Wikipedia:Reference desk/Archives/Computing/2010 July 7

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July 7

How to...?

Please tell me how to make, I think it's called a template(?) like this (example)→

. Thanks  Jon Ascton  (talk) 00:22, 7 July 2010 (UTC)

Just take a look at Template:Stephen_King. You'll notice it calls, among others, Template:Navbox, which is itself a pretty heavy-hitting, complicated template. When you are "editing this page" of a template, at the very bottom of the screen it shows you all of the templates called in it. To recreate this on your own wiki, you'd need all of the used templates in most cases. To recreate this on Wikipedia, just copy the top-level one (e.g. "Stephen King") and change the contents. Note that it would be non-trivial to copy all of these kinds of templates to a private wiki, as each one incorporates many others inside of it to work correctly. --Mr.98 (talk) 00:31, 7 July 2010 (UTC)

If you were copying a template to your own wiki (rather than using it on Wikipedia), you would use Special:Export here to get the template and all its dependencies and then use Special:Import to load in the export file. PleaseStand ^(talk) 01:52, 7 July 2010 (UTC)

Looking for an intercom

Hi all. I'm looking for an easy to use intercom for a mentally challenged person to communicate with their parents (who live upstairs). It can't have a lot of buttons, since he isn't very coordinated and would get easily confused. His memory is also poor, so it has to be simple to use. Just a "Ring" and a "Talk" button would be good with a "Power" light but no button (just unplug to turn it off). It should ideally be duplex, so both parties can talk and hear at the same time, but I could slide on this req. It can't use batteries that need replacing. I think it should use wires to send the messages, since radio or electrical interference might cause confusion and he might occasionally get an unintentional call from somebody else, which would aggravate him. The wires need to be long enough to go up 2 floors and to the appropriate rooms, so at least 50 ft, but 100 would be better. So far this is the best match I could find: [1]. Unfortunately, it's in Australia, so uses a 240 volt plug, while here in the US we use 120. I suppose I could use an adapter to go from 120 to 240, but would prefer to find one that runs directly on 120. Any suggestions would be much appreciated. If anyone can provide more info on that Australian unit (like the manufacturer and model number and full specs), that would also be nice. StuRat (talk) 02:22, 7 July 2010 (UTC)

From the sound of the eBay description and the look of the devices and bit of guessing, thoses device probably just uses a typical wall wart type AC adapter so all you'll need if you want that one would likely be two 2 AC adapters which support a 110 input voltage and with an appropriate current and voltage rating and plug to connect to the units rather then a 120-240 adapter. Of course the AC adapter may be a 100-240V one anyway, many nowdays are as the falling cost of the components required for a switching PSU and the increasing cost of iron makes traditional liners PSUs more expensive so many AC adapters nowadays even for simple small cheap devices have switching PSUs and making one support 100-240V isn't that hard. Have you tried asking the seller whether it's 100-240V (also about the specs, model number etc)? Nil Einne (talk) 03:12, 7 July 2010 (UTC)

I have asked, yes, but not yet had a reply. StuRat (talk) 03:28, 7 July 2010 (UTC)

I got a reply, and they can supply a 120V "wall wart", but they didn't list the model number or manufacturer. One bad thing with this unit is that the buttons either call or monitor/talk depending on how they are pressed, and this may cause confusion. I'd prefer one call/ring button and one talk button, with no monitor option. StuRat (talk) 10:13, 7 July 2010 (UTC)

Indeed this [2] mentions an AC 9V adapter for what looks like the same thing so I was almost definitely right about that part. For that one, the adapter isn't even supplied so you don't waste money on something you maybe can't use. The box suggests to me what I had suspected, this is just some cheap Chinese OEM product so there's probably not much point worrying about the brand or model number. More importantly, a quick search also found [3] which appears to be something very similar from a US seller. You can also get a mmaster+slave variant random e.g. [4] [5]. Edit: Ooops er just realise all those being discuussed including your original link is master and substation version (the one big button in the slave is the same size as the two small buttons combined in the master so I didn't realise they were different).

Well anyway I guess the point is you'll probably have no problem finding something similar in the US. You can even get it in kit form without the boxes [6]

Nil Einne (talk) 03:20, 7 July 2010 (UTC)

I actually don't want the master/slave set-up, which seems to go along with a one-way monitor function. I'd rather have both units be identical. StuRat (talk) 10:09, 7 July 2010 (UTC)

I notice the australian kit only has 20 m of cable. I think you will be surprised how much cable will be required once it is routed around doors & windows and around the edges of rooms. I also note it looks very similar to the kind of thing that sat on my grandmother's wall in her sheltered bungalow; and also similar to the kind of thing I've seen in industrial applications. I'm sure people who build/maintain those kinds of places have suppliers for intercom equipment. Astronaut (talk) 04:52, 7 July 2010 (UTC)

Yes, I'd prefer if it used standard phone cable, so I could buy a cable of the needed length with the proper connectors. I noticed that when you go to an industrial supplier the price goes up around 10X, and if they install it for you, make that more like 100X. StuRat (talk) 10:05, 7 July 2010 (UTC)

If you're going for standard phone cable, why not use a small home PBX (either not connected to the public phone network, or blocking the extension of your "patient" from making outside calls, and not routing any incoming calls to his number, either) and two regular phones? A lot of phones offer an auto-dial feature that will dial a pre-programmed number X seconds after the receiver is taken off-hook, or at the push of any number button. Using standard phone equipment would also allow you to use cordless phones for the parents' end, maybe even their regular (cordless) phone. And if you're afraid that too many buttons would be confusing, just place a cover over the dial pad that leaves only one button available (if the phone requires the press of a button in auto-dial mode). -- 78.43.71.155 (talk) 11:09, 8 July 2010 (UTC)

To clarify the above: Telephone line simulator (set for auto ringdown, no dialtone) + phones with no dial pad + cabling (might be long RJ-11 patch cords with couplers or bulk telephone wire terminated on each end with standard RJ-11 voice grade telephone jacks). The advantage is that no "push-to-talk" is needed to use the system, simplifying operation. However, the equipment is more expensive, and it is not possible to hear the other person talking without picking up the phone. PleaseStand ^(talk) 02:51, 9 July 2010 (UTC)

How about an American baby monitor?

Matlab costs

I am trying to do a cost estimate but Mathworks is somewhat unfriendly about giving out information if you aren't already a customer. Does anyone know how to estimate the annual cost of a commercial subscription for the Matlab Software Maintenance Service (e.g. the service that allows one to download updated software as it is released). I've been led to believe that it is a relatively constant fraction of the base software cost, but am unsure what the rate is for commercial licenses. Dragons flight (talk) 03:00, 7 July 2010 (UTC)

Skype contacts

Hi, just a quick one; I'm very new to Skype. I've 'added' a bunch of people I know as contacts. How will I find out if/when they have accepted my request? Thanks! ╟─TreasuryTag►Captain-Regent─╢ 11:18, 7 July 2010 (UTC)

If you click on them in the "contacts" bar to the left, under conversations it should have a little silhouetted person with a green plus sign, saying "xxx has shared contact details with you". If they did it more than a day before you log on, you'll need to click on "show 7 days" or however many days it is. Tell you what, why don't we try it now? :) sonia^♫♪ 11:20, 7 July 2010 (UTC)

Kilobytes and Megabytes

Given that a kilobyte is 2¹⁰ (1024) bytes, why is a megabyte not always 2²⁰ (1048576) bytes? Roger (talk) 12:32, 7 July 2010 (UTC)

• Because it is 1000000 bytes. Did you read megabyte? Graeme Bartlett (talk) 12:37, 7 July 2010 (UTC)
• It's not, and it is! There is a discrepancy between SI units and common usage. Formally, the "kilo-" prefix always indicates 1000, and the "mega-" prefix always indicates a million. For solid state devices, you usually get powers of two (due to addressing issues), so the closest equivalent was used (what's 2.4% between friends, anyways?), and people got used to it. With terabytes, the difference is up to ~10%, and hard disks do not have the power-of-two preference, anyways. So (cynic) manufacturers try to impress customers with larger numbers or (naive) interface designers want to follow standards and support the general public. See Kilobyte and Binary prefix. --Stephan Schulz (talk) 12:52, 7 July 2010 (UTC)

Even solid-state drives use the decimal prefixes. A 64GB SSD holds about 64 billion bytes (see for example this Intel data sheet, section 3.1). This also goes for USB flash drives and SD cards and so on. Although I do have a Kingston 8GB SDHC card that holds about 8×1024×1000×1000 bytes (and a Kingston 2GB SD card that holds about 2,000,000,000 bytes, so Kingston isn't even consistent within its own product line). -- BenRG (talk) 04:50, 8 July 2010 (UTC)

Whatever you do, a megabyte is not 10²⁰. It is either 2²⁰ (binary) or 10⁶ (SI). If it is binary it is in powers of 2, if it is SI it is powers of 10. --Mr.98 (talk) 13:01, 7 July 2010 (UTC)

Dammit, and here I was about to reactivate my old 500MB hard drive and rent out the spare capacity to Google ;-). --Stephan Schulz (talk) 13:41, 7 July 2010 (UTC)

I fixed my typo, sorry. Thanks for the answers. Roger (talk) 14:03, 7 July 2010 (UTC)

Free flat-file database

I want to use a flat file database. I've already done Google searching and there is too much choice to evaluate all of them. Does anyone have any personal recommendations please? I'd prefer something that was not bloatware.

No, I don't want to use a spreadsheet thanks - the important thing is to be able to sort the records by column with just a click - no spreadsheet can do this as far as I'm aware. Thanks 92.15.27.146 (talk) 20:51, 7 July 2010 (UTC)

How do you intend to use this? Or to what end? I think that would help me give a recommendation. 198.161.238.19 (talk) 21:06, 7 July 2010 (UTC)

I have at least two areas where I would like to create databases where the rows were the entities and the columns were their attributes. I'm expecting a display similar to that of a spreadsheet. Thanks 92.15.27.146 (talk) 21:09, 7 July 2010 (UTC)

I'm not sure why you want to do this strictly with flat files when there are so many simple relational database management systems (RDBMS) out there; you can create simple tables in any RDBMS then you use some GUI tool to query your table, then click on the columns in the query result window to sort them as you wish, like you wanted. A silly suggestion that just came to mind - you can trick Windows Explorer into behaving as a flat file database by creating all your files in a single directory then giving them "attributes" which you can define, then single click the window column headers to sort. Paradox is also a very simple relational database that comes for free with Borland products - it's file based (but not flat file) and 'database desktop' is very easy to use to browse/edit tables and sort data with single clicks. Sandman30s (talk) 11:12, 8 July 2010 (UTC)

Google Documents spreadsheets can be sorted (though technically it takes two clicks): hover over the column you want to sort by, click the down-arrow that appears and choose "Sort A->Z" or "Sort Z->A" (which also work for numbers). There may be similar functionality in desktop spreadsheet programs, but I've never used any of them. Paul (Stansifer) 16:39, 8 July 2010 (UTC)

I'd welcome names of any other quick-to-learn easy-to-use free databases you recommend, suitable for the non-programmer. 92.24.188.89 (talk) 18:52, 8 July 2010 (UTC)

The problem here is that you are asking for database recommendations and then stating what you want the user interface to look like. The user interface is not the database. For example, if I use MySQL as my database, I can use a text-based interface, one of many MySQL-specific graphical interfaces, a web-based interface, or even connect through MS Access to the database. It appears that you are concerned with the user interface, not the database. -- kainaw™ 18:57, 8 July 2010 (UTC)

Well recommend a database with an easy GUI then. There is no point in describing databases that are too complicated for a beginner user to use. 92.24.188.89 (talk) 19:48, 8 July 2010 (UTC)

Like I said, Paradox with its GUI - "database desktop". Microsoft Access is easy enough but recommended for small and simple databases - ideal for your purposes I would think. You can investigate the Microsoft Access text driver (which you can find in ODBC user data sources) if you really want to stick to flat files. You can use almost anything because it's always simple to create tables but more "complicated" when you want to join tables, define master-detail and foreign keys etc. and write complex queries. So you can use something like MySQL and download one of thousands of GUI tools that connect (using whatever method e.g. ODBC) to them, then execute queries (select * from <table name>) and single click on the query result windows to sort by column. Sandman30s (talk) 04:18, 9 July 2010 (UTC)

Thanks, I understood the first two sentences, but you lost me after that. 92.24.181.157 (talk) 09:56, 9 July 2010 (UTC)

Short of giving you a tutorial on how to use Access, I can't help any more. I guess this is why there are spreadsheets, so that beginners who are not comfortable with databases can work with two-dimensional data easily. I assumed that you knew a little more - you used the term 'flat file' which is not exactly what a beginner would use. If I were you, I'd look at the help files in Access and figure out how to create simple tables. Then figure out how to query them. The query result windows (rows and columns) are sortable by single clicks. Sandman30s (talk) 11:26, 9 July 2010 (UTC)

The suitible freeware databases I've found where the records sort with one click on the top of the column are List squared, TablePro (abandonware?), and perhaps Annuaire which I have not tried yet. For a database-pedant it appears that what I'm looking for would be called a "table" rather than a complete database. If you are prepared to spend the time programming then some BASIC languagages can deal directly with "comma seperated values" records and could therefore be used to write a flat-file database. Professional programmers might scoff, but I'm looking to use a bicycle rather than a jet-fighter. 92.15.3.130 (talk) 11:12, 11 July 2010 (UTC)

Buying a DVD drive

I want to buy a cheap internal DVD drive for my old computer, that I can use for back-ups, so it has to be writeable. Are there any pitfalls or anything else that I should look out for? Thanks. —Preceding unsigned comment added by 92.15.27.146 (talk) 21:07, 7 July 2010 (UTC)

I really can't think of any; you're mostly into true commodity territory. It's not at all clear that buying a name-brand model (over a cheaper name that you've never heard of) is cost-effective. It's pretty clear that dual-layer media is rare and disproportionately expensive, so any premium you pay for a dual-layer writer is mostly wasted (but does anyone sell single-layer writers any more?). If all you care about is the occasional backup (and playing DVDs at 1X speed) then you really don't care about speed at all (who cares if a backup, chuntering along in the background, takes 20 minutes instead of 10?). So, tl;dr, no, buy the second-cheapest the store has. -- Finlay McWalter • Talk 01:24, 8 July 2010 (UTC)

One thing I would suggest is to avoid second-hand drives, if you were considering that as a means of saving money. Brand-new ones are incredibly cheap anyway; I was able to find one for under £8 (GBP) with barely any effort, so I daresay even better deals could be found with a little searching. Optical drives (particularly the lasers) have a finite lifespan, and you can't be certain how much use/abuse a second-hand one has suffered. Also, I'm unsure how familiar you are with computer hardware so sorry if this next point is a bit basic for you, but you also need to make sure you get a drive with the correct connection for your motherboard (IDE/PATA or SATA). IDE has been mostly (if not entirely) replaced by SATA, but depending on how old your computer is it may require an IDE drive. AJCham 01:41, 8 July 2010 (UTC)

Thanks, how can I tell if my motherboard needs an IDE or SATA etc? Thanks 92.29.125.22 (talk) 08:21, 8 July 2010 (UTC)

You can check in your BIOS setup, or system information in your OS, or look physically at the connectors on the board; IDE is wide with 40 pins and SATA is usually coloured and a much smaller clip-type connector with about 8 pins. The IDE cable is flat and wide and usually grey whilst the SATA cables are thin and usually coloured. I agree that you should buy a new DVD writer because I've never had an optical drive that lasted, or worked like new, for more than 3 years. Sandman30s (talk) 10:54, 8 July 2010 (UTC)

Oh and consider USB sticks and USB-powered hard drives for backup, as the lower capacity ones work out in some cases to be cheaper than buying a writer and blank disks. It depends on how much data you want to back up though. You could also consider buying cheap web hosting and uploading (ftp-ing) your data there; then the backup is free! Sandman30s (talk) 11:28, 8 July 2010 (UTC)

If this is a second IDE device, depending on the situation you might need to set the jumpers correctly so it is identified as being master or slave. Astronaut (talk) 14:58, 8 July 2010 (UTC)

If you are looking for an SATA DVD burner, there is one drive to avoid: the LG GH22NS50. Some drives of that model carry a spyware program called "Bluebirds" that installs itself when there is no disc in the drive. PleaseStand ^(talk) 02:32, 9 July 2010 (UTC)

ATAPI is what the software SIW says I have for my existing writeable-CD and nonwriteable-DVD drives. Does that tell me that I have IDE rather than SATA? The SATA connectors look unfamiliar to me. Thanks 92.24.181.157 (talk) 12:20, 9 July 2010 (UTC)

Yes if you follow that article and the convoluted history, your connector is IDE. Because you have an old computer you should have at least one and usually two IDE slots. Even some modern motherboards include one IDE slot for compatibility. Sandman30s (talk) 19:18, 9 July 2010 (UTC)

Note that one IDE connector on the motherboard can usually support two drives. -- Coneslayer (talk) 19:21, 9 July 2010 (UTC)

But make sure that your old computer has enough cpu power to write to a DVD. The older Pentium I's probably are too slow. But if you've underrun protection as a feature, you may be covered, it will just take much longer to burn. Graeme Bartlett (talk) 01:02, 10 July 2010 (UTC)

Beautiful colors

I was watching various tv shows and I saw this beautiful light / color effect, see this for example. Is there a specific name for this effect? How would I go about generating a similar effect on my computer so I can look at it all day long? 82.43.90.93 (talk) 21:59, 7 July 2010 (UTC)

Not that I know of... although it does look a bit like an Aurora (astronomy). Maybe some of the aurora-themed screensavers could scratch your itch? Indeterminate (talk) 03:32, 8 July 2010 (UTC)

The Mac OS X Snow Leopard default background is like an aurora - see here. Not really as impressive as the other links and the example you've given, but it's the closest thing I can think of. Chevymontecarlo - alt 19:15, 8 July 2010 (UTC)

Windows Vista has an Aurora screensaver, but it's more of a "hanging curtain" type of aurora. Astronaut (talk) 08:33, 9 July 2010 (UTC)

...which is removed in Windows 7 (no major surprise - it was surprisingly CPU or GPU intense). --Andreas Rejbrand (talk) 22:29, 11 July 2010 (UTC)