The following discussion happened in the comment thread on the answer https://unix.stackexchange.com/a/118428/5197, which began with the question "Is udev working properly on your server?" and continued to suggest that the problem that led to the question might be that udev was either not running or that it was misconfigured. In the end, the problem was discovered to be something else.

The disagreement

Anthon and slm both believe (I hope I do not misrepresent them) that because the answer was hypothetical and asked for further information, it was really a comment asking for further information and not any kind of answer. I believe that because it contained an answer that might be the solution to some people with similar problems, it was an answer, albeit only a partial answer. We then proceeded to disagree on the right interpretation of the FAQ; see the comment thread below.

Ongoing issue

The reason I think the disagreement is worth discussing is that the "when is an answer not an answer" criterion is one of the sharp edges that newbies get hurt by.

The original, question only comment clearly fell under the scope of "should be flagged as not an answer" as the answer consisted of just a question.

The amended question changed the content of the answer from purely asking after information to provide what I understand as a partial attempt to answer the question.

It is the disagreement over the revised answer that I think needs to be resolved. Which of the following criteria are applicable?

The criteria

From How do I properly use the "Not an Answer" flag?

When should I use this flag?

Use this flag when an answer is being used to:

  • Ask a question
  • Communicate with another user
  • Say "thanks," or confirm that another posted answer worked for him.
  • "Bump" the question, as in "I have the same problem, have you found a solution?"

When should I not use this flag?

Do not use this flag when a user posts:

  • A partial answer
  • A wrong or inaccurate answer
  • An answer to a (slightly) different question
  • An answer you disagree with

Cast a down-vote and/or comment instead.

The comment thread

This is really a comment, not an answer. With a bit more rep, you will be able to post comments. For the moment I've added the comment for you, and I'm flagging this post for deletion. – slm yesterday

I know, but since I cannot comment I had to put it like an answer (indeed, it may be the actual answer). – Alvaro yesterday

If this is "an actual answer" then you should explain how to establish whether udev is running, what it is and how to enable if it isn't. – X Tian yesterday

@Anthon - I disagree with the idea that answers have to be complete in that they provide all diagnostic methods and full information on how to apply the solution. Some questions may be concrete and specific, but the qner does not provide quite enough information. That is the qner's fault, though not enough reason to close, and is certainly no reason to fault answers. The qner might not return with more information, or the answerer might not have time to iteratively discuss things with the qner. Do we then close the interesting qn, or leave it with no possibility of acceptable answers? – Charles Stewart yesterday

@CharlesStewart I reviewed "Is udev running in your server?" (IIRC in the LQ queue). That answer is inappropriate as an answer, it should have been a comment, and I flagged it so, do you disagree with that? Alvaro had enough rep for commenting. The answer was later expanded, my flag (which automatically inserts the text, I now removed) was declined, but the system never gives a reviewer a message to re-review an answer, nor does it retract the text it inserts. Had Alvaro used @anthon I would have know about the change and his comment – Anthon 23 hours ago

@Alvaro - You have 200 rep, how are you not able to comment? – slm 23 hours ago

@CharlesStewart - if you have leads or partial ideas then those are comments, this isn't up for discussion, that's just how it is. If you're unfamiliar with this then please read the help on how to answer questions. – slm 23 hours ago

@Anthon - yes I fixed it. – slm 23 hours ago

@Anthon - Yes, I disagree. Per Robert Harvey, "Do not use [the not an answer] flag when a user posts: A partial answer; A wrong or inaccurate answer ..." - meta.stackoverflow.com/a/185074/140179 - and Alvaro's answer does say that problem might be that udev is wrong or misconfigured. Partial, but an answer. – Charles Stewart 21 hours ago

@CharlesStewart I am not sure what you disagree with as that link supports my action. The first point at "When should I use this flag" is Use this flag when an answer is being used to Ask a question. The whole answer was the sentence "Is udev running in your server?" and ends with a question mark. And you don't think it is a question, but a partial answer because of what? – Anthon 21 hours ago

@Anthon - The FAQ text is talking about raising a new problem, something that should be posted as a question rather than an answer or a comment. Alvaro is just indicating that his answer depends on what is going on. It could be rephrased in terms of "if $this, then $that". – Charles Stewart 20 hours ago

@CharlesStewart Which FAQ text are referring to? – Anthon 20 hours ago

@Anthon: Robert Harvey's answer is a FAQ answer on meta.SO – Charles Stewart 20 hours ago

@CharlesStewart According to your standards no question or communication (both reasons for flagging according to Robert Harvey) can be flagged, as they always can rephrased. I might just not be smart enough to see that they could but turned into that. And if you were right I should have a lot more flags rejected than I have. – Anthon 20 hours ago

@Anthon - I do not think anything I have said would be controversial on the other Stackexchange sites I am familiar with. I am really astonished at this dialogue - as I suppose you are. Perhaps a meta qn is in order, either here or on meta.SO. – Charles Stewart 19 hours ago

@CharlesStewart First of all slm flagged this as well. and I don't understand why you only address me on this issue and not him as well Second: I have somewhat less helpful flags on Stack Overflow (almost 300) than on Unix & Linux but the same behaviour in flagging and comparable number of rejects (some bloopers, some edited before being moved to comment/deleted, just as this one). I am sure that if Alvaro had waited even longer than the half-hour between posting his question and expanding upon it it would have been turned into a comment by the mods/10K+ers here, or deleted. – Anthon 19 hours ago

@CharlesStewart I also flagged this as not an answer, it would be considered as such in all of the 5 SE sites where I have enough rep to have an opinion. Comments are for asking for clarifications, answers are for posting solutions. – terdon 19 hours ago

Just for the record, I did not vote on this answer – Anthon 18 hours ago

@CharlesStewart - This conversation is fruitless here, this A is not an A, it's a comment. Let's move this to a meta question either here or on meta.SO to get an actual decision. Sitting here and badgering Anthon and others who are highly viewed within this site's community is doing nothing constructive. Anthon has performed a lot of the reviews on this site as well as other SE sites and hasn't gotten any indications from those site's mods that he's doing it wrong! – slm 18 hours ago

The DV is from me. This is a comment! Expand it to an A and I'll gladly revert it as always! – slm 18 hours ago

@Anthon: I didn't use the '@' to signal slm because the Stack Exchange software has a limit whereby it only notifies one person. I'm prepared to accept that my interpretation is wrong, but my interpretation is the one that is followed on the Tex-SX site. I'll raise this question on meta in due course. – Charles Stewart 1 min ago

@slm: Anthon is clearly conscientious and an asset to the site; this is only an argument about interpretation of rule. I agree that this discussion should take place on Meta. – Charles Stewart just now

  • 1
    So the question is whether it's right to post an answer to give a possible/probable cause of an error or if we should post a comment to ask for more information and wait before answering to be sure of the cause of the error?
    – lgeorget
    Mar 8, 2014 at 14:23
  • @lgeorget - Of course it is good to try to get enough information so that you can post a complete answer. But there are times that is not practical. What I want is to reach a common understanding on whether this rule applies to answers like the one linked to, which are incomplete and ask for information, but provide a possible answer. Mar 8, 2014 at 14:28
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    Ok, I understand your point. That's an interesting question but I'm clueless. Personally, if it's of any help to you to gather habits, I tend to post comments in those cases and I only post an answer when I'm absolutely sure it's going to help. Of course, sometimes I'm wrong and I post a useless answer and sometimes I don't post an intuition which at the end of the day, was the good one. So... your question is a good question! :-)
    – lgeorget
    Mar 8, 2014 at 14:33
  • @lgeorget - Note that when he posted his answer, Alvarro had 1 rep (he did not link his accounts 'til next day) and so could not post a comment. Mar 8, 2014 at 14:35
  • 3
    Note that the original answer posted was "Is udev running in your server?", which is clearly not an answer and is a comment to the question. If he could not have posted a comment due to rep, that doesn't mean he should post it instead as an answer. If he really thought "Udev isn't running" is the answer, he could have phrased it differently. Note that he did greatly improve the A with his edits, but most of the commentary derived from the original A, not the subsequent edits.
    – casey
    Mar 8, 2014 at 15:47
  • @casey: I think all the comments, including the comment of Anthon's that I first replied to (which was deleted by the time I put this Meta post together), appeared after Alvarro's first revision of his answer. Mar 8, 2014 at 16:02
  • @CharlesStewart Anthon explains in one of his first comments to that post that he first saw it in the LQ queue and it was just the original post, prior to the revisions.
    – casey
    Mar 8, 2014 at 17:17
  • @casey - I think it was probably in the FP queue, and I think his first comment explaining why he thought it should be closed came after the initial discussion between slm and Alvarro, when Alvarro had revised the post. It was that comment, concerning the revised answer that I disputed. In any case, this meta discussion should not be about the history of that answer, it should be about when to apply the "not an answer" flag. Mar 8, 2014 at 17:44
  • @Charles It was in the LQ queue, I am not sure why you doubt my word on that. I deleted the automatically inserted comment that is a result from a flagged post that is not an answer, because the question was expanded to something more than just a question. BTW the answer is at this moment still active in the flag queue.
    – Anthon
    Mar 8, 2014 at 18:50
  • 2
    Can you edit your question to include exactly what it is you are asking, or the point you wish discussed?
    – jasonwryan
    Mar 8, 2014 at 19:07
  • @Anthon - I apologise. It should have been in the FP queue as well, since it was the first acount activity, before Alvaro associated his accounts. Mar 8, 2014 at 19:38

2 Answers 2


To give some more background, this is the text I got to review:

Is udev running in your server?

This and only this version of the post by Alvaro is of interest. Because the discussion was about whether I should have flagged this or not.

This was in the Low Quality Post queue (at the bottom of the list).

enter image description here

I flagged it at 14:34.

The above text has to be flagged as not an answer, it is a question and a communication with the OP. Therefore it has to be put in as a comment under the question. If you click [Add Comment] that is unmistakable from the text in grey you see in the box before you start typing:

Use comments to ask for clarification or add more information. Avoid comments like "+1" or "thanks"

Is udev running in your server? is asking for clarification. Of course if the answer from the OP would be yes or no, you can use knowledge to start answering.

I, and others here on unix.se put those questions in all the time, as comments. If they get answered (preferably by improving the question), this will help me or someone else to give an answer to the question. If they comments do not get reacted upon, there is a good change the question gets closed as "Unclear what you are asking".

Instead of asking a question, you can incorporate it in a, what I would call, guessed solution. That would look like:

Have you checked A, B and C.
Because if A is not true, then you problem is X
And if B is not true, then your problem is Y

That is an answer: it guesses what might be wrong in the form of a question and provides an answer. I have seen these evolve as well, first the first line is posted, I flag them, and based on the comment the answerer expands. My flag gets rejected by the MODs but that is not nice, but I think the MODs are aware of a post changing after you judged it as well.

Once I flagged Alvaro's non-answer, the automatic text about not being an answer and being more appropriate as a comment got inserted. And that would have been the end of the line for me. I don't get automatically notified of expansion of the Answer. Alvaro failed to @anthon inform me of the changes that he made. Most low quality answers that I flag never get changed, I don't go back at the end of the day to see if any improvements were made.

What is completely irrelevant is what the answered turned into, after Alvaro updated it the first time at 14:46.

What could be up for discussion after that is whether the comment posted as an answer had turned into something acceptable as answer. That is out of my hands, and the MODs might decline my flag based on what they see when they look at the flag reviews.

IMHO my flagging was correct behaviour based on the information that I got at the time of review. That doesn't mean I have not made mistakes in reviewing before, or that MODs have disagreed with me (here or on stackoverflow), but it has never been cause for complaints.

I have flagged this way on StackOverflow, Unix&Linux, Ebooks and also on TeX (33 flags out of which 1 disputed and that got edited after I flagged it) and I think it is the appropriate way to handle questions posted as answers.

  • Thank you. I had understood that your original comment appeared after Alvaro revised his answer. If that is not the case, or if it was not clear that I was concerned only about clasifying the post-edit answer as "not an answer", then I apologise. Mar 8, 2014 at 19:55
  • 2
    @CharlesStewart. Apologies accepted. It is not easy but you can see the original times (you have to inspect the HTML source for the tag generating "2 days ago"). But that is exactly why I included the text of what I had been reviewing in the reply to one of your comments.
    – Anthon
    Mar 8, 2014 at 20:42

I don't understand the problem here. An answer is something that offers a solution to the problem, explaining how that solution can be implemented. Even in its latest incarnation, the answer in question does not do so:

Is udev working properly on your server?

Clearly not an answer but a request for more information.

udev is the device mapper in charge of the creation of those symlinks, so it can be that it is not working, or that it is not configured properly.

Great, how does one configure it properly then? Again, this is not answering the question, it simply explains what udev is with no details on how it is relevant to the case at hand.

Is it running? (i.e. /etc/init.d/udev status)

Not an answer, again, asking the OP for more details.

It may be that it is not configured properly, so check if your rules are OK:

$ grep "disk/by-uuid" /lib/udev/rules.d/* /lib/udev/rules.d/60-persistent-storage-dm.rules:ENV{ID_FS_USAGE}=="filesystem|other|crypto", ENV{ID_FS_UUID_ENC}=="?*", SYMLINK+="disk/by-uuid/$env{ID_FS_UUID_ENC}" /lib/udev/rules.d/60-persistent-storage.rules: SYMLINK+="disk/by-uuid/$env{ID_FS_UUID_ENC}" (...)

This is the closest the post gets to answering but it does not tell us what to check for! As such, it is completely useless unfortunately. How does the output above help me determine if my udev rules are correct? If the user who posted this had highlighted what to look for and how to fix a possible problem, it might have been an answer. This, however, is not.

So, in summary, an answer is expected to provide an actual answer. This doesn't, ergo, it is not an answer.

  • 1
    Terdon, what you miss is that the whole questioning started about me flagging the original post. What that answer, that should have been a comment, turned into later is IMHO not relevant. THe original answer was: Is udev running in your server?
    – Anthon
    Mar 8, 2014 at 19:39
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    @Anthon I know but as far as I'm concerned, the final version is not an answer either.
    – terdon Mod
    Mar 8, 2014 at 19:44
  • @Anthon - I flagged it too when it was in it's original state, not what it evolved into. I did DV it afterwards, but that was to push it to the bottom, as Terdon had described it, it was still not an actual A and was trying to get the A'er to either fix it or delete it.
    – slm Mod
    Mar 10, 2014 at 12:27
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    @slm I knew that as your comment was above my auto-comment. Unfortunately the quality of the answer seemed to have confused the whole issue even more. I think it is cleared now, but I would like an answer from Michael (my comment on his comment in the original answer), if not I will be my stubborn self and continue as usual.
    – Anthon
    Mar 10, 2014 at 12:38

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