After Acorn withdrew from the desktop computer industry in 1998, Castle Technology acquired the rights to produce the A7000, A7000+ and RISC PC using the Acorn brand.[7]
In 2001, development started on the Iyonix PC (codenamed Tungsten) as a set-top unit (STU) in secret by engineers at Pace's Shipley campus along with a 32-bit version of RISC OS 4 (known as RISC OS 5). When management discovered the project the campus was closed.[8]
Castle Technology acquired the proposed designs and the original engineers from Pace to further develop the Tungsten into a desktop computer. Robert Sprowson, the original hardware designer, declined to join Castle Technology and so Peter Wild was recruited.[8] The Iyonix PC was released six months later. Although it was well received, it was not designed for long-term production and therefore used some components that were near obsolete when it was released.[8]
A problem for the Iyonix PC was that it used leaded components which were outlawed with the adoption of Directive 2002–95/EC in February 2003 by the European Union. However, by this time Castle Technology was financially troubled and could not afford to re-engineer the Iyonix PC without the leaded components.[8] The remaining Iyonix stock were passed to Iyonix Limited which stopped distribution on 30 September 2008.[9]
In 2004, Castle Technology acquired Tematic to further development of RISC OS in embedded systems.[10] In December 2005, Castle Technology moved its main office to the former premises of its software development division,[2] following the migration of Tematic to a neighbouring premises in Signet Court, Cambridge.[11]
In 2018 RISC OS Developments acquired Castle Technology Ltd including the Intellectual Property.[12]