Wikipedia:Reference desk/Archives/Computing/2006 November 18

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[edit] November 18

[edit] "Well known"

Reading Application directory#!Boot, I see a comment about "the well known Extend virus", now, since I'm curious, does anyone remember what this was, or what it did (virus wise)? 68.39.174.238 00:17, 18 November 2006 (UTC)

[edit] Total number of web pages

What is the total number of web pages? Can anyone give me a recent number, please? I know of the 25 billion pages number. Thanks.

It is impossible to say. In the time that I've typed this message an unknown number of pages were created and very few were deleted. --Kainaw (talk) 04:30, 18 November 2006 (UTC)
It also depends on what you mean by webpages because technically if a computer is connected to the internet then its files (or pages) can be accessed by someone else. (yes... that's hacking but......) They are also all stored on servers and some are only password acceptable, so we don't know them and their subpages.......... there's a lot! Cbrown1023 05:01, 18 November 2006 (UTC)
The number which don't show up publically are called the "darknet". --24.147.86.187 23:48, 18 November 2006 (UTC)
If you are counting web pages, I would say the true number is most probably infinite, or so large as to be considered infinite by most practical purposes. This would be because some servers have infinite virtual spaces; I recall, for instance, of a particular "trap" anti-bot script which outputs a small page with some random email addresses together with links to more invocations of the same script with different URLs. The only reason it's not truly infinite is that there's a hard-coded maximum URL length, which limits the theorical maximum number of distinct pages from a single web server to an absurdly large number. If even one server has a single infinite virtual space somewhere in the whole internet, that's enough to render your counting of the number of pages in the world wide web meaningless.
If you are trying to count only "real" web pages (but how would you define a "real" web page?), hostnames with web servers (but some web servers have wildcard DNS records pointing to them, again giving an absurdly large number), or IP addresses with web servers (but some of them host a large number of domains, causing a systematic bias in your measurement), you might get a more meaningful number. For the last two, I'd point you to Netcraft, which has some useful information. --cesarb 12:02, 18 November 2006 (UTC)
Whatever it is, it isn't infinite. There is a big difference between a number even in the trillions and "infinite." Even a number in the trillions is not so large as to be infinite for most practical purposes — the U.S. national debt is in the trillions and is still useful for "practical purposes". The other reason is can't be truly infinite (besides URL length) is the fact that there will always be a limited number of resources which can be expended on net wiring, even in a universe where all resources were dedicated to this purpose. --24.147.86.187 23:48, 18 November 2006 (UTC)
What if you have trillions of web pages that, when accessed produce trillions of trillions of trillions of variations on themselves - each one a unique web page? At what point does the number become irrelevant and "infinite" can be thrown in? I ask because that is the situation as it is now. There are trillions of dynamic web pages that change based on a multitude of reasons. --Kainaw (talk) 01:02, 19 November 2006 (UTC)
I don't think one should jump to "infinite" when the number is "very large but clearly finite". I don't think we're talking "trillions of trillions of trillions" in any case. There are probably not a trillion pages at most and the vast majority of the pages which do exist are probably not accessed very often. I see no reason to suspect there are "trillions of dynamic web pages" — I think you do not appreciate how large a trillion is. There are maybe 1 billion people who use the internet worldwide. Of these users a small percentage create web pages of their own, of those who do a very small percentage create dynamic webpages. If every single person on the internet were creating webpages, they would have to create 1,000 pages for there to be 1 trillion pages. Even if we assume some people create far more pages than others, it seems rather unreasonable to me to assume you are in the "trillion" range given that it is clear that most people wouldn't create more than one page at most, and most probably create no pages at all. --24.147.86.187 02:19, 19 November 2006 (UTC)
I do understand the magnitude of a trillion. I also understand that you made a completely new page when you edited this reference desk. I will make a completely new page when I save this comment. Just in Wikipedia alone, there are about 1.5 million articles. If the average article had only 10 historical versions, that would be 15 million pages alone by Wikipedia. Add to that all the cache sites that keep old versions of pages that update. Add to that all the blogs. It goes on and on - there are many MANY more web "pages" than there are sites because so many pages have multiple versions. --Kainaw (talk) 05:05, 19 November 2006 (UTC)
Does index.php count as only one web page? --frothT C 05:13, 19 November 2006 (UTC)
That is what I was asking in the first place. An index.php file is likely dynamic. If it only changed a welcome message each time it was loaded, it would a different page for each welcome message. You can easily download a text file with a few hundred thousand "fortune cookie" messages. So, with one index.php page you just added a few hundred thousand unique pages to the Internet. --Kainaw (talk) 05:19, 19 November 2006 (UTC)
It's not in the trillions. It's much, much bigger. Consider, for instance, a script which returns a different page for each possible value of a 80-character URL. Consider, for simplicity, that the path part of the URL is numeric—only 10 different characters. Even then, that single script is already responsible for the existence of 1080 different pages, which, according to our article on Observable universe, is about the number of atoms in the observable universe. If the script does not care about the length of the URL, the only thing preventing it from being responsible for the existence of an infinite number of pages is the harcoded limit on the length of a URL (or, if the limit were removed, the amount of memory available on the server running the script). --cesarb 18:44, 19 November 2006 (UTC)
[The internet reached a new milestone in october] Vespine 23:57, 19 November 2006 (UTC)
100 million web"sites". How many web"pages" is that? --Kainaw (talk) 13:37, 20 November 2006 (UTC)

[edit] Simple free calendar software

I'm looking for a simple, free (as in freedom), calendar program that runs on GNU/Linux. I tried out Novell Evolution, but that's not what I want, because it wants to control my email and everything else (I just want a calendar), and even the calendar part itself is too fancy (I just want a database where the keys are dates and the values are arbitrary text). Does anyone know of such a thing? —Keenan Pepper 05:37, 18 November 2006 (UTC)

Not certain that it meets what you want, but what about Mozilla Sunbird? There are a few (very few) others in Category:Free calendaring software, including Plan (calendar program). -- Consumed Crustacean (talk) 05:41, 18 November 2006 (UTC)
There's also WebCalendar . --N·Blue talk 11:54, 18 November 2006 (UTC)
Emacs has a built-in "diary" package that works with its calendar. I don't personally use it, but I believe it to be approximately as simple as you seem to want. --Tardis 17:34, 20 November 2006 (UTC)

[edit] how much does it cost to create an ad network

we are planning a website which would display a new type/kind of text ad instead of the plain text ad shown by google. Google's ads would not work on our website. I just want to know whether it would cost much to create an ad network or should I ask some ad networks to create ads specially for me. Is there any ad network who do custom advertisements for new sites?

the problem is not so much that it would be "costly" but that it would be hard to find advertisers. the advantage to using an existing ad service is that you don't have to devote any of your business time to finding people to buy ads, or handle any of the monetary aspects of it. the net mechanics of an ad network are just a script which serves ads and keeps track of which of them are served and which are clicked (relatively easy) and manages the monetary side of it (complicated). if you are requiring people to create custom ad sizes or formats then you are just going to lower the number of people who are going to be willing to do that to advertise on your site, unless you are going to be a major, major source of revenue for them. in the end I think it is most worthwhile to find a way to build an existing ad network into your site (doesn't have to be Google, could be Doubleclick or something else) than it would be to try and work out an ad network yourself. in the end I think trying to run your own advertising would be a bit of a "tail wagging the dog" problem — you'd be spending as much time on the financing of your site as you would on the content itself. easier to outsource the ad revenue to a dedicated company. in any case, here is a good link about the types of ad serving options you have out there, some proprietary, some open source, etc. --24.147.86.187 23:55, 18 November 2006 (UTC)

[edit] Block size of a Linux block device

What is the (userspace) method for programmatically determining the native block size of a Linux block device? Irix uses the F_DIOINFO fcntl command (man page), but Linux doesn't have that, and I can't find anything that resembles it. -- Finlay McWalter | Talk 13:20, 18 November 2006 (UTC)

I figured it out; sys/mount.h defines ioctl command BLKSSZGET, which takes a long* argument. -- Finlay McWalter | Talk 15:20, 18 November 2006 (UTC)