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Conclusions

The following advantages of basing the porting of the GNU tools have been recognized:

All CERN tests and examples have run correctly, including on power PCs and NoteBooks with as little as 1 MB of RAM.

We therefore suggest that GNU tools and f2c are suitable for the HEP community using PCs---both MSDOS and Unix---with the following restrictions:

  1. Floating point expressions in C are normally evaluated in double precision. To quote from Kernigan and Ritchie (1978 edition): All floating arithmetic in C is carried out in double-precision: whenever a float appears in an expression it is lengthened to double by zero-padding its fraction. When a double must be converted to float, for example by an assignment, the double is rounded before truncation to float length.
  2. The GO32 DOS Extender runs the coprocessor at full precision (64 bits rather than the 53 bits of a double). Therefore many sub-expressions may be evaluated at even higher precision than double.

These points can account for strange results from numerical codes, such as GEANT, run on a PC using the combination of f2c and gcc. The forthcoming g77 --- the GNU Fortran compiler --- should solve at least the first of these two problems.

The libraries using gcc can be used on both MSDOS as well as UNIX/PC as Proggcc produces the same object code and uses a common library format on both systems.

Free software and the f2c converter are currently used to maintain the official release of the CERN libraries for MS DOS, LINUX (Free UNIX for PC) and Windows/NT for the DECpc AXP computer.

The CERN libraries and the PAW and GEANT packages can be obtained via anonymous ftp from the asis01.cern.ch server from an appropriately registered site or computer.



next up previous
Next: Downloading the distribution Up: Using CERNLIB and Previous: General Appearance



Janne Saarela
Tue May 16 13:43:26 METDST 1995