
>
> But, if you're doing this on a *daily* basis (25 insertions?) it's
> not a practical solution ("Gee, I wonder how much abuse these
> DIMM sockets saw *before* the PC came here?")
>

One thing to remember is that the quoted "cycle life" is going to be WAY 
conservative for your application.

The rated life is the  number of cycles you can do and still have a long 
term fully reliable connection over all rated conditions.

In your case, you can actually stand quite a bit of "unreliability". It 
isn't a major failure if the worker needs to remove and reinsert the 
module a second time to test, or a few modules get marked "dead" because 
the tester won't talk to them.

There also are TEST sockets, designed for this sort of work. (These are 
often socketed themselves, so when they do where out they can be easily 
changed.) They are built to be a lot more rugged.

On Sat, 06 Sep 2014 11:23:20 -0400, Richard Damon
<Richard@Damon-Family.org> Gave us:

> so when they do where out


  Those damned gays are everywhere!

  You try soaking them out...  you try scrubbing them out...

  Where is the world coming to???!!!

Hi Richard,

On 9/6/2014 8:23 AM, Richard Damon wrote:
> On 9/4/14, 3:04 AM, Don Y wrote:
>
>> My initial assumption was that I could salvage parts from the
>> hundreds of motherboards to which I'd have access -- sacrifice
>> one (or six!) "to the cause" (in much the same way that other
>> bits of equipment have been cobbled together over the years at
>> these sorts of places -- "Ribbon cable used to connect the hundreds
>> of disk drives to the disk duplicator failed? No problem! Just
>> grab another one and toss the old one in the 'wire recycling' bin!").
>>
>> But, if you're doing this on a *daily* basis (25 insertions?) it's
>> not a practical solution ("Gee, I wonder how much abuse these
>> DIMM sockets saw *before* the PC came here?")
>
> One thing to remember is that the quoted "cycle life" is going to be WAY
> conservative for your application.

I don't think so.  Think: thousands of cycles per month.  And, by
(relatively) unskilled people.  I would imagine the plastic *body*
of the connectors would eventually give way under the abuse.

> The rated life is the number of cycles you can do and still have a long
> term fully reliable connection over all rated conditions.
>
> In your case, you can actually stand quite a bit of "unreliability". It
> isn't a major failure if the worker needs to remove and reinsert the
> module a second time to test, or a few modules get marked "dead" because
> the tester won't talk to them.

A reinsert counts as another cycle.  You are also assuming the
person doing this is technically competent.  E.g., instinctively
realizes the differences in module pin configurations, subtleties
of keyway locations, etc.  As inserting a memory module "takes
practice" (they don't magically self-align), people will EXPECT
some resistance.  And, may be *too* persistent ("No, Tom, that
module will NEVER fit into that slot!  Trust me, the keyway
is one half of a contact spacing *different* from what you need!")
causing damage to the tester.

[I had a friend who was "technically competent" plug a four pin
power cable into a PATA drive "upside down".  I said, "Didn't you
FEEL that it didn't FIT??"  "Yeah, but those are frequently tough
to mate so I just pushed harder..."]

I suspect we'd find a high percentage of "dead" modules -- even
if the tester's design was smart enough to physically sense the
presence and proper engagement of the module (to rule out
misinsertions... i.e., "false deads")

> There also are TEST sockets, designed for this sort of work. (These are
> often socketed themselves, so when they do where out they can be easily
> changed.) They are built to be a lot more rugged.

In a *real* "test" environment, you hire and train someone for the
task.  And, they are *accountable* to their boss/supervisor.  You
have no leverage over these folks as they are volunteers -- GIVING
their time, freely (often elderly, unemployed/underemployed, etc.).
At times, it almost seems like some of them "intentionally" screw
up in order to get some attention, interaction, etc.  <shrug>

My recent observation of stand-less LCD monitors stacked, face down,
atop each other:  "Yes, that's much more organized than the way they
were previously.  Oh, yes!  I see you have also sorted them by size!
That's very convenient!  Unfortunately, I suspect a great majority of
the screens now have permanent 'blemishes'.  Rather than refurbish and
repurpose them, we'll have to just *recycle* them (as scrap).  <frown>"

But, an hour of "generic" donated time is worth about $10 so you
don't casually discard 8 or 40 of those!

The only thing that is likely to work is a solution that they can
easily replicate and replace.  E.g., to clone disks, insert *this*
bootable CD into a generic PC; plug the source disk into *this*
IDE cable and the destination into this *other* cable.  Hit enter.
Wait.  If this "cloner" dies, you simply replace the generic PC
with another generic PC, insert the CD and resume where you left
off.

This is the sort of mentality that you come to *expect* in these
organizations.  The real danger is if there is some "nonobvious"
aspect of a solution that they ("someone" months from now) fails
to perceive as essential to the solution.

For example, taking one of these tiny "toy" PC's and trying to
hang *several* disk drives off of it's *tiny* (intended for a
SINGLE disk drive!) power supply.  Then, wondering why it doesn't
work reliably!

(sigh)  I guess the folks that run these sorts of places deserve
*some* credit -- even if only as recognition of their *patience*!

The adage about "idiot proof" designs simply can not be understated,
here!

Don Y wrote:
> 
> Hi Johann,
> 
> On 9/1/2014 3:56 AM, Johann Klammer wrote:
> > On 08/31/2014 10:54 PM, Don Y wrote:
> 
> >> Is it possible to design a little <something> to query
> >> these devices and extract the parameters -- mapping them
> >> to a human readable form (i.e., as a peripheral to a PC)?
> >> Is this "ID" circuitry powered independent of the rest
> >> of the module? Or, do you, in fact, have to be able to
> >> support every possible memory module (pinout, voltage, etc.)
> >> *just* to gain access to this data?
> >
> > I tried it with i2c-parport. Botched the circuit(transistors instead of
> > diodes? ...not sure, something was inverted), so had to use userspace
> > ppdev access <http://members.aon.at/~aklamme4/scratch/main.c>, but it
> > worked. The power pin for the eeprom is separate, so could be powered
> > from a linreg... 3V, I think..
> 
> OK.  So, no need for a real power supply (as the memory, itself, is
> not powered up).
> 
> > decode-dimms can be used to decode the contents...
> > I only tried on an old DDR ram that had died... If you have some really
> > old/exotic modules it may not work...
> > If you happen to have the DIMM installed in your box, you can directly
> > read it out somewhere at
> > /sys/module/eeprom/drivers/i2c:eeprom
> >
> > Oh, all on LINUX...
> 
> (sigh)  Yes, it looks like its possible to electrically design
> such a device -- and, make it reasonably fool proof.  The *real*
> problem seems to lie in the module connectors:  most are only
> rated at a handful of mating cycles (e.g., 5-25).
> 
> While this may be plenty for a "typical application" (and, I
> suspect often *exceeded* by folks!), I can't imagine hundreds
> and thousands of cycles *weekly* would leave the connector's
> reliability unaltered.  <frown>
> 
> I will have to find another way of interfacing to the modules...

Pogo pins?
-- 
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.