Difference between revisions of "DevKit8600 FAQ"
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Q1: How to alter an existing Root File System? | Q1: How to alter an existing Root File System? | ||
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1. Uncompress the file into an image file; | 1. Uncompress the file into an image file; | ||
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− | + | #cd ramdisk.gz | |
+ | |||
+ | #gunzip ramdisk.gz | ||
2. Mount the uncompressed image file to realize alteration; | 2. Mount the uncompressed image file to realize alteration; | ||
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− | + | #mkdir /mnt/loop | |
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− | + | #mount –o loop ramdisk /mnt/loop | |
+ | |||
+ | #cd /mnt/loop | ||
+ | |||
Now the contents of the file system can be added, removed, or modified as required. | Now the contents of the file system can be added, removed, or modified as required. | ||
3. Unmount the image file; | 3. Unmount the image file; | ||
− | + | ||
− | + | /#cd ramdisk | |
+ | |||
+ | #umount /mnt/loop | ||
4. Create a compressed file by using the altered file system; | 4. Create a compressed file by using the altered file system; | ||
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− | Q2: | + | #gzip –v9 ramdisk |
+ | |||
+ | Q2: How to create a new Root File System? | ||
+ | |||
(Approach one) | (Approach one) | ||
− | + | 1. Create a temporary mounting point for loop devices; | |
− | + | ||
+ | #mkdir /mnt/loop | ||
+ | |||
+ | 2. Create a 15M temporary file; | ||
+ | |||
+ | #dd if=/dev/zero of=/tmp/loop_tmp bs=1k count=15360 | ||
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The size of the temporary file could be changed by adjusting the value of the parameter count; | The size of the temporary file could be changed by adjusting the value of the parameter count; | ||
− | + | 3. Associate device file with the temporary file; | |
− | + | ||
+ | #losetup /dev/loop0 /tmp/loop_tmp | ||
+ | |||
If a message ‘ioctl:LOOP_SET_FD: device is busy’ appears, it indicates that the device /dev/loop0 is still associated with another file. Command losetup /dev/loop0 can be used to view the device, and remove it with parameter -d; | If a message ‘ioctl:LOOP_SET_FD: device is busy’ appears, it indicates that the device /dev/loop0 is still associated with another file. Command losetup /dev/loop0 can be used to view the device, and remove it with parameter -d; | ||
4. Format /dev/loop0 as ext2 file system; | 4. Format /dev/loop0 as ext2 file system; | ||
− | + | ||
− | #mke2fs –m 0 /dev/loop0 | + | #mke2fs –m 0 /dev/loop0 |
5. Mount the virtual disk on the mounting point /mnt/loop; | 5. Mount the virtual disk on the mounting point /mnt/loop; | ||
− | + | ||
+ | #mount –t ext2 /dev/loop0 /mnt/loop; | ||
6. Copy all the required files to the virtual disk by the command cp -af; | 6. Copy all the required files to the virtual disk by the command cp -af; | ||
− | + | 7. Move from current directory /mnt/loop to another directory by the command cd, and then unmount the file system; | |
− | + | ||
+ | #cd /xx (xx means any directories except /mnt/loop) | ||
+ | |||
#umount /mnt/loop | #umount /mnt/loop | ||
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1. Create a temporary mounting point for loop devices; | 1. Create a temporary mounting point for loop devices; | ||
− | + | #mkdir /mnt/loop | |
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Revision as of 03:29, 6 November 2012
Q1: How to alter an existing Root File System?
Let’s assume there is a compressed file system named ramdisk.gz. We could realize alteration on it by the following steps:
1. Uncompress the file into an image file;
#cd ramdisk.gz
#gunzip ramdisk.gz
2. Mount the uncompressed image file to realize alteration;
#mkdir /mnt/loop
#mount –o loop ramdisk /mnt/loop
#cd /mnt/loop
Now the contents of the file system can be added, removed, or modified as required.
3. Unmount the image file;
/#cd ramdisk
#umount /mnt/loop
4. Create a compressed file by using the altered file system;
#gzip –v9 ramdisk
Q2: How to create a new Root File System?
(Approach one)
1. Create a temporary mounting point for loop devices;
- mkdir /mnt/loop
2. Create a 15M temporary file;
- dd if=/dev/zero of=/tmp/loop_tmp bs=1k count=15360
The size of the temporary file could be changed by adjusting the value of the parameter count;
3. Associate device file with the temporary file;
- losetup /dev/loop0 /tmp/loop_tmp
If a message ‘ioctl:LOOP_SET_FD: device is busy’ appears, it indicates that the device /dev/loop0 is still associated with another file. Command losetup /dev/loop0 can be used to view the device, and remove it with parameter -d;
4. Format /dev/loop0 as ext2 file system;
- mke2fs –m 0 /dev/loop0
5. Mount the virtual disk on the mounting point /mnt/loop;
- mount –t ext2 /dev/loop0 /mnt/loop;
6. Copy all the required files to the virtual disk by the command cp -af;
7. Move from current directory /mnt/loop to another directory by the command cd, and then unmount the file system;
- cd /xx (xx means any directories except /mnt/loop)
- umount /mnt/loop
The file at /tmp/loop_tmp is the image of file system.
8. Compress the image file to create a file system;
- gzip –v9 /tmp/loop_tmp >/tftpboot/ramdisk.gz
or
- gzip –v9 /tmp/loop_tmp
(Approach two)
1. Create a temporary mounting point for loop devices;
- mkdir /mnt/loop