Comment by kazinator
In the Cygnal fork of the cygwin.dll, I hacked Cygwin's POSIX chdir() function, as well as the path resolution mechanism, to support the per-drive-letter name current directory concept.
A path like "f:myfile.txt" actually means f:\path\to\whatever\myfile.txt" where \path\to\whatever is the current working directory of the f drive.
This is one of the details which makes the replacement DLL more of a "native" run-time library, whose behavior is less surprising to Windows users of the applicaton based on it.