Wikipedia:Reference desk/Archives/Computing/2014 January 5

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January 5

Multidimensional arrays in HTML

Hi, this is a kind of obscure question, but perhaps someone here might have an idea...

In an HTML document, I can create something like:

<span id=fld>...</span>
<span id=fld>...</span>
<span id=fld>...</span>
...

and then I can reference the elements from JavaScript as fld[0], fld[1], etc.

Is there a similar way to make a 2D array that I can reference by fld[0][0] etc.? 86.160.222.169 (talk) 03:52, 5 January 2014 (UTC)

POP3 & IMAP in WinSer 2008

I am wondering if it is possible to set up POP3 and/or IMAP email accounts in WinServ 2008? This website lists variations of Microsoft "EMAIL PROGRAMS" as they call them which allow POP3 and IMAP. They do not precisely match what I have here which is the only options, and it is "Windows Live Mail but sound very close." The steps I had to take here to set up an email account are very rigid and are limited to only variations of hotmail.com; live.com, etc as domains. I had to establish a new email account which I do not need. I know there is someone around here who has actual hands on experience with WinServ 2008. So I wonder... Thanks --AboutFace 22 (talk) 16:26, 5 January 2014 (UTC)

Not a direct answer, but I just quit all that POP3 nonsense and switched to Internet mail services, like gmail, via my browser, long ago. Life is too short to try to configure POP3 servers. StuRat (talk) 16:32, 5 January 2014 (UTC)

Thank you, StuRat. I do have Gmail at work where I have no choice and also I try to use it for work related communications only. I am kind of allergic to Google :-) since they are so intrusive. It is largely a matter of long standing habit, plus I have an IMAP account with my family name as a domain. I do use POP3 rather seldom. --AboutFace 22 (talk) 17:09, 5 January 2014 (UTC)

It doesn't have to be gmail, per se, just one that works like it. StuRat (talk) 17:18, 5 January 2014 (UTC)

Indexing texts

If you had to index 100+ TBs instead of 1 TB, would it be only 100x more difficult, or, would you need something different for being effective, since you could also index the index, or not have to create a keyword that already exits? That means, does difficulty increase linearly or not when indexing and retrieving efficiently? OsmanRF34 (talk) 16:33, 5 January 2014 (UTC)

One issue that comes up is the size of each index record. 1 byte can distinguish 2⁸ or 256 records, 2 bytes can distinguish 2¹⁶ or 65536 records, 4 bytes can distinguish 2³² or 4.3 billion records. So, at each threshold you increase the size of each index record, and thus the size of the index, more than just proportionally. StuRat (talk) 16:42, 5 January 2014 (UTC)

Can you clarify your question a little? By "indexing" are you referring to a database index, or an "inverted file" (also known as full-text index)? And what do you mean by "more difficult"? Are you asking about time/effort to set up the index, or space to store the index, or time/effort to search the index to perform one lookup? —Steve Summit (talk) 17:22, 5 January 2014 (UTC)

I am asking for a full-text index, and regarding 'more difficult' as more computing time and storage space> OsmanRF34 (talk) 17:52, 5 January 2014 (UTC)

For retrieving records, it ought to be nowhere near 100x slower to retrieve a single record from a 100x larger collection of data, assuming it's properly indexed. However, if you now have 100x as many records that match the search criteria, then it will indeed be 100x slower, at least, to get them all. StuRat (talk) 18:01, 5 January 2014 (UTC)

If the index contains offsets to every occurrence of every word in the text, then those offsets alone take O(n log n) space (barring clever compression) since each one takes log n bits to encode. A particular indexing technique could have worse than O(n log n) overhead, but I think they don't in practice. So one would naively expect an index of 100 times as much text to be several hundredsomewhat more than 100 times larger. Constructing the index might take O(n (log n)²) time and/or temporary storage space, but I think O(n log n) construction is possible in some cases. Lookup is likely to require looking at O(log n) records each of size O(log n), for a total cost of O((log n)²).

An interesting exception to the space requirement is the Burrows–Wheeler transform, which is a kind of "inverted file" that only takes O(n) space. But to use it as an index you need auxiliary data structures, and I don't know whether they can be made to fit in O(n) space (though I wouldn't be surprised if they could). -- BenRG (talk) 02:05, 6 January 2014 (UTC)

If $n=10^{10}$ and $n'=100n=10^{12}$, then ${\frac {n'\log n'}{n\log n}}=100{\frac {12}{10}}=120$, not "several hundred times"; the increase in $\log n$ from a constant-factor increase is not proportional even to itself. (Of course, constants not included; other terms contribute in any real-world scenario.) --Tardis (talk) 13:49, 6 January 2014 (UTC)

You're right of course. Fixed. -- BenRG (talk) 10:12, 7 January 2014 (UTC)

iTunes exe setup file missing

I've got iTunes 11.1 installed on my computer, and would like to install it on another without downloading the entire iTunes again, but I can't found the setup .exe file. The VLC setup file is still there, so does iTunes remove the setup file after installation?

And is there a way to install iTunes on another PC without downloading everyting again? Romeo Kilo 16:41, 5 January 2014 (UTC) — Preceding unsigned comment added by Proudly RSA (talk • contribs)

Microsoft Security Essentials for WinSer 2008

I hope asking trivial questions does not rattle any feathers :-) I just downloaded and installed the above mentioned software and want to know if it commands any respect at all? Especially it would be nice to know if it is popular at large companies with many users. I will ask my people tomorrow (or perhaps just check it myself if it is installed) but I don't think we have it. Thanks, --AboutFace 22 (talk) 17:30, 5 January 2014 (UTC)

It sounds like you're setting up a Microsoft server. What you should do is work through the Server Infrastructure training and certification, which will teach you all you need to know for the setup and operation of your server; or if you don't have time for that, you can hire somebody who has already obtained equivalent credentials (e.g. a Server Infrastructure MCSE-grade Microsoft Certified Professional).

In addition to paid courses, there are many free resources available for current products. For example, here's a free eBook, Introducing Windows Server 2012. If you're dead-set on using the 2008 release, which is now six years out of date (and which was never free software), you should expect to budget some money to pay for a Server 2008 expert. Knowledge and experience about proprietary technology is expensive. Nimur (talk) 18:01, 5 January 2014 (UTC)

Yes, the .pdf file is useful. Thanks for that although I do have printed books, there are quite a few on Amazon. I hope for now I will manage this limited task myself. --AboutFace 22 (talk) 19:00, 5 January 2014 (UTC)

Is it Graphics card problem?

5 days ago, I heard a noise from my thermaltake Xaser VI case. I thought It was wire that was touching my system or processor fans. So I ignored. But this noise persisted and suddenly my PC shutdown. So, I opened the case and found that everything runs fine except my graphics card. I noticed that noise is coming from graphics card. I checked and it was the card's fan which spins a while and then stops. I tried to clean dust which was my primary concern, but there's little to no dust. If I touches the fan, it spins with noise but my pc does not boot. I switched off from main connection and started the pc again. Same noise with card's fan problem. I checked the power supply to see whether it supplies proper power to graphics card. But there's no issue there. It's all about the graphics card fan that spins with noise then stops spinning and PC shuts down or won't boot at all. Does all this mean my card is dying? My graphics card is Nvidia Geforce 9800GT which I bought in 2009. Thank you--180.211.153.121 (talk) 18:15, 5 January 2014 (UTC)

Yep, it sure sounds like bad fan bearings on the graphics card. I'm a bit surprised it won't boot, bypassing the graphics card, and use whatever limited on-board graphics capability it has on the motherboard. You could try removing the graphics card, to see if it will then boot. StuRat (talk) 18:31, 5 January 2014 (UTC)

• My graphics card does not have on board graphics card.--180.211.153.128 (talk) 13:18, 6 January 2014 (UTC)

• You mean your motherboard doesn't ? That might explain why your PC just dies on you completely due to the graphics card problem. This is why it's nice to have a backup. Now you have to get a new graphics card to do anything on that PC. StuRat (talk) 13:41, 6 January 2014 (UTC)

• • Mine is gaming motherboard. It does not have on board graphics card.--180.211.165.103 (talk) 15:25, 6 January 2014 (UTC)

On board graphics are handled by your CPU. Most Intel and AMD CPUs do have built in graphics processors, so I am assuming yours does as well. 158.96.4.13 (talk) 19:39, 10 January 2014 (UTC)

Hyper V in WinSer 2008

I just setup Hyper V as a new role. Stated it. I got two errors (events) 32 & 41 which are explained here. They both suggest the same thing that I should update my BIOS. At the same time I see in "System Services" that they seem to be all running: Hyper V Image Management Service, Hyper V Networking Management Service and Hyper V Virtual Machine Management. So, I wonder what is missing if anything. Thanks, --AboutFace 22 (talk) 18:40, 5 January 2014 (UTC)

Make sure your processor supports Intel VT-x and that virtualization is turned on in the bios. Graeme Bartlett (talk) 04:25, 9 January 2014 (UTC)