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March 20

Networks project

I have to do a network project for college and I'm at a loss with it. I've included what I have done below. Despite it's short length I've been working at if for a while. The brief is intentionally vague, It's basically just design a network for some place under the headings, General Analysis, Network Topology, Manual and Special Notes. I think I'll be OK with the Network Topology. I was just hoping people could read over it quickly and make suggestions on what I could add, or if I have anything wrong. Links to online resources would be helpful also. It's a FETAC 6 Network course.

General Analysis of Requirements

This is a project to design a new network for The River Lee Hotel. The Hotel has 182 bedrooms, features an executive floor and a conference center. The hotel measures 70 × 20 meters and is approx. 5 floors tall. The entire hotel including all the rooms will need to have access to WiFi internet. Staff will have 3 computers at the front desk. These will be connected to an onsite server which houses the hotels database. The conference hall is equipped with several Ethernet ports to provide a high quality network access for business people in addition the WiFi. The internet is provided by Eircom, through a DSL cable.

Network Topology

---

Manual

The network is divided into 3 subnets.

1. 192.168.0.0/24 Is the subnet for all the staff computers and servers.
2. 192.168.1.0/24 Is the subnet for the conference room.
3. 192.168.2.0/24 Is the subnet for WI-FI devices to use.

• All the staff computers (including the server) are connected to a switch. This switch is connected to a wireless router.
• Because the range of the WiFi router is insufficient to cover the entire hotel, a Netgear Universal WN3000RP Wi-Fi Range Extender is used to extend the range of the network easily.

IP Address

• The routers inbuilt DHCP server hands out IP address to any wireless computers that want to connect. The range of IP addresses is 192.168.2.1 to 192.168.2.250 allowing 250 wireless devices to connect at the same time. The wireless connection is not secured to allow guests to connect to the network easily.
• Devices on the staff network are all given static IP addresses.
• The router is given the IP address 192.168.X.251/24 where X is the appropriate subnet number. This router connects to the Eircom DSL router.

Cabling

All the networks are wired together using standard CAT 5E cables.

Thanks, 83.70.217.140 (talk) 01:31, 20 March 2013 (UTC)

Putting an entire hotel on one DSL connection to the wider internet would give disappointing results. Find out if your provider offers any faster connections. EdJohnston (talk) 05:24, 20 March 2013 (UTC)

1) The word "hotel's" needs an apostrophe, since it's possessive, not plural.

2) I'd be wary of range claims for WiFi. They probably say "up to X" range, which means with a clear line-of-sight and ideal conditions. What you need to know is the minimum range, in the actual hotel. I'd do testing in the actual hotel to determine the average range, then provide a fair margin of error beyond that.

3) Can't you estimate the length of the cabling ?

4) If this is an existing hotel, versus a new construction, then the issue also comes up as to how to get the cables into the walls. You could tear out the walls, but this is time-consuming, disruptive, and expensive. Some type of surface-mount wiring in attractive conduit might be acceptable, at least in the conference center and office areas. StuRat (talk) 09:16, 20 March 2013 (UTC)

Got to second the bit about speed. It is a real problem as hotels can be in rather inacessible places as far as broadband is concerned but you just have to cater for people bringing along ipads and smartphones. The notebook use is inconsequential compared to that. Dmcq (talk) 22:54, 23 March 2013 (UTC)

An assembly example that seemed to be doing something the long way

I was looking at a Microsoft assembly example that did the following: 1)It declared in the uninitialized data .data? section a dd variable retvalue 2) At the end of the program, it moved retvalue into eax 3) it XORed eax with itself so that eax had all 0s 4) It invoked ExitProcess with eax as its one parameter (invoke ExitProcess,eax). My question: why do all that when you could just have at the last line 'invoke ExitProcess,0' ? — Preceding unsigned comment added by 67.163.109.173 (talk) 02:20, 20 March 2013 (UTC)

It would help to see the example. Do you have a link? RudolfRed (talk) 02:32, 20 March 2013 (UTC)

http://securityxploded.com/assembly-programming-beginners-guide.php 67.163.109.173 (talk) 02:37, 20 March 2013 (UTC)

You have the mov backwards; in that syntax, the destination is on the left. The return value for stdcall is stored in eax, so it's saving the return value before exiting the process. (This is still pointless, of course, without more to the program!) As for XOR, xor eax,eax — push eax is only 3 bytes, whereas push 0 is 5. For a trivial program, of course, this doesn't matter, but shortening the program text is important for caching in general. --Tardis (talk) 05:13, 20 March 2013 (UTC)

push 0 only takes 2 bytes (6A 00). -- BenRG (talk) 17:50, 23 March 2013 (UTC)

That's "push imm8"; I could be wrong, but I think it'll get promoted only to 2 bytes of stack space (in the 32-bit mode we're presumably using). --Tardis (talk) 23:58, 23 March 2013 (UTC)

No, it pushes 16/32/64 bits in 16/32/64 bit mode unless an operand size override (66) is present. -- BenRG (talk) 22:54, 26 March 2013 (UTC)

That's not an official Microsoft code sample, it's just code by some guy. The rest of the tutorial seems pretty badly written as well. -- BenRG (talk) 05:37, 20 March 2013 (UTC)

That's not Microsoft code sample, but it is Microsoft assembly sample, with syntax parentheses on (Microsoft assembly), i.e. MASM, not (Microsoft sample). --CiaPan (talk) 07:56, 20 March 2013 (UTC)

Yes, I meant it was for use on a Microsoft system, not made by Microsoft company. 67.163.109.173 (talk) 13:51, 20 March 2013 (UTC)

I can answer two bits of that: 1) "XOR AX, AX" is the fastest way of getting a 0 in the AX register on an 8086 CPU (on newer CPUs, there are methods that are as fast, but nothing faster, so the tradition of using XOR to zero has stuck around). 2) "invoke" is an assembler-specific directive that turns into a rather amazing amount of machine code. I don't remember the details of the STDCALL calling convention, but I'm fairly sure that one of the instructions "invoke" hides is a "push", and as I recall, a "push REG" is faster than a "push IMMED" on (at least some) X86 CPUs. --Carnildo (talk) 02:11, 22 March 2013 (UTC)

I think people still use XOR or SUB to clear a register because it's shorter (at 2 bytes) than any other approach. -- BenRG (talk) 17:50, 23 March 2013 (UTC)

It used to be that you needed to clear a whole register using XOR or else accessing bytes via it went quite slowly. The wonders of optimisation. Dmcq (talk) 22:57, 23 March 2013 (UTC)

That's still true, but it's writing part of the register and then reading a larger part that causes the problem (a partial register stall), not the other way around. -- BenRG (talk) 22:57, 26 March 2013 (UTC)

Reduce background proccess priority/improve user experience in Windows XP

My mum's computer has the following specification:

Windows XP Home OS MSI-7100 motherboard AMD Athlon 3200+, 2 GHz CPU 2 GB RAM NVIDEA GeForce 6000 GT graphics card

When copying files from Android MicoSD card to system disk, the user experience degrades to an unnacceptable level. Specifically, the mouse cursor movements are delayed and videos played on YouTube stutter. CPU usage is below 100% most of the time.

How to resolve so that user experience is not impacted during this and similar background operations? How to prrioritise user experience at all times? --92.28.82.133 (talk) 09:45, 20 March 2013 (UTC)

You can try bringing up the Task Manager and lowering the priority on those processes, but, honestly, I haven't noticed much difference when I've tried that. My suggestion: Just wait until she's done with the computer to do mass copies. StuRat (talk) 09:56, 20 March 2013 (UTC)

Has the computer been on for a long time? In my experience with my old computer running XP, if I kept it running for over one week then performance would begin to degrade exactly as you describe. -- 143.85.199.242 (talk) 15:44, 20 March 2013 (UTC)

That's never been my experience. I think you must have been running some background task with a memory leak. -- BenRG (talk) 18:13, 21 March 2013 (UTC)

Windows copy is very bad. Try using FastCopy 92.233.64.26 (talk) 10:44, 20 March 2013 (UTC)

While I agree the native windows copy is not the best (I personally use Teracopy) I doubt it's the problem. It is highly unlikely that copying from a USB device would degrade performance as described. The system drive (probably SATA) has a much higher data throughput than a simple SD card. The bottleneck would be at the card - not the system drive. Secondly, at a hardware level, copying is not CPU intensive. CPU usage should be around 10% - if that. I would first do a "chkdsk /f" of both the system drive and the SD card. File system errors could cause high CPU usage. If the system drive is very full (85% +) there is likely to be a lot of file fragmentation. I would use MyDefrag to sort that out. If your drive is very full you can quickly free up some space by turning System Restore off - this will delete all your old restore points. Be sure to turn it back on. Only do this if you are sure your system is virus/malware free and you won't need to roll back.

I have encountered PCs with 2 different kinds of antivirus and Windoze Defender running all at the same time. Not a good idea. I have also encountered scheduled antivirus scans kicking in in the background and "killing" performance.

You may get a slight performance increase by going to the Control Panel -> System -> Advanced -> Performance Settings -> Adjust for Best Performance. (It will display XP in the Classic Win98 look). 196.214.78.114 (talk) 11:38, 20 March 2013 (UTC)

Sounds to me like the usual system performance slowdown experienced by older Windows machines. Have a look around for unnecessary background apps (do you really nead to check for updates for Windows, and your anti-virus, anti-malware, flash, adobe acrobat, realplayer, skype, etc... every time you log in?), resource hogs (Flash video is one of these so perhaps best to avoid YouTube), things that use a lot of CPU and/or memory, etc. Empty the temporary file locations and defrag the hard drive. Make sure there is no malware using up the resources to send out spam mails. Reinstalling Windows will almost certainly speed it up again, but that is a pretty drastic choice and perhaps the last thing you should try (rather then the first thing you should try). Astronaut (talk) 17:42, 21 March 2013 (UTC)

I think antivirus software is the most likely culprit. Try disabling it while copying files and see if it helps. Unless you're not running any, in which case ignore me. -- BenRG (talk) 18:10, 21 March 2013 (UTC)

Thanks everyone! I optimised for best performance via Control Panel > System > Advanced > Performance/settings, stopped certain programs running at start-up (including Ad-Aware Antivirus since I already have MS Security Essentials running) including some accessed via Start > Run > msconfig > Startup. I also defragmented the System drive with MyDefrag's "Monthly" option (which will probably be run annually!) 78.150.234.51 (talk) 22:54, 23 March 2013 (UTC)

Codecademy for IE8

Hi,

I am looking for a website similar to codecademy to ideally learn Python or a similar language. However my PC at work has IE8, which is as you may know a dreadful browser and not supported by codecademy. I am unable to install a better browser due to my company's insistance on using the most backward software available, so I am looking for a similar website compatible with IE8, does anyone know of any good ones? Thanks! 80.254.147.164 (talk) 10:11, 20 March 2013 (UTC)

Weird, my question has only just become visible to me today.... (OP here) 80.254.147.164 (talk) 13:06, 21 March 2013 (UTC)

Possibility of Recovering a Canceled Wikipedia Edit

Hello, I was wondering if there was any way that I might be able to extract the large amount of content that I had entered into the text box used by the mathematics reference desk to store pending section additions from session data stored either on my computer or on Wikipedia's servers. I accidentally lost it in some clipboard hi-jinx that intervened with the usual copy-and-paste operation that I use to save this content in a local TextEdit (.txt) file. Apparently, my '⌘-C' keystroke did not register with the computer which I was using and therefore did not refresh the clipboard as I was expecting it would.
Please help me,
RandomDSdevel (talk) 15:03, 20 March 2013 (UTC)

Are both of the programs you used to type still open from the time you used them to type the content? Try using the Undo command (⌘-Z/Ctrl-Z) and see if you can recover any content. When I copy text from one area to another, I like to Cut it from the originating program, then immediately undo it in the same program (⌘-X/Ctrl-X, then ⌘-Z/Ctrl-Z). That way, I know that, if it was "removed" from the text editor, it was successfully copied to the Clipboard, while the text is still there because I undid it if I happen to need it later (at least, that's how it works with Windows -- I don't use Macs). Let me know if I'm misinterpreting your problem. -- 143.85.199.242 (talk) 15:31, 20 March 2013 (UTC)

I do the same thing. Copy just doesn't cut it, as far as telling me it worked successfully. :-) StuRat (talk) 17:31, 20 March 2013 (UTC)

No, I closed both programs (Safari and TextEdit) before logging out last night and only realized that my text didn't copy successfully this morning when I looked back at my dump file today. Instead of the text that I had expected to find upon opening the file, I found that the text file now contained what had previously been copied to the clipboard. Although I doubt that even the most remote possibility exists that I might be able to recover my data through some sort of Safari or Wikipedia server history or cache file, could you help me figure out if I could?

RandomDSdevel (talk) 16:00, 20 March 2013 (UTC)

Was the text ever saved ? If so, there might be a backup copy, if that application keeps them. If not, I'm sorry, but I think it's gone for good by now. StuRat (talk) 17:31, 20 March 2013 (UTC)

• I usually edit in a Safari browser, and unless I either close it actively or back over an edit and start forward again, overwriting it, the edit is still there even if I have opened twenty new pages before returning to it. I am not quite sure what you mean by cancelling an edit. as long as the browser is still open you should be able to return to the edit unless you have already gone to an earlier state before the edit and started moving forward by opening new pages, rather than using the previous and next page arrows. μηδείς (talk) 13:00, 21 March 2013 (UTC)

I know it's a little late now, but in the lost horse/barn door security paradigm, you might investigate Lazarus browser extension, which exists to solve the problem of restoring vast quantities of text box data that vanished when the browser hiccups (we've all been there). Just installed it myself and haven't tested it, though. Gzuckier (talk) 17:05, 21 March 2013 (UTC)

Thanks for all of your help, everybody. I have now confirmed my suspicions that my text data is unrecoverable, but have, per Gzuckier's instructions, installed the Lazarus extension in my user instance of Safari as a fall-back mechanism for any future situations in which the event that prompted this post happens again.

– RandomDSdevel (talk) 20:44, 21 March 2013 (UTC)

Traceroute

Resolved

For many years the first hop on my traceroutes has always been "10.224.208.2", which is a private ip address and basically seemed to be synonymous with localhost. Example;

Tracing route to example.com [192.0.43.10]
over a maximum of 30 hops:

  1     7 ms     9 ms    10 ms  10.224.208.2

However, today the first hop displays as "ComputerName [0.0.0.0]" (ComputerName being the name of the computer). Example;

Tracing route to example.com [192.0.43.10]
over a maximum of 30 hops:

  1     7 ms     9 ms    10 ms  ComputerName [0.0.0.0]

I don't understand why this has changed, since I have not knowingly changed any settings or hardware. Nor do I understand why the computers apparent local ip is now "0.0.0.0".

The computer connects via ethernet cable directly to a cable modem, there are no routers or anything else.

I want to learn why this change happened, and if possible return to having 10.224.208.2 as the first hop on the traceroutes

Thank you. 92.233.64.26 (talk) 16:45, 20 March 2013 (UTC)

I can't answer the question, but I would have expected the first hop to be your default gateway rather than localhost (check with ipconfig if you're running Windows). Is this your own private network or at work? AndrewWTaylor (talk) 17:14, 20 March 2013 (UTC)

Sure we can answer the question! 10.224.208.2 is an address on your private network, not on the public internet. It's usually in your LAN, but it doesn't strictly have to be. This "Class A" address space is a very old convention, specified by IANA, "following the standards set by RFC 1918 and RFC 4193" (meaning, it's a convention amongst routers to help cooperate when they're all on the internet; but is not actually a technical requirement of The Internet Protocol). Still, you'd be hard-pressed to find any router in the world - unless you're a specialist in network engineering - that uses 10.x.x.x for anything other than private or local routes. Lastly, just because you don't see a separate box doesn't mean there isn't a separate host in your cable modem. It's very possible that your "modem" is actually many devices in one box: a router, a residential gateway, and a modem, and an RF transceiver. It's non-trivial to say where the 10.224.208.2 host is, geographically - it could be the first router on your link to the Internet Service Provider; or it could be a miniscule little IP-enabled microcontroller inside your modem box. Nimur (talk) 03:33, 21 March 2013 (UTC)

Thank you for the reply but I am not sure that it answers the question. I understand that 10.224.208.2 is private ip address, as I said that in my original question, but why has it suddenly changed to 0.0.0.0? And how can I change it back? The cable modem does not have any router functions at all, it has only 1 ethernet port which 1 computer is directly connected to via an ethernet cable 92.233.64.26 (talk) 12:36, 21 March 2013 (UTC)

The way tracert / traceroute works is that it sends out packets with variable time-to-live settings, and watches for ICMP "time to live exceeded" packets scattering back from routers in the network. It then reports the source IP address that those packets contain; there's no further interpretation to be done (bar the option of a reverse DNS to show a hostname). In your case, the first hop in the IP connection used to report 10.224.208.2, now it's reporting 0.0.0.0. So that first hop device (not your computer) has changed somehow. I've no direct experience of DOCSIS connections, so I don't know if the first device is the cable modem or the CMTS. If it's the former, then the cable company may have upgraded the modem's firmware remotely (which is often something they do with modems they supply); if it's the latter case then they may have changed the configuration of the CMTS. -- Finlay McWalterჷTalk 13:59, 21 March 2013 (UTC)

I see you're on VirginMedia in the UK. Looking at Virgin's forums, I see the change is apparent for many people (perhaps everyone). Looking at this 2010 post, the first IP address reported is in the 10.x.x.x private network. The posting by swt4ajp in that forum page briefly shows some clues as to the structure of Virgin's IP network; it looks like they're doing intra-Virgin routing (for iptv and iptelephony) on 10.x.x.x, and mapping you into a public 92.x.x.x address when you go out to the internet proper. But at some point they've changed - this 2013 post the person gets 0.0.0.0 like you. That doesn't mean the 10.x.x.x addressing has necessarily gone away (if you do a netstat when you're watching iptv, you might still see connections to Virgin's media servers on another 10.x.x.x address), but that the first hop (which, if you don't have a "Superhub", seems to be the CMTS) is responding differently than it used to. If you don't have a performance issue, then you can put this down as a nebbish curio; if you do then you should probably yell at Virgin's support people. -- Finlay McWalterჷTalk 14:46, 21 March 2013 (UTC)

Okay I understand now, they've probably changed something remotely at the cable headend that has caused this, that explains how it happened without me doing anything at my end. I checked the firmware version and it is the same as before. I'm still a little confused as to why the name of my computer is being arbitrated to this first hop though, if the first hop is actually the modem or CMTS 92.233.64.26 (talk) 17:03, 21 March 2013 (UTC)

When traceroute receives the IP packet of the remote host, it's running it back through the name client (DNS, usually) to try to resolve that into a printable name. It's probably calling getnameinfo. I guess if getnameinfo is fed the bogus address 0.0.0.0 it's returning the name of your computer. -- Finlay McWalterჷTalk 17:10, 21 March 2013 (UTC)

Yes, I just checked (with gethostbyaddr) and Windows returns the localhost name when fed 0.0.0.0  ; Linux, given the same info, errors with "unknown host"). -- Finlay McWalterჷTalk 17:16, 21 March 2013 (UTC)

Thank you for explaining, I marked this question as resolved now 92.233.64.26 (talk) 17:28, 21 March 2013 (UTC)

I have a question (about Wikidoc)

I found a E-mail address to someone on wikidoc. and sent the message. In case the person is not currently useing wikidoc. How by knowing there E-mail and full name. On wikidoc can I try to get more information on them to contact them. Like can I get a hold of a another E-mail address or phone number. Does anyone know — Preceding unsigned comment added by 76.191.18.223 (talk) 20:29, 20 March 2013 (UTC)

Wikidoc is not connected to Wikipedia, despide of having a common wiki in their names. Ask directly there how to contact any member. Wikipedia doesn't even have a page about Wikidoc, although it has a page about everything else. OsmanRF34 (talk) 23:20, 20 March 2013 (UTC)

Or maybe you could ask User:Wiki Doc about it.

I added to your title to make it actually useful. StuRat (talk) 06:59, 21 March 2013 (UTC)

March 21

How much can Javascript and other types of scripts do?

For example, can it reveal my true IP address, physical address, mu username, the last site I have visited, and where I download my files to?--Inspector (talk) 02:52, 21 March 2013 (UTC)

You're invalidly conflating Javascript, which is a programming language that happens to (usually) be interpreted, with the security model of its script host - often your web browser. Technically, Javascript is a Turing complete language. Roughly speaking, that means that it can do anything that any other programming language can do. In practice, it is usually sandboxed. For a quick overview of the security model (sandboxing) of, say, Firefox, read the Firefox promotional literature on security or the much more thorough and technical Mozilla/Firefox/FirefoxOS Security model for developers, and the Document Object Model. Nimur (talk) 03:25, 21 March 2013 (UTC)

Great answer for a question that should really be at the computing RD. Vespine (talk) 03:56, 21 March 2013 (UTC)

And so we can set constraints to some actions just like what we do to other programs? Actually, what pieces of information are available for reading and sending for a javascript or other scripts while running on my computer?--Inspector (talk) 06:58, 21 March 2013 (UTC)

• For the "enthusiast" - MozillaZine Security Policies wiki
• For the "developer" - Configurable Security Policies

Of course, these only apply to Mozilla products like Firefox and Thunderbird; but it will help get you into the correct frame-of-mind to pursue this investigation on other web-browsers and other sandboxed programming environments. Nimur (talk) 15:28, 21 March 2013 (UTC)

Mac Powerbook vs Laptop w/ Windows 7

I had a 2005 G4 Mac Powerbook with which I was quite happy until I found it would not support Netflix silverlight or run Flash very well or download with RealPlayer. I got a Gateway Windows 7 laptop which is the only reliable PC I have ever owned. But it needs replacing, and I have never been happy with the picture, which unlike the Mac is dark and cannot be seen at an angle, or with the sound, for which I had to buy external speakers in order to hear half of what's on Youtube.

I intend to buy either a new Mac or PC laptop. It will have to be a 17" screen with HD and a bright clear picture visible at an angle. It will probably be my only source for "TV" watching, and will mostly otherwise be used for browsing and with Microsoft Word. I don't want to waste, but am not afraid of spending money. Under NO circumsatnces will I get Windows 8, with which I am unfortunately familiar.

1. What should I be looking for to give the highest picture and sound quality (and volume in the latter)?
2. Is there any reason to prefer a Mac over a PC running Windows 7 or vice versa for program compatibility, especially Real Player, Adobe, Netflix, VLC, and Real Player?
3. Can I get a laptop of any sort that is region free on dvd/blueray? I watch a lot of Spanish films.

I'd appreciate any advice or links to relevant reviews or resources. Thanks! μηδείς (talk) 12:34, 21 March 2013 (UTC)

1. For TV with the "highest picture and sound quality" you will struggle to beat a proper TV (in a domestic setting). Modern HD flat screen TVs are very good - or at least my 37" Panasonic is very good - especially when linked with a HD source such as a bluray player or the HD offering from your cable/satellite provider. You can also watch it at a comfortable distance in your living room, rather than huddled over the tiny 17" screen of a laptop; I don't understand why so many people think watching TV on a laptop is a good idea. However, from what I can tell, the screen on the higher end Macs is superior to that on many PC laptops, though my Dell laptop screen is pretty good too.

2. A PC running Win7 is compatible with all the software you mention, but you will get better results with more top-end hardware rather than a bargin basement $399 PC. As for Macs, Apple have a well known dislike for Adobe Flash, but maybe that is only on iPhone/iPad. I don't know about Mac's compatibility with t he other software you mention.

3. You used to be able to get your PC's DVD drive switched into region-free. However the spoilsports who watch over that kind of thing (RIAA?) clamped down. Now, you get to change the region a few times before the hardware gets locked to the last used region - 1 for USA or 2 for Europe. Bluray does have region coding - A for USA or B for Europe - but much commercial content is released region-free. As for a region-free bluray player, my 'under the TV' box can be made region free, but I haven't heard of it being possible on a built in player for a PC or Mac.

Astronaut (talk) 17:25, 21 March 2013 (UTC)

Thanks, but I extremely unlikely to lug a flat screen onto the train. Since I am about 95% likely to order from Amazon, I really do need advice on how to identify a better picture and sound quality based on specs, since I won't have the computer before me to compare.

This is the sort of purchase where I like to check out the options as a big-box store such as Best Buy. They won't have as great of a selection, but you should be able to see what the displays on most common models of laptops are, even if you order one online from the same line with different specs. Also, if you find one you like, I know that Best Buy now price matches Amazon. As long as you completely ignore everything any salesperson says it isn't that terrible of a place. :-) 38.111.64.107 (talk) 18:58, 21 March 2013 (UTC)

Unfortunately requiring a decent display is going to seriously constrain your options, since laptop displays these days really suck for the most part. For wide viewing angles you need an IPS or at least a VA panel, so look for that in the specs. Most laptops have TN panels, which is almost certainly the type of the Gateway screen you didn't like. I just searched Amazon for 17" laptops with "ips" and "va" as keywords and found absolutely nothing, so good luck.

I don't know the current situation regarding region-free drive firmware, but VLC will play DVD and Blu-Ray discs from all regions on any drive as far as I know. -- BenRG (talk) 18:06, 21 March 2013 (UTC)

I see Sony VAIO has the IPS display, but the model has other drawbacks I don't like. μηδείς (talk) 18:49, 21 March 2013 (UTC)

Is it time for a Nvidia Volta page?

Is the Nvidia Volta just vaporware trivia, or does it yet rise to the level of deserving its own page?

I've stuck what few details I know over at Nvidia Tesla for now. Hcobb (talk) 15:43, 21 March 2013 (UTC)

Windows 8 upgrade - can it be used for a clean install if you have original product key etc

Hi, my partner's dad has two PCs - a desktop with Windows Vista, and a laptop with Windows 7 (both are the Home Premium edition). He didn't like the change from XP to Vista, but he really likes the look'n'feel of his new Windows Phone, so I've been thinking about recommending he upgrades his PCs to Windows 8.

I can find the upgrade version of Win 8 Pro for under £50 - however his Vista machine currently runs like a dog, so I'd prefer to do a clean install. If he has the original product key for his old OS, can you do a clean install of the upgrade version, or does it need to install over the top?

In case there's more than one type of upgrade, the one I'm thinking about is [1] / [2].

Thanks, davidprior ^t/_c 19:06, 21 March 2013 (UTC)

You won't need your original product key for your old OS. You'll only need the product key for Windows 8. When you install Windows 8, there will be a screen asking you to choose what to keep. Select "Just personal files" (or "Nothing" if you have a back up of all your files). Either option will give you a clean install. Your old Windows directory will be saved and renamed "Windows.old". Here's an article that touches up the subject.[3] I'll see if I can find a better one. A Quest For Knowledge (talk) 20:40, 23 March 2013 (UTC)

Cookies

How do I "enable" Cookies on my iPad please?85.211.138.47 (talk) 19:42, 21 March 2013 (UTC)

Hi, I don't have any real-life experience with the iPad, but this [4] seems to explain how to set it (in the section "To set whether Safari accepts cookies"). davidprior ^t/_c 19:46, 21 March 2013 (UTC)

Wow, that was quick; many thanks.85.211.138.47 (talk) 20:27, 21 March 2013 (UTC)

'The sender of this message has asked to be notified when you read this message.

When reading an email through Thunderbird, I get the message above. However, when I read the same message through gmail I do not get it. Does Gmail reject or confirm such requests automatically? OsmanRF34 (talk)

This feature is called "read receipts", and it's only available for paid Google Apps accounts, not on free personal gmail.[5][6] -- Finlay McWalterჷTalk 20:39, 21 March 2013 (UTC)

According to [7], read receipts in gmail not available on personal accounts. What gmail does for accounts where it is enabled is up to the administrator. For accounts that don't support it, it doesn't say, but I assume the read request is just ignored. RudolfRed (talk) 20:41, 21 March 2013 (UTC)

OK, but it's the sender who has to have a paid Gmail account, not poor me, the recipient with the personal Gmail account, right? I cannot ask for a read receipt, but I can send them when requested. (So I understood it). So, how does Gmail deal when it gets a request for a "read receipt." I know Google is not very eager in respecting privacy, so I won't be too sure that it just ignores it. OsmanRF34 (talk) 20:53, 21 March 2013 (UTC)

From the way I read the link in my previous reply, you cannot respond to receipt requests if you don't have one of the paid gmail accounts. Also, it only works through IMAP, not via POP or other clients. RudolfRed (talk) 22:49, 21 March 2013 (UTC)

RudolfRed: My understanding is that read receipt requests and responses are typically handled by e-mail clients, not by e-mail servers. If you use a POP client to download your e-mail, the linked document only says the Gmail system (Google Apps for Business, Education, and Government) doesn't send a response back to the sender. Your POP client is still free to interpret the read receipt request and send a response.

The document does say that the Gmail system could automatically send a read receipt when a message is opened via IMAP, if the administrator has enabled that option. This kind of feature isn't typically handled by the e-mail server, but I can see how it might make sense for business accounts, so senders can track if messages are read. Because that's an unusual server feature, the document confirms the Gmail system does not send a receipt when you access messages by POP to avoid any doubt. --Bavi H (talk) 02:37, 22 March 2013 (UTC)

I would advise not setting the option to automatically respond. As far as spammers are concerned it means it is a confirmed email address and so more worthwhile to send spam to. The feature was devised long ago by some committee before spammers came on the scene. Dmcq (talk) 22:29, 23 March 2013 (UTC)

Does Intel 4000 GPU support OpenCL 1.1?

I know the 4000 is pretty wimpy. I have software that requires OpenCL 1.1 to use 'GPU acceleration'. Does Intel 4000 GPU support OpenCL 1.1? --157.254.210.11 (talk) 21:44, 21 March 2013 (UTC)

Yes, according to OpenCL#OpenCL-conformant products. Also here's some benchmark results for its OpenCL performance [8]. davidprior ^t/_c 22:35, 21 March 2013 (UTC)

March 22

NLP / computational linguistics

Is computational linguistics a subfield of natural language processing, or is it the other way around? The Transhumanist 00:01, 22 March 2013 (UTC)

Actually it doesn't work in either direction. Computational linguistics basically means using computers or computational methods to study linguistics; natural language processing means using linguistics to make computers work better. In other words, computational linguistics is a subfield of linguistics; natural language processing is a subfield of computer science. Looie496 (talk) 01:51, 22 March 2013 (UTC)

But note that to a large extent the distinction is about self-image and history of the departments. In practice people often do the exact same things in both. KarlLohmann (talk) 11:56, 22 March 2013 (UTC)

HP Printer

Hello, does anyone have any good tips on fixing an HP c3410a all in one printer. I've tried two different ink cartridges. The old ones are still recognized but the two new ones aren't. I tried cleaning connectors unplugging and waiting and cleaning everything I can. Does anyone know of another thing I can try to fix it. — Preceding unsigned comment added by 71.55.93.113 (talk) 17:22, 22 March 2013 (UTC)

Make sure you have the right kind of cartridges. Many incompatible ones look similar. Look at the part number on a cartridge and make sure the printer can use that specific kind. Looie496 (talk) 17:33, 22 March 2013 (UTC)

They are compatable 71.55.93.113 (talk) 17:38, 22 March 2013 (UTC)

Okay, then, what do you mean by "recognized"? What tells you that the old ones are "recognized" but the new ones are not? Looie496 (talk) 17:41, 22 March 2013 (UTC)

It says the cartridges for that printer is either misssing or damage and these are the second new ones I bought. The old ones don't give this message71.55.93.113 (talk) 17:43, 22 March 2013 (UTC)

They are HP cartridges (i.e., made by HP itself)? Or third-party replacement cartridges? Also the HP c3410a is a CD-ROM, not an all-in-one printer. Looie496 (talk) 17:46, 22 March 2013 (UTC)

HP cartridges and it's c410A. Stupid fingers and lack of proofreading skills71.55.93.113 (talk) 17:51, 22 March 2013 (UTC)

Well, that takes care of the usual things. Can you take a look at the HP troubleshooting page for your product and see if it helps you? Looie496 (talk) 17:58, 22 March 2013 (UTC)

The only thing I haven't tried is replacing the printhead, I wanted to see if there was anything I missed or didn't think of before trying to order it. It is not under warranty plus not sure if it is the problem. and all, and thanks. I posted this at the same time as a thing on HP's forum and still haven't heard anything. If I can't find something out I might jsut replace the printhead and see71.55.93.113 (talk) 18:04, 22 March 2013 (UTC)

Something else you could try is injecting ink into the old cartridges. You can buy the ink and injection system online. This should be quite a bit cheaper than buying new cartridges, and I'm guessing you already sank more than enough money into this printer. One caution though, injecting ink is very messy work, so lay down newspapers everywhere and wear old clothes. Also have lots of paper towels handy.

Also, don't toss out the new cartridges. The same needle you will use to inject the ink into the old cartridges can also be used to suck it back out of the new cartridges. StuRat (talk) 00:45, 23 March 2013 (UTC)

C.E.O. or executive management of Lionsea Software Ltd in Beijing China

These people sell technological software to recover system information and photographs. They agreed to refund me my money on thye 6th of March, as the product did not work and they have specific claims on their page about refunds not a problem. They said it would take 10 days; I contacted them after 15 days and they claim their "refund system" is broken. Well they are a huge company making all kinds of claims about their technological prowess. I don't believe for one minute that they have not "one employee" with the technical ability to repair their own issues. I want to write the C.E.O.

I am elderly person on fixed income, with a 100% disabled wife dying of Cancer and have not the time nor the energy to argue any longer with the Chinese about a refund they already told me was approved and coming. Now they want me to go to several different websites and links. I do not trust this company as they never sign anyone's name to the emails, nor do they ever provide a phone number to call for problems.

It may be a small amount of money to everyone else but it is one more prescription I can fill for my wife.

I only ordered the recoverypro product as it claimed they could recover lost photos my wife wanted. It does not do that, and their web-pages claim simple easy no problem refunds.

I want to write the C.E.O. can you tell me who that person is or the executive staff in Beijing?

Thank you — Preceding unsigned comment added by Twoclaws (talk • contribs) 17:52, 22 March 2013 (UTC)

Sorry to hear about your situation. The address given on the company's website is JianCaiCheng West Road, ShangAo Building, 2B-903, Haidian District, Beijing, 100096, China.

They mention on their website that "LionSea™ is backed up by ClickBank's guarantee of quality customer service, so ClickBank will be happy to help you if there is any problem with your purchase." Clickbanks appears to be a US-based company, so you may have more success with them. Their contact details are at http://www.clickbank.com/contact-us/.

Also, if you purchased something using your credit card, your credit card company may be able to offer some assistance, so you could contact them.

Finally, if other avenues are exhausted, Lionsea appear to be a 'Partner' of Intel. As a multinational company, Intel presumably have an interest in their reputation and those of their partners so you may wish to contact them about your experience. Contact details are at http://www-ssl.intel.com/content/www/us/en/company-overview/contact-us.html. Best of luck - Cucumber Mike (talk) 18:47, 22 March 2013 (UTC)

Remotely wake sleeping computer?

I used TeamViewer to remotely access my computer from a distance but it has since gone to sleep. Is there any way to wake it up? --92.28.82.133 (talk) 20:06, 22 March 2013 (UTC)

It could be possible using Wake-on-LAN, but you will need to know the MAC address and for the relevant port to be open on the firewall. If the remote computer is on a company network, the port will almost certainly be closed. - Cucumber Mike (talk) 20:10, 22 March 2013 (UTC)

It's my personal computer at home. What determines the port to be used? I'll check that article out now. Thanks! --92.28.82.133 (talk) 21:21, 22 March 2013 (UTC)

Well, we might be in business. There's a web service at http://www.depicus.com/wake-on-lan/woli.aspx which should allow you to put in your IP address (you need your external IP - for the computer you're currently using it's 92.28.82.133, but you need the one for the remote PC) and the MAC address for your network card (must be a wired card - WoL doesn't work over wifi) along with the Subnet mask for your network (255.255.255.0 is the most usual). You can also specify the port to use, which must be forwarded from your router; see http://portforward.com/ if you need to know how to do that. If you already know of a port which is forwarded, use that, otherwise the default is port 7. Once you've got all the info, just hit the button and cross your fingers! If it fails, either one of the bits of info you entered is wrong, or the router is not set up to forward the 'magic packet', or your computer is not set up to receive it (WoL must be enabled in the BIOS. Anyway, best of luck! - Cucumber Mike (talk) 21:41, 22 March 2013 (UTC)

Wake over WLAN exists too, but it's going to be rare. For this to work the wireless device would have to actually be connected to the wireless network and running when the laptop is in standby, hibernated or even off. Most hardware configurations don't implement this. The wireless NIC would have to remain active and doing varying things for the host, e.g. staying connected to an AP or searching for the network to reconnect. You would have to have configured your computer in advance, so for this time, you'll have to try wake over roomy (WoR) or wake over family member (WoFM). OsmanRF34 (talk) 00:28, 23 March 2013 (UTC)

TalkTalk (my ISP) interferring with my browser searches

When I type something into my Firefox address bar, I'd like it to be sent to Google as a search query. Instead, my ISP, TalkTalk, intercepts and tells me it can't find whatever I typed and presents me with some bullshit links that would maybe be of interest in some parallel universe. Here is an example of what the URL turns into when I search for "rustoleum": http://error.talktalk.co.uk/main?InterceptSource=0&ClientLocation=uk&ParticipantID=nmum6rqpq5q6gkm3933n3nf9s76onu6r&FailureMode=1&SearchQuery=&FailedURI=http%3A%2F%2Frustoleum%2F&AddInType=4&Version=2.1.8-1.90base&Referer=&Implementation=0

Are TalkTalk deliberately hijacking my browser in this way? I've got Firefox and TalkTalk at home (currently at mum's house) and I'm sure this doesn't happen. 92.28.82.133 (talk) 21:26, 22 March 2013 (UTC)

This is a common scummy ISP trick. The attack is not strictly speaking on your browser, and it may be possible to configure it to use a search directly (perhaps with some other gesture than simply typing and pressing Enter). For me, Firefox provides a "search bar" next to the address bar anyway. Also, when my ISP started doing this I found that they were willing to "turn it off" for me (really, mark my account to use different, correct DNS servers). --Tardis (talk) 22:22, 22 March 2013 (UTC)

DNS hijacking is the article on this. The Talktalk error page has an "About this page" link at the bottom of the page, which in turn links to https://www.talktalk.co.uk/optout/index.html, where you can opt out (not that that excuses them). -- BenRG (talk) 22:44, 22 March 2013 (UTC)

It's worth talking a bit about how all this works, as what Firefox (and other browsers) do is fairly clever:

• First, lets say you enter cat.com Not knowing how to talk to cat.com, Firefox (well, the OS's name client on Firefox' behalf) issues a DNS A record query for "cat.com". The DNS server will return the appropriate IP address for that, and firefox opens a socket and does an HTTP GET through that.
• Now lets say you just enter cat, and you're on a "nice" ISP, that isn't doing DNS shenanigans. Firefox is fairly ignorant of what is or isn't an acceptable internet name, and has to cope with local names inside your network (which don't need fully qualified domain specifiers to be addressed; you could have a server in your house called "cat", for example). So it doesn't do anything smart, and does a normal gethostbyname call. Equally unwilling to guess, your OS' nameclient does the same DNS A request as before, just for "cat" alone this time. Its your ISP's name server that can't figure out a way to resolve "cat", and so it returns zero entries (that's how DNS says "not found"). At that point this Firefox feature kicks in; rather than say "address not found" it URL encodes "cat" and prepends some stuff to make a google query string. Then it opens a TLS (that is, an encrypted) connection to www.google.com, which it sends that query to.
• For an ISP like yours, the difference is the response to that DNS A query; even though it doesn't know of a "cat" server, it still returns an IP address - one for TalkTalk's own search service. Thinking it's actually talking to the real "cat" server, Firefox builds a usual HTTP request; crucially with the host:cat HTTP header. TalkTalk's server sees that, and the query string it gets in the HTTP request, and figures out what you initially entered. Then it "helpfully" builds a search query based on all of that.
• Lastly, consider what happens if you enter cats like sausages into the address bar. Note that this contains spaces - valid URLs can't contain naked spaces. So Firefox doesn't try to do a DNS query for the server named "cats like sausages", because that's an impossible name. Thus Firefox immediately repackages as a Google query.

In fairness, both Firefox and TalkTalk are trying to be helpful, and for a lot of people this is useful behaviour. But equally, both make money from doing this; Firefox could be bundling the failed request and sending it to Bing or Yahoo! or Baidu instead, and they send it to Google because Google pays them to. Firefox's approach is much safer, because TalkTalk is really misusing how DNS is supposed to work, and it does this for everything, not just web traffic. -- Finlay McWalterჷTalk 13:45, 23 March 2013 (UTC)

Well, thank you for your very helpful explanation. Even though I'm a bit familiar with DNS (having set up and run a DNS server for many years) I still learned a lot by reading what you say. I am reminded of the "Verislime" (Site Finder} business from a while back which caused a lot of anguish at the time.[9] Thincat (talk) 14:30, 23 March 2013 (UTC)

Wow, thanks for all the help and informations guys. <3 I especially liked the suggestion that cats like sausages. I liked the information on how to opt-out most of all! Thanks! 78.150.234.51 (talk) 23:02, 23 March 2013 (UTC)

You could also add a bookmark to Firefox that will force a Google search. In Firefox's Bookmark Manager, create a new bookmark, put "http://www.google.com/search?q=%s" in the "Location" box, click the button labeled "More", then put "g" in the "keyword" box. Now, whenever you type "g <search term>" into your browser, it will automatically search Google. -- 143.85.199.242 (talk) 16:29, 27 March 2013 (UTC)

March 23

noise jitter effects

can ground loops over usb induce jitter — Preceding unsigned comment added by 77.35.48.216 (talk) 03:31, 23 March 2013 (UTC)

If you mean monitor jitter, I guess it's not inconceivable, but it seems very unlikely. (Presuming you have a CRT monitor. If it's LCD, no chance at all.) Looie496 (talk) 05:06, 23 March 2013 (UTC)

change movie speed in vlc media player does not work

when i play a movie ,and in vlc media player it runs faster,when i try to change its speed using playback-speed-normal,it does not work, how can i fix it.i m using windows xp — Preceding unsigned comment added by 182.187.51.160 (talk) 05:23, 23 March 2013 (UTC)

The VideoLan guys (who make VLC) have a very explicit mechanism for reporting bugs. They are crotchety folks, because they have received spammy, misspelled, and uncapitalized reports for many years; if you expect them to volunteer time, spend some time reading how to report a bug. Nimur (talk) 17:02, 23 March 2013 (UTC)

Chrome

Every time I fire up Google Chrome, a few webpages like http://websearch.just-browse.info/ and (for some weird unknown reason) not one, but two tabs of google.com open up by default. I want a way to switch off the default sites that chrome accesses when I run it. Can anyone tell me exactly where to go and tweak what so I can see the startup sites and turn them off? (Much like turning off unneccessary start-up programs when switching on your computer) 14.96.97.124 (talk) 15:58, 23 March 2013 (UTC)

Moved from Misc desk. Tevildo (talk) 16:40, 23 March 2013 (UTC)

You could tyep in the address bar: “chrome://settings/” and there, in the “on startup” section select the “Continue where I left off” option — Preceding unsigned comment added by Iskander HFC (talk • contribs) 19:50, 23 March 2013 (UTC)

All that stuff without the quotesIskánder Vigoa Pérez (talk) 19:52, 23 March 2013 (UTC)

Thanks. That totally worked. Except now when I start it, the new tab page opens, although it's set to "open a set of pages" and the set of pages contains only google.com's address (google's my homepage). Any way to fix this little bug? Everything else is fine otherwise. 14.99.179.58 (talk) 20:49, 23 March 2013 (UTC)

RPC-1 firmware or RPC-2 firmware?

How in general can one determine whether one has RPC-1 firmware or RPC-2 firmware?

I am specifically curious about a Mac G4 Powerbook from 2005 and a Gateway NV78 Laptop from 2009. Thanks. μηδείς (talk) 20:28, 23 March 2013 (UTC)

This site has a nice bit of information, and suggests using driveinfo to determine your drive's firmware. I can't vouch for the program's ability, nor do I know whether it works on a Mac. - Cucumber Mike (talk) 21:01, 23 March 2013 (UTC)

I think all drives manufactured starting in 2000 are RPC-2 unless you reflash them (see e.g. [10]). If you're interested in reflashing, note that free-software players like VLC will play discs from any region even on an RPC-2 drive, and commercial players will enforce a region even on RPC-1 drives by some software mechanism that may be difficult to circumvent. -- BenRG (talk) 23:27, 23 March 2013 (UTC)

March 24

File system type (Linux) displayed differently by various programs

Resolved

I'm adding a 3 Tb disk to my Linux box. Doing so by using the GNOME Disks utility (aka Palimpsest), resulted in the following error message: "The partition is misaligned by 512 bytes. This may result in very poor performance. Repartitioning is suggested.", without any obvious hints as to how to fix the error. Googling the message produced lots of hits, but no solutions that worked. After spending some hours fiddling with the disk utility + parted + gparted, I moved the disk to my Win7 box, created a 3Tb ntfs partition with diskmgmt.msc, and put the disk back into my Linux box. It now showed up fine in the disk utility, no complaints about errors. I was also able to mount it, without errors.

I then wanted to "convert" (destructively, I know) the /dev/sdb1 partition into an ext4 partition, by entering

sudo mkfs.ext4 /dev/sdb1

No errors in the disk utility. I can mount the disk, it the contents being as expected (only the lost+found directory). However, when I look at the disk setup with blkid, it shows up like so:

myname@mymachine:/mnt$ blkid
/dev/sda1: LABEL="Disk 1 (old Ub)" UUID="9b68bb9e-5cc4-4ab0-a21f-a607466cc2ee" TYPE="ext4" 
/dev/sda3: LABEL="Disk1 - xtra sp." UUID="f2327d30-3e90-4755-9149-7554f669c122" TYPE="ext4" 
/dev/sda4: LABEL="Disk 1 - Lubuntu" UUID="11c896f5-3e0b-44ea-ba20-6f67259e5b86" TYPE="ext4" 
/dev/sda5: UUID="f1b8a66f-916f-4bce-b674-243134373005" TYPE="swap" 
/dev/sdb1: LABEL="DiskWD1" UUID="9C44BB8444BB5FA6" TYPE="ntfs" 
/dev/sdc1: LABEL="Disk3 - 1.5 TB" UUID="4bbff5cb-3cfb-498a-a94b-46b75e36ba8c" TYPE="ext4" 
/dev/sdd1: LABEL="Disk2 - 1.5 TB" UUID="39588a06-9896-41b7-bba4-9c1e1beffdfc" TYPE="ext4" 

The problem is that /dev/sdb1 shows up as ntfs even though it actually is an ext4 partition. I'm not sure whether this is just an annoyance or a disaster waiting to happen. In either case I'd like to fix it before starting to use the disk. I know that cfdisk lets you set a "file system type identifying byte". I suspect this byte is the cause of the discrepancy, but cfdisk won't recognize the disk, which has a GUID Partition Table. Any suggestions on how to proceed? Thanks, --NorwegianBlue ^talk 11:42, 24 March 2013 (UTC)

Addendum: Here are the "file system type identifying bytes" as listed by cfdisk:

Extended content

01 FAT12 4F QNX4.x 3rd part A9 NetBSD 02 XENIX root 50 OnTrack DM AB Darwin boot 03 XENIX usr 51 OnTrack DM6 Aux1 AF HFS / HFS+ 04 FAT16 <32M 52 CP/M B7 BSDI fs 05 Extended 53 OnTrack DM6 Aux3 B8 BSDI swap 06 FAT16 54 OnTrackDM6 BB Boot Wizard hidden 07 HPFS/NTFS/exFAT 55 EZ-Drive BE Solaris boot 08 AIX 56 Golden Bow BF Solaris 09 AIX bootable 5C Priam Edisk C1 DRDOS/sec (FAT-12) 0A OS/2 Boot Manager 61 SpeedStor C4 DRDOS/sec (FAT-16 < 0B W95 FAT32 63 GNU HURD or SysV C6 DRDOS/sec (FAT-16) 0C W95 FAT32 (LBA) 64 Novell Netware 286 C7 Syrinx 0E W95 FAT16 (LBA) 65 Novell Netware 386 DA Non-FS data 0F W95 Ext'd (LBA) 70 DiskSecure Multi-Boo DB CP/M / CTOS / ... 10 OPUS 75 PC/IX DE Dell Utility 11 Hidden FAT12 80 Old Minix DF BootIt 12 Compaq diagnostics 81 Minix / old Linux E1 DOS access 14 Hidden FAT16 <32M 82 Linux swap / Solaris E3 DOS R/O

They're also listed in our article Partition type. --NorwegianBlue ^talk 12:22, 24 March 2013 (UTC)

Spelling out the details is a good way of solving a problem by oneself. I ran e2fsck. Problem disappeared. --NorwegianBlue ^talk 12:40, 24 March 2013 (UTC)

By default, gparted won't create misaligned partitions (the default is 1 Mib alignment), so I guess it was "helping" by keeping the alignment of whatever was on the disk before. In cases like this I generally nuke the partition table with dd and then run gparted to make a nice fresh one. -- Finlay McWalterჷTalk 13:25, 24 March 2013 (UTC)

Thanks, I'll try it! I still have 4 similar disks to go. I need to increase my storage space by a factor of ten, as I'm getting a ton of super 8 and analog video digitized. According to this link, I have to zero both the beginning and the end of the disk since it uses a GUID partition table. So I'll try it, using the linked howto for accessing the end of the disk. I'll dd-save the parts that I nuke, just to be on the safe side. Doing so has saved me more than once! --NorwegianBlue ^talk 21:43, 24 March 2013 (UTC)

Advanced Format might be relevant here. The default formatting on AF disks can result in a 512 byte misalignment and subsequent poor performance on Linux systems. Astronaut (talk) 23:45, 24 March 2013 (UTC)

Ok, here are my conclusions, for the benefit of anyone who might find this thread googling for the error messages:

• The misaligned disk problem affects both Seagate and Western Digital 3Tb disks. The only difference is that with the Western digital disk, the reported misalignment was 256 bytes. With the Seagate disk, the reported misalignment was 3072 bytes. The WD disk is described by the supplier as Western Digital® Desktop Green 3TB SATA 6Gb/s, (SATA 3.0), RPM = IntelliPower, 64MB Cache, 3.5 in., and has the producer ID WD30EZRX. The Seagate disk is described by the supplier as Seagate Barracuda® 3TB SATA 6Gb/s (SATA 3.0), 64MB Cache, 7200RPM, 3.5 in., and has the producer ID ST3000DM001. Both disks had 5860533168 blocks as reported by sudo cat /sys/block/sdd/size, which fits nicely with 3Tb and a block size of 512 bytes. The OS is Lubuntu 12.04.2 LTS.
• Zeroing the start and end of the disks, as suggested by Finlay, initially appeared to have no effect. Exactly the same error messages, with the same reported misalignments, were reported (still using palimpsest). I later checked to see whether the zeroing of the starts and ends of the disks had actually worked (by repeating the process, dd-ing the blocks to a file and doing hexdump -C). The supposedly zeroed beginnings and ends of the disk still contained data! I repeated the process, then did partprobe /dev/sdd (to tell the OS that the partition tables were changed) and rebooted. When I then checked whether the sectors were empty, they were. I then used gparted, created a GPT style partition table, and created one 3Tb ext4 partition. Everything went smoothly. When checking the disk with palimpsest, there was no warning of misalignment.
• Conclusion: Nuking the starts and ends of the disks as suggested by Finlay works, but you have to take care and check that the sectors are actually cleared, and that the OS is aware of it. I'm not sure why my initial attempts failed silently. Maybe I had palimpsest open, while dd-ing, and palimpsest locked the disk. Maybe I had actually succeeded in zeroing the sectors, but failed to tell the OS. I don't know. Anyway, it works now. --NorwegianBlue ^talk 15:58, 25 March 2013 (UTC)

It's very unlikely that any manufacturer would ship a drive with misaligned partitions, since it would kill their performance on benchmarks. Furthermore, a misalignment of 256 bytes is actually impossible, since it's not a multiple of the nominal sector size of 512 bytes. (The misalignment here is with the true sector size, which is probably 4096 bytes. These drives report 512-byte sectors for backward compatibility. If the true sector size is 512 bytes, the "misalignment" doesn't matter.) So I think this must be a bug in the software you're using. In any case, it does no harm to wipe the partition table and start over. -- BenRG (talk) 17:40, 25 March 2013 (UTC)

And even more unlikely that two manufacturers would. Googling "palimpsest misalignment bug" shows that it is a known bug. As far as I can figure out, it's a combination of an alignment bug and a misleading error message. --NorwegianBlue ^talk 18:46, 25 March 2013 (UTC)

You'd be surprised. I had an Seagate external (but USB3.0 so capable of reasonable performance) drive with misaligned partitions. I've heard of the same problem for people with other Seagate external drives of a similar kind. I'm guessing no one thought to update whatever tool they're using. I suspect WD must have done the same thing at some stage. Internal drives don't normally come formatted when purchased by themselves so no experience there. Nil Einne (talk) 20:54, 25 March 2013 (UTC)

There seem to be drives up to at least 3TB that still use 512-byte physical sectors, such as the Hitachi 7K3000. It's possible you had one of those and the tool you used didn't check for it before displaying the warning (perhaps because it was attached over USB). -- BenRG (talk) 03:51, 26 March 2013 (UTC)

ONCE AGAIN, Subscription feed layout on YouTube - how do I change it back?

The Subscription feed on YouTube changed its layout. I liked the old one better. How do I change it back?

The old layout showed its videos about 5 to a row, with titles under them. Very recently, it changed to show a layout that I don't appreciate as much because I see less previews on the same screenspace than in the old layout. That is why I want the old layout back, so how do I change it back? --70.179.161.230 (talk) 20:52, 24 March 2013 (UTC)

In general, you cannot force website publishers to provide the content that you want, in the format that you desire. Some website publishers allow you to configure the user-interface through preferences or settings; Youtube does not have such options. Some other website developers have the goodwill to provide simple, standardized content that makes it easy for you to customize the presentation - for example, you can re-layout an HTML document by applying your own stylesheet using a web browser. In practice, few websites publish their content as simple HTML documents, so it has become prohibitively difficult for end-users to modify the formatting and presentation of web content. Many new websites intentionally (ab)use the capabilities of hypertext, fixing the format so that the document is not even reflowable. This is particularly true for commercial websites whose developers intend to control your viewing experience. If you are unhappy with website publishers' formatting choices, you should contact the publisher directly - in this case, through their form-letter user feedback system, or simply avoid using their website. Nimur (talk) 04:56, 25 March 2013 (UTC)

Cell phone vibrations ?

I have a cell phone which has a vibrate setting. However, when I have it in my shirt pocket I occasionally feel it vibrate when nobody has called. This vibration seems shorter and less intense than an actual ring vibration.

1) Has anyone else noticed this ?

2) What could cause this ?

3) Could it be some type of sympathetic vibration caused by a noise in the environment ? StuRat (talk) 23:27, 24 March 2013 (UTC)

Other events might make your phone do this: An SMS message being received, for example, or maybe your phone detects the changes in signal strength and adjusts something like Facebook status accordingly. Astronaut (talk) 23:39, 24 March 2013 (UTC)

We should probably ask what sort of phone this is. Then again, I have two phones (Samsung Galaxy S2 and an iPhone 4 since you ask) and have also noticed this, but just put it down to ringxiety. (We really do HAAOE...) - Cucumber Mike (talk) 00:00, 25 March 2013 (UTC)

It's a Samsung S425G. I don't recall any previous phones doing this. StuRat (talk) 05:00, 25 March 2013 (UTC)

Sure it is your phone? Might be your heart trying to tell you something. I keep my vibrating phone in my trouser pocket, much more exciting!85.211.138.47 (talk) 11:47, 25 March 2013 (UTC)

• Our article is at Phantom_vibration_syndrome--in short, many people perceive this phenomenon. I believe there is some discussion of it in the scientific literature, but they might use slightly different terminology. Still, a few searches on Google Scholar will probably be rewarding. SemanticMantis (talk) 16:40, 25 March 2013 (UTC)

printer margins

Is there a place that tells what the margins are for various printers? Had I known that the HP 1000 has a minimum bottom margin of more than one inch, I would not have purchased it. (Such a large margin really messes things up, especially labels and pdfs.) Thank you.    → Michael J Ⓣ Ⓒ Ⓜ 23:51, 24 March 2013 (UTC)

You'd probably do best to download the owner's manual for the printer before you buy it. That should include such info under the specs section. StuRat (talk) 05:07, 25 March 2013 (UTC)

March 25

Safari Extensions

These are a useful collection of extensions on my Safari page on my computer. Can I get these on my iPad? if so I cannot see how. Any ideas please? — Preceding unsigned comment added by 85.211.138.47 (talk) 11:07, 25 March 2013 (UTC)

As far as I know (or can tell) Safari extensions are not supported for iPad. --Mr.98 (talk) 20:17, 25 March 2013 (UTC)

Where does Ubuntu store my installation files?

I've just installed The Battle for Wesnoth on my Ubuntu 12.10 32-bit PC, I do not know where the OS stores the game's music, sound effects, and saved gaming sessions. Please tell me where. Czech is Cyrillized (talk) 11:13, 25 March 2013 (UTC)

I don't know the game specifically, but most local files on linux systems are stored in your home directory, but they start with a ., which makes them hidden in most file managers. If you're in the shell use ls -a to see the . prefixed files. Shadowjams (talk) 11:37, 25 March 2013 (UTC)

The game is installed into /usr/share/games/wesnoth/1.10/

Specifically:

• Music: /usr/share/games/wesnoth/1.10/data/core/music/
• Sounds: /usr/share/games/wesnoth/1.10/sounds/ and /usr/share/games/wesnoth/1.10/data/core/sounds/

Save game files are kept in ~/.local/share/wesnoth/1.10/saves/

-- Finlay McWalterჷTalk 12:42, 25 March 2013 (UTC)

Bash comman history customization

Hello, I'd like to change the behavior of the "up arrow" key at the command prompt in Bash_(Unix_shell). In MATLAB, pressing "up" show all previous commands, one-by-one, with repeated presses (this is what my Bash on Ubuntu does by default). But, in Matlab, if you start to type in a command, e.g 'cd', then pressing "up" only cycles through previous commands that started with 'cd'. So- Can I do this in Bash? Can you help me with the appropriate code for configuration scripts? Thanks! SemanticMantis (talk) 16:29, 25 March 2013 (UTC)

Yes, see here. -- BenRG (talk) 17:28, 25 March 2013 (UTC)

Thanks! However, putting those lines in my .bashrc does not make the expected change. It does do something different with the bindings/history, but less - <up arrow> does not return "less foo", which is the most recent command in history starting with 'less'. SemanticMantis (talk) 17:57, 25 March 2013 (UTC)

Nevermind, for some reason it worked in my .inputrc, but not in .bashrc. I also ended up putting in the few extra lines here:[11]. SemanticMantis (talk) 18:05, 25 March 2013 (UTC)

Resolved

Google on Bing?

Can you Google on Bing? Do you still call it googling or do you call it binging? Bubba73 ^{You talkin' to me?} 04:48, 26 March 2013 (UTC)

Just as much as you can hoover with a goblin, or Tannoy an announcement with a Bose. -- Q Chris (talk) 14:15, 26 March 2013 (UTC)

1950s IBM printer

1950s IBM printer

Can anyone identify this 1950s IBM printer? - Jmabel | Talk 06:01, 26 March 2013 (UTC)

That's not a printer. It's an accounting machine closely resembling the IBM 407, which was used as a component of a calculator system called an IBM CPC. You can see a picture of the whole system here -- note that on the right you can see a card punch that also appears in your picture. Looie496 (talk) 06:59, 26 March 2013 (UTC)

More specifically, it could be an IBM 402, 403, 412, or 418 -- they were all essentially identical in outward appearance, as shown on this page. Looie496 (talk) 06:59, 26 March 2013 (UTC)

• Thanks! - Jmabel | Talk 16:09, 26 March 2013 (UTC)

Value of null

In C, is it safe to assume that null will always compare as less than a valid pointer? I know it isn't safe to assume null==0. 173.52.95.244 (talk) 11:53, 26 March 2013 (UTC)

It is generally considred unsafe to compare pointers that aren't from the same allocation. The C specification doesn't seem to cover relational operators with null pointers, so you should consider the result of the comparision to be undefined and unsafe. It is safe to compare a pointer to 0 (as in if(p) or if(p==0)) to determine if it is null. This is because a 0 constant assigned to a pointer will be converted to a null pointer at compile time, regardless of the system's representation of a null pointer. See [12] for some discussion of null pointers, 5.3 is probably the most applicable question. 38.111.64.107 (talk) 13:18, 26 March 2013 (UTC)

yep sounds like mostly what I was going to say but that last edit beat me here. No the assumption is wrong. And comparing a pointer to zero is a valid test for null even if the actual value in a null pointer is not zero (but in practically all machines nowadays it is actually zero and thankfully C++ now has a nullptr to avoid that anyway) Most anything beyond that is machine dependent. See pointer_t and ptrdiff_t for the integer form of a pointer and for getting the difference between two pointers into the same array, they are mainly for getting the size of ther integer form right so a bit of low level work can be done on them. Otherwise one should normally avoid messing around with the contents of pointers. Dmcq (talk) 13:30, 26 March 2013 (UTC)

I have good reasons for messing with the contents of pointers! I think what Dmcq intends to say is that application logic rarely ought to directly modify object representation or allocation in memory; application logic should delegate that work to an abstraction of the memory system. Even if applications are implemented in a language that allows access to the memory representation (like C and C++), the application should let the system library or the program runtime environment handle the details.

On checking my copy of K&R, Section 5.4, I interpret the text to mean "NULL" is a convenience macro defined in stdio.h - and not a strict requirement of the language implementation. I believe K&R differs from ISO C in this definition, but I don't have the ISO C reference so readily available (in cached brain memory). Many computers - particularly small microcontrollers with simplistic memory hardware - can perfectly well store regular data at address 0; on those systems, programmers need to be extra paranoid about algorithm behavior. I can not find a reference that indicates such behavior is a strict violation of any standard C requirement. Nimur (talk) 13:50, 26 March 2013 (UTC)

Ok, my memory read through, and was correct: this behavior differs between C standardization efforts. NULL "may" be zero in K&R, and some of the K&R-esque GNU C; but ISO 9899 lays down the law for C11, and NULL shall be exactly the integer constan 0 as documented in ISO/IEC 9899:2011§6.3.2.3. So to answer the original question: "is it safe...?" Check which standard your C compiler is enforcing, or pass a standard on the compiler's command line. Alternately, enforce the condition with a preprocessor directive. Then it is safe to assume NULL explicitly equals zero. Nimur (talk) 14:02, 26 March 2013 (UTC)

I just had a look there and there doesn't sem to be any real change. According to the standard it is still okay for null pointers to be for instance -1 when stored in memory. For most systems one can assume that zeroing some store with memset will set any pointers in it to null but the standard does not say that. It just says that when one converts between a pointer and integer that 0 means a null pointer. Some old systems for instance had word addresses and the character pointer used the top two bits or a separate word. When converting to integer the two bits would be moved to the bottom and when converting back to pointer they would eb moved to the top. Even nowadays in C++ pointer to member functions for instance can do strange things. Dmcq (talk) 14:29, 26 March 2013 (UTC)

Even if one is assured that NULL==0, that's not sufficient to answer the original question. The OP's comparator safely holds iff pointer comparison is unsigned. Pointers themselves cannot be signed or unsigned (one cannot say unsigned void * p). I see nothing in C99 (6.3.2.3) about ordering of pointers, and all it says about comparison is to do with equality and inequality. One can cast pointers to integers (part 754) but the cast is implementation defined (part 755). It would seem overwhelmingly sensible for pointer comparison to be done unsigned, but that's not the same as that being mandatory (and there's always a weird architecture which does odd things for curious reasons). -- Finlay McWalterჷTalk 14:39, 26 March 2013 (UTC)

Samsung devices, Android versions, predictive text

I'm using a Galaxy S III Mini, with Android 4.1.2, with the default Samsung Keyboard, and the predictive text turned on. This works great. I also have the original Samsung Galaxy Tab, with Android 2.2. The predictive text is XT9, which I don't much like. Is there any way to get the current Samsung Keyboard as it works on my phone onto the Tab, or is it an issue of the later version of Android, and I won't be able to get the newer Keyboard and functions working on the older machine? Thanks if you can advise.