### 6.8 Incompatibilities

There are some features of SCCS implementations with which CSSC cannot maintain compatibility.

- The CSSC behaviour of correcting the problems mentioned above may not be compatible with those versions of SCCS which actually exhibit those problems (then again, some of them are not able to read their own output in these circumstances, either).
- The BitSCCS product, part of the BitKeeper suite, uses special comment lines in the delta table, of the form “^Ac_” where “_” is some character other than a space. When CSSC sees these, it will avoid changing the SCCS file (though it will still work for read-only operations, even though the significance of the special comment is ignored). File flags which are specific to BitKeeper are also treated in this way.