OpenSE
An open source (GPLv2) replacement operating system ROM for the Timex 2000 series and Sinclair ZX Spectrum.
History
SE Basic began development on July 5, 2000, when the first version of the Geneva Mono font was created. Since then development has ceased only to be restarted after a series of gaps of between one to four years. The project has gone from being a patch file through four different base assembly files, with development moving to different assemblers at different stages in development (ZASM, Pasmo, and GNU binutils), and from being a derivative of the original ROM to a complete open source replacement. Version 1 was released as a private beta in Januray 2006. Version 2, which added ULAplus support, was released as a public beta in February 2010. Version 3 was released as a public beta in May 2011.