1:16:24pjbFade: you use gray streams to access data stored in byte vectors or strings. You need to implement a directory structure, so you have to implement PATHNAMEs, and OPEN, DIRECTORY, etc… For those, there's no gray stream API. So you may have to use vfs:pathname and vfs:directory, vfs:open instead of CL.
1:17:08pjbFade: have a look at (the quite incomplete): https://github.com/informatimago/lisp/tree/master/future/vfs