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Package filesystem
 2005, QNX Software Systems Ltd.
Underlying filesystem
There must be a filesystem underneath the redirection layer of the
package filesystem.
If you want to copy a file to one of the virtual directories (e.g. /bin),
then the package filesystem creates the appropriate structure on the
underlying filesystem and then lets the original access request simply
fall through to the next server.
If there’s no underlying filesystem, then new files can’t be added to
the virtual filesystem without first generating a package for them.
Control files
The package filesystem uses these control files:
Manifest files
XML files that you use to put together a package
for distribution. The purpose of these files, which
live at the root of every installed package, is to
describe which files are exported, the services the
package provides, the dependencies of the package,
etc. The packager utility builds these files.
Package-configuration file
An XML control file that’s used to configure the
package filesystem itself. The installer utility,
qnxinstall manipulates this file. Its default
location is /etc/system/package/packages.
Patches
The package filesystem also supports patching. When patches are
issued between releases, the files for the patch are placed into a
package as well. The patch package overrides existing files from
other packages without actually deleting them.
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Chapter 11 ¯ Working with Filesystems
February 1, 2005