A couple of the commercial systems did this for sure. Linux definitely picked it up from UNIX practices, although I have no idea/memory of who did it first. We used the idea at Stellar (Stellix) and at Masscomp (RTU). IIRC, a couple of others like Pyramid made have created a RAMFS - but it was kicking around the UNIX community for a fairly long time - certainly in the late 1970s - *i.e.* post V7. FWIW: V7 had /stand which was a funky UNIX-like standalone system that some applications could be compiled. The problem was that it was a little different so you would end up seeing #ifdef STAND in code for things like fsck, fsdb, even cat. At Masscomp we ended up with three target environments for a couple of the system maintenance utilities: the OS, /stand and the boot ROMS. This was expensive/a PITA to maintain and keep straight, and in the case of the boot ROM, space was a huge problem. The RAMFS idea was created to get rid of at least /stand and IIRC we were able to drop a number of utilities out of the boot ROM. I'm not sure how far they took it. I left for Stellar and it was always the way Stellix booted. On Tue, Aug 6, 2019 at 7:47 PM Grant Taylor via TUHS wrote: > Do, or did, anything other than Linux use a concept of an initramfs / > initrd to create a pre-(main)-init initialization environment to prepare > the system to execute the (main)-init process? > > > > -- > Grant. . . . > unix || die > >