Wikipedia:Reference desk/Archives/Computing/2010 December 26

= December 26 =

What 90s video game had Mayan ruins exploration?
I used to play it all the time. I seem to remember it coming in a multipack of CDs my parents bought us that included re-releases of The Oregon Trail, The Yukon Trail, The Amazon Trail and Africa Trail. I remember exploring ruins and examining Maya stelae, and traveling between Palenque and Chichen Itza, among other sites. I've Googled and searched Wikipedia and can't find it. Does anyone remember the name of this game? I always thought it was a "Trail" game, but it may have just been called Maya Explorer or something similar. coreycubed / talk 03:52, 26 December 2010 (UTC)


 * Of course, I would find it minutes later. *sigh* It was called MayaQuest: The Mystery Trail. We don't have an article on it. coreycubed / talk 03:55, 26 December 2010 (UTC)

StuRat (talk) 04:17, 26 December 2010 (UTC)

How to remove design skins ...
I am using lunascape browser with firefox mode. Currently, I have added some optional skins from here. But the problem is, I can't get rid of them from my browser. I tried every possible way to remove optional skins, but failed to do that. Even there website could not provide any clue about it except to change them. Is there any way to remove those optional skins? thanks--180.234.32.206 (talk) 12:58, 26 December 2010 (UTC)

Other domain name suffixes
What if you want a suffix like .on which is not a country not in the list of common suffixes (like .tv or .net)? (for registering a web-site like get.on). Is it still possible to get somewhere (perhaps in the future)? Quest09 (talk) 14:09, 26 December 2010 (UTC)
 * Yes, perhaps in 2012, according to Generic_top-level_domain ... and it sounds like applying for one would be fairly difficult. 81.131.16.5 (talk) 14:40, 26 December 2010 (UTC)

How to use Class SMTPClient to send emails to my gmail account
I want to write a windows programme that can automatically send emails to my gmail box. Using use VC++ (of visual studio 2005), I wrote the function send(...) for the purpose. The code is very simple (almost following the sample codes in MSDN)

I provided correct username (having @gmail.com) and password, No exception was triggered, but the email can not be receieved. I use port=465 because of the | Standard instructions, and POP is enabled for all mail that has arrived since Mar 5. Also I tried port=587, but it didn't work either.

Can someone help me fixing the problem?

Thanks & regards, SongJie@NTU (talk) 14:57, 26 December 2010 (UTC)

CD-ROM audio connectors

 * Reference: http://www.pctechguide.com/tutorials/SoundCard_Optical.htm

My computer can play audio CDs without them connected to the sound card. This is logical – after all, my computer can always read each of the audio tracks' sectors, decode them, convert them to waveform, and send them to the sound card.

This then begs the question: If a computer can play audio CDs without these connectors connected, then what is their purpose? Why did they exist in the first place? Does it matter whether I connect them?

Thanks for any answers. 118.96.164.179 (talk) 15:04, 26 December 2010 (UTC)


 * On some systems, it is possible to play Audio CD to the sound card without using any CPU, RAM, or any other main computer resources. On computer systems with professional or high-end consumer-grade sound-cards (or if you are an expert device-programmer with a lot of time), it is possible to program the sound-card to process, manipulate, playback, and control the CD drive and its audio (again, without using any main memory or main CPU).  For this to work, it is necessary to connect the data lines between CD drive and sound-card.  Furthermore, these data lines are analog - and usually go to a second ADC channel on most sound-cards - allowing you (the user or the audio professional) to control the mix, volume, sampling-settings, and other audio properties for the audio CD separately from any other system hardware- or software- audio channels.  (If you are connecting over S/PDIF, the audio may still run through a separate digital processing pipeline in the audio card, depending on your particular card).  Nowadays (almost 2011), the measly 96,000 Hz, 24-bit sampling of even the highest professional-grade audio is such an insignificant overhead to the main CPU and RAM that this kind of parallelism really has minimal performance benefit; but in the "olden days" of the 1980s and 1990s, uncompressed audio was a huge bandwidth and CPU burden; so this side channel connection was engineered to alleviate the data required by the CPU and main memory bus.   Nimur (talk) 15:55, 26 December 2010 (UTC)


 * Thank you for your explanation. From your explanation, I take it that the connectors aren't really important nowadays. 118.96.154.33 (talk) 01:45, 27 December 2010 (UTC)


 * Audio CDs don't actually have sectors. They are more like a digital version of vinyl records. Because of the way CDs and CD-ROM drives work, it's tricky to do via your CPU what a standard audio CD player does. That's one reason why there are elaborate CD ripping programs with overlapped reading and online verification and so on. Simpleminded software that just reads from the CD and writes to the sound card will have serious audio quality problems with some drives and discs. When you use the CD drive's audio output, the drive behaves like a standalone CD player, so even simpleminded software can't screw anything up. This is probably not so much of an issue now as it used to be. -- BenRG (talk) 05:18, 27 December 2010 (UTC)
 * Indeed. For the mathematically inclined, Cross-interleaved Reed-Solomon coding explains how most standard audio CDs "splice" data (as an engineered solution to prevent scratches from rendering data unusable).  Consequently, the data is not just a raw binary sequential stream of PCM audio data; so reading it out requires some decoding software.  As BenRG has explained, the cd-drive's internal microcontroller can perform that decoding procedure for you (spitting out in-order, analog audio).  Nimur (talk) 16:07, 27 December 2010 (UTC)


 * Thanks for the interesting indirect link to Reed–Solomon error correction. I've often wondered why scratches don't appear in the sound output.  There are still sectors on the CD though, aren't there?  Just not simple data sectors like on a hard drive.    D b f i r s   20:15, 28 December 2010 (UTC)


 * Not exactly. See Compact Disc subcode for some details. CDs were designed to support dumb players that just place the digital pickup (laser) anywhere on the CD's spiral track and start playing audio. Encoded in parallel with the audio is so-called subchannel data, which is used for non-audio information, such as the disc table of contents and CD-Text and whatnot, but players can ignore that completely and still work (never accidentally playing metadata as if it were audio).


 * The audio (but not the subchannels) is protected with CIRC error correction. Contrary to what Nimur said, almost all consumer drives provide no way to read this CIRC data in software. I think that some early drives didn't support reading CD audio in software at all, and some supported it but did no error correction at all. Other drives correct the audio as much as possible, but don't inform you of uncorrectable errors. Still others report uncorrectable errors but leave the software to hide them (by interpolation). Still others do interpolation themselves. Additionally, there's no reliable indicator of where exactly on the disc you are. This means that if, say, some data from the disc range you're reading was already cached somewhere, and the drive seeks to a slightly different location on the disc the second time, you may get skipped and duplicated audio data with no warning. These things combine to make accurate reading of digital audio from CDs pretty nightmarish.


 * In the CD-ROM standard there is a second independent level of CIRC data added because the CD-Audio error protection wasn't good enough for most other types of data. (Uncorrectable audio errors can easily be hidden by interpolation.) Most (not all) drives do allow you to read that CIRC data, but it doesn't exist on audio CDs. CD-ROM also added a sector header giving the number of the current sector so that reliable seeking is possible. -- BenRG (talk) 07:42, 29 December 2010 (UTC)


 * Thank you for all the interesting information. I always thought that audio CDs were just a special case of data CDs. That is, I was thinking that audio CDs were simply WAV files stored in individual tracks, where each sector of the tracks was individually addressable and seekable, with addressing, seeking and error correction automatically performed by the drive. 118.96.161.20 (talk) 02:35, 2 January 2011 (UTC)


 * In your CD playing software, look in the advanced options for an setting to play CDs using either "digital" or "analog" methods. Try each one and see if your computer behaves differently. On my computer the digital method causes the CD to spin faster and louder. The analog method spins the CD slower and quieter, so I prefer that.


 * Also, some CD drives have a play button right on the front of the drive. If you have the internal audio cable connected to the sound card, you can press this play button and hear the audio from the sound card speakers or headphones. Otherwise, you have to plug into the headphone jack on the CD drive itself. --Bavi H (talk) 05:20, 28 December 2010 (UTC)


 * I looked for that setting in both RealPlayer and Windows Media Player and found it in both players. The interesting thing is that, in every case, the setting is buried quite deep in the player's interface and defaults to Digital. Coupled with the fact that most modern CD/DVD/HD-DVD/Blu-Ray drives don't come with a "play CD" button (and cables to connect the connectors), it's easy to see why the connectors appear useless to modern computers. 118.96.161.20 (talk) 02:35, 2 January 2011 (UTC)

Saving pages in Firefox
When I save a page to HD in Firefox, why does it seem to re-load the whole page to save it, rather than just saving it from cache? Is there any adjustment I can do to make it do the latter option? Thanks 92.24.178.22 (talk) 16:57, 26 December 2010 (UTC)


 * Firefox apparently makes its own decision about where to look for a resource when you use the "save as" feature. Firefox can choose to use its internal cache, or to re-download the resource from the server.  This Mozillazine forum thread discusses a similar problem related to saving images.  You can read through that thread; they make a variety of suggestions and link to some Add-Ons that permit you to explicitly specify that you want to save the cached version.  They also describe the various Firefox cache configuration options, tweaking those (like increasing the cache-size) can "encourage" Firefox to choose the cached version instead of a re-download.  Nimur (talk) 17:53, 26 December 2010 (UTC)

Thanks, I do not understand anything in the linked thread. 92.15.0.200 (talk) 22:12, 26 December 2010 (UTC)
 * Sorry that the thread was too technical. Maybe you can try using this add-on, called Abduction!, which allows you to save a screenshot of a page.  It will not re-download anything; but unfortunately it looks like the output is an image (not HTML).  Nimur (talk) 22:31, 26 December 2010 (UTC)


 * If you want to prevent Firefox from downloading items again, it looks like you can check File → Work Offline, save the page, then uncheck File → Work Offline again. Be aware that while saving one page this way, I got several error messages about files that couldn't be read, and had to click OK several times. (Presumably those files were missing from the cache.) Although this might be annoying, this method might be a helpful fallback to remember when you're using a Firefox you can't customize. --Bavi H (talk) 04:13, 28 December 2010 (UTC)

I wish someone would write a Firefox add-on that allowed you to save the cache to disk, filtered by some criteria if you wish. That would be very useful. Unfortunately I lack the skills to do it myself. 92.15.4.201 (talk) 21:06, 29 December 2010 (UTC)
 * Firefox lets you browse the cache via the link about:cache. It allows you to navigate those items; and for items that reside only in-memory, it provides a hex-editor style display of the data.  (You could save that data to disk manually, but Firefox intentionally does not assist you with that process).  Note that certain items, especially those which Firefox protects by keeping in the RAM cache, are never written to disk.  Certain sensitive information, such as cached HTTPS data, shouldn't be placed in insecure areas (like an unencryped disk), as that would represent a potential security vulnerability.  Secure information should stay in the protected memory area, where no other programs can access it.  Firefox's cache-navigator will permit you to manually save even this HTTPS data to disk by copying/pasting/parsing the hex dumps; in practical terms, it is unlikely that you will compromise your secure sessions by doing so, but it is possible that a malicious attacker who has otherwise gained access to your system could use that data to compromise your secure sessions.  All the other "regular" cache data is provided in about:cache with direct links to their on-disk representations.  Nimur (talk) 14:08, 30 December 2010 (UTC)

help please :)
I'm trying to view http://unichan2.org but it keeps saying "The server at unichan2.org is taking too long to respond." But the site is fully viewable via proxy and my friends reported that it works for them. I flushed the dns at command prompt and even tried going directly to the ip address http://88.80.29.13/ but it still isn't working for me. What is wrong? Is it my isp censoring me? —Preceding unsigned comment added by 95.88.2.248 (talk) 22:04, 26 December 2010 (UTC)
 * The link appears to be to a social networking site. My guess is that your ISP address has been banned. 92.29.122.99 (talk) 23:02, 27 December 2010 (UTC)