Bell developed multiple versions of Unix for internal use, such as CB UNIX (with improved support for databases) and PWB/UNIX, the "Programmer's Workbench", aimed at large groups of programmers. It advertised the latter version, as well as 32V and V7, stating that "more than 800 systems are already in use outside the Bell System" in 1980, and "more than 2000" the following year. Research Unix versions 8, 9, and 10 were developed through the 1980s but were only released to a few universities, though they did generate papers describing the new work. This research focus then shifted to the development of Plan 9 from Bell Labs, a new portable distributed system.