Why can't MacCVSClient open a sandbox checked out with other CVS tools?

Why doesn't command line CVS recognize a sandbox that has been checked out with MacCVSClient?

In detail this means: in standard CVS, information about revisions of files etc. is stored in files in a folder named CVS in each folder in a checked out working copy (sandbox). MacCVSClient stores this information in a single file named CVS which is located in a bundle/package named CVS.sandboxinfo (with a hidden suffix .sandboxinfo).

MacCVSClient stores some additional information in this CVS control file such as module window size and position, the status of folders in the MacCVSClient module view (collapsed/expanded) and files' storage formats.

This additional information is only stored in MacCVSClient style sandboxes. It is not part of the standard CVS control file information used by other tools.

The reason for this difference is — apart from the above mentioned functional requirement — probably best described as historical. Looking back, it probably would have been better to try to adhere to the original format. In Mac OS Classic days though, it seemed more elegant to have a single file (and now a bundle in OS X) as opposed to a folder with a number of files in it. And as additional information had to be stored, the original format could not have been used unchanged anyway.

Support for standard CVS sandbox formats might find its way into MacCVSClient, but there is currently no schedule for it.