Posts by robsmith

1) Message boards : Questions and problems : boinctui on pi zero - calculations fail (Message 102715)
Posted 16 hours ago by robsmith
Post:
Most applications write to the "disk" (SD card in your case) do a write abut once per minute - the "check point" interval Generally these writes are quite small, and over-write the previous one. You can safely increase this time to several minutes (I can't remember which configuration file it is in) to reduce "wear" on the SD card. Given the performance of a Pi I would be comfortable with anything between 5 and 10 minutes (300 to 600 seconds).
As a rough guide - on my PC Einstein is using about 40Mb, running a single task, so not a mega use of disk, but that may increase as the task proceeds.
2) Message boards : Questions and problems : boinctui on pi zero - calculations fail (Message 102712)
Posted 19 hours ago by robsmith
Post:
That certainly looks to have worked.
One task completed on the 26th having run for about 26 hours has been validated.
OK it's slow, but then Raspberry Pi of any description aren't noted for being the fastest computers on the block.
As I type there's another task that's about 12 hours into its run which is looking promising :-)
3) Message boards : Projects : News on Project Outages (Message 102691)
Posted 1 day ago by robsmith
Post:
I'm not sure when the projects list is updated, but its accuracy depends on input from the science projects. BOINC itself has no control over them rather providing an advertising hoarding for projects that are using the BOINC environment.
The BOINC project itslef does none of the computing, provides no server space, administration staff, science staff etc. to the science projects.
Over the years there have been some very long-lived projects (SETI@Home being a prime example - where the initial goal has been reached, and the next goal is being sought/developed). Other projects have only lasted few months until either their goal was reached (a lot of graduate & post graduate "student" work comes in this category). Others have lost their funding, or have suffered major hardware failures (Asteroids comes into that category). But there are other projects that are continuing, CPND (one of the oldest), Einstein and Milkyway, WCG continue to run and deliver good results. Then there are projects like LHC which only run when needed, which can get a bit confusing.
So, is BOINC dead, or is it still continuing to do what it has done for nearly 20 years - personally I would say it is continuing to do what it has done, and is probably going to continue to do so, however individual, independent, projects will come and go.
4) Message boards : Questions and problems : Tasks stuck and not making any progress (Message 102645)
Posted 5 days ago by robsmith
Post:
I've seen similar behaviour you describe with Rosetta in the past, so "not uncommon" with that project.
I can't comment on the other projects, but others might (I hope)
5) Message boards : Questions and problems : Tasks stuck and not making any progress (Message 102642)
Posted 5 days ago by robsmith
Post:
Which project(s) are yo running?
What is your hardware?
6) Message boards : The Lounge : The Seti is Slumbering Cafe (Message 102616)
Posted 8 days ago by robsmith
Post:
It feels like Tuesday......
7) Message boards : The Lounge : The Seti is Slumbering Cafe (Message 102613)
Posted 8 days ago by robsmith
Post:
Another week, another Tuesday and SETI has a slumber in the corner.....
8) Message boards : GPUs : Nvidia/AMD Cuda/OpenCL on Boinc projects - which card to buy? (Message 102540)
Posted 13 days ago by robsmith
Post:
I am not rising to any more of your bait.
9) Message boards : GPUs : Nvidia/AMD Cuda/OpenCL on Boinc projects - which card to buy? (Message 102534)
Posted 14 days ago by robsmith
Post:
Yet another over simplification - and more than 5 sentences - do what I said yesterday and LEARN, it won't hurt.

As for power company not worrying, it's not only the power company, but the excess heat from a high power capacitive dropper might do something far worse than just increasing your power bill.
(b.t.w. There is the potential for the company to bill you for the "real" power draw due to poor power factor equipment....)
10) Message boards : GPUs : Nvidia/AMD Cuda/OpenCL on Boinc projects - which card to buy? (Message 102530)
Posted 15 days ago by robsmith
Post:
Five sentences would lead you into more confusion, just do as I suggested and you won't be confused. This is one of those subjects where there is nothing really of use between the very simple explanation I gave earlier and diving into the theory.

Capacitive droppers have, by dint of the way they work extremely poor power factors, and are at anything over low loads very inefficient. Linear & switched mode psu should have much better power factors, and thus better efficiency (but if poorly designed or implemented can have very poor efficiency and/or power factors).

edit to add
Capacitive droppers are not switched mode supplies, the latter run at high frequencies, where as capacitive droppers run at the frequency of the incoming supply.
11) Message boards : GPUs : Nvidia/AMD Cuda/OpenCL on Boinc projects - which card to buy? (Message 102528)
Posted 15 days ago by robsmith
Post:
Yes, but how many tens of pages do you want - I suggest you dig around and find a copy of "The Art of Electronics" by Horowitz & Hill as that will save me typing. There are any number of other electronics text books, but few are quite as simple to understand and few give so many good, workable examples.

The sort of power supplies used in many small appliance battery chargers are switched mode, and rely on either RC or RL filters to get rid of the residual high frequency that is used to produce the low DC voltage. In other types called "capacitive dropper" there is an RC network, combined with a simple bridge rectifier drops the mains voltage to that required to charge the battery - but those tend only to be used on very low-power batteries.

As I implied a few posts ago, the design of PSUs is not just a simple matter of slinging a few components together, but these days is much more involved - ah the days of the nice simple capacitive dropper used for the heater circuits on valve radios.....
12) Message boards : GPUs : Nvidia/AMD Cuda/OpenCL on Boinc projects - which card to buy? (Message 102513)
Posted 16 days ago by robsmith
Post:
If they released circuit diagrams it would make it easier. Not really easy to trace circuits when they're so small, go under things, and have multilayer boards.


Many complex consumer-level devices have been the subject of many man-years of design, development, testing and the manufactures want to protect this investment so they don't publish their PCB designs (which almost certainly includes more than just the schematic, but "interesting" things like screening layers, power layers. I agree it's a shame, but they have their reasons, we can either like them or not......
13) Message boards : GPUs : Nvidia/AMD Cuda/OpenCL on Boinc projects - which card to buy? (Message 102512)
Posted 16 days ago by robsmith
Post:
Wikipedia has over simplified the function of a decoupling vs. noise filtering. Decoupling is used to stop stray signals, or DC, from crossing between circuits. Noise filtering is used to block the noise normally associated with switching circuits, clocks etc. during normal operation. A subtle difference, and I've oversimplified things somewhat.....
14) Message boards : GPUs : Nvidia/AMD Cuda/OpenCL on Boinc projects - which card to buy? (Message 102499)
Posted 17 days ago by robsmith
Post:
I wasn't looking to fix it - I was looking to see what happened at low supply voltages - I sort of hoped the 12v to 3v dc-dc converters would be sufficiently well designed to shut down if the voltage dropped, but they were controlled by the micro-controller, which of course I'd cut out of the equation.
No shame on you - GPUs are not really designed to be user serviceable to any great extent.

Your 11.5v supply is very close to the trip voltage of the under-volt detection on the GPU I destroyed (11.3v), so given the sort of tolerances these things have suggests you are just on the "safe" side of the line.

Those SM capacitors aren't there to filter noise, they are there to decouple the various supply rails. There are probably a number of fairly large (10mm sort of dimension) that are there to do supply-rail smoothing. On the GPU I had these were fixed pin, through-hole devices, the way the leads had been cropped which made them look as if they were SM on the back of the board, but very careful study showed their true colours.
15) Message boards : Questions and problems : Only 1 out of 2 GPUs working (Message 102496)
Posted 17 days ago by robsmith
Post:
Not like an RTX2060 is that odd of a GPU, that there wouldn't be any work for it from 2 big projects (Einstein and Milkyway) for over 24 hours?


Unless a project has specifically set a performance limit that excludes the RTX2060 then there's no difference between it and any other member of the RTX 2xxx family of GPUs.

BOINC will preferentially use what it perceives to be the most powerful GPU when presented with two of different performance capability, and after being told to use all GPUs it can take some hours for it to start to use the lower power one of a pair to get work. So, as with many things to do with BOINC waiting a day or so before panicking or more fiddling can pay off.
16) Message boards : GPUs : Nvidia/AMD Cuda/OpenCL on Boinc projects - which card to buy? (Message 102494)
Posted 17 days ago by robsmith
Post:
Yes - I did get confused in all the diving between PSU & GPU.

Anyway, I've just caused an ancient and unreliable GPU to let its smoke out....
This GPU was removed from service because it would periodically resort to just displaying a series of broad bands and stop calculating followed shortly after with the computer crashing. It's been sitting on the self for some years. Dismantling it was a "work of art" - six different screw heads of three different patterns in use and a few self-destruct clips later I could see what the circuit looked like.
Starting from the power inputs. Those from the PCI connector and the Molex connectors are brought to one region of the board where they pass a number of voltage comparators comprising pairs of over & under voltage detectors. The truth line from each of those heads off into a single (unmarked) chip - presumably some sort of micro controller judging by its function (more later). The supply lines then head off to various other areas of the board - e.g. memory, fan, GPU chip and a couple of other locations I was too lazy to try and work out.
I had CMDs on all power input lines, and have access to a vast range of bench psu & logic simulators, plus a couple of 'scopes (and a lot of hook-up wires).
One of the output lines of the chip appeared to function as a "I've got Molex 12v" as "PCI has 5v & 12v". Having worked out what happened on the input I decided to skip the protection area for the Molex input (leaving the PCI connector set at its correct voltages), but the "12v Molex is OK" line forced high. Now the fun began - injecting power from a *-off variable power supply I raised the "12 v" line by a couple of volts, to no great effect, but when I started to drop the voltage things got a bit more exciting. At just over 5v the 12v to 3v DC-DC converter started to get a bit warm, dropping the supply voltage further at just under 4v smoke appeared from one of the power devices in the DC-DC converter and the current rose very rapidly from around 10A to well over 50A (limit of the CMD on the line from the bench psu in use), then the bench psu shut-down - trip set at a nominal 75A.
OK the voltages are different to those you saw, but this was not the same type of GPU, but I think it would be fair to assume that the power management is fairly similar across all types (at a functional block level, details like detection and trip levels will vary).

Well, what I saw lines up with what you describe. Neither of us can be sure that all GPUs have both over and under voltage detection on their supply inputs, but if it was missing, it is quite a simple step to see that having a very "soft" 12v line from the computer PSU could result in some quite spectacular destruction. I would hope that most consumer grade computer PSUs would have some form of under-voltage protection.
17) Message boards : GPUs : Nvidia/AMD Cuda/OpenCL on Boinc projects - which card to buy? (Message 102488)
Posted 18 days ago by robsmith
Post:
You need to take measurements and rely on your hand or guesswork.
I doubt that a GPU would drop the voltage on a "car battery" from 12v to 2v without the cables being in serious distress:
Did you get burns on your hands while doing this "test?
Did you actually measure the voltage?
Did you actually measure the current?

The first one is the only one that doesn't need instrumentation, and the only one where you really know the answer - The rest of the figures you have given are nothing more than PURE GUESS WORK and can thus be chucked in the bin as such,.

(Comment - if this GPU did this on a battery there is a fair probability that it would do much the same on any reasonable size PSU, after all "20A" at 12v is only 240W, and you keep saying you have PSUs, and 20A at 2v is 24w - you need to think and test properly before making such claims about the performance of PSUs.)

What "heating element" - you've just invented another part to your so called test.


You've read a lot "somewhere", and so have I, but I've done a whole load of designing and testing of power supplies over the years and KNOW how they work and how they behave, so give up now.
18) Message boards : Questions and problems : Only 1 out of 2 GPUs working (Message 102486)
Posted 18 days ago by robsmith
Post:
...and probably be proceeded by removing the drivers. Probably including one or more re-boots of the computer as the removal takes place.
Yes, it takes time, and can some rather alarming visual effects during the process, including warnings about some features not being available. Fear not- they will come back once the drivers are re-instated.

HOWEVER - it would appear that you now have BOINC recognising both GPUs - In a GUI environment it would be a simple process to see what is being run using BOINC manager's "advanced" view where one can see exactly what tasks are running, what processor(s) is in use. I think BOINCTasks will allow a similar view across a network, but I don't use that I can't make any recommendation either way on that. There is a way of doing it using the command line, but I'm sorry I can't remember what it is - others may well be able to tell you.
19) Message boards : The Lounge : Don't know where it should go? Stick it here! (Message 102480)
Posted 18 days ago by robsmith
Post:
The population to look at for the genome studies is the number of people who have tested positive for Covid-9. So the population sizes are 21.5 million for the US and 2.8 million for the UK. Which means the UK has genome sequences for 7.5% of positive tests while the US has sequenced just 0.2% of its Covid cases.
In the UK's sample they have found a number of minor variants and at least one major variant. Rough figures suggest that the number of major variant for many virus is a fairly linear relationship to the number of genomes sequenced; thus one might reasonably expect there to be another dozen major variants around in the UK. However I think this relates to "mature" virus like the common cold, not "immature" ones like the one that it the cause of the current pandemic, so perhaps my suggested number of major variants is an over estimate (I hope)
20) Message boards : Questions and problems : Only 1 out of 2 GPUs working (Message 102474)
Posted 19 days ago by robsmith
Post:
They should be the same driver.......
But it might need to be configured to work with both GPUs, so re-installation might work. Do a "clean" installation, first remove the existing one, then try again - it should find both and do the correct configuration to cope with the differences between the two.


Next 20

Copyright © 2021 University of California. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation.