page_title: Unix System Laboratories
section_title: Other software work
hierarchical_section_title: Unix System Laboratories / Other software work
caption_attribution_description: English: The Unix System Laboratories building in Summit, New Jersey, featured a large library room that was connected with the AT&amp;T/Bell Labs research library system. (Although the photograph was taken after USL was acquired by Novell, it shows the characteristics of the AT&amp;T/USL era.)
context_page_description: Unix System Laboratories, sometimes written UNIX System Laboratories to follow relevant trademark guidelines of the time, was an American software laboratory and product development company that existed from 1989 through 1993. At first wholly, and then majority, owned by AT&T, it was responsible for the development and maintenance of one of the main branches of the Unix operating system, the UNIX System V Release 4 source code product. Through Univel, a partnership with Novell, it was also responsible for the development and production of the UnixWare packaged operating system for Intel architecture. In addition it developed Tuxedo, a transaction processing monitor, and was responsible for certain products related to the C++ programming language. USL was based in Summit, New Jersey, and its CEOs were Larry Dooling followed by Roel Pieper.
  Created from earlier AT&T entities, USL was, as industry writer Christopher Negus has observed, the culmination of AT&T's long involvement in Unix, "a jewel that couldn't quite find a home or a way to make a profit." USL was sold to Novell in 1993.
context_section_description: Another unit within USL, called the Open Solutions Software business unit and headed by  Joel A. Appelbaum, was responsible for other system software that in some way worked in conjunction with Unix.
  The Tuxedo transaction processing middleware had also been transferred from elsewhere in AT&T to USL.  It had originated as the Loop Maintenance Operations System (LMOS) followed by the Unix Transaction System (UNITS) and was used for projects internally within AT&T.  It was then renamed by USL and, as Release 4.0 of what was now called Tuxedo, in 1989 was offered for the first time as a commercial product.
  USL also developed and marketed the OSI Communications Platform, which was an implementation of the OSI protocols for Unix-based networking.
caption: USL had a library that was connected to the full AT&T/Bell Labs research system
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