I can assure you this was exactly the case. The original was done in C and then compiled. Phil then would optimize it by hand resulting in highly optimized a

I can assure you this was exactly the case. The original was done in C and then compiled. Phil then would optimize it by hand resulting in highly optimized asm code. All the DOS versions were done this way. That was the genius of Phil Katz. The first VAX version was done in C and that code was then ported to the first unix variants at which time it was moved to 32 bit and the extended attributes fields were added.