Working with the #NOVA Control File

An integral part of the NOVA System is the #NOVA control file. This keyed file determines what action will be taken when the operator presses one of the NOVA function keys or when the program uses the Invoke HELP mnemonic.

For example, assume that the operator presses the F1 function key. At this point, Comet suspends the current program and enters the NOVA subprogram. NOVA opens the #NOVA file and examines the record associated with the F1 key, then carries out the specified action (i.e., runs the Comet Help System, enters a specified subprogram, shells to DOS, or displays a text string).

There are "system records" and "terminal records" in the #NOVA file. The system records contain action codes for all of the users in the system, while terminal records contain overriding action codes for specific terminals.

MTB programs can dynamically update the #NOVA file. Here is the structure of the file:

  File type:   Keyed
  Key size:    7
  Record size: 64
  Key format:  see table below

Position

Length

Description

"SYS " or terminal number

function key code:
000  automatic help
001  F1
002  F11
003  F12
004  Shift F1
005  Shift F2
006  Shift F3
007  Shift F4
008  Shift F5
009  Shift F6
00A  Shift F7
00B  Shift F8
00C  Shift F9
00D  Shift F10
00E  Shift F11
00F  Shift F12

Record:  see table below

Position	Length	Description
1	4	"SYS " or terminal number
5	3	function key code (see key)
8	1	action code: H = run Comet Help System E = enter subprogram S = shell to DOS T = display text string
9	8	subprogram name (E option)
17	3	directory name (E option)
20	40	message string: message in COMMON (E option) DOS command/program (S option) text string (T option)

Default records in the #NOVA file (when the file is created):

Key	Record	Meaning
SYS 001	SYS 001H	F1 = run the Comet Help System
SYS 002	SYS 002ECMHELPB	F11 = enter CMHELPB (build mode)
SYS 003	SYS 003EPRTSCRN	F12 = enter the PRTSCRN applet
SYS 004	SYS 004EKEYCAP	Shift F1 = enter KEYCAP applet

Usefile:

  ! 
  !  FILE #NOVA - MASTER SPECIAL KEY DISPATCH FILE 
  ! 
  !  KEY SIZE:  7  ( TXX$ + FKEY$ ) 
  !  REC SIZE: 64 
  ! 
     LENGTH   1  & LOCAL ACTION$ 
     LENGTH   3  & LOCAL FKEY$ DIR$ 
     LENGTH   4  & LOCAL TXX$ 
     LENGTH   8  & LOCAL PROGRAM$ 
     LENGTH  40  & LOCAL MSG$ 
  ! 
  NOVA:  FORMAT _ 
         TXX$;_                      ! TERMINAL # OR "SYS " 
         FKEY$;_                     ! CODE FOR KEY PRESSED 
         ACTION$;_                   ! WHAT TO DO ... 
                 _                   !  H-HELP MESSAGE/LOOKUP PROG.
                 _                   !  R-RUN A PROGRAM 
                 _                   !  S-SHELL TO DOS 
                 _                   !  T-ECHO KEYSTROKES 
         PROGRAM$;_                  ! PROGRAM TO RUN 
         DIR$;_                      ! DIR FOR PROGRAM$ 
         MSG$                        ! TEXT TO ECHO OR MSG TO PASS 
  ! 
  ! 
  ! 
  !  NOTE:  TXX$ IS "SYS" FOR SYSTEM DEFAULT RECORD 
  ! 
  !

Please see also:

The NOVA System