Wikipedia:Reference desk/Archives/Computing/2019 March 11

= March 11 =

Alpha particles and memory errors
I was reading in ECC memory about how alpha particles cause errors in computer memory (roughly 1 per 10GB per hour). But alpha particles are usually stopped by a sheet of paper. Most of the case on my computers is metal (plastic front and top). Also, my ECC memory is encased in a metal heat spreader. Shouldn't the case and heat spreader stop alpha particles? Bubba73 You talkin' to me? 06:20, 11 March 2019 (UTC)
 * I don't understand how a heat spreader or case is going to stop alpha particles emitted from the chip packaging hitting the internal circuitry of the same chip or that matter, other stuff on the same stick. (And alpha particle emissions from the chip packaging seem to be the only context in which the article discusses alpha particles.) I also don't understand how the heat spreader is going to stop alpha particles coming from the side of heat spreader exposed to the stick. (The packaging of the chips probably means alpha particles from the heat spreader are not a concern.) In any case, the section you must be referring to says that it's believed alpha particles are a very minor concern compared to secondary cosmic rays primarily neutrons BTW, our soft error discusses in more detail how attempts are made to reduce the risk of alpha particle emissions  P.S. I'm not sure where in our article you got the figure you cited. The only figures I see are for all errors, rather than those attributed to alpha particles. As said, it says most of these appear to be caused by neutrons from cosmic rays. Nil Einne (talk) 09:30, 11 March 2019 (UTC)
 * P.P.S. As per Soft error, neutrons themselves being uncharged wouldn't generally affect the circuitry and it may be alpha particles emitted from neutron capture that do so. So I guess in that way, you are right that it could be regarded as alpha particles at some ultimate level. But from what I read, alpha or other charged particles coming from neutrons coming from cosmic rays are normally considered separately from alpha particles coming from alpha decay of the chip packaging. And it's not clear to me if we even know what percentage of errors are likely to be coming from alpha particles compared to other charged particles, arising from neutron capture. Also, I still don't see the relevance of the heat spreader or case in stopping alpha particle emissions from neutron capture happening within the chip. Nil Einne (talk) 09:59, 11 March 2019 (UTC)


 * Sorry, I was thinking of them coming from outside the case. But more reading in alpha particles says that they are stopped by a few centimeters of air, so they aren't coming from a long way away.  I also just found Soft_error.  Bubba73 You talkin' to me? 18:39, 11 March 2019 (UTC)


 * As far as the figure I gave, there is a range in the article and I did the calculations for something in that range. Bubba73 You talkin' to me? 21:14, 11 March 2019 (UTC)

Editing existing MS Word footers ... do I have to start by clicking 'Insert'?
In order to edit an existing MS Word footer I seem to need to go Insert >>> Header & Footer >>> Footer >>> Edit Footer. For years having to click 'Insert' to access an existing footer has irritated my obsessive compulsive behavior mode. Is there a more logical way? Hayttom (talk) 11:12, 11 March 2019 (UTC)
 * Hi, ! Have you tried to double-click the footer's contents? --CiaPan (talk) 11:17, 11 March 2019 (UTC)
 * Hi, ! I have now, thanks to your response.  SPLENDID!!  Hayttom (talk) 11:27, 11 March 2019 (UTC)