Uttered "Bloch, Jack" <Jack.Bloch@icn.siemens.com>, spake thus:

Please do not include me in the CC: list as I belong to this mailing
list.

Do not reply privately to this message, keep it all out in the open ;-)

> It is not really a device, simply a file loaded into memory by another
> process at a fixed location.

Userland processes _do_ have resource limits.  Try a "man getrlimit"
for some hints here.

There is a max process size limit (RLIMIT_DATA) and the number of VM
pages kept in RAM (RLIMIT_RSS).

Keep in mind that a child processes usually inherits whatever rlimits
are left unused by the parent process, so if your program is being
started from another program near its limits, the child process
begins with those limitations as well.

1)  Can a standalone test program, started from the shell, map the
    data?

2)  How was the kernel memory used to hold the data obtained?