Wikipedia:Reference desk/Archives/Computing/2013 March 5

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March 5

Backup and restore - mirror entire hard drive to external drive

The HomePlus version of Carbonite for Windows says that it will mirror the C: drive to an external hard drive so if your c drive crashes, you can install a new hard drive and restore everything from the external drive.

1. Is it possible to simply replace the HD, reboot somehow, and restore everything from an external drive, and be back just as you were before the crash?

2. Is there other software that does this? Bubba73 ^{You talkin' to me?} 01:13, 5 March 2013 (UTC)

I don't know the particulars of how Carbonite works... any harddrive is just a series of 1s and 0s... the unix program dd will copy a drive verbatim, and will do a perfect backup. However there are a lot of practical things that come into consideration when doing that. Norton Ghost has done something close to this for a long time. Shadowjams (talk) 01:25, 5 March 2013 (UTC)

About 3 or 4 years ago I had the C drive fail on a Windows system. I had a complete backup. However, I could not restore the Windows Registry, because it would not let me write over it. So it was practically useless. Later I found out that I might have been able to do it in safe mode, but that was long after I had done it the hard way. Bubba73 ^{You talkin' to me?} 01:29, 5 March 2013 (UTC)

I use Windows 8 and Ghost is "not ready for W8". Bubba73 ^{You talkin' to me?} 01:36, 5 March 2013 (UTC)

I heartily recommend Clonezilla, which will do what you want. -- Finlay McWalterჷTalk 01:31, 5 March 2013 (UTC)

Clonezilla says that it has this limitation: "The destination partition must be equal or larger than the source one. ". My C drive is 2TB, but with only 300 GB on it. The external drive I want to use for the backup is only 1TB. So there is plenty of room for the backup on the external drive, but it is actually smaller than the source drive. Will that work? Bubba73 ^{You talkin' to me?} 01:44, 5 March 2013 (UTC)

No; it'll refuse to try. The CloneZilla disk does contain FSArchiver which reportedly will (I've never used it, so I can't say how reliable it is). Even if it does work, the file FSArchiver produces is compressed, so it will not be bootable - you'd need to again boot into Linux (the CloneZilla live disk is a linux livecd) and have FSArchiver uncompress it. -- Finlay McWalterჷTalk 02:21, 5 March 2013 (UTC)

Windows comes with Backup and Restore#System image. I don't know the reliability and features compared to other programs. It only requires a backup disk the size of the used part of the harddisk, but if you restore to another harddisk then that harddisk must be at least as large as the total size of the harddisk or partition you made an image of. PrimeHunter (talk) 03:11, 5 March 2013 (UTC)

It looks like that is gone from Windows 8. From the help file :

What happened to Backup and Restore? You might have previously used Backup and Restore in Control Panel to back up your files. You might also have created and used a system image backup or repair disc to reinstall Windows if something bad happened to your PC. Here’s where to look for info about backing up and restoring in Windows 8. ... File History frequently backs up your libraries, contacts, favorites, Microsoft SkyDrive, and desktop. You can then restore any versions of your backed up files. For more info, see Set up a drive for File History and How to use File History. ... If you’re having a problem with your PC, you can refresh Windows without losing your photos, music, videos, and other personal files. You can also start over by resetting it to factory settings. For more info, see How to restore, refresh, or reset your PC.

It talks about restoring files, restoring to factory settings (which I DON'T want to do), but not a disc image. Bubba73 ^{You talkin' to me?} 03:23, 5 March 2013 (UTC)

Its still there in Windows 8, but Microsoft moved it to "Windows 7 file recovery" in the control panel (look for "Create a system image") Kram (talk) 14:15, 5 March 2013 (UTC)

Thanks, that helps a lot. I didn't know about that. Bubba73 ^{You talkin' to me?} 23:10, 6 March 2013 (UTC)

I want to be able to get back to exactly like I was in case the hard drive crashes and I have to replace it. I went into Windows 7 file recovery. I selected the C drive and included the system image. There was a warning that said that a system repair disc may be needed. It gave a link to click on for more information, but the link had no info. With the backup as above to an external HD, I need the system repair disc too, right? How do I make one of those in Windows 8? Bubba73 ^{You talkin' to me?} 23:28, 6 March 2013 (UTC)

Well, I found these instructions for making a W8 repair disc. I only have to make this disc once, right? Even if the disc image on the external drive is updated, right? Bubba73 ^{You talkin' to me?} 23:39, 6 March 2013 (UTC)

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From what I read, Clonezilla requires booting into Linux just to run it. I'm looking for something for Windows 8 that I can either have continuously update the image or schedule updates. Bubba73 ^{You talkin' to me?} 02:15, 5 March 2013 (UTC)

Yes, that's right. The computer is unavailable while the cloning happens; for a big disk, to a comparatively slow external disk, this can be many hours. I can't help you with Windows software. -- Finlay McWalterჷTalk 02:24, 5 March 2013 (UTC)

I've used Acronis True Image and think it is quite good. I used it just recently when I bought a bigger SSD as my primary drive. I just cloned my C drive onto an external disk, then I swapped in the new bigger disk and 'restored' the backup to it. All went off without a hitch. Vespine (talk) 03:25, 5 March 2013 (UTC)

I used to use that, but that is what I was using when I couldn't copy back the Windows Registry (but perhaps it could have been done in safe mode.) Bubba73 ^{You talkin' to me?} 03:36, 5 March 2013 (UTC)

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I had the Microsoft backup running for several hours and then it failed. It was to a 1TB Seagate USB 2 external HD. I'm also planing to backup to a 3TB Seagate USB 3 external HD. I read an Amazon review of this drive and it said that it won't work with Microsoft's backup and restore because it used 4KB sectors and Windows 7 doesn't support 4KB sectors. Is that right? Bubba73 ^{You talkin' to me?} 07:43, 7 March 2013 (UTC)

The backup to the 1TB USB 2.0 external drive seemed to lock up, but maybe it was just taking a long time. I successfully did a backup to a 3TB USB 3.0 drive - I think it took less than 1 hour. And it accepted the disc being larger than 2.1TB, so that answers that question above.

But the mirror image is not automatically updated with the Windows 7 backup & restore in Windows 8, right? Is it automatically kept up to date with Carbonite? Bubba73 ^{You talkin' to me?} 02:23, 10 March 2013 (UTC)

Dual protection?

I am getting a new computer. I was in Staples recently and wanted to get protection software for my new system. I was looking for "Norton Internet Security 2013" and found it, but also found "McAfee Total Protection 2013". Now my question is: If I were to get both the Norton product and the McAfee product, would it be a good idea to run both at the same time? Will it offer more protection than one would alone, or would it just be more trouble? Thanks! -- Tohler (talk) 02:51, 5 March 2013 (UTC)

Trouble. Anti-virus products notoriously see each other as viruses, and act accordingly. And, even if they would play nice, each slows down your computer considerably, so you really don't want to double the slow-down. StuRat (talk) 03:07, 5 March 2013 (UTC)

Even our Antivirus software article says Running multiple antivirus programs concurrently can degrade performance and create conflicts.Vespine (talk) 03:20, 5 March 2013 (UTC)

Additionally, each of those products are awful. ¦ Reisio (talk) 04:30, 5 March 2013 (UTC)

What products do you recommend? -- 143.85.199.242 (talk) 14:04, 5 March 2013 (UTC)

Microsoft Security Essentials is free and reasonably good. Most malware protection really relies on healthy caution by the user rather than just software alone. 31.185.196.159 (talk) 14:47, 5 March 2013 (UTC)

MSE is good in that it won't drive you crazy, but whether a relatively recent offering from the very company that got you into this mess is a really great idea remains to be seen. Look for some comparisons online, the choices should be clear. ¦ Reisio (talk) 16:26, 5 March 2013 (UTC)

as might be suspected, antivirus is one of the places where the freeware products rival the $$ ones, since expert hobbyists have a vested interest in them. (communication and data transfer being another) avg and avast have done well by me. Gzuckier (talk) 18:19, 5 March 2013 (UTC)

If the OP is getting a new computer then there's a fair chance it will have Windows 8. That being the case as discussed in our article, MSE has basically been discontinued for Windows 8 replace by Windows Defender which on Windows 8 is basically the same thing and bundled by default (as it was in Windows 7 and Vista where it was only anti spyware). I think Microsoft had been meaning to do this for a while, but they were scared off due to anti-trust concerns and so made MSE or AV protection as a separate download from Windows Defender and spyware protection. (Note for the OP: Your PC manufacturer may have disabled removed Windows Defender if they included some AV trial.) Nil Einne (talk) 19:57, 6 March 2013 (UTC)

(OP editing from another computer) Thank you all for the responses! When I ordered online, I chose 7 over 8, because I don't like 8's interface. If I'm reading your responses and the articles correctly, MSE only offers antivirus/malware protection? Also, I'm aware that Microsoft's latest OSes now include a firewall; is that any good? If not, what would you recommend? -- 143.85.199.242 (talk) 20:12, 6 March 2013 (UTC)

Since Vista, I think, Microsoft Windows has had an included firewall that will suffice. http://classicshell.sf.net/ ¦ Reisio (talk) 00:13, 7 March 2013 (UTC)

Hotmail only not work.

Here at the place I work, there is one computer that can't open hotmail (but can open all other websites). All other computers on the network can open hotmail and only this computer can't open it (and can't open on all browsers). What can be the problem? — Preceding unsigned comment added by 201.78.165.190 (talk) 12:00, 5 March 2013 (UTC)

Possible that computer has a virus. Shadowjams (talk) 12:55, 5 March 2013 (UTC)

Well, maybe. Serious suggestions/questions: have you tried with more than one browser? What do you mean by "can't open" - what are the exact symptoms/error messages? Maybe the hosts file has been modified to redirect hotmail.com to the wrong IP address. AndrewWTaylor (talk) 14:08, 5 March 2013 (UTC)

The website keep trying to load but will not load (will not even show something and keep at the same page i am). Until it goes to some page "internet explorer can't show that webpage" or the others webrowsers version of that "site."201.78.165.190 (talk) 17:28, 5 March 2013 (UTC)

Microsoft has ported all of its Hotmail accounts over to Outlook. Although Hotmail should still work, try logging in to outlook.com with your Hotmail information. RNealK (talk) 23:51, 5 March 2013 (UTC)

Using an HTTP proxy such as Fiddler can sometimes help to diagnose problems like this by showing what's going on behind the scenes. AndrewWTaylor (talk) 13:09, 6 March 2013 (UTC)

Getting back into my zip files

A long time ago I stored some images in a series of zip files, simply as a means of keeping all those related to each project together. As a security measure I added a password to the zipfile. Unfortunately, I can no longer remember the passwords I used. I know they were not paticularly secure passwords by today's standards (perhaps 8 characters, letters and maybe numbers). Is there a limit on the number of guesses I can make? And is there an easier way than guessing, perhaps getting some software to decrypt the password. Astronaut (talk) 17:56, 5 March 2013 (UTC)

The fact that these 'Top 5' zip-file password crackers are all brute-force based suggests that there is no retry limit. One of the programs listed may be useful to you - I have no experience with any of them. - Cucumber Mike (talk) 18:02, 5 March 2013 (UTC)

Brute forcing passwords that short won’t take you long at all. :) ¦ Reisio (talk) 18:55, 5 March 2013 (UTC)

That's not true—I doubt it's possible to check more than ~1000 passwords per second per CPU core, in the case of AES encryption. The traditional encryption is broken and doesn't need to be brute-forced. -- BenRG (talk) 19:10, 5 March 2013 (UTC)

There is certainly no retry limit (a file is just a sequence of bytes and can't self-destruct).

If the encryption is traditional zip encryption, and you have any one of the files in decrypted form and the same version of the same product that you used to make the archive, then you can decrypt it with pkcrack. If the encryption is AES, brute force is your only option, but it may still be feasible if you can narrow down the possible passwords enough ("8 letters and digits" probably isn't enough—that's over 2⁴⁰ possibilities, which would take decades on commodity hardware). There are a ton of automated brute-force products out there. I've never used any of them, but you could try ZipCracker. I'd stay away from those closed-source freeware products, personally. -- BenRG (talk) 19:10, 5 March 2013 (UTC)

It seems like there is quite a divergence in passwords per second based on both the encryption scheme and the cracker (e.g. whether they use regular CPU cores or also use the GPU) — I found the numbers in this article interesting, though I don't know if they apply in this situation (and the article is two years old). The difference between 6 and 8 character passwords is particularly dramatic. AES seems particularly slow. --Mr.98 (talk) 02:30, 6 March 2013 (UTC)

I completely forgot about the possibility of using the GPU—oops. But even at 250,000 passwords per second it will take decades to try all combinations of eight uppercase and lowercase letters and digits (though "only" a few months (and hundreds of dollars of electricity) if the letters are restricted to one case). FWIW, the previous page of the article gives a figure of ~9700 passwords per second on a 3.3 GHz quad-core Core i5, which is a bit higher than my guesstimate.

The bottleneck in cracking ZIP's AES encryption is not AES but the key derivation function, which requires computing 2000 SHA-1 hashes of 128 bytes each to obtain the two-byte check value (and another 2000 or more to get all of the key material, but you only need to do that 1/65536 of the time). The article also claims that the AES cracking is harder to parallelize, which isn't true. It's just a lot more work per password. -- BenRG (talk) 06:12, 6 March 2013 (UTC)

It uses PBKDF2 at 1,000 iterations. [1] Shadowjams (talk) 23:11, 6 March 2013 (UTC)

There are products that make a brute force attack far more expensive. For example, [axcrypt] uses an iterative AES Key Wrap As a brute force counter measure with at least 10,000 iterations, and typically 100,000 to 200,000 on modern PCs. You have to run the keywrap again on every guess, which is about the same work that an additional 12-18 bits of key-length would cause the attacker if standard AES encryption (which was designed to be fast) was used. --Guy Macon (talk) 10:41, 6 March 2013 (UTC)

The point of iterating 1000 times in the key derivation function is to make brute force attacks more expensive. That's the normal way that it's done. Googling "iterative key wrapping" (with quotes) yields 87 hits, 100% of which are copies of the claim that axcrypt does it, and none of which explain what it is. Key Wrapping is apparently a thing, though I'd never heard of it, but it's not a widely used technique and I'm having trouble figuring out what it's supposed to be for. The article links to a paper which says "key-wrap's raison d’être is to remove [authenticated encryption]’s reliance on a nonce or random bits". That makes me wonder why axcrypt would use it, since according to the web site it encrypts in CBC mode with a random IV. It also makes me wonder why it's called "key wrapping", a name that axcrypt seems to have interpreted literally. NIST Special Publication 800-38F (which may or may not be what axcrypt calls the "specification for AES Key Wrap"—there's another document titled "AES Key Wrap Specification" on nist.gov that appears to have no official status) explicitly says that key wrapping is for "the protection of the confidentiality and integrity of cryptographic keys". The idea that there needs to be a special encryption technique for cryptographic keys is rather weird, and even weirder is the idea that you can somehow improve security by encrypting your keys. It does sometimes make sense to encrypt keys—PGP uses a symmetric key encrypted with a public/private key because symmetric encryption is much faster, and TrueCrypt uses a per-volume key encrypted with a key derived from the passphrase so that you can change the passphrase without re-encrypting the whole volume. But you can't keep a key secret by encrypting it—you're just trading it for another.

Axcrypt may be fine, but they seem to have been unaware of standard cryptographic practice and invented their own scheme, which is not a good sign. Key wrapping is another item on my list of things whose existence I find inexplicable. -- BenRG (talk) 00:34, 7 March 2013 (UTC)

The big question is (as others alluded to) which version of zip did you use, and thus which encryption did it use. Version 5.2 was the change. As for what kind of key-rates you can actually expect, whether on a cpu, or a gpu, you'd just have to test. Those things are highly dependent. The Tom's Hardware guide one above is a good benchmark because it is analyzing WPA cracking which uses the same key creation algorithm that zip does, so those numbers would give you a good guide, although, WPA uses 4096 iterations, whereas zip uses only 1,000, so divide accordingly. Shadowjams (talk) 23:11, 6 March 2013 (UTC)

As I said, it was a long time ago - maybe 8 or more years now I think about it. Not sure if I used an early-ish version of Winzip (certainly no newer than 8.1, and may have been as old as 6.something), or if I used an even older DOS version of pkzip (probably a version 2.something). Astronaut (talk) 17:23, 7 March 2013 (UTC)

WIndows 8 dual monitors or extended monitor?

I have Windows 8. Its new. I have two monitors. First question, is setting them up as 'extended' the same as having 'dual monitors'? I think it should be. What I'm trying to do is open one browser window (Firefox if that mattered) in the extra monitor, to a webcam (animals in africa), and then fill the side monitor with 'full screen', while I do emails or read other things in a separate browser window on my main screen. The problem seems to be that any 'click' of the mouse or keyboard on the main screen minimizes the picture on the side screen, taking it out of full screen mode. I think I know its possible to do what I'm trying to do, because twice I have had it working just that way...with the streaming live critter cam on my extra monitor in full screen, while I did whatever I wanted to on the main screen (working mainly on my old desktop, not out on the Windows 8 front screen). I've tried everything, and googled, and watched Youtube Windows 8 tutorials. Any suggestions will be appreciated. — Preceding unsigned comment added by 94.208.75.76 (talk) 19:21, 5 March 2013 (UTC)

What you described is a bug in Flash. I had the same issue as you, and it exists in Linux as well. The easiest solution I found was to use Google Chrome, which uses a version of Flash that doesn't have the bug of un-maximizing. Another option is to not use full screen, and zoom the browser to make the video as large as possible (which I have to do in Linux). --Wirbelwind(ヴィルヴェルヴィント) 21:05, 5 March 2013 (UTC)

Agreed. With old CRT monitors, you could also turn dials on the monitor to increase the horizontal and vertical size, so you could effectively zoom in that way. Since the software knows nothing about this kind of zoom, it can't do anything bad as a result.

As for dual monitors being the same as the "extended window" setting, not quite. Dual monitors just refers to the fact that one computer is using two monitors, with no mention of how they will be used. In addition to the "extended window" option, there's often an option to clone one screen onto the other. Why would you want this ? Perhaps you have a huge, low-res wide-screen TV, and a small, but hi-res monitor. You could use the small monitor to set up options to play a movie, where that small text would be blurry on the TV, then actual watch it on the TV, where size is more important than resolution. I've also used such a setup for teaching. StuRat (talk) 21:18, 5 March 2013 (UTC)

Event Standard Syndication

Has anyone heard of Event Standard Syndication? I just noticed an SPA changing our disambiguation page ESS to an article about that, and tried to talk with them on their talk page, but got no reply. Consequently, they created the article Event Standard Syndication with the same content. The concept looks quite neat, but I would like some editors experienced in computing to have a look at it. — Sebastian 20:05, 5 March 2013 (UTC)