Talk:Solid-state drive

First flash based SSD

The article says it started in 1994, but according this this article, https://en.wikipedia.org/wiki/Psion_Series_3 flash memory was sold in 1993. And this article says they sold them in 1989. http://retrocosm.net/2012/03/29/psion-mc-400-mobile-computer/ What gives? — Preceding unsigned comment added by 50.73.88.73 (talk) 21:37, 13 December 2013 (UTC)

 Done Awesome note, thank you! Went ahead and edited the article, so this is included. — Dsimic (talk) 22:09, 13 December 2013 (UTC)

Gross inaccuracies regarding filesystem fragmentation

This article's treatment of the issue of filesystem fragmentation is terrible. Please consider the following statements from the article:

"SSD technology can deliver rather consistent read/write speed, but when lots of individual smaller blocks are accessed, performance is reduced." This statement is true.

"There is limited benefit to reading data sequentially (beyond typical FS block sizes, say 4KB), making fragmentation negligible for SSDs." The article cited for this statement does not discuss filesystem fragmentation at all, making it entirely inappropriate as a source for this statement. As stated earlier in the article, performance is reduced when lots of individual smaller blocks are accessed. To make the claim that the effects of filesystem fragmentation are negligible, with no source or data to back it up, is irresponsible and misleading. The truth is that the effects of filesystem fragmentation vary depending on the situation and absolutely can cause a non-negligible performance impact. I have personally measured up to a 35% difference in a real-world scenario, which does not seem very negligible to me.

"Defragmentation negatively affects the life of the SSD and has no benefit." The first statement here is true, while the second statement is false. This kind of lie has no place on Wikipedia. 24.148.137.64 (talk) 15:09, 22 December 2012 (UTC)

How can fragmentation make a difference on a SSD that is made up of DRAM or NAND etc ? what makes it to take longer to access block sequence 0, 8, 2, 15, 9 than say 5, 6, 7, 8, 9, 10, etc.. ? unless ofcourse the filesystem screws it up with ineffective handling of block mapping. Electron9 (talk) 08:06, 26 June 2013 (UTC)

Persistence

Article states:
SLC to MLC NAND to NOR
10× more persistent 10× more persistent
so both are more persistent? seems strange to me...

The problem is that there are two different tables made to look like one. SLC is more "persistent" than MLC. Nand is more "persistent" than Nor. It is only a "marketing breakthrough" to attempt to combine these into one imaginary concept. I suggest the two tables be separated. --A D Monroe III (talk) 22:18, 9 July 2014 (UTC)

Understanding the Robustness of SSDs under Power Fault

I see mention of reliability issues - but no mention of the largest study on the matter! See: https://www.usenix.org/conference/fast13/understanding-robustness-ssds-under-power-fault Test35965 (talk) 22:21, 8 July 2013 (UTC)

Well, the PDF of this study is within the Solid-state drive § External links section, it was added there on July 8, 2014. — Dsimic (talk | contribs) 05:45, 10 July 2014 (UTC)

sequel to SSD

have heard news that there will be a sequel to SSD drives called "RRAM drives":

https://en.wikipedia.org/wiki/Resistive_random-access_memory — Preceding unsigned comment added by Traversable47w0rmh0le (talk • contribs) 10:27, 27 December 2013 (UTC)

RRAM is one of a few technologies that may well replace NAND flash currently used in most SSDs, but an SSD-compatible product that uses RRAM will likely still be called an SSD. If the external host interface changes it might get re-termed Solid State Storage (SSS) or something, but not due to the internal memory technology. --A D Monroe III (talk) 23:04, 9 July 2014 (UTC)

Well, there's already a newer external host interface, SATA Express (and associated NVM Express), and SSDs haven't changed their name. But, who knows. :) — Dsimic (talk | contribs) 05:35, 10 July 2014 (UTC)

Dubious

From the comparison table: "HDDs generally have slightly lower write speeds than their read speeds." Well, the bits pass the R/W head in exact same speed during reading and writing, which makes me suggest that the read and write speed must be always the same. Objections? 80.223.182.224 (talk) 16:42, 22 May 2014 (UTC)

As there was no objections, I modified the text. 80.223.182.224 (talk) 17:17, 30 May 2014 (UTC)

It isn't dubious. If you look at the detailed specs for hard drives (for example here) you will often find a slightly longer (slower) average seek time listed for writes vs. reads. It's not the actual data transfer, it's the time the drive has to spend to get ready for the transfer. Jeh (talk) 21:07, 30 May 2014 (UTC)

HDD writes have stricter tracking requirements (seek-settle) than reads; reading a little off-track is harmless, but writing off-track can corrupt adjacent data. This means writes must sometimes wait an extra rev to get fully on track, thus overall writes are slightly slower than reads. --A D Monroe III (talk) 22:11, 9 July 2014 (UTC)

A D Monroe III, any chances for a reference, please? — Dsimic (talk | contribs) 05:31, 10 July 2014 (UTC)

HDD companies don't like to publish such inner-working details as to why, but the seek time specs they do publish (such as Jeh's link above) show write seek times about 1ms longer than read seek times. Since the original comparison text didn't give a "why", these data sheets specs should be fine as a reference. --A D Monroe III (talk) 14:54, 10 July 2014 (UTC)

You're right, but in fact I was hoping for a "why" reference. :) — Dsimic (talk | contribs) 20:35, 10 July 2014 (UTC)

Proposal to merge "Disk on module" with "Solid-state drive"

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.

The result of this discussion was to merge Ultimatemythbuster (talk) 01:03, 21 July 2014 (UTC)

---

I would like to propose that the article Disk on module be merged with this article. The former is a stub article and might benefit from being merged into a new section on the SSD page.Ultimatemythbuster (talk) 12:37, 11 July 2014 (UTC)

• Support: Makes sense to me. — Dsimic (talk | contribs) 21:23, 14 July 2014 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Is SSD = Solid State Disk a mistake?

There's been a minor edit skirmish (not up to war levels) on the "correct" definition of the acronym for SSD – Solid State Drive or Solid State Disk. I think we agree most sources say Drive, but can we state that saying Disk is "mistaken"? SSDs have neither disks nor drives; I think both are equally "wrong". We'd need more than our own opinions to declare one as a mistake; we'd need a source, and I don't think any respected source could claim either is right or wrong; at most one might be "preferred". So, I've removed any right/wrong indication, and added this per WP:BRD. --A D Monroe III (talk) 20:20, 18 August 2014 (UTC)

Anon's addition is grammatically incorrect and redundant, since the same parenthetical text already points out that they contain no actual disk. The introductory sentence should keep things simple. Save the nitpicking for later once the basics have been established. --Imroy (talk) 20:38, 18 August 2014 (UTC)

Could you please explain why SSDs are not drives?! Its the same as in HDD = hard disk drive. You wouldn't say hard disk disk, would you? Look at: http://en.wiktionary.org/wiki/drive#Noun "(computing) A mass storage device in which the mechanism for reading and writing data is integrated with the mechanism for storing data, as a hard drive, a flash drive.". So as you can see Drive is correct. And Disk is wrong, obviously.

First, Anon IP, just to answer your question, HDDs have a "drive" -- the spindle motor; SSDs do not. So, yeah, SSDs aren't "disks", but they also aren't "drives", technically.

But that really doesn't matter. Some people call SSDs "disks"; that's just a fact. Maybe they "shouldn't", but stating that here won't change that. Even if it could change people's minds, we Wikipedia editors aren't allowed to even attempt to do that. Wikipedia collects, not corrects information. See Wikipedia's core sourcing policy WP:Verifiability, not truth. If you can find a reliable source that states "disk" is "wrong", then we can state that; in fact, must state that. Without such a source, we must just inform readers of the existing situation, however much we might like to wish it were otherwise. --A D Monroe III (talk) 15:12, 20 August 2014 (UTC)

Why do you say "they also aren't "drives""??? Have you read what I wrote?! Look at: http://en.wiktionary.org/wiki/drive#Noun "(computing) A mass storage device in which the mechanism for reading and writing data is integrated with the mechanism for storing data, as a hard drive, a flash drive." So there you have the prove that Drive is correct and no one says Disk is correct. Why don't you change it? — Preceding unsigned comment added by 134.93.55.218 (talk) 16:29, 20 August 2014 (UTC)

Anon, I did indeed read your source. It definitely implies that an SSD can be called a drive. It does not say it cannot be called anything else. (And it's a tertiary source; Wikipedia relies on WP:secondary sources.)

Wikipedia policy forbids the change you suggest. Wikipedia editors cannot pass judgment on the correctness of commonly-held information, only report it. (For example, the Holy Roman Empire was not holy, was not Roman, and was not an empire, but that's what everyone calls it, so we call it that too.)

There is no source given that actually states "Solid State Disk" is "wrong", so we can't say it is.

Note that even though we state SSD is sometimes called "Solid State Disk", as we must, we currently quickly follow this with "though it contains no actual disk". That's as far as we can go. Please let us preserve this existing compromise. --A D Monroe III (talk) 15:49, 21 August 2014 (UTC)

...and lower power

I suggest adding something about SSD being lower power than spinning drives, in the excellent phrase:

Compared with electromechanical disks, SSDs are typically more resistant to physical shock, run silently, have lower access time, and less latency.[7]

Suggested change: add "require less power"

Compared with electromechanical disks, SSDs are typically more resistant to physical shock, run silently, require less power, have lower access time, and less latency.[7]

Also, since there is an SLC vs MLC table, and now TLC is out, TLC should at least be introduced, perhaps with a reference to:

which has been updated to TLC.

WardXmodem (talk) 23:15, 18 September 2014 (UTC)