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July 26

How many levels of abstraction when running ?

When I run a java program, how many levels of abstraction are there? Is it bytecode - JVM - OS - machine language - physical switch?--Bickeyboard (talk) 00:33, 26 July 2015 (UTC)

That's gonna be implementation-dependent - and very often, there is a micro-code layer below machine code and above the level of physical gates (which in turn are abstractions of transistors and such). But the OS (Operating system) isn't a layer anywhere here. In a sense, the OS is nothing more than a different program that happens to be running on the same computer. SteveBaker (talk) 02:41, 26 July 2015 (UTC)

I wouldn't say the OS isn't a layer anywhere here. AFAIK, Java doesn't usually take care of things like file system implementations and CPU scheduling on its own; that's what the OS should do! That said, it is possible to run a complete program without any operating system (which is quite often the case in embedded systems). --Link ^(t•c•m) 14:51, 26 July 2015 (UTC)

No, of course Java doesn't do things like file systems - but the OS is more like a library as far as Java code is concerned. It's not a level of abstraction between JVM and machine code...no way. If it were a level of abstraction, then you'd be able to point to a complete description of your algorithm described in terms of the operating system - and that sentence doesn't even mean anything! And even if it was - it would still be implementation-dependent - you can run Java code on computers that don't even have operating systems. Consider something like Haiku-vm for Arduino - there is no operating system - there is no JVM either. It converts Java source code into bytecode, then uses a small C program to interpret the bytecode. The bytecode is never converted into machine-code either. Without reference to a specific implementation, the question doesn't even mean anything. You could (in principle) write a program to run on a Babbage analytical engine that would interpret ASCII Java source code directly from punched cards. It would still be a Java program - but there would be no byte code, no JVM, no OS, no machine language, no electronics...just a bunch of gearwheels. Java doesn't care how it gets executed...so it's meaningless to make generalizations about how it runs. Now, if you said "How is such-and-such implementation of Java run under Windows 8?", then we could provide a more definite answer. SteveBaker (talk) 01:16, 27 July 2015 (UTC)

It looks to me like the questioner thinks that the OS operates like a JVM. The OS is often referred to as an abstraction layer because programmers usually program for the OS, not the hardware. However, the OS does not convert the running program into machine code. It is a program that is running at all times and provides a common way to talk to a variety of different hardware devices. It is troubling to get tied down to a specific answer with "operating systems" because there is no universal answer to "What is an operating system?" It is clear though that it is not a "virtual machine". 209.149.113.45 (talk) 13:41, 27 July 2015 (UTC)

• In addition to the points made above, many machines have an additional layer of abstraction between machine code and the physical electronic components, consisting of microcode. Looie496 (talk) 13:50, 27 July 2015 (UTC)

What language uses if!, enter!, exit!?

What language uses if!, enter!, exit!?--Bickeyboard (talk) 00:35, 26 July 2015 (UTC)

I don't know of one. Where did you see them? The context must provide some clue. Scheme has a builtin named set! and a bunch of functions with exclaimed names, but not the three you listed. Vim (text editor) uses ! as a modifier for some commands, but not those. -- BenRG (talk) 21:23, 26 July 2015 (UTC)

I used a stage play markup language (Shakespeare?) long long ago that ran on Perl. The markup language had "enter" and "exit" as commands for a character to enter or exit the stage. Once a character was in use, the ! was a shortcut for that character. So, if I had "John: I'm saying some lines." followed by "Exit !", it would add "[Exit JOHN]" to the stage play. I do not remember any conditionals, such as "if" in the markup language. So... you are probably referring to the Ruby programming language. 209.149.113.45 (talk) 19:35, 28 July 2015 (UTC)

replace character vs add character

I don't know how I got into this (perhaps some accidental control key combination?) but suddenly when I type text in the middle of a line, instead of just adding the next character, NotePad++ replaces the character, So, instead of adding 'c' as the sixth character of 'charater' -> 'character' I get 'characer.' What can I do? --Halcatalyst (talk) 16:49, 26 July 2015 (UTC)

I don't know NotePad++ but I guess you pressed the Insert key or chose it elsewhere. Try to disable the unwanted feature by pressing the Insert key. PrimeHunter (talk) 17:23, 26 July 2015 (UTC)

It worked, thank you! --Halcatalyst (talk) 17:47, 26 July 2015 (UTC)

Unicode Alternatives to: \ / : * ? " < > | in Windows filenames?

Resolved

The following characters are not permitted in Windows7 filenames:
\ / : * ? " < > |
Q: What are the Unicode characters that will look the most like them on a web page (from any browser or operating system) without giving any protests or problems from Windows when I want to use them in filenames?
(The three most urgently needed are alternatives to: the colon :, the slash / and the question mark ?).
Do you have any suggestions?
--Seren-dipper (talk) 17:44, 26 July 2015 (UTC)

One standard method is to use the Halfwidth and fullwidth forms - FULL WIDTH COLON (U+FF1A, ：), FULL WIDTH SLASH (U+FF0F, ／), FULL WIDTH QUESTION MARK (U+FF1F, ？). See the table in the article for the other symbols. Tevildo (talk) 18:10, 26 July 2015 (UTC)

Try the Unicode Consortium's confusables utility for some options. For : you can often substitute a dash. -- BenRG (talk) 20:27, 26 July 2015 (UTC)

Perfect! Thank you both! ☺
--Seren-dipper (talk) 01:51, 27 July 2015 (UTC)

Presumably you're aware that people will hate you if you do stuff like that. They'll try to type the file names and it won't work. Looie496 (talk) 13:09, 27 July 2015 (UTC)

hard drive error

File:Screenshot of HD error.jpg

screenshot of the error screen

This morning Windows started giving me warnings about a hard drive error. I ran SeaTools on it, and it detected a problem. It said to run SeaTools for DOS. I did that but it said "No hard drive found"... "no controllers detected"... I ran Chkdsk /f but it didn't find any problems. Is there some other free or cheap way to test for HD errors and try to fix them? Bubba73 ^{You talkin' to me?} 23:06, 26 July 2015 (UTC)

I suspect your hard disk controller requires a driver that was not available from the DOS version of Seatools you have. If it needs to be said, the very next thing you do before you run any more tests or whatever is ensue if you have ANY data you want to keep on this disk that it's backed up. In my experience, regardless whether you find some software that claims to have repaired your problems, a hard disk that's had an issue is just a ticking time bomb. The cost of disks these days, just replace it ASAP. Vespine (talk) 23:11, 26 July 2015 (UTC)

Thanks - it is a secondary HD and I have current backups. Bubba73 ^{You talkin' to me?} 23:22, 26 July 2015 (UTC)

What warnings did you get from Windows, and what problem did SeaTools detect? The only problem I can think of that might be (temporarily) fixable is bad sectors. You can run chkdsk /r to scan the whole disk for bad sectors and mark them as bad so that the filesystem won't try to write to them later. If any of the sectors were in use, you'll probably lose that data. Chkdsk will allocate a new sector for that part of the file, but I don't know what it does about the unreadable data; it may replace it with zeros, which could contaminate your backup. Hard drives with bad sectors are likely to develop more of them, causing more data loss, so it would be better to replace the drive unless you really don't care about the files stored on it. -- BenRG (talk) 23:53, 26 July 2015 (UTC)

I don't remember the exact errors - something about sectors, I think. I think that replacing it now is probably the best idea. I went out to get a replacement, but the stores that have internal drives wer already closed. Bubba73 ^{You talkin' to me?} 01:24, 27 July 2015 (UTC)

Warning: Inadequate try to repair may cause preventable loss of data. Use an external disk and a Linux Live-CD to backup data. Use another computer to get the CD/DVD's ISO-image. Just boot from the CD, but do not install Linux on such machine. In case of hardware damage, CHKDSK might not be able to write essencial blocks due phyically damaged sectors. First, do not overheat the drive. Second, backup You data first an mention, the files might be damaged already. Do not overwrite or delete existing backups. By booting from an other device, a damage of the operating system is skipped when accessing Your files. When finisted the backup, figure out if the drive is damaged phyically or the filesystem only which can be repaired or renewed by killing all data on the drive. To try a second backup I heard form a software called Spinrite. I suggest not to a drive with physical damage again. Even on notebooks the drive can be removed quickly. Today drives are installed in a tray or drawer of the computer as far it can be called a computer. --Hans Haase (有问题吗) 08:23, 27 July 2015 (UTC)

I've added a screenshot of the error. It still comes up periodically. I ran a check of the drive with HDTune Pro 5.6 overnight (it took a few hours) and it didn't find any problems. CHKDSK /F didn't find any problems. I'm running CHKDSK /R right now. It is out of warranty, but it is a 2TB internal so I can replace it for about $90, so that is what I plan to do. Bubba73 ^{You talkin' to me?} 16:10, 27 July 2015 (UTC)

Seconding Hans Haase's advice above. That error typically means the disk is indeed failing rather than needing defragmenting/repair. It may still last quite a while, but especially if it's your boot drive, you should back up your data now and replace it ASAP (as it sounds like you're doing). I had a drive (which I stored some programs on but didn't boot from) give me that error on startup for more than a year before finally dragging the whole system down to a slow crawl until I disconnected it. One of those things best dealt with sooner rather than later. — Rhododendrites ^talk \\ 17:01, 27 July 2015 (UTC)

Thanks. I bought a new drive to replace it; I'm waiting on an extra backup to finish. This is not my boot drive, but it is where I keep just about everything other than Windows and the installed programs.

I haven't been very fortunate with hard drives over the years - nothing near their claimed MTBF. I estimate that about 1 in 4 or 5 internal drives has failed during the live of the computer and 1 in 3 external drives. Bubba73 ^{You talkin' to me?} 18:25, 27 July 2015 (UTC)

PS - it is getting harder to get internal desktop hard drives in local stores. Bubba73 ^{You talkin' to me?} 00:28, 28 July 2015 (UTC)

Resolved

I got the new drive installed and it is being restored from a backup right now. Bubba73 ^{You talkin' to me?} 03:22, 28 July 2015 (UTC)

Good call.

Having been in charge of mainlining disk farms with thousands of disks in them, I have the following advice to maximize life:

• Keep it cool. Heat kills hard drives. Extreme cold isn't quite as bad, but should be avoided.
• Keep it away from vibration. Cooling fans are notorious for making the entire case vibrate.
• Get a high quality power supply from a reputable manufacturer. Voltage spikes are bad for hard disks.
• Powering down a hard drive one or two time a day is fine, and leaving it running 24/7 is fine, but avoid turning it off ten times a day.
• Run the S.M.A.R.T. diagnostic utilities every 6-12 months. The CCleaner program is a good way to access S.M.A.R.T. from Windows.

--Guy Macon (talk) 05:57, 28 July 2015 (UTC)

Thank You all for reply. Defragging a damaged disk may cause valid data is moved from used sectors into damaged sectors. Is is causing further unnecessary loss of this data. Defragging moves blocks to get them lined up to have quick access by reducing the actuators cylinder change. Each cilinger change of the actuator is in milliseconds range. Never defrag an SSD. SSDs have loss of lifespan by writing. The each block has identical access time. --Hans Haase (有问题吗) 22:02, 28 July 2015 (UTC)

July 27

."Wikipedia" - the name

How did The Free Encyclopedia get its name "Wikipedia"? Does the beginning of the name "Wiki" come from Latin?

"Wiki" is the Hawaiian word for "Quick" - see History of wikis. AndyTheGrump (talk) 00:54, 27 July 2015 (UTC)

See also Wikipedia. Dismas|^(talk) 01:15, 27 July 2015 (UTC)

...And History of Wikipedia while we're at it :) — Rhododendrites ^talk \\ 16:49, 27 July 2015 (UTC)

Decoding QRCodes the hard way.

I want to write my own QRCode recognizer from the ground up...I have lots of programming and graphics experience - so you don't need to use baby-talk - but I've not done much image recognition.

What are the basic steps in doing such a thing? Assume I have a 2D array of pixels from a camera at no particular angle to the QRcode as a starting point.

24.242.75.217 (talk) 01:26, 27 July 2015 (UTC)

Erm? Do you want someone to write you a tutorial? Have you read QR? There are more than a few resources online for similar projects. Vespine (talk) 01:32, 27 July 2015 (UTC)

Hmmm - I doubt either of those things will be of much use to our OP. QR Code doesn't say how it's decoded, and the Swift-reader description you linked can be summarized as "Call the QR-code reading library". Our OP said "from the ground up". I can't find a 'ground up' explanation.

I believe you start off using some kind of edge-recognition approach to recognize the three corner boxes (to be honest, I'm a little vague on that part!) - and once you know those positions, you can generate a matrix that you can use to transform the image of the QR code into a simple, axially aligned 2D square...and from that point on, it's just a matter of reading and thresholding the pixels in the areas where you expect the data dots to lie. There is an error-correcting code (Reed–Solomon error correction) that is applied to extract the actual data.

First you need to detect that there is a QR code. To do that you need to search for the FIPs (the three "finder pattern" squares). This paper talks about using Haar-like features; this discussion talks about using contour detection and analysis, which is a kind of feature extraction. Both of those examples use OpenCV to do the lower level stuff, but you can always choose to do that yourself. The ISO QR spec gives a rather simpler scanline-ratio based algorithm, but I don't know how robust that will be for real-world photos of QR codes. Once you've figured out the locations of the three corner FIPs, you need to transform the image so that it's square (because a real picture of a QR code will likely have some perspective distortion and some rotation) - that's discussed in the second link I give above. At some point (I guess now) you'll need to downscale so one black/white box becomes one pixel, and convert to a 1-bit image (a clever system will presumably use contrast for that, to accomodate images which have a shade gradient over them; a simple decoder might just choose to use a threshhold (based on the range of tones within the inter-FIP area)). From there, you can use the decode algorithm detailed in the ISO specification - this page links to that. If you want to read someone else's code that already solves the problem, you could try Zbar's, although I had a brief look at their QR code and it's rather tulgey. -- Finlay McWalterᚠTalk 11:18, 27 July 2015 (UTC)

The algorithms to locate barcodes can be explained rather easily. Locating a linear one, like an EIN or UPC, is nearly identical to locating a QR.

1. Pick an angle from 0 to 180 degrees (this can be random, it can step through the angles, whatever...)
2. Begin at a location on the left or top of the image and follow the angle across the image (the starting point can be random or step through every point...)
3. If the pixel is blackish, record a 1.
4. If the pixel is whitish, record a 0. (Some algorithms preprocess the image to get a point halfway between the darkest and lightest pixel to be the border between black and white)
5. Scan the image for the sequence that indicates the beginning/end of the code, such as 1n0n1n1n0n1n where n is a quantity. You would match 101101 or 110011110011 or 111000111111000111 or 111100001111111100001111. Some algorithms allow for variance. So, this would match even though there is a missing 0: 11110000111111110001111.
6. If you didn't find TWO beginning/end sequences (most barcodes require a special code at the beginning and end, so they come in pairs), go to the first step and start over.
7. For QR codes, you now have a beginning/end box and the angle of the line between them. Scan at a 90 degree angle off both boxes to find the elusive third box. If you don't find it, go back to the first step.

Once you have the beginning and end of the barcode, scanning the lines or squares between them is a completely different process. This is just for locating the barcode. There are many algorithms that do this. The big trick is finding the "fastest" and "most reliable" method of locating the beginning/end codes. 209.149.113.45 (talk) 13:24, 27 July 2015 (UTC)

That sounds OK for 1D barcodes - but for 2D QRCodes, picked up via a camera - not so much. What you suggest presumes that the plane of the camera sensor is more or less parallel to the plane of the QR code so that a right angle in the QR code is a right angle in the photograph. If it's not then the lines between the top-left corner box and the top-right and bottom-left boxes aren't at right angles and the sizes of the blocks in the code will vary from one place in the image to another due to perspective and such. Also, the pattern of 110011110011 (or whatever) shows up in places other than the corner box. The QR code for my website (http://RenaissanceMiniatures.com) has that pattern showing up in several places - close to the bottom-left corner of the QR code for example).

A good algorithm should also verify that the detection of the three corner boxes is correct by looking for the smaller 4th box that's inset a few blocks in from the bottom-right corner of the code.

SteveBaker (talk) 19:22, 27 July 2015 (UTC)

Often an approximation of a Hough transform is used to estimate how the rotation of a photo of a 2D barcode. Then image rectification attempts to remove most of that rotation. Sometimes perspective control is used to remove most of the perspective projection distortion.

Alternately, I hear that some people use something like a generalized Hough transform#Circle detection process to detect the precise position of the 3 big fiducials (and sometimes the smaller fiducials), then use linear interpolation/extrapolation from those positions to find the approximate size and position of each "module".

Some of these steps are exactly the same for almost every 2D barcode.

"How to put your logo in a QR code" has a few details.

You might be interested in seeing how other people decode QR codes. There are several open-source barcode scanners available, including:

• ZXing ("zebra crossing")
• QrCode.Net [1]
• Open Source QR Code Library [2]
• ZBar bar code reader [3] (Thank you, Finlay McWalter)

(My understanding is that Wikibooks: Android/PhoneGap#Barcodes uses ZXing).

Is there a better place to describe and discuss techniques for decoding 2D barcodes "from the ground up", and ideas for designing entirely new 2D barcodes that are even easier to decode? (My understanding is that Wikibooks is more accepting of such "how-to" information than Wikipedia WP:NOTHOWTO).

--DavidCary (talk) 01:33, 29 July 2015 (UTC)

Movie file

Hello, I recently collected a movie of two copies, one of which is 1.56GB and the other 4.00GB.

1. Which one of this should I keep in my ‘treasure box’?; both copies look alike without any defects/pixel issues…
2. What software decreases the GB?
3. What do I lose, together with the ‘kb/Mb/Gb’/What's the difference between the two files I possess; rather than the 'GB'?

Space Ghost (talk) 18:41, 27 July 2015 (UTC)

@Russell.mo: What format are the two files? What information do you have about them? Are these DVD rips? Captured streaming video?

The relevant articles are video file format, Comparison of video container formats (these two articles are actually a little redundant, it appears), and video coding format.

Basically a movie is a bunch of video data (for which there are multiple formats) and audio data (for which there are multiple formats) wrapped one of many "containers". The size of the original audio and video data, the kind of compression, and the level of compression are what lead to varying file sizes. Practically speaking, if they look exactly alike [and sound exactly alike] what kind of rationale would there be to keep the bigger one? — Rhododendrites ^talk \\ 19:02, 27 July 2015 (UTC)

It might be that the larger one has a higher resolution, but this difference isn't visible at the resolution he is using. The place I find the resolution is most obvious is in the credits, particularly the tiny tiny ones at the end, like these: [4]. StuRat (talk) 19:17, 27 July 2015 (UTC)

@StuRat: Where is the resolution in that image? Are you talking about the kind of film/camera/aspect ratio the film was shot in? It's indeed true that the resolution of the bigger file may be higher than in the smaller one and the difference is small enough that OP would need a bigger display to really notice. I suppose it's possible that the credits vary based on medium such that the DVD, BluRay, streaming, etc. versions all have their own figures, but that wouldn't be the same as what resolution the video file is, because not only can you reduce the resolution to reduce the size, but you can also artificially increase the resolution (no real gain, but it would certainly take up much more space). The resolution of the file should be visible in the properties of the file as visible through any playback application. — Rhododendrites ^talk \\ 20:38, 27 July 2015 (UTC)

You may have misunderstood me. I don't mean that they list the resolution there, I mean that you can get an idea of the resolution by viewing tiny credits. If they are blurry, it's low res. The image I linked to is only 640×360, and, as you can see, it's rather blurry. A 1920×1080 image would look crystal clear, but of course, only if you displayed it at full resolution, and it had never been downconverted then upconverted back to full HD, had a lossy compression applied, etc. So, when I get a copy of a movie, I go right to the credits to see if it's a good version or if it's crap. (If it's total crap, I may try to find a better copy or just not bother watching it.)

And yes, I have noticed that newer 1920×1080 movies have started using even smaller credits, just when I finally was able to read them all. It's a conspiracy I tell you ! StuRat (talk) 20:46, 27 July 2015 (UTC)

Ah. Yes. I did misunderstand. I see now that you're suggesting a practical test for comparing image resolution (focusing on a detail with high contrast). Makes sense. — Rhododendrites ^talk \\ 22:00, 27 July 2015 (UTC)

That's right. Just looking at what it claims is the resolution won't tell you if it's been downconverted then back up, or had a lossy compression applied, but this test will. StuRat (talk) 22:30, 27 July 2015 (UTC)

Rhododendrites, StuRat: '.avi' is on 1.56GB and '.mp4' is on 4GB. I heard and checked on the internet something similar to what both of you said, a long time ago, can't recall now, that either the picture/sound (or both) is affected. Based on your experience, up to what 'Kb/Mb/GB' would you guys suggest, in order to retain a movie? The bigger the better of course, but...? -- Space Ghost (talk) 22:55, 27 July 2015 (UTC)

In my experience it's a completely personal preference. Sometimes I don't mind retaining even a 800MB file of a movie, but sometimes i want to retain the 4GB or larger version. Is the movie very "visual"? Does it rely on special effects and amazing cinematography? (Big file). Or is it a indy drama filmed on a low budget? (small file). Would I watch it with friends if I'm having a movie night? or am I likely to watch it on the train on my ipad? (Small file). And, certainly not the least consideration: how much disk space do you have left? ;) but if you watch both and you literally can't tell the difference, just keep the small file. Vespine (talk) 23:10, 27 July 2015 (UTC)

Points you stated, noted, thank you.

1TB (931GB) RHDD, 560GB available. I have many useful softwares, good games and movies, and at least 10GB of adult videos (you’ll never get tired of it). I’m planning to make it a ‘treasure’ box (RHDD) for my upcoming future. -- Space Ghost (talk) 19:02, 28 July 2015 (UTC)

On the large end are VOB files, which is what commercial non-BluRay DVDs use. I find they take about 8 GB for a 2 hour movie. Did you do my suggested test and look at the smallest credits ? That will allow you to compare the visual quality. StuRat (talk) 00:08, 28 July 2015 (UTC)

Yes I have, thereafter messaging you guys yesterday, a slight blurriness seen that can be tolerated I guess, as I would not have known/noticed it if you didn’t point it out…thanks. -- Space Ghost (talk) 19:02, 28 July 2015 (UTC)

I thought mathematics could be used to estimate, for example if 1.50GB (.avi) file producing credible quality resolution and sound - comparing with the 4GB (.mp4) - then will at least (or less than) 1GB movie file do the trick, for treasuring purpose? Or does it also depend on the 'file extension'? If so, what 'file extension' is the best? -- Space Ghost (talk) 19:02, 28 July 2015 (UTC)

Well, it's all going to depend on the time, resolution, color depth, frames per second, etc., and some types of video (like traditional animation with large areas of constant color) will compress far better than others (like a dark scene with live action). And then there's personal preference for how much quality you are willing to trade off for how much space savings. Somebody might be able to answer on which formats (file extensions) are better, although again with lots of caveats. For your particular case, since you said the visual quality is acceptable on the smaller file, I'd use that one. StuRat (talk) 19:08, 28 July 2015 (UTC)

Hey buddy, I thought I messaged you yesterday, but the message did not appear... Anyway, I wrote "Okay, I'll. Thanks" or something like that... Take care! -- Space Ghost (talk) 18:14, 29 July 2015 (UTC)

file extension is meaningless. Even if the extension is the normal extension, the vast majority of common video container formats support different video codecs in the spec (if there even is one). Even WebM now supports VP8 and VP9. And even if you have the same video codec and the same source file, the quality is going to depend on the settings used for the codec (profile etc), and the actual encoder used. Nil Einne (talk) 20:17, 29 July 2015 (UTC)

I don't believe file extensions are meaningless, since they determine the default program used to open or run that file. For example, an HTML extension file is typically opened with a browser, capable of displaying HTML. If you change the extension to TXT, then it will likely open with a text editor, and you will be able to edit it, but not display it, which is quite a different action. (Yes, you could alter the default actions for each file extension, but changing those two would really mess up how your PC handles those common file types.) StuRat (talk) 13:52, 30 July 2015 (UTC)

I understand what you both said. I guess file extension is nothing to worry about 'for the time being' or 'ever' unless I'm dealing with it in a professional manner... -- Space Ghost (talk) 18:49, 30 July 2015 (UTC)

Migrating Fedora Linux to a new hard drive

My 2 TB hard drive for Fedora 20 Linux is almost filling up. I think it won't even last until Christmas. I can buy a new 4 TB hard drive, which should last for several years, but how do I transfer my system to it? I know I can just plug both hard drives in at the same time and use cp to copy my entire /home directory partition and the entire partition where I keep my photographs in (which takes up the vast bulk of the drive). But what about the /boot and / partitions? Can I just use cp to copy them across as well and have a bootable system?

I'm also planning to finally upgrade to Fedora 22 Linux in the process. But a fresh install of Fedora 22 Linux would mean I would lose all my installed programs, only keeping my personal data and my photographs. Is there a way to copy them across or do I have to reinstall them all over again? JIP | Talk 20:59, 27 July 2015 (UTC)

Copy the old disk to the new (boot sectors, partition tables, etc.) wholesale from the old disk to the new with dd (Unix). Then use GNU Parted to resize the partitions on the new disk to fill the disk up. I don't know anything about upgrading Fedora. 84.51.142.140 (talk) 21:18, 27 July 2015 (UTC)

With Fedora, you should be using lvm virtual file system. You can put in the new drive and expand your virtual partition to contain the new drive. See the many lvm expand tutorials for how to's.

Though brief, I agree with this. If you have the ability to add the new drive along with the old drive, use LVM. Fedora's Anaconda uses LVM by default (even if you only have 1 drive). So, you should have an LVM drive that you are using - which is a virtual drive that encompasses your current drive. Now, add the new drive. Now, hopefully, you installed system-config-lvm. Run that. It is a nice and easy GUI. You will see the second drive listed as unused. Select it and add it to your LVM. Now, you will see both drives as a single 6TB drive and you won't have to copy/move any files. 209.149.113.45 (talk) 13:47, 28 July 2015 (UTC)

That would be a good idea, but my current computer is actually my company's property, and it only has two drive bays, both filled up. One has my Fedora 20 Linux system and the other has a Windows 8 system I'm not allowed to wipe clean in order to install Linux there, it must remain intact. However, I haven't actually used the Windows 8 system in over a year. I might be able to simply remove it and keep it in a safe place, and then put the new 4 TB Linux drive in its place. If my company ever wants the computer back, I can simply swap the drives again, putting the Windows 8 system back in place. Then I have to buy a new computer with more drive bays. JIP | Talk 17:06, 28 July 2015 (UTC)

I would ask if you could just drop the Windows. The immediate answer is always "No", but sometimes you get a delayed, "Well, if you never use it and never update it and it is just sitting there wasting space, go ahead and remove it." I've been lucky. I haven't had to use Windows since 1994. 209.149.113.45 (talk) 18:36, 28 July 2015 (UTC)

The thing is, everything about this computer except the Linux drive and the Linux on it is actually my company's property, not mine. It's technically just on loan. The company has a finite amount of Windows licences and likes to hold on for them, and as well as that, the Windows drive has my company's own proprietary code on it. So wiping the Windows drive is not an option. Temporarily removing it is. And anyway, I've never used LVM like that before. My current Linux drive has separate partitions for /boot, /, /home and /storage. The last one is by far the largest and has all my photographs on it. It would be that partition I want to expand, keeping the others intact. Is that possible? And how does LVM across several physical drives even work? If the drives ever separate, will each have its own share of files or are the files themselves somehow spread? How is it determined which drive gets which files? JIP | Talk 18:45, 28 July 2015 (UTC)

I have never converted a hard partition into an LVM partition because, since about F16, LVM was default. I'm not certain that it is possible. But, as for working across multiple disks, that is exactly what LVM is used for. Instead of having multiple mount points, you have one root. Internally, it manages the disks (kind of like a RAID with no striping or mirroring). Once you have LVM running, you can add disks, remove disks, resize the volume, etc... I've also used it to get around problems. For example, I had a JBOD with 12T of data on a very old Gateway machine (yes - that old). The server would corrupt the disks all the time because, as I discovered, the SCSI driver never expected more than 4T of space to work with. So, I split the JBOD into 4 3T logical drives (staying well below 4T) and then used LVM to make it all one volume. I've also done what you are trying to do. I added a disk to an LVM, which was rather quick. Then, I told the LVM that I didn't want to use an older disk. It took a while to get everything off the old disk. Then, when it was done, I popped out the old disk and I was done. 209.149.113.45 (talk) 19:17, 28 July 2015 (UTC)

Well, if LVM was default since about F16 and I have F20, it might be that I'm already using it. I'll have to check. But I still need an answer to my question about the files. Does each physical drive get its own share of the files, or is the data spread out at a lower level? And how is it decided which drive gets which data? I need to know this so I know what to do when I have to update the drives again. And I think that to preserve the integrity of the files, it's a good idea to copy them all to a new drive every couple of years instead of keeping them on the same drive for decades. After all, every physical medium is prone to fault, and physical faults in the drive's disks themselves will corrupt the files. JIP | Talk 19:54, 28 July 2015 (UTC)

I just found out that F20 dropped system-config-lvm. So, there's no GUI for LVM. Why? They switched from LVM to LVM2 and the old tool wasn't apparently designed to handle LVM2. So, you are apparently stuck using command-line tools. They aren't actually complicated, just not as easy as the GUI. For example, sudo lvdisplay will quickly tell you if you are using LVM by displaying all logical volumes in use. 209.149.113.45 (talk) 13:50, 29 July 2015 (UTC)

Downloadable link sought

Friends, has anybody seen the 2D (cartoon) version of 'Transformers'? I'm planning to download the complete version (full/all the episodes or seasons) using 'YTD' (Youtube Downloader), would anyone kindly guide me to the link(s) please? I'm also willing to change the 'downloader' if required...whatever you guys recommend... -- Space Ghost (talk) 23:08, 27 July 2015 (UTC)

Just a note that doing so is likely illegal wherever you may live. There's a 15 disc version available for purchase. Dismas|^(talk) 13:19, 28 July 2015 (UTC)

Yeah, I forgot. Sorry.

I'd be grateful if you could let me know the title of the 15 disc version one... If can, does it have everything? All the seasons, episodes, and so on? -- Space Ghost (talk) 18:18, 28 July 2015 (UTC)

Which series of Transformers are we talking about? If it's the original 1980s one I'd also be interested in purchasing this 15 disc version. JIP | Talk 19:14, 28 July 2015 (UTC)

The 15-disc version is, to my knowledge, the original series (80's). To be certain, this is the series with Peter Cullen as Optimus Prime. See it here. 209.149.113.45 (talk) 19:24, 28 July 2015 (UTC)

That's exactly what I was wanting. And the price seems affordable as well. But will the DVDs play here in Finland? After all, the entertainment industry seems to be doing its utmost to set up limits on how people can use the content they bought fully legally and paid good money for. JIP | Talk 19:46, 28 July 2015 (UTC)

Only if you have a DVD player that will play Region 1 DVDs. Here is a link to the Transformers: The Complete Original Series in Region 2. CambridgeBayWeather, Uqaqtuq (talk), Sunasuttuq 00:54, 29 July 2015 (UTC)

Okay guys, thanks... -- Space Ghost (talk) 18:14, 29 July 2015 (UTC)

July 28

Simulating scanner distortion

I'm looking for an online service that can simulate the characteristic distortion that a scanner makes. Basically I have a JPEG image of a document, and I want a JPEG image of how said document would look if it were printed out, and then scanned. Currently I'm printing them out and then scanning them, which is A. a waste of time, and B. a waste of trees. Please help me save some trees. Thanks. My other car is a cadr (talk) 13:52, 28 July 2015 (UTC)

What type of "distortion" do you mean ? If it's just a loss of resolution, that's simple enough. Or maybe it goes from a full color image to black and white ? That's easy too. If you could include before and after pics, that would help. StuRat (talk) 14:42, 28 July 2015 (UTC)

You've never seen a scanned document before? Here's a random example I got off the net[5]. Notice how there are random specks of dust here and there and that the edge of the document contrasts with the white scanner bed. The resolution doesn't need to be changed, and it can stay a colored image. My other car is a cadr (talk) 15:02, 28 July 2015 (UTC)

OK, so you are talking about a raw scanned image, not cropped to the document and not cleaned up to remove specks. No OCR either. StuRat (talk) 15:11, 28 July 2015 (UTC)

I have seen thousands of scanned images. Sometimes there are specks. Sometimes there aren't. Sometimes the text looks great. Sometimes it gets some aliasing. Sometimes there are lines cutting horizontally or vertically across the document. Sometimes it is tilted. Sometimes you can see text from the other side of the sheet. Sometimes the scans are in color. Sometimes they are grayscale. Sometimes they are strictly black and white. Sometimes they get darker. Sometimes they get lighter. That is just a few things that COULD happen - and you didn't explain a single one in your question. So, why do you think it is acceptable to ask a belligerent question like "You've never seen a scanned document before?" Try putting some effort into asking a well-formed question. 209.149.113.45 (talk) 15:15, 28 July 2015 (UTC)

Thanks, but I didn't see it as belligerent, they just didn't know that scanning causes a wide variety of "distortions" (defects). StuRat (talk) 16:45, 28 July 2015 (UTC)

For the speck/dust look, try something like this [6]. That might be good for single-page bed scanners, but it won't help with the shearing you get when a document feeder changes speed a little bit, nor things like the crease on the inside of book's spine. See also similar questions and decent answers here [7]. Here's even a way to do it in LaTeX: [8]. The Gimp has a photocopy-effect tool [9], and it looks like ImageMagick does as well [10]. SemanticMantis (talk) 15:22, 28 July 2015 (UTC)

Thank you so much! That ImageMagick command does the trick perfectly! My other car is a cadr (talk) 16:52, 28 July 2015 (UTC)

I liked the one suggestion of rotating it 1-2 degrees (in addition to speckle, downrez, etc). I thought that was a nice touch that really helps sell it :) Also funny that several of the other threads' OPs seemed to have the same motivation as you... SemanticMantis (talk) 18:28, 28 July 2015 (UTC)

BTW, I am curious, why do you want to make images look bad ? StuRat (talk) 16:47, 28 July 2015 (UTC)

Soulless bureaucratic machine expects each document to be printed out, stamped, scanned, and then shredded. Your tax dollars at work, people.My other car is a cadr (talk) 16:52, 28 July 2015 (UTC)

Resolved

So, you are basically cheating the government by pretending that you print, stamp, and scan the digital documents, right? However, how will you explain that there won't be any shredded paper left over? --Yppieyei (talk) 22:01, 28 July 2015 (UTC)

(This is off topic - OP asks questions, we give references if we choose. If you want to question the morality of the scenario, keep in mind you know very little about it. Also I'm reminded of a quote from MLK "One has not only a legal but a moral responsibility to obey just laws. Conversely, one has a moral responsibility to disobey unjust laws." [11] SemanticMantis (talk) 13:18, 29 July 2015 (UTC)

Unjust != Inconvenient SteveBaker (talk) 02:43, 30 July 2015 (UTC)

July 29

Extracting tagged text

What algorithm can I use to, for example, extract "abc" from "xxx<abc>yyy" if I give it "<" and "> as delimiters (or another, extracting mediawiki style templates)? What is the most efficient way to do this? 24.255.17.182 (talk) 01:33, 29 July 2015 (UTC)

The usual way of completing this sort of task is to use a Regular expression.--Phil Holmes (talk) 07:04, 29 July 2015 (UTC)

• sed -e 's/[^<]*<\([^>]*\)>.*$/\1/' or something like that will extract one occurence. Graeme Bartlett (talk) 11:04, 29 July 2015 (UTC)
• sed -e 's/[^<]*<//' -e 's/>[^<]*<//g' -e 's/>[^<]*$//' will extract multiples in one line (as long as it is well formed). Graeme Bartlett (talk) 11:12, 29 July 2015 (UTC)

Right, that's sed, available by default on Unix (including OS X), and Linux systems, Windows users commonly access it via cygwin. Some text editors also have built-in regular expression support. SemanticMantis (talk) 13:12, 29 July 2015 (UTC)

The "algorithm" is very simple. Given a value START as the start character and END as the end character, then a STRING as the string of text:

1. Make an empty string DEST.
2. Set a flag TAG to false (or zero).
3. Set a pointer to the first position of STRING.
4. Set CHR to be the character in STRING at the pointer.
5. If TAG is true:
   1. If CHR equals END, set TAG to false
6. Otherwise (else):
   1. If CHR equals START, set TAG to true
   2. Otherwise (else), append CHR to the end of DEST
7. If the pointer is not at the end of STRING, increment the pointer to the next character in STRING and go to 4.
8. DEST contains all chracters in STRING, omitting everything found from START to END.

This algorithm does not handle escape characters. It is not better than a regex as it is the algorithm used by regex. 209.149.113.45 (talk) 13:36, 29 July 2015 (UTC)

Release data of Raspberry Pi 2 Windows 10 ARM port?

Hello everyone. Does anyone know when the free ARM port of Windows 10 for the Raspberry Pi 2 will be released? I would imagine it wpuld have been released when Windows 10 it self was released right? Thanks for your help in advance. —SGA314 I am not available on weekends (talk) 14:33, 29 July 2015 (UTC)

Information about this Microsoft port is available through their developer program: Windows for IoT, as announced in Windows 10 Coming to Raspberry Pi 2, a February 2015 blog update. Here are instructions: Setting up Raspberry Pi. Here are downloadable files. If you aren't already in the developer program, consider joining; they'll give you first-hand news and information long before it hits a wider audience. Nimur (talk) 14:45, 29 July 2015 (UTC)

Ok cool. so it has released already. Here is question 2. I have only 1 32gb sd card. So how would I setup the pi to dual boot off the sd card? For instance, on a pc you can set it up to boot into Linux or Windows on the same hard drive. How would I do this with Raspbian and Windows 10 n the Pi's sd card? —SGA314 I am not available on weekends (talk) 15:57, 29 July 2015 (UTC)

Glympse or alternative

Background: I will be an adjunct at another university this fall. It is a little over 1 hour's drive away. I will be giving myself 1.5 hours to drive there, but in that long of a trip, there is a high possibility of traffic issues. The class period is 1.5 hours. I don't want the students to walk out after 10 minutes if I am just 5 minutes away. But, how do I let them know if I am close or still very far away? Question: Is there an application that will share my location for a certain period of time with anyone and everyone in the world? I don't want to deal with having students sign up for a service and then become "friends" in the service and then install apps on their phones and then lose their passwords and have to reset them every class... I want to turn on an application on my phone and then anyone who knows something, such as my user ID, can see where I am until I turn the application off. I looked into the following:

• Google Maps: I don't see how to share a "here I am" pin automatically.
• Life360: I can only share with my "family" or "circle". So, everyone has to have an account and install Life360 to see me.
• Glympse: This looks promising, but they have almost no documentation on their website. There is a video, but I don't watch videos. I am not illiterate and I don't have time to waste when I could quickly scan text (if there was text) ... trying to avoid a rant about the general shift of the Internet to publishing all information in videos instead of text.

So, any suggestions? On my end, I have a lot of resources. I own multiple web servers. I have an Android phone with GPS and I doubled the battery (screw the warranty). I have handheld GPS device that has WiFi. I can write my own Android app, but I would like to avoid doing so if someone else already wrote something that does this. 209.149.113.45 (talk) 15:13, 29 July 2015 (UTC)

For a decidedly "old school" approach, you might consider walkie-talkies. Although they claim ranges up to 30 miles, the longest you are likely to get is about 2 miles: [12]. Still, if you are pulling into the parking lot 5 minutes after the class starts, you should be able to use the walkie-talkie to tell everyone you are almost there. The advantage: You wouldn't have to rely on anyone checking anything, just leave the other unit plugged into it's charger and turned on in the classroom, and it will speak when you speak on your unit, without anyone having to answer it or check anything. If theft is a concern, I suppose you could lock it up in such a way that it can still be heard (in a metal cage ?).

I also agree that video sucks for giving info. When somebody asks or "answers" a Q here with a 2 hour video and no time index, I rarely bother to watch it. StuRat (talk) 17:08, 29 July 2015 (UTC)

I don't own the classroom. So, I would be dependent on one student to always be in the class with the other handset. Optimally, I would like to find something that I can embed in a web page. I own my web servers and I can ask that the first student in the class direct the overhead projector to my website, which would then have a map showing where I am - along with notes that I can update every day, indicating what they can do while I'm stuck in traffic. 209.149.113.45 (talk) 17:14, 29 July 2015 (UTC)

Set up a webpage someplace - write yourself a tiny Android app that sends the amount of time until your arrival to the server. All you have to tell your students is the URL. Doing this without the app is plausible - but if you're driving, you'll want something that's as close to one tap on the screen as possible. (Four big buttons: On time/5mins late/10mins late/Lecture cancelled ought to cover it). SteveBaker (talk) 02:25, 30 July 2015 (UTC)

More general suggestions

( I don't know, but I advise discussing the situation with your new superiors, dept. chair, etc. When I've been a lecturer, being more than 10 minutes late to class more than once or twice a semester would be grounds for dismissal. The way you write your example, you're actually running at least 15 minutes late for a 90 minute course, and many institutions would consider that inexcusable outside of rare emergency circumstances. Most universities will not consider traffic to be an emergency circumstance. The university may or may not have explicit policies on this. Some universities explicitly say the students are allowed to leave after 10 minutes of no instructor. Maybe the simplest thing to do is allot 2 hours for the drive. Sorry to give a non-answer but no amount of tech will save your job if you are consistently late to scheduled class meetings. ) SemanticMantis (talk) 17:18, 29 July 2015 (UTC)

I agree and understand. We have discussed this - which was a reason I was very reluctant to agree to take the class. We discussed doing it remotely and moving the time. There are no good solutions to the problem. Having me race from one city to another, past two large factories during shift change, in a car that will likely not survive the semester, is the best solution they could find. Last year, they simply canceled the course, which happens to be a required course for the program. 209.149.113.45 (talk) 17:41, 29 July 2015 (UTC)

Suggestion: Have an activity at the beginning of the class that doesn't actually require your presence. A written quiz is one idea. I'd make it not graded, just so they can gauge their progress, and you would have to rely on an assistant (pick a student) to deliver it on days when you are late (give them copies the previous session), if there's no place you can leave it, that's accessible to the students. It can have answers on the back, and you can then answer questions about it when you arrive. You can also write on the quiz "feel free to ask other students for help, if you need it".

I'd also explain the situation to the students in advance, so it's not a surprise to them when you are late. And have alternate routes planned out and listen to traffic advisories, so you have the best chance of bypassing any traffic problems. Also monitor construction zones. StuRat (talk) 17:50, 29 July 2015 (UTC)

I actually do little quizzes at the beginning of every class - it replaces the concept of taking roll. If you did the quiz, you were there. My fear is that the traffic is simply going to be hellish. As mentioned before, I have to drive past two factories during shift change. So, no matter what path I choose, I have to deal with a thousand people leaving and a thousand people arriving all at the same time - twice. Also, they just started major development projects at the start and end point. So, no way to get around either one since I start in the middle of one and end in the middle of the other. All around, this semester is going to be terrible. I'd be forceful with my "no" if I didn't really need the money. 209.149.113.45 (talk) 18:30, 29 July 2015 (UTC)

The satellite navigation app Waze can let you share your drive with your friends who use the app. This shows your approximate position and ETA to them. I'm not sure if it would be possible to rig up something to let anyone in your class see this (short of adding them all as freinds on the app), but it might be a potential solution. (It will also route you along the best route it can find, given it's traffic reports, which tend to be fairly good). MChesterMC (talk) 08:42, 30 July 2015 (UTC)

I'm curious about how accurate and current traffic reports get loaded into it. Let's say a TV news reporter in a helicopter says "it looks like there's an accident in the right lane, the right lane is blocked. Traffic is proceeding slowly in the center lane, but moving at near normal speed in the left lane. Police are on the scene, but no tow truck is present." How does this app get that info in a usable form ? StuRat (talk) 17:45, 30 July 2015 (UTC)

Most of those apps are driver-based. Drivers see an accident and then rush to grab their phone, start the app, and report it (and then create another accident). 209.149.113.45 (talk) 12:45, 31 July 2015 (UTC)

I like Glympse. My friends and relatives can see me moving, stopping, resuming. I use their Email address when they are home, SMS when they're out, or both. I can send it to one or two or ten, whatever. Since it isn't part of some other navigation or social network, they don't need to install the app. They don't need to know there is such an app. The message just appears, and says to tap or click to see the Web map of where I am. Yes, they do need Web, which most cellphones have nowadays. The author seems to assume it's so simple, it needs no documentation. This is correct. Jim.henderson (talk) 18:12, 31 July 2015 (UTC)

Networking switch query

I have 2 computers connected to powerline ethernet adapters, and a 3rd connecting to my router. This can be a little slow sometimes (at least for game streaming and stuff). To speed things up would I be able to connect the 2 PCs via a switch, and then route that switch to the router via a powerline adapter? If I send traffic from 1 PC to another does the traffic have to go all the way to my router then back (presumably what is happening now), or will it go via the switch, which should be much much faster, as both PCs have Gigabit ethernet? 81.138.15.171 (talk) 15:42, 29 July 2015 (UTC)

What I would first do is get a crossover cable (very cheap) and plug both computers into one another. You will need to hard-set the IP of each one to something like 192.168.0.1 and 192.168.0.2. Then, you will have the absolute maximum speed of data transfer between the two computers. If there is lag, it isn't the network. Next, if you think you can make your network better, a hub will do. Two computers on a switch is a bit of a waste - especially when you are combining both signals into one upstream. 209.149.113.45 (talk) 16:07, 29 July 2015 (UTC)

How to do a dual boot of Windows 8 and 10: no USB drive or DVD?

I have already created the hard-drive partition.

Currently running Windows 8.1, with a 1 TB laptop. —24.228.117.156 (talk) 16:30, 29 July 2015 (UTC)

There's not a single USB port on there? What input options are there? Ian.thomson (talk) 16:41, 29 July 2015 (UTC)

Considering that upgrading from Windows 8.1 to Windows 10 is done through windows update, using a USB drive or a DVD is most likely not necessary. —SGA314 I am not available on weekends (talk) 17:05, 29 July 2015 (UTC)

First you must create a botable image of the partition that contains Windows 8.1. Next, you must 'extract' that image onto the other partition. you will need a special program to do this. do a Google search for something like 'hard drive image creator' or 'bootable hard disk image creator.' when you find the right program, use it to create an image of your partition that contains 8.1. This file should be roughly the same size as the size of the windows 8.1 partition. You should store this file on a SEPARATE hard drive or if you have enough space, on the 8.1 partition. This will allow you to extract the image onto the other partition. It would be helpful if you gave the amount of space taken up on the 8.1 partition as well as the size of both partitions. —SGA314 I am not available on weekends (talk) 17:02, 29 July 2015 (UTC)

This is actually the exact same thing I am going to do as well except that I will use a separate hard drive instead of dual booting. —SGA314 I am not available on weekends (talk) 17:07, 29 July 2015 (UTC)

Not an answer, but I agree with your plan for a dual boot, noting that Windows 10 is for suckers. So, committing to Windows 10 now as your only O/S would be foolish. StuRat (talk) 17:40, 29 July 2015 (UTC)

I run alot of VST and audio production software on Windows 7. Thus it would be wise for me to make a copy of all me software and try and run it on Win 10. I am also not very confident in the upgrade process's ability to keep all my files intact. I was able to setup a dual boot nce with XP and Win 7 but I don't remember what software I used. —SGA314 I am not available on weekends (talk) 18:57, 29 July 2015 (UTC)

Downloading NTSB hearing video

Hello Wikipedia! I am trying to download the video of yesterday's National Transportation Safety Board meeting on the SpaceShipTwo crash last October. Their video archives are at http://ntsb.capitolconnection.org/ and I'm able to play it using the Flash Media player running in Iceweasel (rebranded Firefox) on Debian GNU/Linux, but I don't see how to download it. I installed the "Flash and Video Download 1.74" add-on, but while it seems to work on other sites such as YouTube where it lists the various formats and resolutions of video files available for download, it doesn't seem to recognize any videos to download at the NTSB video's page http://ntsb.capitolconnection.org/072815/ntsb_archive_flv.htm . Can you suggest a Linux friendly method for doing this? I am also open to Windows only methods, but would have to borrow a friend's computer.

PS Copyright is not an issue here as the recording of this board meeting is a work of the US government. 2602:306:C4D5:C340:C8FB:D7A2:D78C:2586 (talk) 18:38, 29 July 2015 (UTC)

The player used on that site is JWPlayer. This video shows a Firefox extension which, it says, will process web pages which host JWPlayer and will download the flash videos embedded in them. I've not personally tried the specific extension it recommends (I'm running too many already), so I can't personally vouch for it - but if you opt for this approach, I'd be interested to know of that method works for you. -- Finlay McWalterᚠTalk 19:11, 29 July 2015 (UTC)

note: I did try other flash download tools, which are often successful - youtube-dl and VideoDownloadHelper (a Firefox addon) and neither worked for this video. -- Finlay McWalterᚠTalk 19:13, 29 July 2015 (UTC)

Thank Finlay, but it (the "Flash Video Downloader" extension shown in the video you linked) doesn't seem to work on this NTSB video. The download arrow never turns blue but stays gray with a red x (even after the video starts playing), though it does work for the video on the http://jwplayer.com/ page which is using JWPlayer.

Any other suggestions welcome.

I am also trying the rtmpdump utility, but it isn't working yet, with:

$ rtmpdump  -r "rtmp://fms.0172.edgecastcdn.net/000172/flv/ntsb/ntsb082712a.flv" -o ntsb20150728.flv
RTMPDump v2.4
(c) 2010 Andrej Stepanchuk, Howard Chu, The Flvstreamer Team; license: GPL
Connecting ...
WARNING: HandShake: client signature does not match!
INFO: Connected...
ERROR: rtmp server sent error
ERROR: rtmp server requested close
$

I got the URL by looking inside the source of the video's page, but I think that it may need more command line options, and I'm still trying to figure out how to run rtmpsuck. 2602:306:C4D5:C340:2DE3:2DBF:6157:E5DD (talk) 20:02, 29 July 2015 (UTC)

Well, the issue is still not resolved, but someone else must have managed to download it and put it up on YouTube: https://www.youtube.com/watch?v=QnMIfY_Wbrc .

So while I no longer have an immediate need, I'd still appreciate any pointers if someone here knows how to download from the NTSB site. Thanks! 2602:306:C4D5:C340:2DE3:2DBF:6157:E5DD (talk) 18:08, 30 July 2015 (UTC)

Windows update on Windows 10

Where is Windows update on Windows 10? It is no longer in the control panel and if I try to go to it from IE, it says that it can't find wuapp.exe. I want to make sure that it doesn't reboot without me telling it to. Bubba73 ^{You talkin' to me?} 21:02, 29 July 2015 (UTC)

Does this article address your question? http://www.cnet.com/how-to/windows-10-lets-you-schedule-windows-update-restarts/ 2602:306:C4D5:C340:2DE3:2DBF:6157:E5DD (talk) 21:12, 29 July 2015 (UTC)

That is what I'm talking about, but it says to open "settings". Where is "settings" on Windows 10 desktop? Bubba73 ^{You talkin' to me?} 21:21, 29 July 2015 (UTC)

OK, I found settings. Bubba73 ^{You talkin' to me?} 21:31, 29 July 2015 (UTC)

What do you think of the options it gives? I understand that W 10 keeps updates on automatic. Are the update restart options rich enough? 2602:306:C4D5:C340:2DE3:2DBF:6157:E5DD (talk) 23:14, 29 July 2015 (UTC)

The options seem to be more limited. I don't really want to schedule a reboot because sometimes I'm running something that is going to take a long time and a reboot will lose all of the work up to that point. Bubba73 ^{You talkin' to me?} 23:27, 29 July 2015 (UTC)

Running a PC with one single application (or not much more than that)

If I wanted to run just one single application like Vi/m or emacs on a PC (an x86) what else would I need? Would I need an OS at all or can I compile it to run without one? Could a PC be run without OS like an embedded computer can?--Yppieyei (talk) 21:10, 29 July 2015 (UTC)

You would need a kernel and whatever libraries the program needs, at which point you now have an operating system. "Operating system" is really a vague concept. It's more of a marketing term than a well-defined technical term. Now, to clarify, you could sit down and start adding code to vim to do all the things that a kernel and libraries do, but then you will just have written your own little embedded operating system that's only designed to run vim. A lot of embedded systems run operating systems. The only computers that don't have operating systems are really basic chips that you find in things like the proverbial elevator controllers and toasters. --108.38.204.15 (talk) 23:30, 29 July 2015 (UTC)

You can certainly work without an OS. That's actually how Linus Torvalds started writing Linux - he wanted a 'dumb terminal' program that could run on his PC with a modem without having to boot up DOS first...features were gradually added to it until it kinda accidentally became close enough to an operating system to actually become one! (For some reason, our articles on Linux and Linus don't discuss this very formative stage - but it's described in Linus' autobiography "Just for Fun").

I've also used PC's in things like Disney rides where we got rid of the OS entirely and ran our code on the bare metal. You don't necessarily need either a kernel or libraries or even device drivers - it's perfectly possible to write code that directly reads device registers and such...it's really no different when you're using something like an Arduino (which has no OS) or a PC. The biggest issue with running stand-alone programs on a PC is getting them loaded into memory in the first place. In my work, we replaced the BIOS ROM with our own EPROM chip...but it's been a while since that trick became impossible.

For something like Vim, which is probably single-threaded - only has to write to the screen and to save files to a disk drive - and only reads from the keyboard and loads files from the disk drive - that might not be too difficult. But if you wanted Vim to be able to read and write files on the disk drive that also needs to be used by (say) Windows - then you'd have to add a ton of code to handle how directories are formatted, where to find free space on the disk and mark that it's been used or freed. The code to do that might easily get bigger than Vim itself! Writing to the screen might not be difficult if you used your awesomely powerful graphics card to run in very-mundane VGA mode - but if you wanted a nice high-res screen with full color, you'd need some insanely complicated emulation of (say) an nVidia card's device driver - which would probably be impossible to write because those cards aren't documented to the degree that would allow that - and which would need a total re-write to run on an Intel graphics chip.

What tends to happen when you do this is that your stand-alone program tends to absorb more and more of the functions of an operating system (like handling files and directories on a hard drive - loading proprietary device drivers, handling interrupts, creating threads - dealing with memory management, etc) - until...just like Linus' dumb terminal program...you have actually written most of an entire operating system yourself.

Incidentally, when Linus needed disk operations for his growing dumb terminal project, he use the code from the pre-existing 'Minix' operating system - and thereby avoided the need to write his own until the project was already quite clearly an operating system in it's own right.

But for VERY simple situations, particularly if your I/O needs are very simple - you can indeed write programs without an operating system quite easily. Debugging them tends to be a bit of a challenge though - when you're running on the bare metal, you have no debugger to help you out - and even getting a "printf" to work might be a major problem!

SteveBaker (talk) 00:05, 30 July 2015 (UTC)

One interesting alternative is Tiny Core Linux. With Tiny core you just get the Linux kernel, BusyBox and (optionally if you want to run a GUI, FLTK). 9MB without a GUI, 15MB with. Add your application and you are done. --Guy Macon (talk) 00:18, 30 July 2015 (UTC)

If all you want is ultra lightweight cheapness - buy a "Pogoplug" for around $7 [13]. It's sold as a network backup box - but you can install Linux on it. With a USB port, ethernet and SD card slot and nothing else, it'll happily run Vim...if you have a way to SSH into it because it has no way to hook up a display.

This comes down to why our OP wants to do this. The cost of hardware that'll run an actual OS has fallen to essentially zero...so NOT running an OS has to be done for a reason. I can think of lots of reasons - security, for example. The less software that you didn't personally write, the easier it is to be secure. Maybe you want to be able to write poetry on your toaster - in which case Vim might be needed. But a $7 Linux box is hard to beat. The best advice here would come from understanding the true nature of the problem.

SteveBaker (talk) 02:41, 30 July 2015 (UTC)

Historical CPUs were much simpler than today's systems, too. It might have been possible to write code to the bare metal of an Intel 8051 or even an actual Intel 80386. Today, even trying to boot the CPU on a modern Intel Core Architecture programmable computer requires profound familiarity with a seven hundred page manual. A lot has changed: simple architectures gave way to complex systems tuned for higher performance. Even your main memory on a modern computer - say, one that uses DDR4 SDRAM - needs a software driver to initialize and calibrate it! Heck, even to retrieve a word of data from SDRAM is complicated: you need an elaborate control command sequence. Unlike SRAM, you can't just push an address into a register and read back data! You literally need to write an algorithm to retrieve a byte from an address. This is the sort of work that you don't even realize your operating system is doing for you. The hardware designs have evolved so that their feature-sets are well-matched to sophisticated operating systems, not to make life easy for bare-metal assembly code writers.

In the absence of an operating system, you cannot take advantage of such modern hardware. The job of the operating system is to relieve programmer pressure. You don't have to engage in the gritty details of the hardware in order to use it. You could pursue ancient computing machinery with simpler hardware interfaces, but you have to go back a long way to find machines that are architecturally "simple." Nimur (talk) 13:26, 30 July 2015 (UTC)

There are boot disks (or USB drives) that will boot up a PC and run a single program. They use some operating system, but don't have all the overhead of running full Windows, for example. They seem to avoid the periodic pausing that Windows seems to do when it checks for updates or whatever the heck it's doing. For example, if the program doesn't require Internet access, it can skip connecting to the Internet. One application is utility programs, like a disk reformat program, since you really don't want to reformat a disk while it's being written to. StuRat (talk) 13:45, 30 July 2015 (UTC)

Add User in Windows 8

How do I add a user account using Windows 8 on a laptop? I know how to get to the Control Panel to add a user in Windows 7, but I can't seem to navigate to a user accounts interface in Windows 8. Robert McClenon (talk) 22:11, 29 July 2015 (UTC)

Is what you are looking for under "PC Settings > Accounts"? I reached PC settings by just hitting the windows key and typing PC. Vespine (talk) 06:51, 30 July 2015 (UTC)

July 30

What language uses if!, enter!, exit!? II

This question reformulates my previous question with the same name above. I was quoting from memory, now I checked more details. There is a sample of code below.

I saw it in a French documentary about high-frequency trading on the stock market.

In what language is the code below written?

   Effectively buy
   IF Entry! >=0 THEN
       IF Entry! >0 THEN Prof! - (Curr! - A
   BS (Entry!))
       Entry! = Curr!
       Ext! = Curr!
   END IF

(...)

   LOOP
   CLOSE #1

(...)

   NEXT x!
   NEXT w!

Maxim! = -100 (...)

--Bickeyboard (talk) 11:26, 30 July 2015 (UTC)

This is BASIC Asmrulz (talk) 12:46, 30 July 2015 (UTC)

Specifically QBasic, judging by the compound IF, DO..LOOP and file descriptors Asmrulz (talk) 13:14, 30 July 2015 (UTC)

Even more specifically, the exclamation marks are type declaration characters, indicating that the variables are single-precision floats. Other such characters are # for double-precision floats, % for 16-bit integers, and & for 32-bit integers. Tevildo (talk) 16:01, 30 July 2015 (UTC)

Convert a PDF file to Microsoft Word

I have a PDF file. Is there any way to convert a PDF file to a Microsoft Word document? Thanks. Joseph A. Spadaro (talk) 18:15, 30 July 2015 (UTC)

That market is flooded. See lmgtfy.com/?q=convert+pdf+to+word 209.149.113.45 (talk) 18:40, 30 July 2015 (UTC)

Thanks, but those seem to do the opposite. Namely, take a Word document and convert it to a PDF format. I can already do that in Word itself (under "Save As" or "Export", I forget which). I am looking for the other way around: starting out with a PDF file and converting it into a Word file. Thanks. Joseph A. Spadaro (talk) 22:16, 30 July 2015 (UTC)

I do not understand how to think that way. For example, the third hit on the list for me is https://www.freepdfconvert.com/pdf-word which, if you go to the website, asks you to upload a PDF file and it returns a word file. The same with the other links https://www.pdftoword.com/ http://www.pdfonline.com/pdf-to-word-converter/ https://docs.zone/pdf-to-word ... as I said, it is a flooded market. 209.149.113.45 (talk) 12:48, 31 July 2015 (UTC)

For simple text copy-and-paste should work. For the general solution I would guess that there is a fundamental problem: The pdf might use a font that is not available on your computer, even if the structure of the document is converted correctly, line and page breaks will be off. 109.155.73.150 (talk) 00:07, 31 July 2015 (UTC)

You can "copy-and-paste" from a PDF file? You're kidding. I never knew that! Joseph A. Spadaro (talk) 02:59, 31 July 2015 (UTC)

No, I just tried that. And that is not what I mean. When I did a "copy-and-paste" from the PDF into a Word document, that simply "took a picture" of the PDF page and copied it onto the Word page. I want the actual text from the PDF (not just an image of the text), so that I can go in and change some words, add words, remove words, fix typos, etc. Can this be done? Thanks. Joseph A. Spadaro (talk) 03:03, 31 July 2015 (UTC)

You can copy and paste text from many PDF files. If you got an image when you did that, it's probably because the PDF only contains images (of text). You will have to use an OCR program to extract the text from the images, or transcribe them by hand. -- BenRG (talk) 03:49, 31 July 2015 (UTC)

It totally depends on how the PDF file was published. You can publish PDF files to be completely readable / copyable, or you can "lock them down" to the point where all you can do is take a screenshot. Vespine (talk) 04:17, 31 July 2015 (UTC)

This may be just an Acrobat Pro feature, but I am able to Save As -> Microsoft Word -> Word Document. Justin15w (talk) 16:28, 31 July 2015 (UTC)

That sounds perfect. I assume that Acrobat Pro is a product to purchase? And not free, like regular Adobe Acrobat. Correct? Joseph A. Spadaro (talk) 18:09, 31 July 2015 (UTC)

How to create "fillable" forms

Sometimes, I use "fillable" forms. These are forms that have most of the information already printed on them, but then I go in and "fill" various blanks (such as name, address, etc.). How does one create such a fillable form? Is there a way to do so, in Microsoft Word? Thanks. Joseph A. Spadaro (talk) 18:17, 30 July 2015 (UTC)

Specific instructions depend heavily on the version of Word you are using. In general, see the instructions. 209.149.113.45 (talk) 18:41, 30 July 2015 (UTC)

Thanks. I am using Microsoft Word 2013. Is the link above the applicable one? Thanks. Joseph A. Spadaro (talk) 20:09, 30 July 2015 (UTC)

Did you click on the link? 209.149.113.45 (talk) 12:49, 31 July 2015 (UTC)

Thanks. Yes. It seemed quite long and complicated. I wasn't expecting such a long and drawn-out process. I thought it would be maybe 2 or 3 quick steps. (Since I know nothing at all about creating a fillable document.) So, I was not going to go through that entire process if it did not work for my particular version of Word. Thanks. Joseph A. Spadaro (talk) 18:11, 31 July 2015 (UTC)

Cursing the Cursor

On my laptop running Windows 7, when the pointer stays over a control field for too long the field is "activated" as if I left-clicked it. This to me is a major nuisance, opening unwanted windows, etc.

There must be a way to disable this but I can't find it. Please help.

The pointer is moved around the screen by a touch-pad below the keyboard. I know where the touch-pad settings are located but they do not seem to govern what happens if the pointer is left too long in one place. Thank you, CBHA (talk) 20:23, 30 July 2015 (UTC)

I don't have a Windows system handy but I think this might be controlled by some handicapped assistance settings. Try looking for that while you wait for a better answer maybe. Dismas|^(talk) 21:07, 30 July 2015 (UTC)

Thank you. I found a program group called "Ease of Access" which seems to be relevant to the problem. I'll have to experiment. CBHA (talk) 02:11, 31 July 2015 (UTC)

July 31

Updating to Windows 10

I have four computers in my office and I reserved the Windows 10 upgrade on all of them. I upgraded two of them yesterday and one more today. On the fourth one, until recently, it said that Windows 10 was reserved and it would let me know when I could update. But starting an hour or two ago, the Windows 10 stuff is gone and checking for updates doesn't show anything. What happened? Bubba73 ^{You talkin' to me?} 01:53, 31 July 2015 (UTC)

You got and W10 ISO image? If any trouble was on the system, backup all data, and perform a clean install from the DVD, means all data is wiped from the computer until backup is restored. I recommend to do so, I never made good experience when upgrading an existing system of any operating system. --Hans Haase (有问题吗) 11:15, 31 July 2015 (UTC)

You can "manually" upgrade to Win10 or create an ISO using the tool on this site: http://www.microsoft.com/en-us/software-download/windows10. Justin15w (talk) 16:23, 31 July 2015 (UTC)

Two Questions About Windows 10 Upgrade

• 1. Is it true that the upgrade is only free for one year? After which, what happens?
• 2. I tried to upgrade, but before the upgrade was complete, my computer was unable to connect to the internet - I am thinking of compatibility issues with the wi-fi driver - so I had to perform a system restore. If I decide not to continue with Windows 10 after the first year is up, can I roll-back?

KägeTorä - (^影_虎) (もしもし！) 11:30, 31 July 2015 (UTC)

1. The upgrade is available for a year - i.e. if you upgrade now, you keep it forever (though it's bound to the device - if you get a new computer, you'll need a new copy). If you reserve your upgrade now, but don't actually upgrade by 29 July 2016, you would have to pay for a copy of Windows 10. See the footnote on this page [14] MChesterMC (talk) 14:25, 31 July 2015 (UTC)

2. According to BBC article, there's a rollback option available for 30 days after install (final line of the article). MChesterMC (talk) 14:53, 31 July 2015 (UTC)

A few questions about accessing audio streams and sending data to a USB port with python

Hello everyone. I have recently gotten a hold of a Raspberry Pi 2. I got it for a project that I am about to embark on. The project is simple; put this credit card sized computer into my electric guitar to run VST effects on my guitar's sound and output the result to the jack. The logistics behind this are quite complicated. The first thing i need to know is how to retrieve the PCM data from the DIN pin on the Pi's GPIO connectors. As a note, any code I will be writing I hope to only use python. If I absolutely have to, I will do some C++. My next question is how would I send data to a USB port on the Pi? I ask this because I am going to setup a feature that will allow me to plugin a USB chord from the Pi to my Windows PC to record the sound. I am completely new to Linux and have used windows pretty much my whole life. I have many more questions but this is just a start. Thanks for your help in advance. —SGA314 I am not available on weekends (talk) 15:41, 31 July 2015 (UTC)

Audio effects processing of this nature requires low latency. In plain english: every instant that the sound is delayed because of your input electronics, software, and output electronics, will cause annoying audible effects (similar to reverberation). This is not usually desired (at least, not for most guitar effects - a handful of effects intentionally use reverb or delay).

The short of it is that python is rarely a good choice for real-time hardware I/O. Python's runtime requires a buffer; the OS runtime requires a buffer; the audio device driver requires a buffer; the audio input hardware requires a buffer. Your processing may be nearly instantaneous; but the output must be buffered in Python, and again at the operating system runtime, and the device driver, and the hardware ... and before you know it, you've got 200 milliseconds of audible delay without even considering how long your effects processing calculations actually require.

Here's a website with details to set up low latency audio on a Pi. If you aren't already familiar with JACK on Linux, you'll want to brush up on that, too. Here is the introductory documentation. Nimur (talk) 16:03, 31 July 2015 (UTC)

I will be sure to take a look at those 2 very useful links. Ok so python no go. I know all about latency(this is why I love ASIO) and I messed with Jack a little bit yesterday. I take it that I will have to use some C++ or C, right? Because in the end, I am going to send the audio to a USB port on the Pi to be outputted to my Windows PC(Yes I know this I will have to write a driver to make it show up in the list of connect audio devices). For my next question, I will ask, how would I use Jack to access the audio coming from the DIN GPIO pin on the Pi? And would there be any way that I could send an analog signal to that pin and convert it to digital on the software level? This would eliminate the need for me to use an external Analog-to-Digital converter. —SGA314 I am not available on weekends (talk) 16:14, 31 July 2015 (UTC)

Where do you get this thing about quadruple buffering? There's no reason you can't get direct access to the audio hardware's buffers from Python. -- BenRG (talk) 16:50, 31 July 2015 (UTC)

Well how would you do that? —SGA314 I am not available on weekends (talk) 16:56, 31 July 2015 (UTC)

(edit conflict - same question, with fancier language):

Using which Python API may one access or control the Raspberry Pi audio hardware? Are you aware of any such method? If we remit ourselves from real software that does exist, and venture into the realm of theoretical programming, then of course the hardware can be controlled directly from python... or Lisp or Forth. In fact, one could run python on bare metal without an operating system, and a purist could access I/O using only native python code! But these implementations do not exist today, and creating an implementation in that fashion is not an accessible task for programmers with finite time. Nimur (talk) 17:00, 31 July 2015 (UTC)

I've never programmed for the Raspberry Pi, but buffering and Python have nothing to do with one another. Whatever you plan to do in C, you can do in Python with ctypes. The idea that Python requires a buffer, and the OS and audio drivers require their own buffers (but apparently only when you're using Python, not when you're using C), is something that you made up. There's no reality to it. -- BenRG (talk) 17:49, 31 July 2015 (UTC)

BenRG, direct access to audio hardware I/O in Linux occurs inside the kernel. (Here's the Raspberry Pi implementation for kernel-4.2). If you wish to bypass these software buffers, you must not use user-space APIs; you must not use ALSA kernel modules; you must directly write to the hardware. Are you seriously suggesting that python modules can be compiled and linked into a Linux kernel - and furthermore, that this task is accessible to a novice programmer? Nimur (talk) 19:03, 31 July 2015 (UTC)

So onto the next question. How would I send data to a USB port on the Pi. I would prefer to do this in python but because of latency issues, I don't think I will be able to do this in python. —SGA314 I am not available on weekends (talk) 17:14, 31 July 2015 (UTC)

After creating back-up disks, can I delete files on C drive?

I run an ASUS laptop with Windows 7. The computer did not come with installation disks. I was prompted to burn Windows restoral disks on 4 DVD's. At no point after the creation of the restoral disks was I prompted whether I wanted to delete those files (must be at least 12GB-16GB) from my hard drive. Can I free up that space? What files should I be looking for? I have googled this and searched windows help, but the kewy words are to vague to get a meaningful result. Thanks. μηδείς (talk) 19:12, 31 July 2015 (UTC)

The few laptops I've installed Linux on tend to have a partition on the drive that contains the installation software. I wipe that partition because it won't be used. If that is how your system is set up, you have to work with a partition manager to erase the partition and expand your main partition to use the space. 209.149.113.45 (talk) 19:30, 31 July 2015 (UTC)