Disk Utility - erasing the HDD, putting all to zero

Hi,
Ive heard that you should do this several times cause 1 time is not enough is this true?
Also, Once I've done this do I restart the computer, hold the C button and do it again or will I be automatically thrown into that Mac intro video?

Why do you want to erase the HD? The "zero data" option is a security feature, meant to make any data on the HD unrecoverable trough the use of specialized data recovery software. Normally, you would use this only if the HD was being sold or discarded to prevent someone from recovering any sensitive data it contains.
It has no other useful function. It does not 'put all to zero' -- it just writes binary zeros to data sectors, overwriting whatever was there, even if nothing was there to begin with. (Contrary to what some believe, a new drive is not necessarily uniformly filled with zero data bytes or any other specific data pattern when it leaves the factory. Mostly, it is just garbage, whatever is left over from the factory testing process.)
So there is no benefit in doing this even once unless you are doing it for security reasons. Moreover, there is some debate about the need to do one of the multi-pass secure erase options even for security reasons on any modern, high precision, high density drive you are likely to have. The 7 pass option is based on an obsolete U.S. Department of Defense (DOD) specification & the 35 pass one is intended to defeat the exploitation of a characteristic of much older drives -- they could not precisely keep the head in the center of the track, so it was possible to read residual data patterns from the track edges to recover them. Modern drives must very precisely position the head because track densities are so high, so it is extremely unlikely that much data could be recovered this way, & some experts estimate that it could take weeks or months to recover enough data using this technique to make it worth trying, even for the most valuable data.
So basically, unless your drive has sensitive data on it worth millions of dollars and might fall into the wrong hands there is no truth to what you have heard.
Regarding your second question, if you erase the drive (either normally or securely) there is no movie or anything else on it until you install it.

Similar Messages

Disk Utility missing the Erase tab

Tonight, I was attempting to reformat my Mac Mini FileVault encrypted hard drive. I have Mountain Lion 10.8 installed on it, and I have a bootable Mountain Lion USB stick.
I booted from the USB device, and first tried to format. Everything was greyed out. I had to "Unlock" the encrypted drive and then it was available.
I then tried to do an Erase, and it failed with an error I didn't catch, and then only "Macintosh HD" shows up (no volume below it in Disk Utility) and the Erase tab is unavailable. The Partition tab is also locked and nothing can be chosen.
I can Verify and Repair with no problems, but I am unable to repartition or erase the drive.
Any thoughts?

I ran in to this issue once again, when trying to clean install Mountain Lion on my MacBook. I rebooted to the Recovery partition, and tried to format/erase using Disk Utility and that failed and left the system where only the drive (Macintosh HD) would show up, and Erase was greyed out. I was unable to format using the command line due to seeing the message:
"The disk is in use by Core Storage as a Physical Volume"
I found a solution here:
http://apple.stackexchange.com/questions/59026/how-to-install-mountain-lion-on-a -disk-that-cannot-be-formatted-in-recovery-mode
See the post by Anderson, where he shows how to clobber this Core Storage volume:
Basically, you need to run diskutil CoreStorage list from Terminal. Identify the logical CoreStorage volume from that list and note the UUID string.
Then type diskutil CoreStorage delete UUID where UUID is the string you identified.
You can then partition with Disk Utility and run a Mountain Lion install.
This did the trick for me, and I was then able to 0-byte format the drive and do a clean install over the internet.

Disk Utility - Erase Free Space-what does it really do?

Hey Forum,
I am using mac os 10.6.4 on my macbook and i have a doubting question for quite sometimes, what does disk utility erase free space feature really do? Does it gives you more free space? or what? I know it prevents the recovery of deleted files but i want to know what more it does and do not do? Like, now my hdd free space kept increasing and decreasing, by a few 100 mbs or 50mbs etc, so do i erase free space so to solve this problem? Ok, i do not only want to know does it solve the previous problem, but also the questions stated in the whole long paragraph i have wrote. If you know anything related to disk utility's erase free space, feel free to tell me!
Pls help me, I need you guys' help!
Thank you.
Regards
Ala.

Erase free space simply writes zeros over the space occupied by deleted files to prevent data recovery. That's all it does. It does not give you extra disk space.
Your disk space goes up and down a bit because the system creates temporary files and logs which take up space, such as the Safari cache. You can clear these file using a utility like Onyx (which is free)

Macintosh HD won't boot, but disk utility says "The volume Macintosh HD appears to be OK." How do I repair the hard drive?

I have a MacBook that needs its internal hard drive's Macintosh HD partition repaired, as the boot screen freezes on startup. I am running a separate, working mac OS from an external hard drive in order to run disk utility and repair the MacBook's internal OS. The issue is, it has dismounted the internal Macintosh HD partition, and won't remount. And in addition to that, the Verify Disk option returns with, "The volume Macintosh HD appears to be OK." I've run Verify Disk and Repair Disk a few times, all with that same result. And the internal OS still won't boot.
I have attempted to make a disk image of the internal Macintosh HD partition and save it to my external hard drive so I can wipe the internal hard drive clean and restore the image, but I receive errors when trying to create the disk image, and when trying to erase the hard drive (I know, I should try to erase the hard drive when I haven't made an image. When I tried to erase the hard drive, the image wasn't done and I thought it was. I got an error for erase, and I got an error for making the disk image) I have tried making a disk image multiple times and haven't been able to create one.
There is also a boot camp partition on the internal hard drive which is of no importance as to whether it stays or is erased.

Reinstall OS X without erasing the drive
Do the following:
1. Repair the Hard Drive and Permissions
Boot from your Snow Leopard Installer disc. After the installer loads select your language and click on the Continue button. When the menu bar appears select Disk Utility from the Utilities menu. After DU loads select your hard drive entry (mfgr.'s ID and drive size) from the the left side list. In the DU status area you will see an entry for the S.M.A.R.T. status of the hard drive. If it does not say "Verified" then the hard drive is failing or failed. (SMART status is not reported on external Firewire or USB drives.) If the drive is "Verified" then select your OS X volume from the list on the left (sub-entry below the drive entry,) click on the First Aid tab, then click on the Repair Disk button. If DU reports any errors that have been fixed, then re-run Repair Disk until no errors are reported. If no errors are reported click on the Repair Permissions button. Wait until the operation completes, then quit DU and return to the installer.
If DU reports errors it cannot fix, then you will need Disk Warrior and/or Tech Tool Pro to repair the drive. If you don't have either of them or if neither of them can fix the drive, then you will need to reformat the drive and reinstall OS X.
2. Reinstall Snow Leopard
If the drive is OK then quit DU and return to the installer. Proceed with reinstalling OS X. Note that the Snow Leopard installer will not erase your drive or disturb your files. After installing a fresh copy of OS X the installer will move your Home folder, third-party applications, support items, and network preferences into the newly installed system.
Download and install the Combo Updater for the version you prefer from support.apple.com/downloads/.

My external LaCie drive gets an error message "the disc you inserted was not readable by this computer." The only options offered are "ignore" or "eject" Disk Utility sees the disc but does not give a repair option. What can I do?

When I plug in my external LaCie drive I get an error message "the disc you inserted was not readable by this computer."
The only options offered are "ignore" or "eject"
Disk Utility sees the disc but does not give a repair option.
What can I do?

The good thing about mac-centric resellers such as OWC, is they have people on staff that can answer questions without you buying things first. They also have how-to information, and instructions are included in many of their products. I saw a link to watch a DIY video in one of their pages; an example of a RAID (with its own power supply) is shown on their drives page. Also a few in there, with no power supplies, for less money.
If I were looking to backup and perhaps also have a partition for a system clone, I'd consider something like one of these: http://eshop.macsales.com/shop/firewire/1394/USB/EliteAL/eSATA_FW800_FW400_USB
Some ideas on the RAID backup methods appear in google search, some of the pages are ideas and concepts; and the better ones also warn about using RAID for the only backup plan.
Oh, OWC has live chat. Haven't tried it, nor have I bought anything from them. I have what appears to be two products from them, but have not used either. One is in a box as-new, but has only USB2.0 ports & my Macs needed FW400/800. It has been said their RAM is a good way to upgrade, too. But I can't confirm!
A 'RAID-ready' unit for backup may be more versatile for just that, but I have not checked into these details. I use single HDDs in powered enclosures, and usually manually make backup clones to FW drives, of bootable OS X systems. Some of the OWC raid-ready use eSATA ports so that may not be viable for a computer without them.
The unused in-box external drive I have is like the base model in the link above. However mine is USB2.0 (maybe) and won't boot my older Macs due to hardware variance; and my preference would be for FireWire options, these models do offer that. But the one I have does not. Dual 500GB HDDs, and they could be used in tandem as a RAID. That would be a choice set up in software. I'm not sure and not interested enough to read up just now.
My backup method is not automatic, or a moving backup plan, if I don't get a move-on and make full system clones. I do make copies of photos and documents the manual way, to USB external drives; and occasionally backup to DVD or CD media. And USB flash, that helps to move files between computers without need to use file sharing via wi-fi. {Like Why fly? Walking is better exercise unless one is a bird. Squawk!}
https://www.google.com/#q=raid+backup+mac
Depending on the ports in your Mac, you may be able to use other cables to attach between a backup or externally enclosed hard disk drive with multiple partition and bootable clone in one of them. Not sure about the Thunderbolt, and where that is the main port, adapters are required to access other devices, as allowed.
Anyway, I am going on and on, yet not really saying anything.
My ideas would not be all that interesting to follow as a backup
plan when matching available newer hardware to task, but you
can get some into better ideas if you are not in a rush. Get a
good setup and then look into more an betterer stuff.
Good luck & happy computing!

How can you reinstall SL on a older mini, I just upgraded to Lion .Since I downloaded it, I made a disk copy for the future when all the kinks are work out. But would really like to go back to SL for now. I tried my reinstall disk, which didn't work.

I have an older Mac mini using SL as my last upgrade and really like it.. Just last week I upgraded to Lion, and do not like it,,,I would like to reinstall SL but do not know how to go about it,,,I did burn a copy of Lion and will reinstall it when all the kinks are worked out..Can someone tell me how uninstall Lion and reinstall SL.....Thx

Downgrade Lion to Snow Leopard
1. Boot from your Snow Leopard Installer Disc. After the installer loads select your language and click on the Continue button. When the menu bar appears select Disk Utility from the Utilities menu.
2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Note the SMART status of the drive in DU's status area. If it does not say "Verified" then the drive is failing or has failed and will need replacing. SMART info will not be reported on external drives. Otherwise, click on the Partition tab in the DU main window.
3. Under the Volume Scheme heading set the number of partitions from the drop down menu to one. Set the format type to Mac OS Extended (Journaled.) Click on the Options button, set the partition scheme to GUID then click on the OK button. Click on the Partition button and wait until the process has completed.
4. Quit DU and return to the installer. Install Snow Leopard.
This will erase the whole drive so be sure to backup your files if you don't have a backup already. If you have performed a TM backup using Lion be aware that you cannot restore from that backup in Snow Leopard (see below.) I suggest you make a separate backup using Carbon Copy Cloner 3.4.1.
If you have Snow Leopard Time Machine backups, do a full system restore per #14 in Time Machine - Frequently Asked Questions. If you have subsequent backups from Lion, you can restore newer items selectively, via the "Star Wars" display, per #15 there, but be careful; some Snow Leopard apps may not work with the Lion files.

Disk Utility Error: The underlying task reported failure on exit 1

    #!/bin/bash
      # Author : Bill Hernandez
    # Location : Plano, Texas
    # Updated : Saturday, June 6, 2009 (1:48 PM)
    # script name : setdisk_ownerenabled
    # make sure to set permissions to execute
    <hr>
    # Description :
    <hr>
    # I've noticed that sometimes when using disk utility I cannot repair permissions, or I might get :
    # ERROR: The underlying task reported failure on exit 1
    # This shell script seems to have solved the problem.
    # It worked very well for me,
    # IF YOU USE THIS SCRIPT, IT IS AT YOUR OWN RISK...
    # DO NOT USE IT UNLESS YOU UNDERSTAND WHAT IT DOES
    # After running it, it is best to restart before using Disk Utility again
    <hr>
    # Details :
    <hr>
    # After partitioning a disk using "Disk Utility", and then begin using it, at some point I would get
    # an arror message when trying to save to one of the partitions, yet when I looked at the permissions
    # everything looked fine. I would then try to use Disk Utility to repair permissions and end up with a
    # cryptic error that pretty much told me nothing.
    # I noticed that while in Disk Utility, if I selected a partition the lower LH corner of the dialog
    # showed : Owners Enabled : No
    # I tried selecting the partitions at the Desktop and doing a (CMD-I) and at the very bottom of each
    # info dialog there was a checkbox :
    # [ ] ignore ownership of this volume
    # which I would check, even after logging in as root, and I couldn't seem to get a consistent way
    # to get rid of the permissions dialog failure, so I found the vsdbutil command which can be used
    # as follows to get partition, or disk info :
    # $ vsdbutil -c /Volumes/driveor_partitionname
    # ----> Permissions on '/Volumes/driveor_partitionname' are enabled.
    # if it is not enabled you can enable the disk or partition using :
    # $ vsdbutil -a /Volumes/driveor_partitionname
    # It will set "Owners Enabled : Yes"
    # This below script loops through the mounted disks, partitions, etc. and gives you information.
    # You can leave the three flags below all set to TRUE, or selectively use what you want and change
    # the rest to false...
    <hr>
    # CHOOSE {"TRUE", "FALSE"}
    <hr>
    getvolumestatus="TRUE"         # get "Owners Enabled : (Yes|No)" status
    setvolumestatus="TRUE"         # set "Owners Enabled : Yes"
    list_volumes="TRUE"                   # show volume names
    <hr>
    # DO NOT CHANGE ANYTHING BELOW HERE
    <hr>
    if [ $getvolumestatus == "TRUE" ]; then
     echo '============================='
     echo '$getvolumestatus'
     echo '============================='
     # get "Owners Enabled : (Yes|No)" status
     for i in $( df -l | sort -u | awk '{print $6}' | grep '/' ); do
     vsdbutil -c $i
     done
    fi
    <hr>
    if [ $setvolumestatus == "TRUE" ]; then
     echo '============================='
     echo '$setvolumestatus'
     echo '============================='
     sudo echo -n
     # set "Owners Enabled : Yes"
     for i in $( df -l | sort -u | awk '{print $6}' | grep '/' ); do
     sudo vsdbutil -a "$i"
     echo "setting Owners Enabled : Yes for ---> $i"
     done
    fi
    <hr>
    if [ $list_volumes == "TRUE" ]; then
     echo '============================='
     echo '$list_volumes'
     echo '============================='
     for i in $( df -l | sort -u | awk '{print $6}' | grep '/' ); do
     echo $i
     done
    fi
    <hr>


As it turns out, this didn't completely solve the problem, it solved part of the problem.
Here is a summary to the root cause of the problem.
SUCCESS...
Problem Summary : The system crashed and would hangup during boot, tried many things, until I eventually erased the disk and started over again.
iMacG5 24 GHZ Intel with One internal disk partitioned into 3 logical drives
Cub_1 OS X 10.5.7
Cub_2 OS X 10.5.7 (Carbon Copy Cloner backup of Cub_1)
Cub_3 OS X Server 10.5.7 (standard os x server setup)
At some point after setting up standard preferences, OS X Server crashed.
When I tried to restart, the machine would hang up during boot.
Finally after several attempts, ran Disk Utility from install dvd and repaired Cub_3
When I tried to run "Repair Permissions" on Cub_3 from install dvd, I got an error
Disk Utility Error: The underlying task reported failure on exit 1.
Rebooted, and started in single user mode (CMD-S) during boot until I saw the unix commands on the screen
RAN : root # fsck -fy
Then I began seeing the same command filling the screen :
posix_spawnp("/usr/sbin/mDNSResponder") could not find file or directory
Called Enterprise Support and spoke to Frank Alcorn, he said this was most likely a permissions problem and asked me to try repairing permissions from the install dvd. I told him about the error, but nevertheless I tried it again and got the same Disk Utility Error: The underlying task reported failure on exit 1..
He asked me to try booting into single user mode again, and to try
root # chmod 775 /
root # reboot
During the reboot process the machine got hung up again, and could not get the single user mode to work at all.
Frank said the command needed to be :
root # chmod 1775 /
Frank asked me if I had changed anything in file sharing, and I told him I had. He asked me what I had shared, and I said the entire drive Cub_3. He asked me what I had done for permissions, if I had denied permissions to anyone. I told him that I had set myself up as the only user that could have access to it, and when he said that's where the problem was the lightbulb went off, and it made sense.
Shortly after I set the sharing preferences is when the server crashed. It all makes sense now...
Frank said not to share the entire disk, only portions (share points) of it. I had done this in Panther Server, and Tiger Server and it worked fine, but apparently Leopard Server works a little differently, maybe more secure.
It seems to me that if sharing the entire disk, which is what I needed would cause such a problem there should have been some sort of warning from the operating system, but there wasn't. I had run into this problem several times over the past three weeks since I had started working with Leopard Server, but in each case I ended up re-installing OS X Server and starting over again.
I told him I would try to reboot from the OS X partition (Cub_1) and try it from there.
He asked me to let him know if it worked, and I said I would...
Problem FIX :
I booted back into the partition containing OS X (Cub_1) and did the following via the Terminal.
$ su - root
$ chmod 1775 /
$ reboot
During the reboot process I held down the (OPTION) key, and selected Cub_3 (the os x server partition) and sure enough after a few minutes of holding my breath the login window magically appeared. So I logged in, and did not have to re-install the server. Hallellujah....
This solved the boot hang problem. It is great to finally have an answer. In retrospect it makes sense, but that's why its hindsight...
The reason for sharing the entire disk in my mind was that since I was the only user on the system, it was easier to have one disk mounted on my workstation rather than several folders. It made sense to me, it still does. I don't need a bunch of folders, just one disk is easier...

Disk utility/erase and lost HD free space

HELP!
In an attempt to clear up space from deleted files I ran the disk utility>erase>erase free space>35-Pass erase deleted files programme. Then did verify disk permissions and repair disk permissions.
Iv now dropped from 7.8GB of free space to 1.8 of free space on the HD. So that things aren't working right. Plus, I can't download music that I bought on iTunes because there isn't enough space on the HD.
How do I get all that space back? What did I do wrong?
All I was doing was trying to free up space from deleted files that Iv been getting rid of. I know that when you delete from one portion of the HD it doesn't always delete it totally off the system only the portion where you're looking at it.
HELP

Do you by any chance have FileVault enabled?

Disk Utility - Erase Free Space - Creating Temporary File Freeze

I used "Erase Free Space" with Disk Utility after trashing several files I no longer wanted on the hard drive or recovered. I used "Zero Out Deleted Files" option. It took over 12 hours before an error message appeared "Your start up disk is almost full. You need to make more space available on your start up disk by deleting files." I thought that was what I was doing. Disk Utility continued but got stuck on "Creating Temporary File." I force quit Disk Utility after several more hours. I had to manually shut down the computer because the restart command wouldn't work. It rebooted and appears to be OK. Evidently, this temporary file consumes significant amounts of disk space. This is an older iMac with 10.4.11 (18 GHz PowerPC G5) - I know, pretty old but I still have OS 9 on it and several files I need to extract before I trash it.
1. Should I do nothing? The iMac seems to be working fine.
2. How do I know if this Temporary File exists and consuming space? Spotlight doesn't find it. Where is it?
3. Is my start up disk in fact almost full? How would I know that?
Thanks!

Then I would not do any secure erasing. It's exceptionally time consuming and unnecessary. Before you take it in for recycling boot it from your OS X installer DVD. Do this:
Drive Partition and Format
1. Boot from your OS X Installer Disc. After the installer loads select your language and click on the Continue button. When the menu bar appears select Disk Utility from the Utilities menu.
2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Click on the Partition tab in the DU main window.
3. Under the Volume Scheme heading set the number of partitions from the drop down menu to one. Click on the Options button, set the partition scheme to GUID then click on the OK button. Set the format type to Mac OS Extended (Journaled.) Click on the Apply button and wait until the process has completed.
4. Select the volume you just created (this is the sub-entry under the drive entry) from the left side list. Click on the Erase tab in the DU main window.
5. Set the format type to Mac OS Extended (Journaled.) Click on the Security button, check the button for Zero Data and click on OK to return to the Erase window.
6. Click on the Erase button. The format process can take up to several hours depending upon the drive size.
A one-pass Zero Data option is all that is required to prevent access to your erased files.

I have a white Macbook 2009 on OSX Lion. It came with the OSX Snow Leopard CD, I erased the HDD and am trying to install the OSX from disc but am getting "cannot install OSX from disc" message. What can I do?

I have a white Macbook 2009 on OSX Lion. It came with the OSX Snow Leopard CD, I erased the HDD and am trying to install the OSX from disc but am getting "cannot install OSX from disc" message. What can I do?
I got the macbook from a friend a few years ago and it already had OSX Lion installed. Whenever it boots from the Snow Leopard disc it says it cannot install from disc. Is there anythingI can do or should I take it to an Apple store to get them to boot OSX Lion for me?

Insert your Snow Leopard disc and restart, press and hold the C key as soon as you hearthe startup chime, hold C until you see the Apple Logo. When your computer starts up you'll be at the first install screen, choose your language and click the arrow to go to the next screen. This screen has a menu bar, from the Utilities menu select Disk Utility, select your hard drive, this is the one with the manufacturers name or numbers, click the partition tab and then delete any existing partitions by selecting them and clicking the minus. In the drop down box select one partition and click apply. Name your hard drive and click erase. When it's done quit DU and go back to the installer, install Snow Leopard. When the installer is done and the computer is back up and running run Software Update to get to 10.6.8

Disk utility erase problem

I am trying to get my ibook G4 ready for sale. I want to do a secure erase of my hard drive. I followed Apple's instructions on the topic, did a boot from the CD, chose disk utility, then erase, then options, I chose 8 times random, then clicked to go ahead. It ran all day (I expected that) and into the night. When I woke up and checked on it, I saw that it was stuck on "partitioning", the blue progress bar was only about half way, and I had the spinning beach ball. An hour later, no change. So I forced a power down. Can anyone tell me what went wrong? It's a 30g Fujitsu original equipment drive and I use OS 10.3.3.

There's really no need to zero data more than one pass. Do the following:
Prepare Your Mac for Sale
Boot from the OS X Installer Disc One that came with the computer. After the installer loads select your language and click on the Continue button. When the menu bar appears select Disk Utility from the Utilities (Installer menu if using Panther or Jaguar) menu. After DU loads select the startup volume from the left side list then click on the Erase tab. Set the format type to Mac OS Extended (Journaled) then click on the Options button. Select the one pass Zero Data option and click on the OK button. Then click on the Erase button.
Note: You can skip the Zero Data option if you are not concerned about removing sensitive personal data from the hard drive. If you choose to skip this part of the process then it is possible for others to recover data from the hard drive. The Zero Data procedure will prevent others from getting access to your personal information.
This process will take 30 minutes to several hours depending upon the size of the hard drive. After formatting has completed quit DU and return to the installer. Now complete the OS X installation. At the completion of the installation do not restart the computer. Instead just shut it off. The next user will be presented with the Setup Assistant when they turn on the computer just as it would if new out of the box.

Killed Disk Utility Erase Free Space. Now 0 available

(I erroneously posted this earlier to the Safari forum; posting here again)
I ran Disk Utility "Erase free space" on my iMac G5 250GB boot drive (I had about 130GB free). It ran for about 50 minutes, and got to "creating temp file" and then seemed to hang (thermometer didn't move for 20 minutes). So I force killed it. It seems to have left that "temp file" that takes up all available space since Disk Utility now reports 0 bytes available (and MS Entourage says insufficient free space and exits). I ran Finder "Secure empty trash" to delete 57 files with no error. But Disk Utility still says 0 bytes available.
First Aid "Verify Disk" reports no problems. "Verify Permissions" reports no problems.
Is there a way to regain my available space?
Thanks,
Ken

Restart did it. Thanks very much.
Ken

Creating a Master virtual hard disk and using the same for all other VM's

Hi,
We would like to create a master virtual hard disk and use the same for all other VM's. Can we do that ?
my requirements :
1) create 10 VM's
2) first create a master virtual hard disk with win OS and use the same to create the 10 VM's.
3) After creating the VM's change the HDD size.
              -- if i have created master virtual disk with 500GB , and use the same for creating a virtual machine. can we change the HDD size to 1TB ?
After creating the VM's ,i will change the system names and activate the windows accordingly.
Will there be any implications ,if we can/will do like this.
Thanks.

Hi Suren424,
I think Using Differencing Disks may cover your needs .
Please refer to following setps:
   "Create the Parent Virtual Machine Configuration and Virtual Hard Disk
    Install the Operating System, updates, and common software
    Generalize the installation
    Prepare the parent virtual hard disk
    Create the differencing disks
    Create virtual machines that use the differencing disks
For details please refer to follwing link:
http://social.technet.microsoft.com/wiki/contents/articles/1393.hyper-v-virtual-machine-vm-parent-child-configuration-using-differencing-disks.aspx
Hope this helps
Best Regards
Elton Ji
We
are trying to better understand customer views on social support experience, so your participation in this
interview project would be greatly appreciated if you have time.
Thanks for helping make community forums a great place.

Disk Utility - Erase Free Space

Hey Forum,
I am using mac snow leopard on my macbook and I wanted to erase the free space on my hard drive, so is the zero-out free space enough, or do I need the 7-pass erase free space. I just wanted more disk space, thats it. So can anyone tell me what are each options for? And do i need to 7-pass erase if i just wanted more disk space?
I await your favorable replies.
Thank you.
Regards.
Ala.

As The hatter says, the erase free space option has nothing to do with creating more free disk space -- the space is already free.
If you are confused about this, just open Disk Utility to the "Erase" tab & click the purple question mark at the bottom of the window. This will open Disk Utility Help to the topic *Erasing disks*. Refer to the last subject, *Securely erasing empty space* & if necessary click the link below it to go to the help topic *Erasing free disk space*, which explains this function in more detail.
FWIW, should you ever need to use this security function, a one pass secure erase is probably adequate to make the data unrecoverable.

SSD - Disk Utility - Erase Free Space

Hi Community,
does the function in disk utility, which erases the free space by writing zeros into it, in context to a SSD drive the same like a block refresh which some drive vendor utilities does to increase the write performance? Or is a block which contains only zeros not really empty for the SSD controller?
Thx & Bye Tom

I am guessing a little here, but I suspect that "Trim" support ensures that data in free space can't be reaccessed once the files are deleted.
Another guess is that erasing the SSD free space may not be a great idea from the point of view of unnecessary writes and also filling the entire usable space up with what may appear to be data.
We are also discussing this subject in a German newsgroup and there we came to the result that the only way to inform the SSD-controller that the content of a specific block is invalid, is either to overwrite a specific logical address, so than the controller knows which physical blocks are invalid or to send the TRIM command.
To write zeros into the empty space is from the controllers point of view only content and will result in a full SSD drive afterwards. As longer I think about this as more I belief that this is correct and the use of the disk utility to refresh a SSD drive isn't the best idea... ;-)
Bye Tom

Disk Utility - erasing the HDD, putting all to zero

Similar Messages

Maybe you are looking for