Alsys Ada

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A 16-bit Ada software development environment targeting DOS and OS/2 1.x and later ported to 32-bit OS/2 and 32 bit extended DOS using VCPI. Because the VCPI version had been validated the company was unwilling to bear the cost of validating a DPMI version and thus the 32 bit code output by the DOS compiler will not work in OS/2 or Windows.


Alsys Ada was the first full Ada implementation for microcomputers and the first to pass a full validation test in 1986, but at the time required an IBM PC AT with at the least 4MB and preferably 16MB of extended memory so hardware wise represented very small if any savings over their workstation counterparts.


Alsys was taken over by Thomson in the mid 90's, they sold the OS/2 version for a while but dropped it fairly quickly and soon thereafter sold the Ada product line to German safety critical software specialist Aonix, who in turn merged with British embedded specialist Artisan Software to form Atego, who themselves were taken over by PTC more recently. PTC still supports and updates the old Alsys Ada development systems however it is by now squarely targeting the embedded market and all desktop development tools have been dropped.


  • Accounts differ on what was the last OS/2 version, a large number of version 5.5 are out there branded Alsys, but some claim that a bug fixed version 5.6 existed as well that was branded Thomson/Alsys.
  • Note that the company kept version numbers in sync, a new platform version of the Alsys toolkit got the same version number as the existing versions on other platforms rather than v1.



  • Commercial - Discontinued


  • Jean David Ichbiah
  • Alsys