Umbriel (moon) that obliterated its older surface. Covered by numerous impact craters reaching in diameter, Umbriel is the second most heavily cratered satellite of Uranus after Oberon. The most prominent surface feature is a ring of bright material on the floor of Wunda crater. This moon, like all moons of Uranus, probably formed from an accretion disk that surrounded the planet just after its formation. The Uranian system has been studied up close only once, by the spacecraft "Voyager 2" in January 1986. It took several images of Umbriel, which allowed mapping of about 40% of the moon’s surface. Umbriel, along with
Oberon (operating system) PC-Native Oberon. Other versions of the Oberon System, i.e. without "Native" in the name, had partially modified interfaces of low level modules. In 2015 Peter Matthias revitalized LNO under the Name OLR (Oberon Linux Revival) as a multi-platform Distribution running seamlessly under Intel x86, RISC-V, MIPS, and ARM. It runs nicely on the Raspberry Pi and on the inexpensive CHIP computer; with some tweaking (adjusting group membership or/and permissions on some devices) it runs nicely under Tiny Core Linux. OLR interfaces with Linux kernel by direct System calls. OLR currently (mid 2017) misses a network layer. In 2013 Niklaus Wirth