There is GNU/HURD that was supposed to be the kernel. However, its development hit roadblock when microkernel design ended up extremely difficult to debug. Sometimes you can't predict real complexity from the architectural drawing board and prevailing hype in academia, pointing to microkernels as the future at that time. Linus just wanted to implement his own, simple UNIX kernel, based off proven principles, without doing original kernel research.

In addition to sibling comments, remember that Linus announced Linux as:

"Hello everybody out there using minix -

I'm doing a (free) operating system (just a hobby, won't be big and professional like gnu) for 386(486) AT clones. (...)"

GNU couldn't use MINIX due to the license (unlike minix 3), and as I recall, the bsd's were also in somewhat unclear license terms.

Gnu made the libc, compiler and various userland tools - but no-one did a" simple get it working"-kind of kernel, and then Linux came along.

I suppose part of this might be because in early gnu days, most gnu hackers used university Unix machines - not personal 80x86 for development.

If you bough sun hw you got Solaris. Only if you bought a pc clone would you be wanting a "real" os...

Thanks.

They tried it's GNU Hurd.