Memory allocation problems arise with 16-bit applications because only 64 kilobytes of memory are addressable without advanced memory management techniques. By comparison, at least 4 gigabytes of memory are addressable in a 32-bit application. We have listed several such compilers below. Optimization Advances in computer chips often involve advances in the way that they handle instructions. However, the Pentium has features which the earlier chips do not, and likewise the 80486 has features which the 80386 does not.
Many compilers optimize code with regard to a particular processor.
Optimizers can make compilers more expensive. Likewise, programs using either OWL or MFC may not compile on UNIX platforms. Compilers for UNIX may have libraries for things like X-Windows or Motif that are not portable to other platforms. Many compilers have user interfaces to simplify code generation for building other user interfaces. To further confuse things, even required libraries may be more efficient under one compiler than another.