the file systems on disks (see fsck) on every reboot. Another innovation was shared libraries which avoid the need for static linking from an application to the libraries it used. The resulting smaller binaries used less of the hardware RAM to run, and used less disk space to install. Besides improving performance, it was a boon to developers: executable binaries could be in the tens of kilobytes instead of a megabyte for an executable statically linked to the C library. AIX v3 also scrapped the microkernel of AIX v2, a contentious move that resulted in v3 containing no PL/8 code and being somewhat more "pure" than v2. Other notable subsystems included: IRIS GL, a 3D rendering library, the progenitor of OpenGL. IRIS GL was licensed by IBM from SGI in 1987, then still a fairly small company, which had sold only a few thousand machines at the time. SGI also provided the low-end graphics card for the RS/6000, capable of drawing 20,000 gouraud-shaded triangles per second. The high-end graphics card was designed by IBM, a follow-on to the mainframe-attached IBM 5080, capable of rendering 990,000 vectors per second. PHIGS, another 3D rendering API, popular in automotive CAD/CAM circles, and at the core of CATIA. Full implementation of version 11 of the X Window System, together with Motif as the recommended widget toolkit and window manager. Network file systems: NFS from Sun; AFS, the Andrew File System; and DFS, the Distributed File System. NCS, the Network Computing System, licensed from Apollo Computer (later acquired by HP). DPS on-screen display system. This was notable as a "plan B" in case the X11+Motif combination failed in the marketplace. However, it was highly proprietary, supported only by Sun, NeXT, and IBM. This cemented its failure in the marketplace in the face of the open systems challenge of X11+Motif and its lack of 3D capability. In addition, AIX applications can run in the PASE subsystem under IBM i. Source code IBM formerly made the AIX for RS/6000 source code available to customers for an additional fee; in 1991, IBM customers could order the AIX 3.0 source code for a one-time charge of US$60,000; subsequently, IBM released the AIX 3.1 source code in 1992, and AIX 3.2 in 1993. These source code distributions excluded certain files (authored by third-parties) which IBM did not have rights to redistribute, and also excluded layered products such as the MS-DOS