The QNX 4 filesystem (fs-qnx4.so) is a high-performance filesystem that shares the
same on-disk structure as in the QNX 4 RTOS.
The QNX 4 filesystem implements an extremely robust
design, utilizing an extent-based, bitmap allocation scheme
with fingerprint control structures to safeguard against
data loss and to provide easy recovery. Features include:
- extent-based POSIX filesystem
- robustness: all sensitive filesystem info is written through to disk
- on-disk "signatures" and special key information to allow
fast data recovery in the event of disk damage
- 505-character filenames
- multi-threaded design
- client-driven priority
- same disk format as the filesystem under QNX 4
Note:
In QNX Neutrino 6.2.1 and later, the 48-character filename limit
has increased to 505 characters via a backwards-compatible
extension. The same on-disk format is retained, but new
systems will see the longer name, while old ones will see a
truncated 48-character name.
For more information, see
"QNX 4 filesystem"
in the Working with Filesystems chapter of the
QNX Neutrino User's Guide.