Wikipedia:Reference desk/Archives/Computing/2013 April 26

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April 26

Buying a used SSD -- pros/cons?

What are some of the pros and cons of buying a used SSD? --Navstar (talk) 00:43, 26 April 2013 (UTC)

Can’t say I have ever met someone who has bought a used computer drive before, but:

• Earlier model SSDs were not as reliable as those you can get new today.
• A used drive will probably be more used and therefore have a theoretically shorter lifespan after you acquire it.
• Potential data remanence issues*.

As ever, if the price is right, it’s right. :) ¦ Reisio (talk) 01:52, 26 April 2013 (UTC)

pro - if you're a criminal they may not have erased their bank details and passwords properly or left incriminating evidence or something you can sell to the papers.[1] Dmcq (talk) 03:34, 26 April 2013 (UTC)

Quantum computers disprove Church-Turing thesis.

Do quantum computers disprove the Church–Turing thesis. Look at Grover's algorithm for instance, which can search an unsorted database in $O(N^{1/2})$ time, but a Turing machine can only do it in $O(N)$ time. Although Grover's algorithm only gives the correct answer with high probability, any $O(N^{1/2})$ unsorted database search algorithm on a Turing machine can only find the correct answer with meager probability $1/{\sqrt {N}}$. AnalysisAlgebra (talk) 03:51, 26 April 2013 (UTC)

The Church Turing Thesis is that a function can be computed by algorithm iff there is a turing machine that computes that function. It doesn't matter that quantum computers may be able to do things faster, only that they can't solve problems a turing machine can't. If P != NP, you would have NTM's that are faster than regular TM's, but there is no problem an NTM can solve that a TM can't; same idea with QC.Phoenixia1177 (talk) 09:12, 26 April 2013 (UTC)

Also, you can read that stuff in the article on QC's, which states for example that they can't solve their own HP, which might be of interest. IBE (talk) 15:47, 26 April 2013 (UTC)

Choosing 'favorites' in Imgur

In Imgur, how do one choose a picture into his 'favorites' folder, technically ? It might be simple, but somehow skiped my eyes. Thank you, BentzyCo (talk) 04:14, 26 April 2013 (UTC)

Click on the heart icon below the image. Or if you prefer to use the keyboard, type a zero. You'll see a heart appear over the image when it gets favorited. There are also some keyboard shortcuts here. Dismas|^(talk) 04:47, 26 April 2013 (UTC)

A Wikipedia-like clickable "contents" section in Wordpress

I'm not yet well versed in the art of our office website's Wordpress so I need your help here.

Anyways, one of my colleagues asked me if it is possible to have clickable words or phrases in our relatively long FAQ that will point to the reader's desired section. Anyways, I think what he was saying is that I do a "contents" like section in the FAQ similar to the way clicking "Nature" in the Wikipedia article redirects the reader to Wikipedia#Nature.--Lenticel ^(talk) 07:50, 26 April 2013 (UTC)

That's called a hyperlink, or just a link. If it's an HTML page, then it's doable. StuRat (talk) 07:54, 26 April 2013 (UTC)

Yeah, I want to do it within the same page. Its easier to link outside the page but I'm not sure how to do it within the same page. --Lenticel ^(talk) 07:59, 26 April 2013 (UTC)

Ah it seems that the thing that I wanted to get is the HTML Anchor. Thanks for the lead StuRat.--Lenticel ^(talk) 08:05, 26 April 2013 (UTC)

You're quite welcome. Can we mark this Q resolved ? StuRat (talk) 10:16, 26 April 2013 (UTC)

• Wikipedia turns Section headings in an article into a Table of Contents (TOC) at the top of the page automatically when there are more than a certain number of sections, which is cool. Maintaining this sort of stuff (creating such links manually) is not much fun. It would probably be possible to run WordPress and Wikipedia together on the same site—with WordPress looking after some pages and MediaWiki looking after others—but you probably don't want Wiki pages that anybody can edit ;-) I don't know if anybody has modified the MediaWiki software to restrict editing to members only. There is third-party Wiki software, but I don't think it has MediaWiki's automatic TOC feature. LittleBen (talk) 10:38, 26 April 2013 (UTC)

Maybe the Wordpress plugin Table of Contents Plus is what you're looking for: "A powerful yet user friendly plugin that automatically creates a context specific index or table of contents (TOC) for long pages (and custom post types). More than just a table of contents plugin, this plugin can also output a sitemap listing pages and/or categories across your entire site. Built from the ground up and with Wikipedia in mind, the table of contents by default appears before the first heading on a page." - Cucumber Mike (talk) 12:52, 26 April 2013 (UTC)

Old form of email address

When I first got access to email in the mid-1990s, I remember that the way I sent email to people was different to how it is today. The email address was always quoted in the usual format i.e. localpart@domainpart, but I was not able to enter that format directly into my email client (which was text-based). Instead I had to enter some long string of characters which was essentially the email address in reverse. I can't remember the exact format, but it went something like uk:name of network:something else::username. There were definitely colons involved. What was all that about, then? Email address doesn't seem to mention it. Thanks, --Viennese Waltz 09:26, 26 April 2013 (UTC)

Perhaps UUCP mail, which used "bang paths" separated by ! and written in a range of orders including the reverse of the RFC 822 format. -- Finlay McWalterჷTalk 09:49, 26 April 2013 (UTC)

Another scheme was JANET NRS, which again used "big endian" addresses, but with periods (still not colons). Really, before Internet-working RFCs were adopted, individual networks and individual platforms used a variety of schemes - and even once the RFCs were adopted, for a while things were translated from the local scheme into the RFC scheme for Internet transmission, and then back translated into another local scheme at the other end. So you probably need to specify what network you were on, what platform (e.g. VMS), and perhaps what institution. I do seem to recall having a decnet email address back in 1987 with colons in, but I can't be sure. -- Finlay McWalterჷTalk 10:29, 26 April 2013 (UTC)

Yes, I'm thinking you were on a VMS cluster using DECnet node addresses as Mail addresses (before they added SMTP address support to the Mail program): examples of mail using that format are in this PDF (p36-). An example of OpenVMS mail showing how SMTP (RFC 822) email addresses were represented in the VMS Mail client is shown at the bottom of this document. -- Finlay McWalterჷTalk 10:56, 26 April 2013 (UTC)

Yes, the abbreviations VMS and VAX ring bells so I think it was that last one. There were no @ symbols and there were definitely colons, not periods or exclamation marks. It was a UK academic institution and I remember my lecturer telling me that it wasn't necessary to have as much information for JANET email addresses as it was for those outside of JANET. Thanks Finlay. --Viennese Waltz 12:27, 26 April 2013 (UTC)

Flat pocket computer

Is there any flat pocket small single-board computer? Something like a Raspberry Pi, but thiner as a smartphone. OsmanRF34 (talk) 16:29, 26 April 2013 (UTC)

I don't know of one offhand. But the height of the Pi is governed not by the chip, but by the other components. In particular, the Pi Model B's maximum height is that of the ethernet port and USB ports. The Model A is slightly thinner, due to having no ethernet and only one USB port. So, if you took the USB ports, ethernet port, audio jack and HDMI port off the Pi's board, you'd have your 'flat computer'. You'd also have, more or less, a smartphone. See here for a list of devices based around the same ARMv6 architecture - many of them last-gen smartphones, including the original iPhone. If you let us know what application you have in mind for your flat computer, maybe we can come up with a decent suggestion for you. - Cucumber Mike (talk) 18:42, 26 April 2013 (UTC)

Gumstix comes to mind. ¦ Reisio (talk) 00:35, 27 April 2013 (UTC)

Differences in Pasting Methods?

As a sort-of tech support in my office, I send emails to the employees with instructions on how to perform some tasks. This time, we received a new printer, and I needed to make instructions on how to connect with the printer via the print server: "\\<server>\<printer name>". After completing said instructions, I got people who told me my instructions didn't work -- I went over to their systems and performed the operation exactly as I had instructed, and it worked...what? Were the employees doing it wrong? I asked one employee to show me how he was following my instructions in order to see if there was some unforeseen problem I was missing. I removed the printer and let the employee try again: 1) Copy the printer server-name address from my instructions. 2) Paste it into the Windows 7 Start Menu "Search programs and files" bar. 3) Hit Enter. Now it failed to find the printer! Confused, I tried it again, using the same Clipboard data, and it worked! I thanked the employee, went back to my desk, and tested it myself. All attempts were successful! However, I suddenly remembered that the user used a different method of pasting the address into the Search bar: They were using "right-click menu, select Paste", while I was using the good old Ctrl+V keyboard shortcut. I tried the right-click method and...it failed! Multiple attempts using the right-click method failed each and every time! However, all attempts using Ctrl+V worked! The text ended up in the Search box exactly the same every time. My ultimate question is: why in the world would two methods of performing the same operation give two different results, with no visible difference of text between said methods? Thanks! -- 143.85.199.242 (talk) 20:33, 26 April 2013 (UTC)

Well, if they both look the same, I suspect that trailing spaces, or line feed/carriage return, or some other special character is embedded in the string. Another possibility is that the paste which fails is trying to copy over tags setting the font, color, etc., although I'd expect those to be visible. StuRat (talk) 21:21, 26 April 2013 (UTC)

My office’s counterpart to you found this particular task sufficiently tedious to create an installer that did it all, leaving the end user nothing to do but run a provided executable. ¦ Reisio (talk) 00:36, 27 April 2013 (UTC)