Software to test flash storage

Western digital made a drive a while back that was exlpicitly designed to work with the Pi. 314GB in capacity of something.

Gordon

I have one. It comes with a special power supply which supplies the hard drive and Pi separately using a Y cable.

This sounds like it would do the job. Terabyte capacity is far greater than needed but seems the smallest available. How warm does it run? How long did it stay in service, and what event ended service?

Thanks for posting!

bob prohaska

Why would malloc() fail if there was swap space?

ulimit can cause that.

But the question was why malloc succeeded but the process was later zapped by the OOM killer. The answer is Linux doesn?t back newly allocated memory mappings with anything until they are actually used; thus it?s possible to allocate much more memory than you have (in the form of RAM and swap) and only run into trouble when you try to use it.

The reason is that it?s fairly routine for Unix process to request much more memory than they actually need, so without this strategy you?d have to allocate an awful lot of swap that you never actually used. The most obvious example is that process that forks and then execs, i.e. anything that ever runs a subcommand.

AFAIK you can turn this behavior (?overcommit?) off if you want.

Not answering your power query, but smaller 2.5" drives are still being advertised on Amazon UK and one of the local (UK) computer mailorder sites, eBuyer, has 500 GB external drives for quite a lot less than the equivalent 1Tb units.

On Tue, 9 Oct 2018 09:18:35 +0100, The Natural Philosopher declaimed the following:

The other way the program shutdown/reported results is when the /time/ to run a "step" suddenly increases drastically. This happens when a pass/step starts severe swapping.

The HINT algorithm, in simple terms, tends to double the needed memory on each pass, measuring the "improvement" in the calculation. It did take some tuning of the parameters to get it to run with reasonable results on modern processors -- when originally written a 200MHz processor was practically a supercomputer. Now, the pass time-limit had to be cut down so much it is beginning to beat against OS time-slices (so plotting results for Linux tends to show some spikes, but the No-OS run had smooth curves).