Wikipedia:Reference desk/Archives/Computing/2011 November 30

= November 30 =

Can't get on internet
I can't get on internet, comes up with unauthorized, with air station, I have buffalo router, what can I do, thank you zach at (REMOVED EMAIL) — Preceding unsigned comment added by 112.198.83.34 (talk) 10:31, 30 November 2011 (UTC)
 * Sorry but I removed your email address because we can't reply by email and you'll end up getting lots of spam otherwise (see the text at the top of this page). --Colapeninsula (talk) 10:42, 30 November 2011 (UTC)


 * Were you ever able to get on the internet using that setup? To have any chance of helping, we need to know if this never worked or if it did work until you just did something which you will certainly avoid telling us about. -- k a i n a w &trade; 13:54, 30 November 2011 (UTC)

Exit values in Windows Command Prompt?
It is a well-known fact that Unix shells can make use of exit values of programs or shell built-ins, for example with the  shell built-in or the   variable. Can this also be done in the Windows Command Prompt? J I P &#124; Talk 19:57, 30 November 2011 (UTC)
 * I don't know what unix exit values are, so this may not be what you are looking for 82.43.90.142 (talk) 20:46, 30 November 2011 (UTC)


 * That is what he wants. Windows puts the exit code into an environment variable called errorlevel. But, it isn't a true environment variable, so you have to use the weird syntax shown in that article to check it. -- k a i n a w &trade; 20:49, 30 November 2011 (UTC)


 * I imagine by "windows command prompt" you mean CMD.EXE, which really is a compatibility program best left for running ancient software you can't get rid of. Windows 7 has (and vista and xp can readily get) PowerShell, which makes a decent approximation at being a good, unix-likey shell, with access to .NET and an overall lack of sucking. PowerShell's errorlevel equivalents are (wait for it) $? and $LASTEXITCODE.  Eerily familiar, huh? 2.122.75.79 (talk) 00:00, 1 December 2011 (UTC)

business logic: when is it better in web server, when in appl server and when in db server?
and when is it better coonect the internet browser directly with the db (eg silverlight)? thank u


 * Business logic is a meaningless mumbo-jumbo phrase bandied around by business school professors who've never had a real job in their lives and still think computers work the way they did in the "batch processing for beginners" class they took forty years ago. In practice code should be located where the complex interrelated demands of the specific problem and the systems used to solve that problem best require it. Deciding what goes where is a sophisticated analytical task for someone with in-depth knowledge of the task and environment at hand; parts may very well go in all of the spaces you describe, and others.  If your professor insists this question has a "right answer", I respectfully suggest you move forthwith to an educational establishment whose faculty does not comprise box-tickers and unambitious root vegetables. 2.122.75.79 (talk) 00:16, 1 December 2011 (UTC)
 * I mostly agree with the previous contributor though I doubt the suggested educational establishments really exist. No single guru or book has the definite answer to architectural questions because there are always exceptions and usually you are working on an exception. This even holds for widely agreed on notions like "XML is better than CSV, object oriented programming is better than procedures, business logic should be implemented there, GOTO/TABLE/RegEx is considered harmful, 'not invented here syndrome', passwords should contain more than letters, C is better than VB, parsers should always be written using a cursor, cursors are bad in SQL, etc." As an employer I like a CV with 10 years of "amateur" programming and high school much more than a gamer who got a degree in CS. The first knows how to fix a problem, the latter knows a few hundred very clever algorithms most IT companies never need. Joepnl (talk) 02:09, 1 December 2011 (UTC)


 * I expect this to be a question in relation to business logic tiers. Apparently, the anon who commented above doesn't feel that tiers exist (or even should exist) outside of a classroom, but tiered hardware and software systems are very common. In business logic, you usually have a presentation tier (the web browser), a logic tier (the application server or web server), and a data tier (the database). These are all software tiers, so they could exist on the same hardware system or be separated across multiple hardware systems. Ignore the hardware. Only think about the software. So, what should be in the presentation tier? Should the web browser validate the data in the database? Should the web browser ensure submitted data is valid? Should the web browser cache all data in a huge javascript database and then send it off to the database at some time in the future? Similarly, should the database store all the HTML used to the display the data? Should the database resort all of its data if a user clicks on a sort button at the top of a table? If you think of this as web browser, web server, and database engine, it is pretty easy to see how the tiers are separated and what should go where. Some of it isn't so easy. Should the web browser validate the data a user submits? No. What if a person hacks the HTML/Javascript and sends invalid data to the web server? The web server should validate the data. But, that doesn't mean that everyone does it that way. As the anon above states, people in business will do whatever seems right at the moment. Who cares what people who spend their life studying this stuff have to say. They are just assbags in a classroom that couldn't survive in business. (sounds to me like someone who flunked out of CS201) -- k a i n a w &trade; 03:00, 1 December 2011 (UTC)
 * I guess the anon totally accepts the concept of tiers, as anyone does. But you can't just say "this is UI, this is business logic, this is the database" and act as if they're totally independent with just a small contract for sending data back and forth. Databases are nowadays very well equipped to handle any business logic, turning every transaction into atomic actions which I think is a solid way to do things. The logic tier might be obsolete. But then again, there are always exceptions. The assbags in the classroom do think that every application consists of a nice looking website where someone clicks submit expecting to see a list of books. Not a website that within seconds changes the whole page for every key the user presses. The fact that even Microsoft is struggling with it, currently shipping its third way of sorting out tiers (which again is full of compromises!) suggests that there is not a definite answer. I think that the (incredible) designers of Twitter did not start with "how about the tiers" but "how to sync thousands of databases in near real time". CS201 didn't cover that subject. Joepnl (talk) 04:48, 1 December 2011 (UTC)

TV tuner ?
The above link takes me to TV tuner card, but that's not what I'm asking about. I want to know if there's a TV tuner without a monitor which can then be plugged into a monitor via an HDMI cable, etc. That is, it should receive digital signals and send out digital signals, and no PC should be required. Does such a device exist ? Am I calling it the wrong thing ? StuRat (talk) 23:10, 30 November 2011 (UTC)


 * In the UK one can get a Digibox (that is, a Freeview decoder box) like the Goodmans GDB15HD which decodes digital TV and emits the signal in upscaled 1080i on HDMI. While it's intended for people with old tellies that just can't decode Freeview, I don't see why one couldn't plug it into a monitor that had HDMI.  I imagine digital switchover will have necessitated the existence of these wherever you live; note that HDMI output is a fairly unusual feature (as they figure if you have an HDMI input you're probably a modern TV that doesn't require a digibox in the first place). 2.122.75.79 (talk) 23:49, 30 November 2011 (UTC)


 * A google search for "atsc tuner hdmi" yields several promising results. -- 24.254.222.77 (talk) 00:04, 1 December 2011 (UTC)


 * There are many models of this. It is just a "digital antenna". When the U.S. converted to digital broadcast, there were dozens of models available for around $50 (if I remember correctly). The price was set by the government indirectly. You could get a free coupon for $50 off one of the digital antennas, making the conversion pretty much free. The cheapest ones only have NTSC out through coax or RCA connectors. Nicer ones have HDMI out. While it is called an antenna, it actually has a tuner built into it. -- k a i n a w &trade; 00:46, 1 December 2011 (UTC)


 * Actually, Kainaw, they're called digital converter boxes, not digital antennas. In the USA, "digital converter box" by itself usually means the same thing as "coupon eligible digital converter box". To be eligible for the government coupon they couldn't include HDMI output. However, searching for "HDMI digital converter box" may find something with HDMI output. Some quick Google searches also suggest "HDTV STB tuner" or "HDTV set top box tuner" may be appropriate terms to find a tuner box with HDMI output. --Bavi H (talk) 01:48, 1 December 2011 (UTC)
 * I am in UK. I think one would have to link the computer to a coaxial cable leading to an aerial. Kittybrewster  &#9742;  17:57, 1 December 2011 (UTC)
 * How did a computer come in to this? (Yes I know STBs can technically be called computers, but if that was the intended meaning it's confusing in this circumstance.) Nil Einne (talk) 21:28, 1 December 2011 (UTC)

Interpolation frames
Thanks so far. One follow-up Q: Is interpolation of frames between those in the broadcast signal done in such tuners, or does the monitor do it ? StuRat (talk) 04:02, 1 December 2011 (UTC)


 * "Depends on the details of both boxes." The the tuner typically demodulates and then decodes the incoming data from the analog signal received by the antenna; and then the tuner transports it over HDMI (or some other transport medium).  HDMI allows recompression; depending on the details of the HDMI endpoints, the data may be recompressed and redecoded on each side of the HDMI wire.  The monitor (or television) may provide any of a variety of other image and video processing stages; it may perform frame upconversion; pixel resampling, and image filtering for image quality tuning.  It may also apply inter-frame filtering, framerate adjustment, and so on.  Nimur (talk) 19:09, 1 December 2011 (UTC)