| 1967: | An ALGOL-60 extension implemented on a Zuse Z 23 computer with
operators and a number of elementary functions for a new data type interval. | 
| 1968/69: | Implementation of the above language on a more powerful
computer, an Electrologica X8. | 
| 1976: | PASCAL-SC, a PASCAL extension implemented on a Z-80 microprocessor
with 64 KB main memory (funded by the german company Nixdorf).
The programming convenience of PASCAL-SC allowed a small group of collaborators
to implement a large number of problem solving routines with automatic
result verification within a few months. | 
| 1980: | PASCAL-SC with a large number of problem solving routines
was exhibited at the Hannover fair. | 
| 1980/89: | ACRITH-XSC, a FORTRAN 77 extension for the /370 architecture
was developed and implemented in cooperation with IBM. | 
| 1983: | IBM shipped the first edition of the ACRITH library. | 
| 1986: | ARITHMOS for BS 2000 (with Siemens) | 
| 1990: | IBM shipped ACRITH-XSC | 
| 1990/91: | Development of a new Runtime System (RTS) for PASCAL-XSC
in C | 
| 1991: | PASCAL-XSC shipped. The PASCAL-XSC system compiles a given
PASCAL-XSC source code into C code which is passed to a C-Compiler. | 
| 1992: | C++ class library C-XSC shipped, available for many computers
with C++ compiler translating der AT&T language standard 2.0 | 
| 1993: | "Numerical Toolbox for Verified Computing" in PASCAL-XSC is
published by Springer-Verlag. | 
| 1994: | "C++ Toolbox for Verified Computing" in C-XSC is published
by Springer-Verlag | 
| 1996: | Begin of the implementation of Fortran-XSC (TU Dresden, Prof. Walter) | 
| 1997/98: | Oberon-XSC (Universität Karlsruhe, Dr. P. Januschke; 
ETH Zürich, Prof. Gutknecht) | 
| 1997: | XSC General Public License, all XSC software has been available
FREE OF CHARGE since 1997. |