Wikipedia:Reference desk/Archives/Computing/2011 April 18

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April 18

Email Client

Where is the descendant of Outlook Express in Windows 7 ?  Jon Ascton  (talk) 00:15, 18 April 2011 (UTC)

There isn't one, you need to download it as part of Windows Live Essentials  ZX81  ^talk 00:46, 18 April 2011 (UTC)

Cookies and Google Chrome

Hi,

I'm trying to create a webpage which uses cookies. It works fine on all browsers other than Google Chrome. I'm creating cookies in a php script and attempting to read them in with javascript, using code very similar to this. My page does manage to save the cookie, but can't retrieve it.

After of bit of googling, I can see that chrome handles cookies differently from other browsers. Specifically, it apparently doesn't allow "local cookies." My page is on a server, not running on my own computer. Is that still probably my issue?

In general, could someone please give me an example of a setcookie call in php which should be chrome compatible? Thanks!

137.165.171.130 (talk) 04:30, 18 April 2011 (UTC)

Apologies. I've resolved the problem. I spent two hours trying to figure it out, ask it here, and immediately spot my problem (not at all what I thought). Magic.

Thanks anyways, 137.165.171.130 (talk) 04:35, 18 April 2011 (UTC)

Glad we could help, if only via Murphy's Law (in this case, that you couldn't fix the problem until you wasted your time posting it here). :-) StuRat (talk) 10:29, 18 April 2011 (UTC)

Resolved

Visual Studio 2010 not installing

Hi everyone, I've downloaded Visual Studio 2010 Professional from DreamSpark (a Microsoft academic thing) and it won't install. I've uploaded the log file to my SkyDrive:

http://cid-cf9b0aa66e9b2bfc.office.live.com/browse.aspx/.Public

The installer gets to installing Visual Studio 2010 (the stuff before that works fine), I have downloaded 2 ISOs (at 2.2GB a pop!), burned the ISOs to a DVD, tried to install it from a mounted ISO, I've extracted the ISO contents and tried it locally as well. I have tried it with no anti-virus/other programs running, I have installed an Express version of Visual Studio 2010 without any problems, and I have Googled the HRESULT error in the log file, and tried everything there. I'm absolutely stumped, and was wondering if anyone has done this before/has any ideas?

Thanks in advance!

110.175.208.144 (talk) 08:00, 18 April 2011 (UTC)

Hello Aussie! (from IP address)

Perhaps contact your school administrator? He/she may be able to shed some light. Or have you uninstalled the Express version? Perhaps that will clear some issues. General Rommel (talk) 08:50, 18 April 2011 (UTC)

Compute the SHA-1 hash of your ISO image and compare it against the one published by Microsoft. You can probably find it on the page where you originally went to download the file. If the hash doesn't match then you'll have to download the ISO again. If it does match then I don't know what to suggest... -- BenRG (talk) 09:23, 18 April 2011 (UTC)

The original page does not have the MD5/SHA-1 hash of the original file, so maybe there is something wrong there, I will find an alternate source overnight... Also, the whole DreamSpark thing is done pretty much entirely separately from the school - it is self-registered, etc., all you need is a school e-mail address. And before I installed the express version, I was getting the exact same errors as afterwards. 110.175.208.144 (talk) 09:58, 18 April 2011 (UTC)

If you can't find the official SHA-1 hash, you could also try searching the web for your file's hash (as a 40-letter word). If neither Google nor Bing finds any occurrences of that word, the file is probably corrupt. -- BenRG (talk) 22:52, 18 April 2011 (UTC)

Googled the SHA-1 checksum, and precisely zero results... I shall download a copy from a different source overnight :) 110.175.208.144 (talk) 08:17, 19 April 2011 (UTC)

Blue line suggestion in MS Office 2010

Hi,

Does anyone know how to get rid of the silly new blue line suggestion in MS Office 2010? It keeps trying to get me to hyphenate words (such as take over) which I find incredibly distracting as I'm trying to take notes during a lecture! I mean technically perhaps there should be a hyphen there but I don't really want one and would much prefer not seeing blue lines everywhere

The worst thing is, it doesn't allow an 'ignore all' or auto correct feature so you have can't have it automatically do its thing (which may actually be useful)

Thanks, --58.175.32.140 (talk) 12:11, 18 April 2011 (UTC)

Untick "Use contextual spelling" in the Spelling & Grammar options. AndrewWTaylor (talk) 12:20, 18 April 2011 (UTC)

Thanks! --58.175.32.140 (talk) 11:56, 19 April 2011 (UTC)

Resolved

Extra Rams For Computers

Dear All i have one question abot adding new rams for my pc but i dont want to remove the old one just iwant to increase the ram ( add new rams only ) my question is what i need to check before install the new rams ?

to make sync between tow rams check the Memory clock , Cycle time .......... , CAS latency its should be same or not or what i can check it before installing the new rams with my rams . — Preceding unsigned comment added by Net-order (talk • contribs) 12:23, 18 April 2011 (UTC)

As a general rule, on a modern motherboard, all RAM is clocked at the speed of the slowest RAM module you have loaded on the machine; so you want to make sure your new RAM is at least as fast as your existing RAM. Depending on your motherboard, your performance optimizations will work best if each RAM cartridge is the same size (to be technical, this only makes a difference if your hardware uses naive implementations of virtual memory management and memory access load balancing). So, in order, make sure:

1. The new memory is compatible with the motherboard (make sure it is the correct type of memory and the correct module connector), e.g. "DDR3 in a 240-pin DIMM"
2. The new memory should be ideally clocked at the same speed as your existing RAM module, e.g. "800 MHz", or "800/1066/1333" if it supports multiple frequencies; at least one of those available speeds should match your existing RAM
3. The new module may be any size (in MB/GB), but for peak performance on most motherboards, select the same size as previous modules, e.g. "1 GB"

A lot of the other specs on your RAM will only matter if you are really fine-tuning your system, or doing something very unusual with your hardware. Here's a relatively recent article, Memory Upgrade, from Tom's Hardware, a reputable computer hardware review website. Nimur (talk) 14:19, 18 April 2011 (UTC)

You may have no choice but to replace some of the RAM. PCs only have a limited number of slots into which the RAM can be fitted. For example, my laptop has 2 slots; both slots are occupied by the current memory so if I wanted to add more RAM I would have to replace the memory I already have. Also, some motherboards restrict you to certain memory configurations - check your PC's hardware manual (it either came in the box when you bought it, or you can download it). Astronaut (talk) 17:22, 18 April 2011 (UTC)

Note that there are different form factors for RAM, so you have to get the right shape, such as DDR, DDR2, or DDR3. I suggest you download and run the tool at Crucial.com, which will examine your current configuration and recommend possible upgrades to your RAM. StuRat (talk) 17:33, 18 April 2011 (UTC)

Adobe Acrobat and Data Execution Prevention

An irritating feature has recently cropped up on my laptop. I have been opening (and creating) PDF files using Adobe Acrobat v8 for ages with no problems. In recent weeks though, whenever I try to open a PDF file, I get an error message saying that Acrobat has to close down. When I click 'search online for a solution' I am referred to some security software called Data Execution Prevention (DEP). The notes about DEP instruct me on how to disable it for a specified program, but when I attempt to do this I am told that I am not allowed to do it in the case of this particular program. So I'm in the ridiculous position - alone in the whole world I should think - of not being able to open a PDF file. Can anyone help? —Preceding unsigned comment added by 86.186.85.177 (talk) 13:12, 18 April 2011 (UTC)

I've heard that Foxit reader is a good lightweight PDF reader for Windows. Unfortunately, given the error that you're getting, it sounds like you may have a PDF that uses fancy (and possibly insecure! Do you trust the source of the PDF?) features that Foxit won't be able to handle. It's worth a shot, though, especially since disabling protection against potential Adobe Acrobat security holes sounds like a bad idea. Paul (Stansifer) 14:05, 18 April 2011 (UTC)

(ec) DEP is a legitimate safeguard, and it "exists for your protection," but it sounds like it's incorrectly identifying either Adobe Reader, or the PDF, as a forbidden file. The PDF may have active script-content, and instead of falling back to a read-only mode, DEP is forbidding all access to the file. Unfortunately, only a computer administrator has permission to enable and disable data execution prevention; if your user-account on the machine is not an administrator, try logging in as one to make the change (or ask your system administrator for help). If you prefer, you can try an alternative PDF viewer; we have a list of PDF software. Foxit Reader and Evince are both well-liked alternatives to Adobe, and may circumvent whatever DEP error you're having by loading the document as a read-only file. (Though, if you're having DEP permission problems, you may be unable to install new software). Nimur (talk) 14:08, 18 April 2011 (UTC)

Thanks for your efforts, much appreciated, but I think possibly not getting to the root of the problem. One thing that puzzles me is that this has only started to happen recently. Another surprising feature is that it applies not just to a single file, but to all of the many files I have tried to open in recent weeks, including those I have created myself (which I hope answers the question about whether I trust the source of the PDFs!) My account is that of an administrator, but that does not seem to be the problem - I'm not told 'you can't do this because you're not an administrator', I'm told 'DEP cannot be disabled for this program'. Any further thoughts would be welcome. I'm reluctant to use an alternative PDF reader because I swap files with other organisations, all of whom use Acrobat, so any files I create need to be in the same format - and I don't want to be in a situation where I create files that I myself cannot read, which is where I am at the moment. —Preceding unsigned comment added by 86.186.85.177 (talk) 14:17, 18 April 2011 (UTC)

Have you had recent update to Adobe Acrobat ? Perhaps that messed it up. If so, a rollback to before that update may be in order. StuRat (talk) 17:40, 18 April 2011 (UTC)

Foxit reads ordinary PDF files; if it can read something, Acrobat can read it (and vice versa most of the time). But it can't create PDFs; if you need that, I don't have any suggestions. Paul (Stansifer) 18:57, 18 April 2011 (UTC)

Hotmail emails all deleted - why?

Recently I looked at my Hotmail emails and I found that they had all been deleted, apart from one or two hundred recent ones. Luckily I was able to un-delete them. It appears to be the "Windows Live" variant of Hotmail - I don't understand the difference.

Does anyone know why they were deleted? Is this a MS "surprise!" policy? Is it going to happen again? 92.28.241.233 (talk) 18:30, 18 April 2011 (UTC)

This sounds like the sort of thing a hooligan might do if they got control of someone's email account. Change the password immediately (and of any other accounts that share that password). Paul (Stansifer) 18:48, 18 April 2011 (UTC)

Are you using Hotmail's web interface or a mail program? If the latter, check whether your POP3 settings say to leave messages on the server or not. --Mr.98 (talk) 19:06, 18 April 2011 (UTC)

Hotmail recently had some problems with mails being deleted. See here. Astronaut (talk) 10:43, 19 April 2011 (UTC)

Mr. 98, I installed Thunderbird with a view to backing up my emails, but have not figured out how to do that yet. I've used Thunderbird a few times to send emails. Thanks 92.15.24.113 (talk) 21:28, 20 April 2011 (UTC)

harddisk size, is it real

somebody please this question for me. assuming my hard disk is 20G and it is filled with a data of 20G. now, i delete this 20G data and store another 20G data. if there is a software that can retrieve the first 20G deleted then where was it hidden? or my hard disk is not 20G as labeled ? — Preceding unsigned comment added by Rhaskhan (talk • contribs) 22:18, 18 April 2011 (UTC)

The process you describe is, in general, not possible. Data that is deleted, and then overwritten, can not be recovered. There can be slight variations in the reported size of a disk, related to details of how data is actually stored on the file system, (and whether convention dictates the use of "1000" or "1024" for "kilo"); but a factor of 2x is unheard of. Nimur (talk) 22:28, 18 April 2011 (UTC)

Think of your hard disk like a book with a table of contents at the front which lists where each file is located on your hard disk. When you write 20GB of data to the hard disk, the table of contents is updated for you automatically, to tell you where to look for each file. When you delete the 20GB of data, most operating systems just erase the table of contents, because it's fast to do so. All your old files are left there, untouched, but the table of contents tells you that the book is empty. Now when you start writing new files, the new files will overwrite whatever used to be on all those pages, and the table of contents will be updated to tell you where to look for the new files only. If you write, say, 8GB of new files, then you know that about 12GB of your old files are still there on the hard disk, if you have software that can go and identify them. (The old files may be scattered all over the place, and parts of the files may have been overwritten by the new files; but that's another matter.) This is what undelete software does — it finds the old files and changes the table of contents to point to them. Comet Tuttle (talk) 00:15, 19 April 2011 (UTC)

In some cases it may be possible for a forensic lab to recover data which has been overwritten. In this case, don't think of the bits as ones and zeros, but maybe having any range of values between one and zero. The software then normally considers everything above, say, 0.5, to be a 1, and below to be a 0 (or they could have some range in the middle which is considered an error). So, if you had a zero and overwrote it with another zero, maybe if would be very close to 0.0, while a one overwritten by a zero might be more like 0.1. Now that 0.1 contains some hidden data that it was a one previously. The same also can happen with a zero overwritten by a one, you might get a value close to 0.9. This is a lot like erasing pencil writings then writing over them, they still leave a faint trace behind. However, if you continue to erase and rewrite things, the earlier messages are eventually completely obliterated. Some software will actually overwrite each bit several times to ensure that no record remains of the original. StuRat (talk) 01:06, 19 April 2011 (UTC)

It's often said that someone with good enough technology might be able to read overwritten data. However, there are currently No credible cases of anyone reading any significant amount of overwritten data on a hard drive with any reasonable accuracy. Maybe the CIA and their electron microscopes are doing this without anyone knowing, but even the U.S. government considers one overwrite sufficient to protect against even laboratory attack in modern hard drives [1]. In practice, the armed forces typically use three to four overwrites [2]. Any more than this, and you're into "voodoo incantation" territory. See also Data erasure. Buddy431 (talk) 01:56, 19 April 2011 (UTC)