QNX compressed filesystem

QNX SDP8.0System ArchitectureDeveloperUser

The QNX compressed filesystem (QCFS) provides a read-only filesystem that supports the compression of files and metadata so that they take up less space.

The fs-qcfs.so shared object supports the QCFS.

It includes the following features:
  • directory indexes
  • metadata compression
  • sparse file support
  • tail-end packing (fragments)
  • hard link support
  • a single or a double period entry (. or ..) in readdir()
  • real inode numbers
  • 32-bit user or group IDs
  • file creation time
  • ACL support
For information on generating a QCFS image, see the mkqfs utility. For information about ACL support in QNX OS, refer to the Working with Access Control Lists (ACLs) chapter in the Programmer's Guide.

Supported compression algorithms

QCFS supports the following compression algorithms:

lz4hc
LZ4 high compression algorithm, which provides the best decompression speed at the cost of a lesser compression ratio.
zstd
Zstandard compression algorithm, which provides a good compression ratio and decryption speed.
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