Talk:Non-volatile memory

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Unnamed section[edit]

I think there is a need for a table describing properties of memory types such as reading speed, writing speed, number of writes before getting worn out, advantages, disadvantages, produced unit densities, price per MB or GB etc.

  • Disagree with proposed merge to NVRAM; many non volatile memories are not NVRAM -- hard drives and other magnetic media, for example. FT2 (Talk | email) 00:28, 16 April 2007 (UTC)
  • I also disagree with the merge. There are notable differences between the two. Non-volatile memory isn't RAM it's something completely different. —Preceding unsigned comment added by Vermishis (talkcontribs) 29 April, 2007

Bubble memory[edit]

Is there a reason that Bubble memory isn't included in the list of "electrically addressable" systems? EJSawyer (talk) 19:22, 15 March 2008 (UTC)

I disagree that non-volatile memory includes hard disk space. There is a difference between memory and storage. (talk) 22:33, 8 December 2008 (UTC)


Does anyone know what kind of memory storage devices provide best longevity? ...I mean, how to eliminate the risk of losing data archieved for more than 20/40 years? :) —Preceding unsigned comment added by (talk) 04:38, 7 July 2009 (UTC)

Memory storage devices (at least non-volatile memory) is usually qualified and characterized for longevity - among other attributes. These are industry-based HTOL (high temperature operating life) and HTS (high temperature storage). Their lifespans are accelerated and then longevity calculated statistically from the results.Quixote1024 (talk) 19:50, 4 September 2009 (UTC)

Suggest merge[edit]

The following discussion is closed. Please do not modify it. Subsequent comments should be made in a new section. A summary of the conclusions reached follows.
Result was: concensus not to merge

Suggest merge from Non-volatile random-access memory as its contents are redundant with the discussion of non-volatile semiconductor memory here. --Wtshymanski (talk) 15:50, 18 April 2012 (UTC)

Random Access Memory is a subset of 'memory', so it strikes me as a perfectly logical move. Most 'memory' types are random access in the true sense of the phrase anyway. DieSwartzPunkt (talk) 13:21, 21 April 2012 (UTC)

The following objections were made to the article to be merged's talk page. They should have been placed here. I have copied them from the other talk page so that a full and proper discussion can be made. The fact that I have copied them does not necessarily mean that I agree with them, but a proper and full discussion is essential. (talk) 13:27, 25 April 2012 (UTC)

<Copied from Talk:Non-volatile random-access memory>

  • Disagree with proposed merge to Non-volatile memory; many non volatile memories are not NVRAM -- hard drives and other magnetic media, for example. FT2 (Talk | email) 00:28, 16 April 2007 (UTC)
  • Also, the article is a bit to long and detailed for a merge. -- (talk) 01:42, 26 November 2007 (UTC)
  • I am removing the merge template per the comments above and at Talk:Non-volatile memory --Lox (t,c) 21:58, 7 January 2008 (UTC)
You had no right to do so. Merge template restored so that the discussion can be found. (talk) 13:27, 25 April 2012 (UTC)
  • I would like to see a page or so related to the physics of EEPROM - existing EEPROM article does not cover that, whereas NVRAM article does. How about separate articles for 'physics of non-volatile memory' (new), then existing EEPROM and NVRAM articles which could be more product-related. I am willing to contribute to the first article. Keble6 (talk) 19:53, 5 December 2007 (UTC)


  • oppose merge
We should probably merge the content that's currently here. As W. describes, there's mostly overlap. An article on NVRAM (by its scope for use as frequently-written, rather than construction) can easily include a footnote section for magnetic hard drives, with a footnote to that footnote on paper tape, punch cards, pinboard etc. I can see no significant difference between frequently-written NV memory and NV RAM that isn't either (hard drive) so important that it's clearly covered elsewhere, or that it (punch tape) can't fit within such a footnote.
However there's also a significant scope for "rarely-written" ROM that's either writable or erasable, yet also non-volatile. EPROM, UVEPROM, EEPROM and even PROM falls under this. Yet it's clearly not NVRAM. The final state of the two articles should leave one at Non-volatile memory that clarifies these two groups - and can also mention the hard drives and paper tape. Andy Dingley (talk) 13:58, 25 April 2012 (UTC)
I'm looking for a source that explains the difference between "memory that can be read and written by the processor at (about)the usual speed" and "memory that requires extra I/O cycles or some extra time delay". There's a continuum; battery-backed SRAM is (practically) indistinguishable from DRAM from the processor's point of view, but is getting the "non-volatile" property the hard way. (I used to change flashlight batteries in PLCs for the "memory backup".) Flash memory on a PIC can be written by the processor but requires more time than scratchpad RAM. Then there's EEPROMs, EPROMs, PROMs, mask ROMs, tape libraries...cycle time goes way up. I think what this article is supposed to be about is memory devices that can be read or written at CPU speed, with maybe a wait state or two. IEEE standard 100 isn't terrifically instructive, it just says "non volatile memory is that which doesn't lose its contents without power" so IEEE didn't think this needed further classification. --Wtshymanski (talk) 14:55, 25 April 2012 (UTC)
I would agree both of your detail points here. So as they indicate there's clearly a group that's non-volatile, yet outside NVRAM, then why merge? Andy Dingley (talk) 15:48, 25 April 2012 (UTC)
  • oppose
I note that a merger of the articles was first proposed in February 2007. At that time there were 5 comments opposing the merge and none supporting spread across both discussion pages. The merger did not take place. The two articles have undergone some expansion since that time, but the essential scope of each does not seem to have changed much. Although I would agree that there is an overlap of subject matter, I do not believe that the overlap is sufficient to warrant a merge.
I also note that the merger has been carried out. The merge proposer has not really given any justification as to how the articles' scope has changed to now warrant such a merger when it was rejected first time around. Unless any significant support for a merge is forthcoming, I believe that the merge should be undone. DieSwartzPunkt (talk) 15:33, 25 April 2012 (UTC)
I've undone the merge. Let's see if Wtshymanski proceeds to blank NVRAM for a fourth time today. Andy Dingley (talk) 15:51, 25 April 2012 (UTC)
Surely we don't need to include disk drives and paper tape in "non-volatile memory"? The articles are very badly factored but what people seem to be writing about when they write about non-volatile memory is everything that was in "Non-volatile random-access memory ". And wasn't the discussion previously the other way around (merging "non-volatile memory" to "non-volatile random access memory" ? --Wtshymanski (talk) 16:01, 25 April 2012 (UTC)
Yes we do. They are non-volatile. At the time they were developed, this non-volatility was one of the reasons for why they were developed - particularly some of the high-speed magnetic techniques.
Memory at this time was difficult to provide, by any means. Pre-dating RAM, there were techniques like acoustic memory and Wilson tubes that were so restrictive that the seemingly tautological "random access memory" was a significant improvement and worth distinguishing. So by the time that solid-state RAM is a commonplace, the idea of hard drives as being within the broad scope of "memory" is less significant. Indeed we don't need to list it along with NVRAM. However for non-volatile memory, we certainly ought to. Andy Dingley (talk) 16:46, 25 April 2012 (UTC)


People writing about non-volatile memory don't usually mix in paper tape, punch cards, mag tape, removable media, etc. in the "non-voltatile" context. Neither should Wikipedia. --Wtshymanski (talk) 13:48, 25 April 2012 (UTC)

Yes, they do. Not many people write about punch cards. Back when they did, they commonly emphasised their non-volatility. Often there wasn't any other available way of doing it. (Plenty of machines in the post-core era that still used cards.) Andy Dingley (talk) 16:48, 25 April 2012 (UTC)
Really? We're really talking about punched cards in the same context as core? You must point me at the authors who have such an...inclusive...concept. --Wtshymanski (talk) 21:43, 25 April 2012 (UTC)
Punch cards are stretching it, because they were always a pretty slow way of handling data (they were mostly favoured because they were easy to edit, and in most ways more robust than paper tape). However there are plenty of coding books of the era of early Knuth that discuss mag tape as a serious choice for large-size, non-volatile working memory, not merely as long-term archival storage. Many sort algorithms of the period were written to make best use of it, with all sorts of arcane serial merge algorithms, because there was no way to do an in-memory sort for lack of space. Andy Dingley (talk) 22:38, 25 April 2012 (UTC)

The above discussion is preserved as an archive. Please do not modify it. Subsequent comments should be made in a new section.

Merge tag restored.[edit]

I note that in spite of the clear concensus not to merge the articles, Wtshymanski has restored the merge proposal tag to the article Non-volatile random-access memory. Is he a bad loser or something? No one supported the merger - no one. Even the one note of support that was made seems to have changed his or her mind (presumably due to the very valid points that were made). Let's just remove the tag and move on. (talk) 14:20, 26 April 2012 (UTC)

You are correct: I did change my mind. It was the arguments over the older technology that swung it. Wikipedia is often the only place to find information on the way things used to be done. There was a time when magnetic tape and discs were the only viable non-volatile memory when (what is now called) random access memory was a rack of thermionic valves (vacuum tubes), or something even more exotic such as a cathode ray tube or mercury delay line. I have used a computer system decades ago where punched cards or punched tape was the only way of retaining your program or data after the machine was switched off.
I am intruiged that User:Wtshymanski has declared that the discussion is not closed. It was he himself who (effectively) declared it closed by proceeding with the merger just seven days after first proposing it. He can't have it both ways. DieSwartzPunkt (talk) 12:29, 27 April 2012 (UTC)
I tag an article for merging, wait about a week, if I see no comments, I merge. Then everybody weighs in with their carefully reasoned and dispassionate reasons to undo the merge, then there's an edit war, I get threats and bluster from various quarters, and the unmerged articles carry on as before. Isn't collaboration great? --Wtshymanski (talk) 13:10, 27 April 2012 (UTC)
I take your point. Technically, you don't even need to propose the merger, or initiate a discussion. The merge help page (See H:M) does state that articles can be merged without any proposal or discussion. It does warn that if the merger is controversial, then it should be proposed and a discussion initiated (which to be fair, you did). I'm not convinced that 7 days is sufficient time though. The last time I proposed a merger, I left it for a couple of months or so. After a week, there was not a single comment. But during the rest of the time several objections did appear, and so I abandoned the attempt. Allowing too short a time for discussion and then carrying out the merge may well precipitate comments more quickly, but I'm not convinced it actually achieves much in the long term. Some editors, such as yourself do seem to spend their entire waking time editing articles. Others, such as myself are much more sporadic. It can be weeks between even looking at Wikipedia sometimes. Of course, if you leave the discussion too long, much water flows under the bridge and you move on yourself and forget that you ever proposed a merge and 2 articles sit there with almost permanently attached merge tags. DieSwartzPunkt (talk) 15:05, 27 April 2012 (UTC)
More concisely, "you're dammned if you do and dammned if you don't". Indeed, the enemy of happyness is desire. By desiring change in Wikipedia articles I make myself unhappy. I should get AWB and confine myself to changing hyphens. --Wtshymanski (talk) 15:26, 27 April 2012 (UTC)
I can think of many more important things to be 'unhappy' about than Wikipedia. DieSwartzPunkt (talk) 16:04, 27 April 2012 (UTC)

battery-powered memory[edit]

battery-powered memory is usually also considered non-volatile, see Nonvolatile BIOS memory. --MrBurns (talk) 23:12, 19 December 2012 (UTC)


Is NVDIMM the same thing as NVRAM ? If not, then it probably needs an article on its own. Here some detalils about it:

. —  Ark25  (talk) 08:20, 5 April 2013 (UTC)

A DIMM is a type of memory module, a NVDIMM is a DIMM which uses NVRAM. In this case it uses normal DDR3 SDRAM + a supercapacitor + a flash SSD.[1] In case of a powerfailure, the data is written to the SSD and the supercapacitor provides the power for that. --MrBurns (talk) 08:10, 7 May 2014 (UTC)