Rather than emitting code directly, the ICODE macros first build up a simple intermediate representation; the ICODE
run-time system then analyzes this representation to allocate registers and perform other optimizations before emitting code.
There are three components: the tools suite,
run-time system, and communications package.
Other requirements include an EGA, VGA, SVGA or Hercules graphics card compatible with version 3.1 of Microsoft Windows; a hard disk drive; at least four megabytes of random access memory (RAM); a GPIB-PCII/IIA IEEE 488 card, with Windows driver software installed on the PC; the Microsoft Windows 3.1
run-time system; version 3.3 or later of DOS (version 5.x is recommended); and a pointing device, such as a Windows-compatible mouse or trackball.
In Wu and Larus [1994] the values given in Ball and Larus [1993] were used for the Dempster-Shafer combination method, even though the study by Wu and Larus used a different architecture, compiler, and
run-time system. In this section, we show that the a priori heuristics described by Ball and Larus are sensitive to differences in architecture, compiler,
run-time system, and selection of programs.
* By exporting the Legion
run-time system interface and retargeting existing compilers and tools.
It is a constraint that the
run-time system should support on the behavior of two or more components.
DOWL is not radically different from the few other known distributed object-oriented languages, but excels by some rather subtle advantages, e.g., the ability to circumvent distribution transparency if required, the sophisticated Trellis type system and programming environment, and the production-level quality of both language and
run-time system.
Hence, inclusion of a query language, an optimizer and the corresponding
run-time system was a primary design goal.