Wikipedia:Reference desk/Archives/Computing/2009 December 7

= December 7 =

What is the Pipeline Depth of Intel Core and Nehalem CPUs?
I've scoured Google for the answer to this, but can't find any info. The closest I've found is the instruction pipleine depth for the fastest Pentium IV (30?). Thanks. —Preceding unsigned comment added by 24.8.105.96 (talk) 11:37, 7 December 2009 (UTC)


 * p258 of Inside the Machine by Jon Stokes says Core has a 14 stage pipeline (up from 12 in P6). As of its writing (its copyright 2007) he says Intel hadn't released a full breakdown of the Core pipeline. That book predates Nehalem. -- Finlay McWalter • Talk 12:13, 7 December 2009 (UTC)


 * Thanks, but that's the number of stages per instruction, right? I'm looking for the number of stages executed per clock cycle (the depth). —Preceding unsigned comment added by 24.8.105.96 (talk) 13:10, 7 December 2009 (UTC)


 * Intel Core 2 Microarchitecture Whitepaper] doesn't seem to have a solid number. The real answer probably varies based on current instruction, because new processor architectures are very effective at shutting down unneeded logic circuits and activating them as needed.  Actual numbers might be proprietary, which is why it's hard to find an answer.  Nimur (talk) 16:36, 7 December 2009 (UTC)


 * Would it be two per core? I'm talking about superscalar architectures and instruction pipelining. I read today about Intel's hyper threading technology, which executes two threads per core, although I read somewhere else that the Pentium (586) processor introduced superscalar execution with two per clock cycle. Then, the book said that the Pentium II (686) executed three per clock cycle, which really confused me. —Preceding unsigned comment added by 24.8.105.96 (talk) 00:44, 8 December 2009 (UTC)
 * No - "two per core" is roughly the number of pipelines, not the depth of each pipeline. Each core is a separate pipeline, in a handwavey approximate explanation.  In fact, each core contains multiple "semi"-pipelines (execution pipelines or "data flow graphs"), with a different pipeline used for different instruction logic execution.  These "semi-pipelines" are partially what make out of order execution possible - i.e. allowing a later instruction to progress through its logic before a prior instruction has returned its result.  But these logic circuits are really just separate functional units and do not actually independently have the capacity for a single, arbitrary instruction to complete.  The set of all logic pathways necessary to execute all possible next instructions is a "core."  The number of stages of logic is the depth of that core's pipeline.  The ambiguity in pipeline depth is because (as I mentioned above), different instructions have different logic complexities (e.g. an add instruction is simpler than an SSE 4 instruction, and so it has a shallower pipeline).   So if you want the depth of the pipe for the entire core, the best answer is to give you the deepest possible pipeline - almost certainly, this would be on one of the recent SSE or x86-64 extensions.  But most of the time, when simpler instructions are executed, an instruction does not have this long latency and does not traverse through that "worst-case" number of pipeline stages.  So, as always, it depends on your particular program and the exact assembly code that it compiles down to.  Nimur (talk) 05:08, 8 December 2009 (UTC)

VGA & SCART connections for monitor & PS2
Not exactly a computer question, though it is related. I've just got a playstation 2, which has a SCART connection for plugging into a tv (male scart into which the 3 audio & video plugs from ps2 plug). I don't have a tv with a scart or individual audio/video plugs, just a 15 pin VGA connector, which is plugged into the computer. I want to ask what type of adaptor connector I need to get to run my ps2 through the computor monitor. I was thinking of a VGA splitter though they only seem ot display a computer signal on 2 monitors rather than allowing you to choose which feed displays on 1 monitor. Any ideas? AllanHainey (talk) 13:23, 7 December 2009 (UTC)
 * If all the PS2 has is a SCART output or other component, composite or S-video outputs for TVs this isn't going to work with any passive connector. You're going to need some sort of active box cable of inputing a component/composite/S-video signal and converting it into a VGA signal. I came across this site from a search but can't vouch for their reliability, but that is the sort of thing you'll need. Alternatively if you have a computer you could use a video in card (including many TV tuners) but this is likely to introduce a fair amount of lag depending on the setup. Nil Einne (talk) 14:54, 7 December 2009 (UTC)
 * The PS2 has a Euro-AV connector plug with a scart socket (labelled VMC 91), this connector has 3 plugs going into it - red yellow & white 1 video & 2 audio. I've got a computer but I don't know how to run the PS2 through it. AllanHainey (talk) 18:22, 7 December 2009 (UTC)


 * Did you read Nil Einne's response? You need to get a converter box with a composite video input and which somehow outputs VGA video; or you need to get a video card for your PC that has composite video input.  Both options are probably more expensive than buying a used PS2.  Comet Tuttle (talk) 18:38, 7 December 2009 (UTC)
 * I did read the response, but wanted to clarify as its not just only a scart output. I see what's meant now though, I'd misunderstood as I'd focussed on the scart reference. I've got a video card in my pc, how would I go about checking to see if I can run the ps2 through it? Thanks AllanHainey (talk) 20:01, 7 December 2009 (UTC)


 * If the PC has a female RCA connector meant for video on the back of it, then you're in business. Some video cards have a weird proprietary connector on it, which you're supposed to plug another weird proprietary octopus-like splitter cable into, and that cable has the female RCA video connector you need.  If you have none of these, you'll need a video capture card &mdash; either a dedicated PCI card whose only function is to input video; or, more likely, a graphics card that also has a composite video-in connector.  The All-in-Wonder is the first that comes to mind but there are hundreds of other choices.  You should attempt to verify you like the quality of the end setup before you purchase, if possible.  Comet Tuttle (talk) 20:55, 7 December 2009 (UTC)
 * I don't reckon it has, there's a socket coloured yellow (and one white & red which my speakers are plugged into) but the plug is too loose in it & it doesn't have the raised ring of metal around the hole for the plug's ring to fit over. It doesn't work either when I plug into it so I don't think its an option. I've done a wee search and found | this product which looks like it may do the trick. Do you agree or am I missing something? AllanHainey (talk) 21:17, 7 December 2009 (UTC)


 * Looks good to me, though again I'd recommend you try it out before purchase because the results may not be what you are expecting. Comet Tuttle (talk) 22:52, 9 December 2009 (UTC)

dropbox
Does dropbox ever delete files, say if you're not using the acount for ages? This is on the free option —Preceding unsigned comment added by 82.44.55.75 (talk) 17:06, 7 December 2009 (UTC)


 * According to policies on their website: "Dropbox reserves the right to terminate Free Accounts at any time, with or without notice. Without limiting the generality of the foregoing, and without further notice, Dropbox may choose to delete and/or reduce: (i) any or all of Your Files if your Free Account is inactive for 90 days; and (ii) previous versions and/or prior backups of Your Files." Lukipuk (talk) 18:32, 7 December 2009 (UTC)


 * Your files will still be safe on any computers synced with dropbox. As long as the dropbox application is running, your account is active.  They will only delete files off their server and not your computer.  Additionally, dropbox also keeps backups of deleted files while your account is active.  If you are looking to permanently delete these files, this help page may be relevant. Caltsar (talk) 18:45, 7 December 2009 (UTC)

If the DVD Video specification is only licensed with a non-disclosure agreement...
Then how do we have open source DVD authoring software? 20.137.18.50 (talk) 17:16, 7 December 2009 (UTC)
 * The DVD spec isn't licensed with an NDA. You can create menus and encode to MPEG-2 using open source software.  However, the use of CSS to "protect" the DVD is where open-source software falls apart.  It's actually much harder to play commercial DVDs using open source software than to make a DVD for personal use.  This is assuming the software isn't using deCSS or a similar library.  This is why there is no DVD player included with Ubuntu and other high profile Linux distros.  That said, if you want to author commercial DVDs with encryption using open source software, I believe you are out of luck due to the CSS problem. Caltsar (talk) 19:22, 7 December 2009 (UTC)


 * I think that the secret parts of the DVD-Video standard all became public through legal reverse engineering. Once a trade secret becomes public, it's not a trade secret any more. Even if it was disclosed in breach of an NDA (which wasn't the case here), there are no legal restrictions on using the now-public information. Patents and the circumvention clause of the DMCA are bigger problems for open source free software, since they place restrictions on how you can use already-public algorithms. -- BenRG (talk) 21:06, 7 December 2009 (UTC)


 * So the statement "The specification is not publicly available, because every subscriber must sign a non-disclosure agreement." at DVD-Video is false? 71.161.40.220 (talk) 01:11, 8 December 2009 (UTC)
 * Phrased properly, "The official specification is not available..." may be accurate. A specification, which was the result of a now-infamous reverse engineering effort, is available and is the basis for some software.  The legal status of this now open-source code is disputed.  Nimur (talk) 05:15, 8 December 2009 (UTC)
 * There's a lot more to DVD-Video than CSS. It also includes the IFO file format, the navigation sectors in the VOB files, the subtitle and menu and closed-caption formats, alternate-angle interleaving, the disk file layout, and so forth, and of course the public parts (MPEG-2, AC3, UDF, DVD-ROM). As far as I know no part of the official NDA'd specification has ever been leaked. If it had, it couldn't be freely distributed anyway because it's covered by copyright. -- BenRG (talk) 07:11, 8 December 2009 (UTC)

Accessing files from a digital voice recorder
I have an old (pre-Vista) USB digital voice recorder that requires proprietary software to access the files on the drive. It isn't set up to be accessed like an external drive, but there aren't any drivers for the device for any OS after XP. There is only one computer using XP in the house left, and it's on its way out. Is there a way to "hack" into the device to get the files off of it, without having the appropriate drivers for Vista (which I have now) or 7 (which I will likely have soon)? Thanks &mdash;Akrabbimtalk 18:45, 7 December 2009 (UTC)


 * What make and model is it? -- Finlay McWalter • Talk 19:09, 7 December 2009 (UTC)
 * Olympus, VN-480PC. Their website has an update for the software that claims to make it compatible with 32bit Vista, but the driver installation has always failed with locating the .inf file or something. And even if that did work, I would still like to find a solution for my 64bit lappy. &mdash;Akrabbimtalk 19:18, 7 December 2009 (UTC)


 * Have you considered installing a virtual machine like VirtualBox, installing Windows XP and the device's XP drivers on the VM, and using the VM every time you want to access the device? Comet Tuttle (talk) 20:36, 7 December 2009 (UTC)
 * I think 7 has a "XP Mode" that would let you do that. Thanks, 174.114.4.18 (talk) 20:43, 7 December 2009 (UTC)


 * Windows Virtual PC is our article on Windows XP Mode. Comet Tuttle (talk) 21:34, 7 December 2009 (UTC)
 * I might just have to resort to that. Thanks. &mdash;Akrabbimtalk 23:41, 7 December 2009 (UTC)

Turning off one of two monitors?
I've been assigned to work with a Windows XP desktop computer that is equipped with two monitors, set to work as one wide one. Because my tasks are unrelated to the purposes for which the double-monitor setup was put in, I only need one monitor, and having the second is distracting. Is there any way to have the computer go to one monitor in such a way so that it stays that way until I turn it off, but so that it defaults to having both monitors whenever the computer is turned on? I've tried turning off the power button for one monitor, but that doesn't help at all. Nyttend backup (talk) 19:45, 7 December 2009 (UTC)


 * Control Panel -> Display, then click the Settings tab. You'll see a drawing showing the two monitors.  There is some setting where the computer will "Extend the desktop onto this monitor" &mdash; at least, that's what it's called in Vista (sorry, that's what I'm using at the moment, no XP machine with 2 monitors in front of me right now) and you should be able to turn that setting off.  Comet Tuttle (talk) 20:13, 7 December 2009 (UTC)
 * Monitor #2 is disabled, just as I hoped it would be. Now we'll have to see if it comes on automatically when the computer is restarted.  Thanks!  Nyttend backup (talk) 20:20, 7 December 2009 (UTC)
 * Restarted, but the monitor is still off :-( I guess I'll have to leave a note on how to turn it back on.  Thanks again!  Nyttend backup (talk) 20:25, 7 December 2009 (UTC)


 * I don't think monitor and screen resolution are a "per-user" setting. Consequently, it's probably impossible to set automatic resolution changes or disable monitors based on the login.  You might be able to get third-party software to do this, but I would just allow users to change settings per their individual needs.  This tutorial and this knowledge-base article from Microsoft are good tutorials - you can send those to whoever might need to change settings.  Nimur (talk) 20:47, 7 December 2009 (UTC)
 * While this isn't an ideal solution, you could set the desktop image to be solid black on the secondary monitor. It won't be off, but you also shouldn't have much to distract you as long as you keep in mind that your workspace extends further to one side than you want it to.  This will have the benefit of not messing with system settings, and it requires no real tinkering. Caltsar (talk) 21:06, 7 December 2009 (UTC)

Thanks for the input. I'm just volunteering at my local historical society, and I know that they don't have money to spend just for this (definitely minor) purpose. Somehow, a maximized window only fills the default left screen (although it can be dragged into the right), so filling the right screen with black wouldn't help me any more than turning it off — the main thing is that I generally close a window by moving the mouse up and right, and that obviously doesn't work when the little X is effectively in the middle of the top. Nyttend (talk) 03:53, 8 December 2009 (UTC)
 * Try training your fingers to use alt-f4 to close things. Or, try making the right monitor your main one, the ignore the left one. (And I fixed your unindent template.) Ariel. (talk) 10:07, 8 December 2009 (UTC)