If I output the /proc/<pid>/smaps, I find several segments which do not have any name associated with them and also with inode number as 0. As per the linux kernel Documentation, 0 indicates that no inode is associated with the memory region, as the case would be with BSS (uninitialized data).

I tried searching for BSS but could not get exactly what it is. The information that I got is that BSS is that segment of memory responsible for unititalised global and static variables.

My question is what else does memory region with inode number 0 contain?

I wrote a C program in which I dd the following:-
(i) Malloc 4 Mb for an array on integers
(ii) Cat /proc/<pid>/smaps
(iii) Found an added memory segment with inode number "0" in the smaps.
(iv) Inittialised some part of this array to 5.

STILL found that this memory segment is attached with inode number 0 only. Another question is when does this memory segment get converted to heap?