Wikipedia:Reference desk/Archives/Computing/2011 June 17

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June 17

Figure out what type of server a site is running

I once saw a website that could finger a domain and figure out what type of server software it was running. I was quite impressed. I can't find it, but I'd like to. Anybody know a way to do that? Magog the Ogre (talk) 08:13, 17 June 2011 (UTC)

netcraft.com -- Finlay McWalter ☻ Talk 08:20, 17 June 2011 (UTC)

Strictly, you can only find out what server is running if the server self-identifies. You can read the HTTP headers, which often indicate the HTTP server by name; some servers also append their identification to the HTML or other content that they deliver. If you don't know how to read an HTTP header, you might start by reading our article, and playing with the Live HTTP Headers add-on for Firefox; or, try telnet to connect to the server. Some HTTP servers respond differently, especially if you send "malformed" HTTP requests; so you can use these "quirks" to try to identify the server type even if it does not explicitly self-report. For example, it was once common that Microsoft servers would reject "ping" after 4 or 8 successes; so, this could be used to "guess" the server-type. But, it's never definitive - any server or firewall can be configured reject ping after an arbitrary number of requests. Similarly, most servers can falsely report their own identity. Nimur (talk) 16:21, 17 June 2011 (UTC)

some tools like nmap are able to guess the server type. --helohe (talk) 00:33, 19 June 2011 (UTC)

Open source compability with powerpoint

Hello! I'm about to start working on a university assignment - creating a powerpoint presentation, which will not be presented by me but rather sent to the teacher for grading. The teacher will then look at it using the latest version of microsoft powerpoint. However, I haven't got the Microsoft Office suit, and I don't have the money for it either. I am currently using openoffice.org, but the "Impress" presentation software creates rather ugly slides which look even worse when opened in Powerpoint (often not even readable/text in the wrong place etc). So now to my question: which open source "office suit" has the presentation software which is the most compatible with the latest version of Microsoft Powerpoint? /Marxmax (talk) 09:01, 17 June 2011 (UTC)

I don't really think other tools will do a significantly better job than Impress. The biggest problem with portability (and it's a problem from one Powerpoint install, and one Powerpoint version, to another) is font availability - if you design your presentation on your machine (which has one set of fonts) and someone views it on another (which has a different set) then the presentation program does a best-guess substitution, which often isn't what you'd want at all. If you want very good fidelity and portability, and your presentation is just slides (not fancy transitions or embedded objects) export it not to the PPT format but to PDF. PDF readers have a fullscreen "presentation" mode which works much like a basic Powerpoint player - but you get total control over appearance and fonts, and much better portability. -- Finlay McWalter ☻ Talk 09:12, 17 June 2011 (UTC)

Of course! I didn't even think of exporting to PDF - thank you! However, the other problem is that even if your impress-presentation looks as intended, it still does not look very good, with a meagre choice of background colours etc. Do you know if for example Calligra Stage or Libreoffice's presentation software is better? /Marxmax (talk) 09:21, 17 June 2011 (UTC)

Libreoffice hasn't diverged much from its OpenOffice roots (it may have some different templates, but they're not noticeably lovely either). I don't know anything about Calligra. Having spent decades of my life staring at horrible blue-gradient Powerpoint presentations, I'm firmly in the "black on white text, no boxes, no Arial" camp. I've never seen a nice Powerpoint presentation in my life, and unless your presentation is about design itself, I wouldn't bother. -- Finlay McWalter ☻ Talk 09:35, 17 June 2011 (UTC)

I didn't find Impress to be that bad - it even has a number of features Powerpoint lacks. Are you sure you have a recent version? In my experience, in the long term it pays to learn and use LaTeX Beamer. I do make some quick presentations with Keynote, but for sustained productivity, I like Beamer better. However, Beamer is an investment for life. You won't get any payback for one university presentation. --Stephan Schulz (talk) 11:18, 17 June 2011 (UTC)

I'll add a second vote for Beamer, especially if there is any need for non-standard symbols (math, chemistry, physics, non-roman alphabets, etc). It also comes with a wide variety of themes. One of them is likely to suit your needs/tastes, and the resulting presentation will usually be more consistent and coherent (IMO) than the average .ppt SemanticMantis (talk) 16:06, 17 June 2011 (UTC)

Another vote for beamer. I noticed our article mentions that LyX has support for making beamer presentations. I've never used LyX, but it is supposed to give LaTeX more of a word processor feel, which might make it a little more painless if you have never used LaTeX or anything like it - though editing a LaTeX document is in many ways quite similar to editing a Wikipedia article - Wikipedia even uses bits of LaTeX for mathematical expressions. All this software is completely free and cross-platform, by the way. 81.98.38.48 (talk) 20:19, 19 June 2011 (UTC)

I just want to also point out that I know some people who don't use dedicated "presentation" software for this at all — they use Inkscape or Illustrator or whatever and just export to PDF. If you're going to be doing PDFs anyway, you are a lot less constrained. --Mr.98 (talk) 14:35, 17 June 2011 (UTC)

I do a lot of presentations, and there is nothing close to PowerPoint. I would borrow time on a friend's computer or a library computer that has Office if that's what it takes to make a presentation that isn't the worst-looking presentation in the whole class. Or the professor may have some other solution to suggest when you explain you can't afford the home & student version of Office. Comet Tuttle (talk) 17:13, 17 June 2011 (UTC)

Have you ever tried Keynote? There is at least one feature I miss from PP (intelligent connectors, but then PP's are at best semi-intelligent), but on the other hand, PDF integration and overall usage is so much better, and the templates are fairly nice. Of course, this is unlikely to help the OP unless he already has a Mac (in which case Keynote now is a ~US$15 download).--Stephan Schulz (talk) 18:49, 17 June 2011 (UTC)

I would second Keynote. As a longtime PP user who recently switched, it's made a world of difference. The UI is much more intelligently put together, it works better, and things generally look better by default. Especially if you are using a Mac (where MS Office 2008 is really so slow and buggy as to be intolerable). --Mr.98 (talk) 21:43, 17 June 2011 (UTC)

Animated JPG??

A friend of mine just stumbled upon this. Since when have jpg files been animateable and how? - filelakeshoe 10:48, 17 June 2011 (UTC)

It's a gif with the wrong file extension AvrillirvA (talk) 10:51, 17 June 2011 (UTC)

The linked image is a GIF. But, JPG files can be packaged in an "MJPEG" or "Motion JPEG", a "semi-standard" format. Usually, a Motion JPEG is an AVI container that contains a sequence of individual JPEG images. Some digital cameras, especially those that lack a hardware-accelerated video codec, produce MJPEG video output. (Again, for clarity, this is not the file-type that was linked above - the linked file was a GIF with the wrong file-extension). Nimur (talk) 16:16, 17 June 2011 (UTC)

Taking pictures without using my hands

Thank you, for telling me about the digital photo frame. Is there a product that is designed to take pictures without the need to use hands? — Preceding unsigned comment added by 109.74.50.52 (talk) 13:13, 17 June 2011 (UTC)

My Android phone can be used with voice commands. I can tell it to go to applications, then camera, and then take a picture. The problem is that it will likely take a black photo of the desk it is laying on if I'm not holding the phone and pointing it at something. But, that is solved by having a camera with a mount - which I also have and it doesn't require hands either. I have a webcam on my desk. It snaps a photo every 5 minutes and I never touch it. -- kainaw™ 13:17, 17 June 2011 (UTC)

Pretty much even the cheapest digital cameras these days have a self timer function. You (or someone) still has to press the shutter release, but you then have a typical time of ten seconds to get yourself in the shot and do whatever you like with your hands. I'm not sure if this is in the spirit of what you are asking. --jjron (talk) 14:33, 17 June 2011 (UTC)

It might help us to know why you don't want to use your hands. If it's just because they shake the camera and give you blurry pics, then the timer is the best solution. StuRat (talk) 22:48, 17 June 2011 (UTC)

Or a remote control. Can you also explain what kind of camera it is? A camera phone, a DSLR, or something in between? --T H F S W (T · C · E) 05:22, 18 June 2011 (UTC)

I was thinking about something that I can mount on my head somehow, because my hands are supposed to stay sterile. I know about glasses with built-in cameras but are there any that can take pictures by voice command. — Preceding unsigned comment added by 109.74.50.52 (talk) 08:47, 18 June 2011 (UTC)

If you are standing in the same place all the time, at a table or something, you could build a pedal that controls a remote trigger, and step on it to take a picture. Or duct tape a remote control to a table leg and use your knee to hit it. Or if you can still move your hands, just not touch anything, a light or proximity sensor and some electronics tinkering could interface to the camera's remote control port - wave your hand near the sensor to take a picture. Or how about using a video camera, record everything you are doing, and later pick individual frames from that - there are small head-mountable video cameras meant for recording sports and such from the participant's perspective. Can you explain more about what you are trying to do? It's hard to guess what would work when we don't know the parameters of your problem. 88.112.59.31 (talk) 11:05, 18 June 2011 (UTC)

(e/c) I guess you could mount a camera on your head and operate a cable release with your mouth, or jig it up to operate by foot. Alternatively, you could just video what you're doing (I know a number of people that mount a cheap camera on their helmet and video their motorbike rides, tricks, whatever, for an 'on bike' view - it's not hard to do). Then you could do screen grabs or extract frames from the video if you want still frames. May depend what you actually want to do, how good quality you need, etc, which still isn't very clear. --jjron (talk) 11:09, 18 June 2011 (UTC)

My goal is to be able to take pictures of the burn wounds of kids in a hospital during the changing of their bandages so that the doctors who didn't happen to be present during bandaging, can see them. And having a series of pictures showing how the wounds heal over time would also be useful, I think. I can't record everything because I can't expect my colleges to feel comfortable in situation like that and I think it would be against the law too. But taking pictures of the wounds is allowed. — Preceding unsigned comment added by 109.74.50.52 (talk) 16:41, 18 June 2011 (UTC)

There are numerous video cameras that mount on a pair of sunglasses.[1] If image quality isn't a big issue you could record video of the whole procedure than go back and capture the frames you're interested in. APL (talk) 18:24, 18 June 2011 (UTC)

The obvious way to keep your hands sterile in a medical setting is to wear sterile gloves. You should also do your best to sterilize the camera, say by wiping it down with alcohol swabs. However, due to inaccessible crevices, the camera can likely never be completely sterilized without putting it into an autoclave (and thus destroying it). StuRat (talk) 01:29, 19 June 2011 (UTC)

I'm no expert, but I have noticed that microscopes (and other mechanical devices used in surgery) are usually swathed in what looks like simple plastic (presumably sterile) sheets. If the camera is wrapped in sterile plastic (bar the lens) this may help. I also had a random though that an underwater housing may be easier to sterilize than the actual camera? (some of this is also mentioned by '88' below)- 220.101 talk^\Contribs 15:18, 20 June 2011 (UTC)

I'd experiment with a wired remote trigger attached to your elbow, arm or wrist. Press it to your body to activate.

But I'm worried about composing the shot and zooming. How do you see the viewfinder if you can't hold the camera.

Also time and money are an issue. If this was a product development program, I could envision a wrist-mounted camera, like a large watch, with the optics on one side and an LCD viewfinder on the other. But if you only want to make one that's an unreasonable amount of development work.

Digital video cameras have LCD viewfinders that can be turned to different directions. Are there small digital photo cameras like that, that could be strapped to one's arm so that you could point the camera one way and still see the viewfinder? I tried a quick google but couldn't find a point-and-shoot like that.

Low tech solution: place a point-and-shoot inside a rubber glove or sterilized plastic bag, cutting a hole for the lens. Maybe have a sterilized steel bowl so you have somewhere to put the camera down. Of course I know nothing about sterile procedures so I there is every chance I am talking total nonsense here. 88.112.59.31 (talk) 11:39, 20 June 2011 (UTC)

Ad problems

These problems have occurred at libraries, where I doubt anyone wants to install ad-blocking software, though that doesn't mean they won't. One library has Firefox and the other IE.

And I don't go to these particular sites at home. I avoid potentially problematic sites there.

The worst problems have been happening on the Seattle Post-Intelligencer web site, a great site for comic strips. I've also observed one problem on the Asheville Citizen-Times web site where I go for news of that area.

Problem number one: after I click on a link to go elswhere on the site, the URL appears the same at the top of the screen but the content is an ad and I'm not sure how to bypass it other than hit "back" and hope I can remember how to get back to where I was trying to go. When I am in this situation, I don't have time to wait around to see what will happen. Most libraries want to limit my time and I don't dare get in the habit of being patient.

Another more serious problem is when the ad "forms" and turns the entire screen black or something like that, then the ad appears. I really don't know what to do then.

On an unrelated note, on an IE computer, I clicked on "back" with the Seattle site's comics several times (not because of ads) and the URL changed but the comic strip stayed the same.

What is taking place in all these cases, and what is the solution?Vchimpanzee · talk · contributions · 21:46, 17 June 2011 (UTC)

You might try hitting ESCAPE first, this often gets you out of full screen applications, like your ads. In the worst case scenario, you could always do CONTROL-ALT-DELETE to go to the Task Manager and kill the browser there. Obviously, the security settings need to be changed to prompt if you want to allow each pop-up (since some are useful), but with limited time, you may not want to spend the time to do that on each computer you use. StuRat (talk) 22:44, 17 June 2011 (UTC)

From my experience, most ads of that sort have a close or minimise button that appears within seconds usually in the top right corner where such buttons tend to be. Having said that, I haven't be able to reproduce the behaviour in either IE, Firefox or Chrome on [2]. I do get a rather large ad that appears the first time I vist (some sort of father's day one at the moment) but it has a close button that appears immediately and doesn't block out the content anyway, it's just pushes it down so you have to scroll more and even with a large text size on a fairly low res some of the actual content is still visible at the bottom. Many of those sort of ads are Flash so if you don't need it you can look and see if you can disable it in addons. Nil Einne (talk) 22:49, 17 June 2011 (UTC)

Remember, these are libraries, and they're not likely to disable add-ons. I supose the close button is taking a long time to appear, though I don't want to minimize since I want to look at what's on the Seattle site. I also don't want to kill the borwser as there is usually stuff I'm trying to save. And these are not pop-ups. There is a pop-up blocker that doesn't always work. To my knowledge, the Jack in the Box ads are not pushing anything down but entirely replacing what's on there, and they don't change the URL, though after clicking on a link, you would expect the URL of the destination.Vchimpanzee · talk · contributions · 15:51, 18 June 2011 (UTC)

Do you know the trick of holding down the "ctrl" key on the keyboard when you click a link? Try it right now by holding down "ctrl" and, while doing so, clicking, say, this link right here. The browser will stay on this page, but you'll notice a new tab has been created and the browser has gone to the link in that tab. If you get bad behavior when clicking certain links, this technique will "save" the page you're currently on (and its history) from whatever the link does. Comet Tuttle (talk) 20:23, 18 June 2011 (UTC)

Read my reply carefully. I said "Many of those sort of ads are Flash so if you don't need it you can look and see if you can disable it in addons". In other words, I am suggesting you should look for yourself and see if they give you the level of control needed to disable addons (in particular Flash). You don't need the librarians to do every single thing for you. Disabling addons is not exactly a dangerous thing so it's resonable to presume if they let you do it, it isn't something they don't want you to do although particularly if the computers don't use logins, you should reenable them before leaving for courtesy to avoid confusion for future users before quiting. I forgot to mention as an alternative to close button, some ads do show a 'skip this ad' or similar usually above the ads with some ads showing a countdown to how long before you can skip. You should also make sure you hover of the ad, since some hide such UI elements when you're not hovering over them (but don't hover over the ads which pop out when you hover over them). I do agree with CT that you should get in to the habit of using more tabs, in fact I planned to suggest it myself earlier that if it was really taking too long for any close button you should open what you want to read in a tab and hope it's appeared by the time you visit it. Nil Einne (talk) 01:04, 19 June 2011 (UTC)

CT, did you mean hold down "SHIFT"? That's what works with Opera running under Vista, but perhaps it varies with browser and operating system? Dbfirs 08:07, 19 June 2011 (UTC)

Interesting, in IE7 ⇧ Shift and link opens a new window, CTRL and link opens a new tab, as Comet Tuttle said - 220.101 talk^\Contribs 10:21, 20 June 2011 (UTC)

Yes, I've just checked Firefox and Google Chrome, and the behaviour was exactly as you describe for IE7, so CT was correct for most browsers. It must be just Opera that's different. I should've checked these first, but I just read the advice and thought "that's not what I do". Dbfirs 12:01, 20 June 2011 (UTC)

Dunno what's it like for other browsers, but in IE, in the "pop-up blocker settings" section under the "tools" tab, is a function to enalble/disable pop-ups... could be just me but I've so far found that it drastically cuts down on the number of pop-up adds... 69.154.182.24 (talk) 17:07, 20 June 2011 (UTC)

The computers in question do block most pop-up ads. These are different. The ones that color the screen haven't shown up lately, and no one has given me a term for those. But today, the annoying ad was different. The URL did change to what I wanted it to, though an ad was on screen instead. However, the "close" button appeared immediately in the upper right corner. I also saw "stat.flashtalking.com" on the lower left corner of the screen where the URL appears as it is coming up, and where URLs of ads appear even though they are different from what is at the top of the screen. I did, however, click on "close" this time, but ithis was very slow to give me a result. since the URL was correct, I tried clicking on the URL and pressing "enter" again. I don't remember how quickly that worked. The annoying ads were far fewer today.Vchimpanzee · talk · contributions · 18:44, 20 June 2011 (UTC)