NT "the modern reinvention of the operating system", but at the same time claimed that it was unlikely that the promised backward compatibility would be kept for the final release. In March 1992, Microsoft also released Win32s, which would allow Windows 3.1 to have partial compatibility with Windows NT programs for the purposes of developing software optimized for the platform. At Microsoft's Win32 Professional Developers Conference in June 1992, Windows NT was demonstrated running on x86 and MIPS processors, while a beta version of Windows NT and an updated development kit were also made available. Concurrently, Microsoft announced a new version of its SQL Server product for Windows NT; Unix vendors feared that the software could be a killer app that would affect the market share of Unix systems. Concerns were also raised over NT's memory usage; while most computers of the era shipped with 4 megabytes of RAM, 16 MB was recommended for NTs. Due to the high cost of RAM at the time, critics thought that its high system requirements could affect the sales and adoption of Windows NT. Steps were taken to reduce its memory usage through methods such as paging. Microsoft began releasing public beta builds of NT in October 1992, and a month later at COMDEX, a presentation focusing on third-party software for Windows NT was held. The final pre-release version of NT was released in March 1993, alongside the unveiling of the server version, LAN Manager for Windows NT. Although its stability and performance had improved, there were still fears that the OS could be released in an unfinished state or delayed further into 1993. Release Windows NT 3.1 and Windows NT 3.1 Advanced Server (so numbered to associate them with Windows 3.1) were released on July 26, 1993. At first, only the x86 and MIPS versions shipped; the DEC Alpha version followed in September. Microsoft sold the workstation version for , and the server version for . Ostensibly, the server price was meant to be a promotional discount offered only during the first six months of sale, but they never raised the retail price to the listed one—. 250 programmers wrote 5.6 million lines of code; the development cost . In the last year of development, the team fixed more than 30,000 bugs. During the product's lifecycle, Microsoft published three service packs: Service Pack 1 was released on October 8, 1993; Service Pack