Power-Safe filesystem

The Power-Safe filesystem, supported by the fs-qnx6.so shared object, is a reliable disk filesystem that can withstand power failures without losing or corrupting data.

Its features include the following:

• 510-byte (UTF-8) filenames:

  You can't use the characters 0x00-0x1F, 0x7F, and 0xFF in filenames. In addition, / (0x2F) is the pathname separator, and can't be in a filename component. You can use spaces, but you have to quote them on the command line; you also have to quote any wildcard characters that the shell supports. For more information, see Quoting special characters in Using the Command Line.

• copy-on-write (COW) updates that prevent the filesystem from becoming corrupted by a power failure while writing
• a snapshot that captures a consistent view of the filesystem
• encryption capabilities that let you encrypt all or parts the filesystem

For more information about the structure and features of this filesystem, see Power-Safe filesystem in the Filesystems chapter of the System Architecture guide.

mkqnx6fs /dev/hd0t76

You can use the mkqnx6fs options to specify the logical blocksize, endian layout, number of logical blocks, maximum number of inodes (and hence, files), and so on.

mount -t qnx6 /dev/hd0t76 /mnt/psfs

By default, the Power-Safe filesystem creates sparse files when growing a file with ftruncate() or when writing at an offset that is beyond the end of a file. The filesystem counts sparse blocks against the total free space, so it isn't possible to overcommit the disk blocks. To maintain compatibility with previous versions of the filesystem prior to QNX Neutrino 7.1, use the nosparse mount option.

For more information about the options for the Power-Safe filesystem, see fs-qnx6.so in the Utilities Reference.

To check the filesystem for consistency (which you aren't likely to need to do), use chkqnx6fs.