How is this different from say mounting s3 as a volume with fuse ?
Mounting S3 lets you view the objects in a bucket, but it doesn't behave like a regular file system.
"large subset of POSIX including reading/writing files, directories, symlinks, mode, uid/gid, and extended attributes"
Our implementation has these features and works with linux programs.
sounds like maybe they're just packaging s3fs-fuse and then charging for it "as a service"? they're extremely light on technical details.
ObjectiveFS is a log structured filesystem that we implemented completely from scratch. It is a POSIX filesystem and works with the existing Linux and OS X tools and software.