Wikipedia:Reference desk/Archives/Computing/2014 December 3

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December 3

Damaged HDD

What tools do we have to analyze a possibly physically damaged HDD thatcan still be detected?--Senteni (talk) 17:45, 3 December 2014 (UTC)

You should image the entire HD then only worry about what to do. Or if you can afford it, don't do anything and send it to a professional recovery service (possibly costing $1000 more). Of course the best bet by far is to ensure you never have to recover data from a physically damaged HDD by having good backup practices. Nil Einne (talk) 18:21, 3 December 2014 (UTC)

That's not very helpful. --Senteni (talk) 18:25, 3 December 2014 (UTC)

Imaging requires that the drive be readable. TestDisk saved me a while back. I used it to repair the drive, then used Macrium Reflect to clone the drive. --  Gadget850 ^talk 18:27, 3 December 2014 (UTC)

Reading the TestDisk page, I don't see how it helps if you can't read the disk since all it seems to be doing is fixing partition tables. This what you should never do if you care about the data enough and have sufficient space to fully image the entire disk. Tools like TestDisk should only ever be used on a backup of the image you took, never on the raw disk or even the first image since they could easily make things worse. Well if the physical disk is fine, it's fine to work on the image since you can always take another image if you kill your first one. Similarly, if the tool doesn't modify the image and only tries and recover data elsewhere you can use the image direct. Or even the physical disk direct if it's undamaged and the parts you're interested in aren't mounted or otherwise likely to be modified by anything.

Are you confusing a disk with borked partition table so you can't see any of the partitions to a disk which is physically unreadable? These are quite different things and should not be confused.

If the disk can't be read, you're basically SOL as an end user. Okay there are various things you can try like freezing the disk, but these should only be tried once you've at least attempted to image the disk. They also aren't software. Despite the hype over SpinRite, there's no software tools which can help with a physically damaged disk that's unreadable.

If the disk is damaged but still partially readable, the best you can hope for is a tool which lets you select how many times to try re-reading (keep it to 1 or even zero) and recording what part of the image failed to read properly. This way, you can if you want, try and reread the damaged parts more times later after you've taken your first pass (so you're not not worried about further damage), although you're chance of recovering more is slim. (As I mentioned, if you can afford it you shouldn't do anything, instead pay for a professional recovery service.) There's not really much you can do with software to try and read the disk more beyond trying and trying again.

To be clear, once you have an image, there are plenty of tools you can use to try and recover data from a image/backup of the image (like PhotoRec, TestDisk etc etc), but that's quite a distinct point and it's vitally important you have the image first, particularly in the case of a physically damaged disk.

P.S. In case it still isn't clear, when I say image I mean an image of the entire disk from the first sector to the last (or at least the readable parts thereof) such as made with dd or plenty of other tools. This doesn't require the partition tables can be understood or anything like that, it just requires the disk can be detected by the computer and is at least partially readable.

Nil Einne (talk) 18:36, 3 December 2014 (UTC)

Can you explain why it's unhelpful?

P.S. If you don't want to recover data but simply want to try and work out if the disk may be useable for non mission critical data, I apologise as I found your question fairly unclear. In the later case, I would suggest one or more S.M.A.R.T. tools, perhaps one from your HD manufacturer and one which submits data online for comparison purposes like SpeedFan. You should run a full surface scan using one of these tools, probably one from your manufacturer. Ideally you should always zero fill or otherwise overwrite the entire disk to see if writing is okay. And probably do a surface scan again after zero filling. It may also be helpful to run a full (not partial) speed test on the HD with something like HD Tune and look for any unexpected spikes during reading (and if possible) writing. (Try to keep CPU and HD controller usage to a minimum while testing the speed.) See [1] for an example from a hopefully (it's mine) healthy disk. Bear in mind these tools will often not detect problems until it's way too late, so if you have a good reason to think the disk is physically damaged you shouldn't be using it for anything important. As mentioned before physically damaged or not, you shouldn't be using it to store the sole copy of anything you can't afford to lose.)

Nil Einne (talk) 18:30, 3 December 2014 (UTC)

@Senteni:but imaging/backing up your HDD is very good and common advice that I wish I followed, having had a 500 GB laptop HDD suddenly die on me with no backup! All gone, and I am not even sure what I have lost that is unrecoverable. (Reloading and re-registering lots of games tactical simulations is very tiresome! And I'm having trouble re-registering some! ) --220 of ^Borg 02:35, 6 December 2014 (UTC)

Depends on what you mean by "possibly physically damaged". I have an HDD that has an ongoing problem with random bad sectors (possibly caused by a since-corrected overheating problem). A bad sector in the wrong place can easily brick your computer. I can't speak to "hype" about SpinRite, but for $89 it has kept this HDD alive for several years. I could simply replace it, but I would lose things that are not easily backed up and restored to a new HDD. ‑‑Mandruss ☎ 18:46, 3 December 2014 (UTC)

SpinRite can't magically make failing hardware work. At best it might relocate and mark bad sectors (which chkdsk /r will do for free) or recover files from a badly damaged filesystem (which PhotoRec will do for free). Modern hard drives automatically relocate marginal sectors behind the scenes without reporting them to the OS. If you're seeing a bad sector at the OS level, the drive is usually pretty far gone. The fact that yours has limped along for years is luck, not the power of SpinRite. Spend $89 on a new drive and use SystemRescueCd or a similar free tool to move all your data. -- BenRG (talk) 21:01, 3 December 2014 (UTC)

All I know is 1. My computer becomes unusable. 2. I run SpinRite. 3. SpinRite identifies one or more bad sectors and recovers what it can. 4. My computer becomes usable again. Every time, probably a hundred times now. But yeah it could be just coincidence. And I don't know of a way to transfer all of my paid-for software to a new HDD for free, given that I've lost track of the licensing information for a lot of it. I'm not even sure Windows itself could be transferred for free. And saved emails? Maybe, with some new software and a lot of effort. Or, I could just keep doing what I'm doing for as long as the HDD holds out. ‑‑Mandruss ☎ 23:15, 3 December 2014 (UTC)

If you really have a damaged drive with essencial data on it, never power it up. Crashed heads will destroy the magnetic surface and make the data lost. What is the data's value in US$? --Hans Haase (talk) 09:08, 4 December 2014 (UTC)

Replacing the C:\ disk

Hi there. I have a Dell R5400 (a rack mount). It is a good machine that has served me well. The OS is Windows7 now. The size of the internal disk where the OS resides as well as all my major software is 275 GB. I feel it is a bit restrictive now. I run an Oracle VB with Ubuntu Virtual Machine (VM) and it is where I do all my stuff now. I've also made a mistake of allocating not enough memory to the VM. I cannot update the Ubuntu now, I get errors that I do not have enough memory, etc. I've made this plan and want to hear comments if it is realistic.

I do have a second OS on the second inernal drive. It is a MS Server. So, I want to start it, open cmd prompt in there and use this command: C:\copy *.* G:\*.* By G: I mean an external drive which has a terabyte or so capacity. Hopefully every byte from C:\ will end up there. Then I will purchase a 600 GB Lenovo 15,000 rpm internal drive, insert it in place of my old internal drive C: and copy all code back to it. Some Dell computers have slots for two additional internal drives. Mine does not.

Is it going to work? Thanks, --AboutFace 22 (talk) 20:04, 3 December 2014 (UTC)

No. It's a lot more complicated that that. The copy will not work because certain system files will have "access denied" and will not be copied using the copy command. Secondly, the MBR (master boot record) will also not be copied. The boot files will also not be where they should. etc. etc. Your best approach will be to clone the C drive directly to the 600GB Lenovo drive. Cloning will create a partion that is the same size as the original partition. You will need to resize the partition on the Lenovo and add the unallocated space to the partition afterwards. Google "ultimate boot CD" and use that to do all of the above. It is Linux based. Disclaimer: You could wreck the bootloader and not be able to boot either of the OSs. There is a lot more to it than what I've said but to answer your question - no - your method will not work. Backup! BACKUP! 196.213.35.146 (talk) 07:56, 4 December 2014 (UTC)

Thank you. I do back up regularly. Now I will have to look into it all carefully. --AboutFace 22 (talk) 15:35, 4 December 2014 (UTC)

The easiest way to copy all the data from the Windows 7 OS disk to a new disk is to boot the PC with a linux CD, such as SystemRescueCd, and copy all the contents of the old disk to the new disk, like so:

dd if=/dev/sdx of=/dev/sdy bs=1M

"sdx" and "sdy" should be replaced with the device names of your drives. IMPORTANT: You need to be absolutely certain that you are copying the data in the right direction, otherwise you'll overwrite your Win 7 disk with useless data from the unformatted disk. As long as the new disk is larger than the old one, this should work fine. Next, use the partition manager from the linux CD, and expand the partitions on the new disk to make them use all the space on the new disk. Remove the old disk before booting Windows. Otherwise, there will be error messages complaining about two disks with the same signature, it may refuse to boot, or boot from one of the disks and hide the other disk. --NorwegianBlue ^talk 16:03, 4 December 2014 (UTC)

NorwegianBlue, thank you. It is a cute idea. It would not be difficult for me to implement it. --AboutFace 22 (talk) 01:10, 5 December 2014 (UTC)

What are some of the most secure and affordable wireless routers?

I have a Cisco/Linksys AE2500. Everything in DD-WRT is setup for maximum security, including a 63-character WPA2 password. I have been the target of harassment in the past, and have been hacked, despite the aforementioned security measures. Is the following merely marketing: Box Security If no, any cheaper alternatives? FM99717731 (talk) 20:21, 3 December 2014 (UTC)

First, there is the human factor. See this as user behavior like drivers cause accidents which can not be avoided by engineering of the vehicle's manufacturer. It is what you click. When you read something, alwas think, do I need to click this or do they want me to click this. About WLAN you should know, pending on the country, most of them are unsecured. In public places, WLAN often is free available like the glas of water in an american restaurant. If communication is restricted an monitored, always think, is is for securing agains terrorism or is it to make the current government resilient against other opinions. Is some countries the phone billing system essential part to pay all the monitoring of communication. The US were one of the first with volume billings, some European call this "flatrate". If you need to secure the WLAN, use WPA/WPA2. Never use a simple password to avoid Dictionary attacks. Never give your providers DSL login or personal data away. Change the default password ot the router management login. Check for firmware updated for your router if avail to close backdoors or known security issues. Ensure the firmware is made for your router. A wrong firmware will make the router unable to operate. A firmware from other source or download provider may be compromized. Never use that. In social networks, chats or forums, ignore harassment or simply delete without notice. Ensure the author does not know you removed the harassment. Only make it unsucessful. Never make him know you took notice of it. Never respond. Successful social networks allow to limit access to published information. Use this. Block if not neccessary to grant access. --Hans Haase (talk) 08:30, 4 December 2014 (UTC)

Why do you think you were hacked, and why do you think it was through a flaw in your wireless router? Both sound unlikely to me, especially the second. -- BenRG (talk) 02:17, 5 December 2014 (UTC)

Thanks for your inputs. I believe the main reason I got hacked was my general carelessness with CTRL-C and CTRL-V, plus the fact that I use a clipboard logger. (Ditto) One would only need a packet sniffer and voilà. FM99717731 (talk) 03:05, 5 December 2014 (UTC)

Do you mean you log the clipboard to a remote location or that your clipboard logger supports some sort of remote access? If not, I don't see how it's relevant. If someone were able to get access to your clipboard logger, they could probably install their own clipboard logger, or screw the clipboard logger and just use a keystroke logger. Nil Einne (talk) 01:47, 6 December 2014 (UTC)

Alignment Problem with Access Report

I am using Microsoft Access 2010 on a Windows 7 desktop computer. I created a new database and am trying to print Avery 5162 address labels containing two lines of name fields, one line of address, and one line of city-state-ZIP. I used the Label Wizard to generate a report to produce the labels. When I print the labels, the first line positions above the top of the first label. I have used the same technique with other Access tables to generate Avery 5162 labels, and have compared the Properties of the report and the section of the report that generates a label, and I don’t see any obvious difference, and my existing reports render the labels correctly, but the new report renders the label above the top of the page. I can arbitrarily correct the problem by adding height to the report page header, but that seems kludgy. Does anyone have any suggestions for what I should look at? Robert McClenon (talk) 20:52, 3 December 2014 (UTC)

obert McClenon, if your access report has border widths in the page settings, set them to 0 or possible minimum. Sometimes, data has longer text strings a fit into the reports text field. Enlarge the filds inside the label as large as possible. When even too large, some labels remain empty. Check this in preview. When names differ in lenght, combine data into one field of the report.

For example, never use

field1=[addresstable.firstname] field2=[addresstable.middlename] field3=[addresstable.lastname]

field4=[addresstable.house] field5=[addresstable.street]

field6=[addresstable.zipcode] field7=[addresstable.city] field7=[addresstable.state]

field7=[addresstable.country]

Better to use:

field1=trim(replace([addresstable.firstname]&" "&[addresstable.middlename]&" "&[addresstable.lastname]," "," "))

field4=trim(replace([addresstable.house]&" "&[addresstable.street]," "," "))

field6=trim(replace([addresstable.zipcode]&" "&[addresstable.city]&" "&[addresstable.state]," "," "))

field7=[addresstable.country]

to fit the data into the label. --Hans Haase (talk) 08:56, 4 December 2014 (UTC)

Check text items are free of control characters like CR/LF/TAB or anything below ASC(32). --Hans Haase (talk) 12:30, 4 December 2014 (UTC)

Thank you. I haven't gotten it to work yet, but am still trying. By the way, in the United States, the postal code follows the city and state, but that doesn't matter for the example. Robert McClenon (talk) 20:56, 4 December 2014 (UTC)