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openSUSE:SUSE Studio Disc Image Howtos

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How to image USB flash drives (in Linux)

  • To make a bootable USB stick from the appliance you've created, select the disk image type in the build tab, and then build and download the gzip-compressed appliance. Uncompress and untar the appliance.

The GUI way

The dd way

  • In order to write your appliance to a USB stick, you will need to find the device to write to. After inserting the USB stick, open a terminal and type:
    df
  • You will see output similar to this:
/dev/sda2             30969600  15533336  13863100  53% /
udev                   1997904       108   1997796   1% /dev
/dev/sda5             92888248  85548000   2621560  98% /home
/dev/sda6             23671572    935276  21533836   5% /var
/dev/sdb1              7816228      1492   7814736   1% /media/disk
  • The last entry should be the USB stick you just plugged in. If you're in doubt, try removing it, running df again, and see if the line disappears. The left column in df's output is the partition, and the path up to the number is the path to the device. In our example, '/dev/sdb1' is the partition, and '/dev/sdb' is the path to the device.
  • Important note: It is really, really important that you get the device path right - you can cause irreparable damage to your system if you don't.
  • After finding the device path, you will need to run dd to write your appliance to the USB stick. dd needs two arguments: the input file (your appliance), and the output file (the path to your USB device). In our example, the input file is named "/home/suse/myappliance.raw" and the path to the device is "/dev/sdb", so we would run this command from a terminal window:
    sudo dd if=/home/suse/myappliance.raw of=/dev/sdb bs=4k conv=fdatasync
  • The next to last argument (bs=4k) is optional, but adding it will make writing to the USB device much faster. The conv=fdatasync argument should ensure the appliance is fully written to the USB device prior to dd completing.
  • Please bear in mind that this will *completely overwrite the USB device so make sure you don't have any important data on it first!
  • Writing to a USB stick is usually quite slow, so don't be alarmed if it seems like it takes forever. When dd has finished, it will tell you some statistics about how much data it has written to the USB stick. If your USB stick has a light on it that blinks when data is being written, wait until it stops blinking before removing it.
  • Note: As writing images blockwise is a critical process, please compare the md5sums of the raw image and the newly created device
    md5sum /home/suse/myappliance.raw
    md5sum /dev/sdb
  • Now you have a custom software appliance ready to be booted from your USB stick!

To get persistence on live hybrid USB stick system you have to create second partition on the stick:

 fdisk /dev/sdb
 The number of cylinders for this disk is set to 3935.
 There is nothing wrong with that, but this is larger than 1024,
 and could in certain setups cause problems with:
 1) software that runs at boot time (e.g., old versions of LILO)
 2) booting and partitioning software from other OSs
 (e.g., DOS FDISK, OS/2 FDISK)

 Command (m for help): n
 Command action
 e extended
 p primary partition (1-4)
 p
 Partition number (1-4): 2
 First cylinder (661-3935, default 661):
 Using default value 661
 Last cylinder, +cylinders or +size{K,M,G} (661-3935, default 3935):
 Using default value 3935

 Command (m for help): w
 The partition table has been altered!
 
 Calling ioctl() to re-read partition table.
 Syncing disks.

How to image USB flash drives (in Windows)

The GUI way

The hard way

  • Danger! This instruction is for experts!
    You can cause irreparable damage to your system if you make errors here.
  • To make a bootable USB stick from the appliance you've created, select the disk image type in the build tab, and then build and download the gzip-compressed appliance. Uncompress and untar the appliance. Perhaps you can use 7-zip, a tool unter GNU LGPL licence.
  • In order to write your appliance to a USB stick in a Windows enviroment, you will need to the 'dd for windows' tool.
  • To find the device to write, after inserting the USB stick, open the command line (cmd) and type:
    dd --list
  • You will see output similar to this:
C:\temp>dd --list
rawwrite dd for windows version 0.5.
Written by John Newbigin <jn@it.swin.edu.au>
This program is covered by the GPL.  See copying.txt for details
Win32 Available Volume Information
\\.\Volume{ac56bf46-66cc-11dc-86f6-806d6172696f}\
  link to \\?\Device\HarddiskVolume1
  fixed media
  Mounted on \\.\c:

\\.\Volume{ac56bf47-66cc-11dc-86f6-806d6172696f}\
  link to \\?\Device\HarddiskVolume2
  fixed media
  Mounted on \\.\d:

\\.\Volume{d8bf0b41-66cd-11dc-a7a7-806d6172696f}\
  link to \\?\Device\CdRom0
  CD-ROM
  Mounted on \\.\e:

\\.\Volume{65668b14-8a7b-11dd-ab31-545543445208}\
  link to \\?\Device\Harddisk1\DP(1)0-0+8
  removeable media
  Mounted on \\.\f:


NT Block Device Objects
\\?\Device\CdRom0
  Removable media other than floppy. Block size = 2048
  size is 695670784 bytes
\\?\Device\Harddisk0\Partition0
  link to \\?\Device\Harddisk0\DR0
  Fixed hard disk media. Block size = 512
  size is 120034123776 bytes
\\?\Device\Harddisk0\Partition1
  link to \\?\Device\HarddiskVolume1
\\?\Device\Harddisk0\Partition2
  link to \\?\Device\HarddiskVolume2
\\?\Device\Harddisk0\Partition3
  link to \\?\Device\HarddiskVolume3
  Fixed hard disk media. Block size = 512
  size is 6366334464 bytes
\\?\Device\Harddisk0\Partition4
  link to \\?\Device\HarddiskVolume4
  Fixed hard disk media. Block size = 512
  size is 468808704 bytes
\\?\Device\Harddisk1\Partition0
  link to \\?\Device\Harddisk1\DR7
  Removable media other than floppy. Block size = 512
  size is 1014497280 bytes
\\?\Device\Harddisk1\Partition1
  link to \\?\Device\Harddisk1\DP(1)0-0+8
  Removable media other than floppy. Block size = 512
  size is 1014480896 bytes

Virtual input devices
 /dev/zero   (null data)
 /dev/random (pseudo-random data)
 -           (standard input)

Virtual output devices
 -           (standard output)

C:\temp>
  • The entry we are looking for is the one that says removable media which is the USB stick you just plugged in. If you're in doubt, try removing it, running dd --list again, and see if the line disappears. The information we need is the \\.\f:
\\.\Volume{65668b14-8a7b-11dd-ab31-545543445208}\
  link to \\?\Device\Harddisk1\DP(1)0-0+8
  removeable media
  Mounted on \\.\f:
  • Important note: It is really, really important that you get the device path right - you can cause irreparable damage to your system if you don't.
  • After finding the device path, you will need to run dd to write your appliance to the USB stick. dd needs two arguments: the input file (your appliance), and the output file (the path to your USB device). In our example, the input file is named "c:\temp\myappliance.raw" and the path to the device is "\\.\f:", so we would run this command from a terminal window:
    dd if=c:\home\suse\myappliance.raw of=\\.\f: bs=4k
  • The last argument (bs=4k) is optional, but adding it will make writing to the USB device much faster.
  • Please bear in mind that this will *completely overwrite the USB device so make sure you don't have any important data on it first!
  • Writing to a USB stick is usually quite slow, so don't be alarmed if it seems like it takes forever. When dd has finished, it will tell you some statistics about how much data it has written to the USB stick. If your USB stick has a light on it that blinks when data is being written, wait until it stops blinking before removing it.
  • Now you have a custom software appliance ready to be booted from your USB stick!

How to check the MD5SUM of the raw image and the USB stick

  • We got some feedback that defective USB sticks can show problems with whole systems but not with single files. If your USB stick shows confusing behavior check the MD5SUM to be sure that your Linux system is not broken.
  • Note: As writing images blockwise is a critical process, please compare the md5sums of the raw image and the newly created device
    md5sum /home/suse/myappliance.raw
    md5sum /dev/sdb

How to copy an image into hard disc

  • That is the same case as How to copy an image into the USB drive but with the difference that you need to boot with some external media, like another USB stick or livecd with the dd tool in it.
  • An alternative is to boot from some live medium and then transfer the image over the network from another machine. To do that you need a live medium which contains netcat and you have to execute the following command on the machine, where the image should be written to:
 netcat -l -p1234 | dd of=/dev/sda

Make sure that the of argument points to the disk you want to write to. Content on this disk will be lost.

Then on the machine where the image is execute this command:

 dd if=/path/to/image.raw | netcat 1.2.3.4 1234

Replace 1.2.3.4 by the IP address of the machine you are writing to. 1234 is just a random network port. Use a different number here, if needed.

How to change configurations on disc image

  • You can mount the disc image by using the following command:
kpartx -av yourimage.raw <- this will tell you the mapper. i.e loop0p1
mount /dev/mapper/loop0p1 mnt/ <- substitute loop0p1 for the mapper you got in the previous command
  • Then change whatever you want to change and umount.

How to try out an image on qemu

  • You can try out the images on qemu before copying them into USB or disc. Even thought you can do that with qemu, I would recommend to use qemu-kvm as it has a better performance. In any case, the disc image has no free space, as it would expand on the USB or disc, but it would not on qemu. So, after making a copy of it, you can add some free space by doing:
dd if=/dev/zero of=image.raw bs=1 count=1 conv=notrunc seek=3G	
  • And then try the image on qemu or qemu-kvm:
qemu image.raw	
  • or
qemu-kvm image.raw
  • or
qemu-kvm --snapshot -m 512 image.raw

How to make a USB drive bootable

  • It is known that in some situation the USB drive would not boot. Even sometimes it will boot once and stop booting afterwards. The problem is that the main partition should be marked as bootable. In order to do that, connect the usb disk and from a terminal do:
    (/dev/sdb has to be your USB: Make sure of that!)
umount /dev/sdb1 (and any other partition you have mounted automatically. Check it with the mount command)
fdisk /dev/sdb
\tp     «--- print partition table
\ta     «--- activate partition (bootable)
\t1 «--- partition 1 is bootable
\tw    «--- write changes to partition table