Wikipedia:Reference desk/Archives/Computing/2010 April 27

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April 27

TI Nspire CAS - Clickpad vs Touchpad

What's the difference? —Preceding unsigned comment added by 115.178.29.142 (talk) 05:39, 27 April 2010 (UTC)

Sign your posts. Try looking at the pictures of each calculator to see the difference. --Buffered Input Output 13:47, 27 April 2010 (UTC)

A course for learning coding and similar (UK)

Can anyone recommend a particular course for learning C++ or similar, with no previous knowlege, like a GNVQ or a foundation degree or something. I'm looking to get into coding and while I'm quite knowlegable in IT, holding a Level 3 qualification in System Support (Whos name I forget at the moment), I would like to get into programming, but am at a loss as where to start. Would a Computer Science qualification work as a jumping off point? Gunrun (talk) 08:14, 27 April 2010 (UTC)

C++ is a really poor choice for a first language. I suggest Python. There may be some useful lectures at MIT Open Courseware, i.e. here. 69.228.170.24 (talk) 11:25, 27 April 2010 (UTC)

Which first language works for you depends critically on what you want to use it for, the best language to learn is the one you'll use. I'm learning perl as my first language because that's what's used most in bioinformatics (and I know it's unfashionable but I rather like the "there's more than one way to do it" philosophy). Python is a good "general" choice though. C++ would be considered by most people to have too many low level features to be easy to learn as a first language.131.111.185.68 (talk) 15:38, 27 April 2010 (UTC)

C++ Programming WikiBook is a pretty good resource. Be sure to read our article on C++ and make sure you clearly understand the details of C++ - it is a compiled language that is object oriented and designed for both systems programming and application programming; it is very versatile, but suffers from several key drawbacks, including some complicated structure and ugly memory management complexity. Most importantly, (especially if you are a novice), make sure you clearly understand the subtle but significant differences between C++ and the C programming language. (There are also plenty of not-so-subtle language differences and additions, but these will be obvious even to the novice). C++ carries over much syntax from C, and it is generally true that any C program can be a valid C++ program also; but make sure when you are acquiring resources (books, websites, software tools, and so on), that you are getting things geared towards C++, or at least be aware of the details and differences. If you have firmly decided that C++ is your language of choice, you have many tool options, depending on your platform. I recommend g++ as the compiler; or if you will be on a Windows platform, mingw, a minimalist port of the g++ compiler to Windows. Microsoft also makes many of its C++ compiler and development tools available for no charge for noncommercial uses: Visual Studio Express. Nimur (talk) 16:07, 27 April 2010 (UTC)

The issues with C++ as a first language are 1) its features were designed to meet the requirements of large multi-programmer projects, and as someone learning a first language you'll probably start with solo projects so C++'s design won't make much sense to you; 2) because of the lack of pointer safety, C++ programs are harder to debug than "safe" languages are, and that will slow you down a lot as a beginner; 3) The C++ language itself is just bloody big and complicated. I'm not a Perl fan (an ugly language IMO) but the book Learning Perl is exceptionally good as a beginning programming text and it might be worth holding your nose and starting with Perl just to gain that benefit. If you're mathematically oriented you might like Scheme and the (readable online) book SICP. 69.228.170.24 (talk) 23:55, 27 April 2010 (UTC)

Agree about C++. Computer programming is always difficult, but there is a difference between incidental and inherent difficulties. C++ is rife with the former - it's a very large language and it still fails to hide the machine model well. In other words, if C is a "portable assembler", C++ is a portable assembler on steroids. Python is a much gentler introduction. And indeed, if you have no previous exposure to imperative programming styles, Scheme is a great language and always very good for the mind. --Stephan Schulz (talk) 17:42, 28 April 2010 (UTC)

I think C++ is underrated from a language design perspective. I'm not a big fan of the "unrestricted aliasing and let the garbage collector clean up the mess" approach that's so popular in other languages these days. C++ forces you to think about who has access to your objects, which is something that you should be doing in any language. It also lets you request and grant only read access to an object, which is important for designing good abstractions, yet unsupported in most other popular languages.

The problem with teaching with C++ is crappy reporting of runtime errors like out-of-bounds array accesses. But the standard doesn't require crappy error reporting, it just permits it, and implementations have a tradition of taking it up on that offer. This is getting better. All the major implementations now support runtime checking of the standard containers (vector, etc.). There are implementations that check pointers too, but you shouldn't be teaching pointers to beginners anyway. Anything that you'd do with pointers in C you can and should do with standard or boost containers. Some of the C++0x changes also make the language better for beginners, and a lot of them are implemented already in g++ and Microsoft C++. -- BenRG (talk) 21:05, 29 April 2010 (UTC)

Do actual people still work at yahoo (apart from in accounting)

I've been unable to access my mail account since switching to a different system at the office. I've done several rounds of "verify ID - change password - sign in gizmo" clear cache (redo). All it gets me to is the yahoo home page, which tells me I'm signed in, but when I click on the mail icon I get back into the loop. I think this is some bug and can't possibly be resolved by a friendly poster at some forum. (Glad if one of our resident wizards could prove me wrong.) So I was trying to find some contact info for a human being at yahoo mail who could sort this out. All I found were oodles of links to "helpful" junk about how to use the mail account I can't get into. The link is called "contact" but should probably be renamed "who do you think you are to try and contact us." or shorter "no stinking yahoo contact here". :-) Any help highly appreciated. 99.11.160.111 (talk) 08:38, 27 April 2010 (UTC)

You don't get real people support on free services for the mostpart. You get what you pay for. Gunrun (talk) 08:58, 27 April 2010 (UTC)

Try calling 1-408-349-3300. That's Yahoo!'s corporate office.--Best Dog Ever (talk) 09:08, 27 April 2010 (UTC)

Thks. I'll give it a try.  :-) 99.11.160.111 (talk) 09:22, 27 April 2010 (UTC)

Are you sure this is a Yahoo problem and not something to do with your specific setup in the office? Yahoo works OK for me just a few minutes ago. Astronaut (talk) 14:22, 27 April 2010 (UTC)

Which software was used to draw this diagram?

I like this biological diagram:

Does anyone know which software was used to draw this diagram?

Thanks!

--david —Preceding unsigned comment added by 141.14.232.129 (talk) 11:19, 27 April 2010 (UTC)

Ask the creator at User talk:Crenim. --Tagishsimon (talk) 11:23, 27 April 2010 (UTC)

It seems that Crenim hasn't visited Wikipedia for some time. Does someone have a guess on the software? --david —Preceding unsigned comment added by 141.14.232.129 (talk) 11:38, 27 April 2010 (UTC)

If I had to create something like it, I'd use Inkscape, but there are some things about it (like getting all those lipids adjacent to each other) that I'd have no idea how to do well. I wouldn't be surprised if some software more specifically oriented towards diagramming (a plugin to Adobe Illustrator?) were used. Paul (Stansifer) 13:15, 27 April 2010 (UTC)

It's not too hard. Inkscape has a robust set of "alignment" tools, and making good circular arrangements is not too hard (you group the little part to a circle of the radius that you want, duplicate it, rotate the circle, repeat, etc.). --Mr.98 (talk) 13:39, 27 April 2010 (UTC)

Common tools for vector graphics of that sort include Adobe Illustrator and Inkscape. It could easily have been either of them. My guess is Inkscape based on the way the arrowheads look (just from my familiarity with how Inkscape renders arrowheads). --Mr.98 (talk) 13:17, 27 April 2010 (UTC)

I was going to say, the text looks like the default font for Illustrator - Myriad Pro - but that's not a sure indicator of anything. Nimur (talk) 15:41, 27 April 2010 (UTC)

Thank you all! How did the author draw the RNA strands? Thanks. --david —Preceding unsigned comment added by 141.14.232.129 (talk) 15:50, 27 April 2010 (UTC)

Hey, David. I once had a similar question; check out this thread: http://www.inkscapeforum.com/viewtopic.php?f=5&t=1476 - the second-to-last post pretty much gives the answer (you can use one or two strands according to taste) and then, as I suggested in my last post, you can use this as a 'pattern to follow a path'. I can't remember how one does that exactly, but I'm pretty sure it's easy to look up. --Seans Potato Business 18:26, 27 April 2010 (UTC)

Thanks a lot! --david —Preceding unsigned comment added by 141.14.232.129 (talk) 14:47, 28 April 2010 (UTC)

email

Is it possible to send emails from my home computers ip address, for example 1234@80.217.236.213 —Preceding unsigned comment added by 80.217.236.213 (talk) 12:51, 27 April 2010 (UTC)

You could set up an SMTP server on your home computer, sure. Note that doing so in a simple or sloppy way will probably get your e-mail classified as spam by the servers that receive the mail. --Mr.98 (talk) 13:43, 27 April 2010 (UTC)

Adding to the above, you can't send straight to an IP address like that, you'd need to put it in square brackets otherwise the sending mailserver wouldn't know it's an IP and it'll just bounce before it even gets to you - i.e. 1234@[80.217.236.213] ZX81 ^talk 15:04, 27 April 2010 (UTC)

Virus infection in GPS Data Logger

Hi, I am currently traveling and use a GPS data logger which can work as a portable storage device also. It worked all right on the first two days but today I don't see anything on it. The properties show 3 MBs but I don't see any file. But all folders show 0 bytes. There is an auto-run folder with some sub-folders but no files. The GPS data folder is empty. I am afraid I got the thing infected. What could be that 3 MB? My data or the firmware/software pre-installed? Will I lose my recorded data? I am a bit worried. No efficient anti virus tool available. Use systems in Internet kiosks. I can delete all dat using the GPS function, but I will loose all GPS data. If I don't delete my future data could also be lost. What should I do? Can somebody offer some advice to salvage the data? 110.139.197.227 (talk) 14:24, 27 April 2010 (UTC)

It would help us identify the problem if you tell us what type of GPS data logger you have. With the information you provided, there isn't much we can do to diagnose or fix the problem. Nimur (talk) 15:44, 27 April 2010 (UTC)

I am using Amod GPS Data Logger. It works like a portable drive in computer. GPS data is stored as text file.125.167.177.215 (talk) 23:44, 27 April 2010 (UTC)

Styling HTML definition lists to deal with wrapping

Hi all,

I have a definition list which can be seen at http://geniverse.dev.concord.org/. This list is styled so that the dt is left-aligned and the dd is left aligned. In general, this works fine. However, when my dt is too long and wraps, the dd on the right doesn't respect this and leave whitespace. In otherwords, I would like to see

Word 1                      Definition 1
Word 2                      Definition 2
Really long and
wrapped word 3              Definition 3
Word 4                      Definition 4

Instead I see

Word 1                      Definition 1
Word 2                      Definition 2
Really long and             Definition 3
wrapped word 3              Definition 4
Word 4

(note, I don't actually care if the whitespace is above or below Definition 3 -- all that matters is that definition 4 should be lined up with word 4.

Here is the styling I'm currently using:

dt {
  float: left;
  clear: left;
  width: 40%;
  text-align: right;
}

dd {
  margin: 0 0 0 110px;
  text-align: right;
  clear: right;
}

Any idea how to fix the list so that it respects wrapping correctly? (I'll use a table if I really must, but I'd prefer not to.) Thanks! — Sam 63.138.152.155 (talk) 15:22, 27 April 2010 (UTC)

I would recommend using a table. There is a lot of propaganda related to proper use of tables in HTML, and somewhere along the way, the message got garbled. The original idea was "do not use tables to format your entire page"; this concept was corrupted into "do not even use tables to format tabular data." This is silly - your data is tabular. Format it with table tags, and use CSS as you are already doing to specify the format styling for the table. Here is the official W3 recommendation - the standards body for defining HTML - "avoid tables for layout". The critical element of this guideline, which is actually a superset of the design principle, is create tables that transform gracefully. Nimur (talk) 15:49, 27 April 2010 (UTC)

Ok, you're right. I had been resisting but there's no reason to. And with search and replace, it's pretty darn easy to turn a definition list into ta table. Ok, it looks fine now. Thanks! — Sam 63.138.152.155 (talk) 15:59, 27 April 2010 (UTC)

Polipo

How can I allow other people to connect to Polipo running on my computer to use it to have my ip address? The Polipo documentation on the site is too vague —Preceding unsigned comment added by 80.217.236.213 (talk) 15:51, 27 April 2010 (UTC)

The users will need to configure their web browser to use a proxy server. Here are instructions for Firefox, for Internet Explorer, for Opera, and for Safari. On your end, you need to make sure that your proxy server is configured properly and that your network is accessible to the other users (this requires knowledge of any firewalls you or your administrator has set up at the network, hardware, operating-system, or application level). You then need to install and run your proxy; Polipo's manual explains how to do this. Is there a reason you chose Polipo over the much more common squid proxy server? Nimur (talk) 16:14, 27 April 2010 (UTC)

I've looked at Polipo's online manual as I said, but it's too vague and doesn't explain it properly. Currently I have polipo.exe on my computer. When I start it, a command prompt box opens saying polipo is running and accepting connections on port 8123. This works fine with firefox with the settings localhost:8123. But I cannot connect from another computer to polipo using 80.217.236.213:8123 as settings. This is not a router issue or anything because I can access other servers at that ip address. polipo is deliberately refusing non-local connections. I want to make it allow those connections but I don't know how; the online manual is vague and doesn't tell me what to do with the commands. For example, the manual says "The variable proxyAddress, defines the IP address on which Polipo will listen". Where do I define "proxyAddress"? It doesn't tell you. —Preceding unsigned comment added by 80.221.2.13 (talk) 17:00, 27 April 2010 (UTC)

polipo -c "" proxyAddress=0.0.0.0 proxyPort=8123, or put those on separate lines in a config file and then do polipo -c "config file". I learned this from polipo --help. --194.197.235.240 (talk) 18:29, 27 April 2010 (UTC)

Influence diagrams, causal diagrams, mind maps, or similar?

I've posted this question here as I think some software engineering techniques have similarities to this.

I want to be able to draw on paper informal freehand diagrams that represent the sorts of things that happen in business or organisations. The purpose is to create clarify or design, rather than communicating to others. For example I might have a diagram of the money flows in a supermarket, where the direction of the arrow shows the direction of the money flow. There would be arrows between things like customer, wholesaler, staff, and so on.

My question: is there any standardised way of expressing more complex or abstract things than the above? For example I might want to show in a diagram "Apply to Organisation A to be issued with Document A. Organisation B will issue Document B only if they recieve Document A. (Your goal is getting Document B)." Or "The Customer will shop at Store X only if they think Item Y will be there. (No direct concrete causal link between item Y and the Customer)". Thanks 78.151.102.119 (talk) 17:16, 27 April 2010 (UTC)

Possibly Business Process Modeling Notation. Should you want to transfer your hand-drawn plans onto a computer, there's a stencil set for visio here --Tagishsimon (talk) 18:45, 27 April 2010 (UTC)

Thanks. I do not have Microsoft Visio, I assume it costs money. Is there any free software that can read Visio files. such as .vss please? 89.243.189.97 (talk) 19:40, 27 April 2010 (UTC)

Sadly yes it does cost money. OpenOffice Draw if the free alternative, but it will not be able to read the BPRN visio stencil set. Reading .vss is on the OpenOffice Draw wish list, but that's of little use to you right now. I know of nothing else that provides BPRN notation in a free package; sorry. --Tagishsimon (talk) 19:45, 27 April 2010 (UTC)

When I last did something in BPRN, I found this poster to be the most useful thing (apart from the visio vss, of course). It should allow you to evaluate whether BPRN has the ability to serve your need. --Tagishsimon (talk) 19:47, 27 April 2010 (UTC)

I have copied the poster to my HD and will study it. 89.243.189.97 (talk) 22:32, 27 April 2010 (UTC)

Ethical implications of encoding YouTube videos in DivX vs Xvid?

I want to start uploading videos to YouTube soon, and I'm looking into how I will encode them. Are there any ethical considerations in regards to choosing between Xvid and DivX? --84.13.97.134 (talk) 18:20, 27 April 2010 (UTC)

Ethical? I don't know. Xvid is free and open source, and performs slightly better overall than DivX. Btw you don't need to encode videos before uploading them to youtube, as youtube will just re-encoded them anyway into flv 82.43.89.71 (talk) 18:36, 27 April 2010 (UTC)

As 82.43 says, they will simply be re-encoded by Youtube. So you should upload the original source videos if you have these and they're supported by Youtube. If you're transferring from analog or something, then you're probably best ignoring the Youtube aspect and choose whatever is best for your purposes, which may very well be x264 at a resonably high bitrate. Youtube generally uses H264 in fact I've read the x264 implementation in particular for the encoding, but your material will still almost definitely be reencoded. However this will mininise quality loss. Nil Einne (talk) 10:16, 1 May 2010 (UTC)

You might also think about whether there are ethical issues in uploading to youtube. 69.228.170.24 (talk) 20:02, 27 April 2010 (UTC)

I don't know whether you're serious or not, but that's pretty funny! :D ----Seans Potato Business 20:29, 27 April 2010 (UTC)

Semi-funny semi-serious ;-). If the video is of encyclopedic interest and you can put it under a suitable free license, you should upload it to commons.wikimedia.org instead of youtube of course. You'll want to use the Ogg Theora video codec rather than divx/xvid. 69.228.170.24 (talk) 23:58, 27 April 2010 (UTC)

Problem With Internet Explorer

Internet explorer has started saying that websites are unsafe and have certificate errors, like google, facebook, Yahoo, wikipedia and even msn websites

what is going on? and how do i stop this

Im using IE 8

--89.240.167.8 (talk) 22:04, 27 April 2010 (UTC)

I haven't touched IE in ages, so I can't quite remember how it goes. But go to Tools--> Internet Options--> click on the "Advanced" tab--> Go to "Security" in the "Settings" window, and make sure you don't have "Check for server certificate revocation" and "Check for publisher's certificate revocation" checked. If they are, uncheck them and restart IE. 24.189.90.68 (talk) 00:53, 28 April 2010 (UTC)

Do you just visit the websites or are you trying to log into them? 24.189.90.68 (talk) 01:06, 28 April 2010 (UTC)

Good heavens, don't do that! If major sites are all suddenly reporting security problems, it's not that they've been careless with their certificates, it's malware, and those warnings should be heeded. (Hopefully, even with those particular settings off, IE would detect the problem. But don't go disabling security settings willy-nilly.) The first step is to run free anti-malware software. This should make the problems go away by removing the malicious software that causes it. Years ago, I would use Spybot - Search & Destroy for this purpose, but maybe someone who's dealt with troubled Windows systems more recently will have a better suggestion. Paul (Stansifer) 04:02, 28 April 2010 (UTC)

Sounds like standard malware to me. "started" most likely means "started, right after I tried to open that attachment on that email,". It is very common for malware to claim your computer has a virus, or something is insecure, or something bad will happen. To fix it, purchase such-and-such program. It should be obvious that the program you purchase will make things worse (unless you buy another program). Get a good malware cleaner and it should fix the problem. -- kainaw™ 03:38, 28 April 2010 (UTC)

Kainaw's comment makes wonder if the OP has a fake AV software that is actually malware. 89.240.167.8, you don't have Antivirus 2010 installed on your PC, do you? 24.189.90.68 (talk) 03:50, 28 April 2010 (UTC)

I wonder if their clock is set correctly? If the date is off, then Windows might think that the certificate is expired or that the issue date is invalid.--Best Dog Ever (talk) 03:54, 28 April 2010 (UTC)

OP here
everything now works again, no error messages :) —Preceding unsigned comment added by Sghfdhdfghdfgfd (talk • contribs) 15:20, 28 April 2010 (UTC)

But, did you simply disable the error message, or did you fix the problem? If you followed the advice of 24.189.90.68 above, you have not actually fixed the problem, only ignored it. Internet Explorer was informing you of a serious security problem, probably due to a malware infection. Nimur (talk) 10:55, 29 April 2010 (UTC)