Peter MacDonald (computer programmer) the Linux Kernel into Dynamically Loadable Modules"). MacDonald co-developed early features of the Linux kernel in the early 1990s, including shared libraries, pseudo terminals, the select call and virtual consoles. He announced Softlanding Linux System (SLS), the first standalone Linux install, for testing in August 1992 (on 15 floppy disks), and for general release in October 1992 (recommending at least 10 MB of disk space). SLS became popular, but also drew criticism. MacDonald was criticized for trying to make money on free software, but defended by Linus Torvalds. Two of the early Linux distributions were made specifically in reaction to
V (operating system) modular windowing system for both local and remote applications. The little-known W Window System got its name because it was first hosted on the V operating system, and the better-known X Window System in turn got its name because its first version was based partly on W. V also spawned another pure microkernel effort at Apple Computer known as Vanguard, which added a number of improvements to the basic system. Vanguard later disappeared in a reorganization. The Tektronix VM700 television measurement instrument was developed in a networked V environment in the late 1980s and ran a lightly modified version of