History and Goals of Ada

History of Ada

• 1970's DOD uses 400+ languages
• International Competition for new language
• Strawman, Woodman, Tinman, Steelman specifications


• Ada 83 designed and implemented by Green Team in France (Jean Ichbiah)


• For the curious: Ada Byron King, Countess of Lovelace
  
  

Design Goals

1. Reliability and maintainability
2. Concern for programmer
3. Efficiency (Size and execution speed)

Support for Design Goals

• Readability favored over writability (eg begin .. end vs {})
• Error prone notations avoided (eg = and :=)
• Strong typing (stronger than Java)
• Keep language small and consistent


• Support for large systems (ie packages)
• Support for abstract data types
• Support for multiple threads


• Validation suite: set of programs that test compiler
• Standardized before implementation

Application Areas

• Areas where reliability and/or execution speed are critical:
• Transportation
• Defense
  
• Banking
• Medical systems
• Industrial control
• Science (eg National Ignition Facility uses Ada to control the world's most powerful laser)


• Examples
  
  
• More examples


• On the relation between Java, Ada, and C++:
  

Some languages, such as Ada, fit well and are pretty straightforward ports of the Java virtual machine. Sun will not attempt to run C and C++ code on the virtual machine, however, because it is more difficult to ensure the reliability and, therefore, the security of downloaded code.

James Gosling - Inventor of Java

Versions

• Ada 83
• Original version
• Partial support for OO


• Ada 95:
• Complete support of OO (but not interfaces)
• Expanded support of threads
• support for multilanguage programming, ...
• Gnat: free compiler part of GNU gcc
• Upward compatible


• Ada 05:
  • Java-like interfaces (ie multiple specification inheritance)
  • Object notation allowed
    
  • Improved standard packages
  • Upward compatible