On Mon, Feb 08, 2016 at 18:26:49 CET, Sven Eschenberg wrote: > Indeed usually a disk should be able to finish the sector write with > remaining power. Actually most modern disks do have voltage shifters > and most parts operate on lower voltage. At least for the R/W logic. The heads do not need to be moved during a started write and the platters will keep spinning far longer than needed. > Thus a drop on the > changer's input does not immediately lead to a drop on the output of > the voltage shifter. If's theres enough power left for the physical > layer scrambler and the head to write, then everything should be > fine. As this depends on the buffer-capacitors, you can design how long they keep the lower voltage (typically 3.3V or 2.5V) up after the input has gone below, say 4.5V. With a low-drop 3.3V regulator you get about 1V of drop, before 3.3V drops. That is plenty. Maybe I will have a look into an older 2.5" hdd and check when it stops spinngin and what voltage the R/W amplifier is fed. > I was rather wondering if there's definite sources on that? There is not even a definite source on what error-correcting codes are used today or what the actual rate of non-correctable errors is. Disk manufacturers like to keep the user in the dark about potential problems... I used to look at technical manuals of disks, but in the last 10 years or so they were impossible to get, at least from public sources. > BTW. The burst errors I mentioned did not happen on a power loss, > but rather during operation. Reading twice, one time with burst > errors, one time without. I checked the RAM for ages - no failures. > That was really weird. Indeed. Maybe you did run into a firmware error or some PC-side controller problem that was not properly caught in the driver. Maybe also a DMA error or the like that failed to move all the data into RAM. I found that checking alignment on such errors often gives good clues. Regards, Arno -- Arno Wagner, Dr. sc. techn., Dipl. Inform., Email: arno@xxxxxxxxxxx GnuPG: ID: CB5D9718 FP: 12D6 C03B 1B30 33BB 13CF B774 E35C 5FA1 CB5D 9718 ---- A good decision is based on knowledge and not on numbers. -- Plato If it's in the news, don't worry about it. The very definition of "news" is "something that hardly ever happens." -- Bruce Schneier _______________________________________________ dm-crypt mailing list dm-crypt@xxxxxxxx http://www.saout.de/mailman/listinfo/dm-crypt
