Wikipedia:Reference desk/Archives/Computing/2012 September 28

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September 28

Graphing Calculator

Does anyone know of a graphing calculator that is cheaper than the TI-83 but can be used for University Calculus I and II courses? Thanks. — Preceding unsigned comment added by 149.152.23.34 (talk) 00:07, 28 September 2012 (UTC)

The requirements of the calculator will depend on the course. The low-level calc classes I took could be done entirely with a basic scientific calculator, just enough to handle the arithmetic and trig side of things. A more advanced calculator such as the TI-89 will have a CAS that is very useful for verifying your work. I recommend e-mailing the professor or asking about it on the first day of class. There is also no reason to get a brand new calculator - they tend to hold up well and a used one should work just fine, so you may be able to save money that way. 209.131.76.183 (talk) 19:34, 28 September 2012 (UTC)

I totally agree with the previous response. Just look around at amazon or ebay or something to maybe get a used one. I wouldn't worry about how "new" it is anyway unless you plan on using it for years. Chances are you only need it for a couple of courses. When I started calculus, I actually got a TI-92 complete with the manual, CD, and the USB cable for like $30 and it looked brand new with no scratches or anything.174.16.229.18 (talk) 23:37, 28 September 2012 (UTC)

Note that free online graphing calculators are available, too, like GCalc 2: [1]. If you can use them on a portable device, then they would even be useful in class. StuRat (talk) 05:44, 29 September 2012 (UTC)

Probably you are not allowed to use anything different than a portable scientific calculator. And it's also better to study with the same calculator that you'll use at the examination day. OsmanRF34 (talk) 15:19, 29 September 2012 (UTC)

Now you can, now you can't (find a server)

I've been having trouble reaching the Internet. When I click on a link, "Server not found" comes up frequently. (These are links found on pages at normal sites.) The error page offers the opportunity to try again, which usually works after as couple of times. If not, I go back to the page I started from and retry. So far, nothing has remained totally inaccessible.

How can the browser fail to find a server, and then a moment later find it? Is there anything I can do? My browser, Firefox version 15.0.1, assures me I have the latest version. --Halcatalyst (talk) 02:10, 28 September 2012 (UTC)

P.S. Sometimes the browser does return the page, but as the text version. --Halcatalyst (talk) 02:15, 28 September 2012 (UTC)

You're probably not seeing a "text version", but a version without CSS, as that failed to load. "Server not found" implies a DNS problem. Perhaps you have no local DNS cache, and your DNS provider is flaky. What is your operating system? Cdwn (talk) 02:40, 28 September 2012 (UTC)

There are actually many things that could cause this problem. You should follow the steps described at http://support.mozilla.org/en-US/kb/server-not-found-connection-problem. Looie496 (talk) 02:43, 28 September 2012 (UTC)

Whilst true, intermittent failure rules out most of those. Cdwn (talk) 03:13, 28 September 2012 (UTC)

First, what is a local DNS cache? Do I have access to it? (My OS is Windows 7).)

I found out another computer in the household is also experiencing this problem. It's a Mac Powerbook OS X 10.5.8, Safari ver. 5.0.6 (5533.22.3). Also, I followed the steps at the Firefox (Mozilla) "server not found" site, which told me that Firefox was not the problem and that I should look for help at the manufacturer site. Microsoft advised me to use the troubleshooter, but it couldn't identify any problem. Any further thoughts? Thanks, --Halcatalyst (talk) 01:52, 29 September 2012 (UTC)

There's a good chance the problem actually lies with your Internet Service Provider. You might try contacting a customer service representative there. Looie496 (talk) 15:56, 29 September 2012 (UTC)

I called and they took ownership of the problem. They have been having outage issues, but I had not seen interruptions this short. --Halcatalyst (talk) 20:24, 30 September 2012 (UTC)

E-mail content - further use

A person sends e-mail content to several co-members of an organisation. Does that content remain his personal property or can it be forwarded by a recipient to others who are not members of that organisation.?

If forwarded, can the new recipient use the content of the original e-mail? — Preceding unsigned comment added by Cestria998 (talk • contribs) 08:17, 28 September 2012 (UTC)

Both of these are legal questions, for which you would need to consult a lawyer. -- Finlay McWalterჷTalk 13:05, 28 September 2012 (UTC)

They are questions about intellectual property law, but I don't think they're necessarily solicitations for legal advice. One can talk about how copyright works in the general, hypothetical situation (with lots of caveats) without giving legal advice for any specific situation, I think. We are not prohibited from discussing any aspect of how the law works, are we? --Mr.98 (talk) 14:04, 28 September 2012 (UTC)

Generally speaking, one's e-mails — like all of one's writings — are automatically copyrighted if you are in a Berne Convention country, assuming you have not already signed some kind of contract that assigns all work-related copyrights to the organization or institution in question. The rules governing further use of those e-mails vary a lot by jurisdiction, though; fair use comes heavily into play in such situations in the United States. In the past, people who have forwarded e-mails to unauthorized parties, or reprinted them publicly, have sometimes been charged with copyright infringement, but the cases in which one hears about this are usually "whistleblower"-style incidents, and in such cases, such use is often found to be fair use. But, as noted, this is fuzzy legal territory and the specifics make a big difference in any actual, real-life case. --Mr.98 (talk) 14:01, 28 September 2012 (UTC)

As Mr.98 says, it might not be your property in the first place. If you are sending the email as a part of your work, most employment contracts (or at last the ones I have signed) explicitly state that anything you create in the course of your work remains the property of your employer. I have always assumed this is to prevent the kind of (imaginary) scenario where a former employee of Apple claims that he invented the iPhone and Apple must therefore pay him a license fee for each iPhone sold; but it could apply to many other things too. Astronaut (talk) 10:02, 29 September 2012 (UTC)

It's not an entirely imaginary scenario. These contracts emerged when big employers realized that there's actually a lot at stake, especially since a number of big inventions of the 20th century came not from the work someone was explicitly assigned to do, but from stuff they did on the side while doing other work. Universities picked up on this in the early 1910s and 1920s, if I recall correctly, because they realized that if they got a cut of every cool thing their employees discovered or created, that would be a very large cut indeed over the long term. These sorts of contract clauses became very very common in the mid-20th century. --Mr.98 (talk) 15:19, 29 September 2012 (UTC)

Live Twitter updates on mobile

I don't use Twitter a great deal, but I do like using it to follow live events. On my PC I use TweetDeck, which automatically adds new tweets to the top of the timeline. Is there something similar for iOS or Android? All the apps I've found so far rely on manual 'pull to refresh' updates, and I'd rather have it update itself so I can have the full second screen experience. If there isn't something, why not? That is, what's stopping me writing something myself - is there some deficiency in the operating systems or Twitter's API that makes this impossible? - Cucumber Mike (talk) 11:17, 28 September 2012 (UTC)

The official Twitter client for Android does what you are asking, unless I've misunderstood. Cdwn (talk) 11:54, 28 September 2012 (UTC)

I'm not sure. Unless I'm missing a setting somewhere, it only delivers updates on a set schedule - at most refreshing every 5 minutes - or requires a manual refresh. When using TweetDeck updates are delivered instantly. If I'm watching a Grand Prix a lot can happen in 5 minutes, and I like to be able to see people's insights as soon as they are written. - Cucumber Mike (talk) 12:14, 28 September 2012 (UTC)

I use UberSocial on my mobile phone where you can set the refresh interval, they warn that setting it to 5 minutes or shorter will drain your battery rapidly. I assume from this that a live, continuously updating client would be highly impractical. Zunaid 17:23, 28 September 2012 (UTC)

Mmm. I take your point, but let's assume that my device is plugged in and charging, so that power consumption is not an issue. What I want is something like the TweetDeck Chrome app - as that's an HTML5 app I had hoped it would be platform-agnostic, but I can't find a way to make it work on iOS. Thanks for the suggestion of UberSocial though. I'll check it out. - Cucumber Mike (talk) 23:32, 28 September 2012 (UTC)

Bash Shell Options

In the Bash shell, set -o allows you to set these options:

allexport        braceexpand     
emacs            errexit         
errtrace         functrace       
hashall          histexpand      
history          ignoreeof       
interactive-comments    
keyword          monitor         
noclobber        noexec          
noglob           nolog           
notify           nounset         
onecmd           physical        
pipefail         posix           
privileged       verbose         
vi               xtrace

while the shopt builtin lets you set these:

cdable_vars      cdspell         
checkhash        checkwinsize    
cmdhist          dotglob         
execfail         expand_aliases  
extdebug         extglob         
extquote         failglob        
force_fignore    gnu_errfmt      
histreedit       histappend      
histverify       hostcomplete    
huponexit        interactive_comments    
lithist          login_shell     
mailwarn         no_empty_cmd_completion 
nocaseglob       nullglob        
progcomp         promptvars      
restricted_shell shift_verbose   
sourcepath       xpg_echo        

Is there any logic behind the division of options into these two categories? Rojomoke (talk) 16:40, 28 September 2012 (UTC)

bash, like all other shells, has many attributes that are the result of legacy and decisions made for backward-compatibility. So, while there are reasons behind the existence of two seemingly redundant commands - "set" and "shopt" - to set shell options, it's certainly debatable whether these reasons are good or necessary. Here's where you should look for justification: the official bash reference, particularly Section 4.3.1 - the Set builtin - and Section 4.3.2 - the Shopt builtin. From the official documentation, the difference is: set is "so complicated that it deserves its own section"... and shopt "allows you to change additional shell optional behavior." Nimur (talk) 17:37, 28 September 2012 (UTC)