The ports of the now rather unknown MkLinux (Linux based on Mach-Kernel) and HPBSD operating systems to early HP PA-RISC hardware were among the first non-commercial, usable OS offerings besides HP-UX. Development of both stopped in the mid to late-90s, MkLinux is still available although of rather obscure technical nature and use. Distribution of HPBSD is sadly still not generally possible due to license restrictions on the source code; it reportedly was a very solid operating system.
