HP 3000 Manuals HP 3000 Manuals
Differences in the Programming Environment Creating an efficient programming environment implies the effective use of a computer's resources. Thus, utilities that make demands on a system's processing time and memory allocation must efficiently use the architecture of the parent computer. The main differences between HP Link Editor/XL and the MPE V Segmenter relate to differences between the underlying architecture of the Series 900 systems and the segmented architecture of MPE V systems. Programs running under MPE V are partitioned into variable-sized pieces called segments. Segments are limited to 16K instructions and they group code by logical relationships; you can use them to place related procedures into one contiguous area of virtual memory. This property of segments - grouping code by logical relationships - is called code locality. HP Precision Architecture (HPPA) systems do not have a segmented architecture but they do allow code locality with the use of locality sets. (See "Improving Performance with Locality Sets" in Chapter 7 for information on locality sets.) Locality sets allow the use of more intelligent memory management algorithms, which results in fewer page faults during a program's execution. Since HPPA systems do not have segments, they have no code size restraints and the address space is (effectively) unlimited.