Crystals Primer

Chapter 15: Tailoring The Program

15.1: General Instructions

15.2: File processing

15.3: DOS file name limitaions.

15.4: Automatic Disc extension.

15.5: CRYSINIT files.

15.6: Environment Variables

The user has some control over the run-time aspects of the program. Commands put into a CRYSINIT file are automatically obeyed each time CRYSTALS is started. Under VMS this file is in the users root directory, under DOS it is in the current working directory.
 

\TITLE                       any text for a title
\SET UEQUIV type             Geometric or arithmetric mean
\SET PAUSE value             Pause interval after each 24 lines of OP
\USE CONTROL                 Skip the SCRIPT startup mode.
\SET GENERATE state          Generate filename 'extensions'
\SET LOG state               Control the logging of input
\SET MONITOR state           Control monitoring of input
\SET PAGE length
\SET TERMINAL device         Set VT52 or VT100 for SCRIPTS
\SET COMMUNICATION speed     Set relative line speed
\SET TIMING state            Enable timing messages
\SET LIST   state            Messages about disc transfers
\SET WATCH number            Select lists to watch
\SET PRINTER state           On or Off

When CRYSTALS is running, instructions stored in a data file can be executed with:

             !\USE  filename

To find out what is in a file without obeying it, issue:

            !\TYPE  filename

CRYSTALS automatically hooks in suitable files or devices to input and output channels. These can be changed while the program is running. For example, the listings can be directed to a new file, so that the previous file can be printed without stopping CRYSTALS. Output can also be directed to specially named files, or devices. The commands used is:

\RELEASE devicename filename

Permitted devices inclued:

      MONITOR   The screen for online work, otherwise the .MON file (not PCs)
      PRINTER   The main listing file
      LOG   The copy (log) of all input
      PUNCH A card image file

The filenames can be any system permitted file name. If omitted, a newfile with the default name is opened, possibly over-writing the previous file. Special devices are often available

      :TT   The terminal screen (not PCs)
      :LP   The line printer itself
      :NL   The null device (dustbin)

 e.g.
    !\RELEASE PRINTER LP:
        sends output directly to the printer
    !\RELEASE LOG
        releases the log file, which could then
        be edited and used as input
    !\RELEASE PRINTER NL:
        sends the full listing to the dustbin.

Under VMS file generation numbers prevent accidental over-writing of previous output. Under DOS and UNIX this facility is not available, nor is it alwys permitted to switch output to and from the screen or printer directly. The command

      !\SET GENERATE ON

If the .DSC file becomes full, CRYSTALS makes an attempt to extend it. The number of attempts and the increment are set by the program installer. The user can over -ride the defaults. See the section \DISK. The following commands permits very substantial disk extensions.

      !\DISK
      !EXTEND SIZE=10 TRIES=100
      !END

Their function is similar to a LOGIN.COM or AUTOEXEC.BAT file, and they contain commands the user always wants executing when CRYSTALS starts. The special instruction \USE CONTROL by-passes SCRIPT mode startup.

      !\ A CRYSINIT file to minimise output and pass directly
      !\ into command mode. Disc extensions are set large.
      !\DISK
      !EXTEND FREE=100 SIZE=10 TRIES=100
      !END
      !\SET TIMING OFF
      !\SET WATCH 5
      !\SET LISTS WRITE
      !\SET SRQ OFF
      !\SET SPEED FAST
      !\USE CONTROL

The file CRYSTALS.SRT, usually in the directory CRIMAGES, is a master CRYSINIT file obeyed every time CRYSTALS starts. You may edit this, but take care.

      CRDIR  The directory where CRYSTALS expects to find or put files.
      CRIMAGES The directory containing CRYSTALS
      CRSCP The directory containing the SCRIPTS