Wikipedia:Reference desk/Archives/Computing/2015 November 1

= November 1 =

Connection between the the desktop and the mobile version of all OSs
Is there any connection between the Apple's and Microsoft's OSs - desktop and mobile? (within it's own products obviously). I was thinking about whether they are like Linux/Android. Developing an OS is hard, so maybe both companies though about adapting their existing desktop OSs for the mobile devices. — Preceding unsigned comment added by Denidi (talk • contribs) 02:10, 1 November 2015 (UTC)


 * It might work better to do the reverse, start with a nice tight mobile O/S, then add in all the bloatware they feel they need in a desktop O/S. (Or, better yet, just keep it small and fast.)  StuRat (talk) 03:08, 1 November 2015 (UTC)


 * Apple's desktop OS, OS X, is based upon Unix, and so is ironically closer to Android than it is to iOS. Rojomoke (talk) 04:21, 1 November 2015 (UTC)
 * Linux is not the same thing as Unix... and furthermore, Android is not the same as Linux... I believe your assessment is generally inaccurate. Nimur (talk) 11:25, 1 November 2015 (UTC)
 * As far as I know both OS X and iOS use the Mach kernel. Windows Phone 8 and later use a version of the NT kernel, and consumer versions of Windows since XP are also based on NT. So current versions of the desktop and phone/tablet OSes do use the same or at least similar kernels. -- BenRG (talk) 05:02, 1 November 2015 (UTC)
 * OS X uses xnu, which is largely comprised of open source software. Inside xnu is the code that implements mach, and there is also code that implements the BSD interface, and the I/O Kit interface.  In some documentation, including the Kernel Programming architecture overview, it is these three pieces of software (mach, BSD, I/O Kit), that are defined as "the" kernel or "the kernel environment" on OS X.
 * In some common technical parlance, "the kernel" on OS X might be construed more broadly, including other projects and kernel extensions at large.
 * I am not aware of any public documentation regarding the iOS kernel.
 * Nimur (talk) 11:25, 1 November 2015 (UTC)
 * Not much from Apple perhaps, but I believe some info is known from people who've studied it via jail broken devices and the like. See e.g. and Darwin (operating system). Shared vunerabilities like  also give some clue. Nil Einne (talk) 12:34, 1 November 2015 (UTC)
 * At one time, Apple proudly announced iOS as a version of OS-X. The underlying technology is the same - as described above, it's a microkernel with a BSD personality on top. The original higher level frameworks of OS-X were derived from NextStep, also a BSD-based operating system - that is the reason why the basic datatype are called e.g.  or  . Later frameworks are somewhat different between iOS and OS-X (with e.g. support for touch in iOS and much more focus on screen sharing multi-tasking in OS-X), but there is a certain convergence. It's certainly true that a modern iPhone is a UNIX-based parallel supercomputer. --Stephan Schulz (talk) 19:22, 1 November 2015 (UTC)

windows failure
My computer wont boot. Says it cant find 'hal' file. What is this file and what does this message say about my hdd..? [Originally posted by 31.55.64.216 (talk) ] Tevildo (talk) 11:17, 1 November 2015 (UTC)
 * This is the file that manages the Hardware Abstraction Layer. See this thread on the Microsoft support forum for instructions on how to fix it. You'll need a bootable XP disk (and I'm sure many people will recommend that you upgrade from XP to a more modern OS). Tevildo (talk) 12:05, 1 November 2015 (UTC)


 * I had the exact same problem a week or so ago. The disk had gotten mildly corrupted due to an unclean shutdown in the midst of an earlier boot cycle.  The straightforward fix (which was straightforward for me and the colleague who helped me, but might not be so straightforward in your situation) was to temporarily connect the disk -- as a secondary disk, that is -- to another, working Windows computer, and boot.  The working computer recognized the damaged disk and automatically repaired it for us, after which we could reconnect it to the original machine whereupon it booted normally. —Steve Summit (talk) 15:42, 1 November 2015 (UTC)

formal name of device that connect to usb and boost incoming wifi signal, increase power of signal coming into device
OP curiousMahfuzur rahman shourov (talk) 14:17, 1 November 2015 (UTC)


 * Shouldn't think there is one. Such an amplifier would also amplify the noise equally in proportion to the signal. So no point.--Aspro (talk) 18:26, 2 November 2015 (UTC)

Ghost devices on my network
Many moons ago, I set the lease duration in my router's DHCP server to "Forever". Using Advanced IP Scanner, I now see a couple of ghost devices on my network. One is a laptop that has been turned off for about six months and will likely not be used again. In addition, there are two IP addresses associated with the same device (a network extender), only one of them actually being used. I would like to get rid of the ghost devices to clean things up and free up those IP addresses. I changed the lease duration to 30 minutes and then waited 30 minutes, and I have rebooted the router several times, but the devices remain. Is there any solution? The router model is Belkin F9K1001v4. 68.97.47.54 (talk) 15:56, 1 November 2015 (UTC) It does make me wonder what they were thinking when they included the "Forever" option. It appears to be essentially the same as a static IP, except that (1) a static IP address is chosen by the network admin, not the DHCP server, giving them more control, and (2) a static IP can easily be removed when no longer needed. I know I could choose to ignore the ghost devices until I replace the router, but I'm sometimes a little compulsive about little things like this, as well as wanting to better understand what's going on. The router has a DHCP client list display, but it doesn't allow deletes and it doesn't show these ghost devices anyway (I see them only in Advanced IP Scanner). I had thought about the factory reset, but disabling the DHCP server hadn't occurred to me. I'll consider both options. Thanks to all for the help. 68.97.47.54 (talk) 02:04, 2 November 2015 (UTC)
 * Changing the lease duration will only affect new leases. There's no way for the server to tell clients that old leases that it said were valid forever are actually not, and no way for the server to know that clients with such leases won't rejoin the network someday, so it can never safely reassign those IP addresses.
 * I've used routers that let you manually delete DHCP leases from the web interface, but I assume you looked for that. You could try disabling the DHCP server entirely, rebooting the router, and reenabling it, but I don't know whether that will work. In the worst case you could factory-reset the router and reenter all your other settings. -- BenRG (talk) 18:51, 1 November 2015 (UTC)
 * Instructions on resetting the router to factory default setting are on page 22 of [ http://www.belkin.com/networking/manual/MAN_F9K1001_8820-00773_RevA01_N150_Router.pdf ]. --Guy Macon (talk) 19:46, 1 November 2015 (UTC)
 * Unless you've run out of assignable IP addresses on your LAN (or expect to), there's no reason to bother. The router isn't going to suddenly stop working because it can't count all the addresses it assigned, or something else that might happen to a human. In a related vein, this is a good teachable moment. Computers are stupid and do exactly what you tell them to. It turns out that when you tell them "forever", they actually take it literally, as opposed to its common meaning of "an indeterminate but finite amount of time". This is one reason why programming is hard, because you have to think literally. The computer can't guess at what you "really meant". --71.119.131.184 (talk) 23:10, 1 November 2015 (UTC)
 * Speaking of teachable moments, it's possible to have spent 30 years in various computer- and software-related jobs, giving a good understanding of computers in general, and still be fairly clueless in many, many specific technical areas (I know even less about JavaScript and have never owned a smartphone). The word "Forever" was chosen for this use by humans, not computers, and it could mean whatever those humans wanted it to mean. But no offense taken, I know you meant well.
 * Static and "forever-DHCP" addresses aren't the same thing. With a static IP, the router would not be expected to use the DHCP protocol to tell the client what IP address is has - that would be left to the client's /etc/host file (or whatever mechanism it uses).  With a "Forever" IP address, the client doesn't have to be aware that it'll always have the same address, and can continue to use DHCP protocol to learn what IP has been permanently assigned to it.  Also, even though the address never changes, it was still picked by the router.  With a static IP, the administrator gets to decide what address to use...and sometimes one might choose a "vanity" IP address like 192.168.1.123 that might be easier to remember.  SteveBaker (talk) 04:53, 2 November 2015 (UTC)
 * Adding to my sense of wonder (bewilderment), several different people have accessed my network using their smartphones since I set the lease interval to Forever, but there are no ghost devices for them. Maybe smartphones do an explicit release on disconnecting from the network, while other devices do not? 68.97.47.54 (talk) 06:10, 2 November 2015 (UTC)