HVPLOT for Fortran 77 This is an updated version of the older HVPLOT for Fortran IV/RT: it is designed for Fortran 77 and should run under TSX+, RSX and VMS. A couple of points should however be noted: You must assign PL: to something for the plotter output (a NON-spooled CL port under TSX+ or a NON-spooled TT port under RSX or VMS, for example.) The string handling in Fortran 77/RT (& RSX) is not the greatest: all strings MUST be put into suitable character variables rather than in the call itself. Have a look at the source code of SPIRAL for examples. The CHECK routine is in the HVPLOT sources but has not been tested yet, neither have the PREAD routines been tested. In fact, no data return from the plotter has yet been tested in this version. The double-buffering in the older version of the I/O to the plotter (via PL:) appears to be both unnecessary and the source of some problems. It has been removed. Any helpful advice or problem reports to Dr R N Caffin CSIRO Div of Textile Physics 338 Blaxland Rd Ryde NSW 2112 Australia