compressed tarball, aka package. The file system assumes that the
files are layed-out in the same order as needed to allow for the
package to be streamed. As such, it does not read an entire package
into memory first.
Some properties of the file system:
o Files that start with '+' are silently skipped. These are found
in FreeBSD package files.
o Files smaller than or equal to 4KB will be cached in memory and
as such allow for some flexibility in accessing files out of
order.
o Files with the .tgz suffix are assumed to be (sub-)packages and
signal the end for a directory scan.
Obtained from: Juniper Networks, Inc.
