;  Kaypro BISHOW v3.1 - buffered bi-directional file scroll utility
;
; Version 3.0 and 3.1 mods by Steve Sanders, original program
; code by Phil Cary (vers 1.0) and in-between versions were
; modified by many to get it to this present level.
;
; This is a complete replacement for TYPE.COM offerring many
; more advantages such as backward and forward scrolling.
;
; KPBISHOW is useable only if you have a video-able Kaypro
; computer like the New 2, 2X, 2'84, 4'84, 4E, 10, or ROBIE.
; Older 2s and 4s cannot display inverse video or use the 25th
; status line display incorporated in this program.
;
; KPBISHOW now handles squeezed files as well as regular ASCII
; files automatically.
;
; KPBISHOW is now completely compatible with standard Wordstar control
; keys and uses the Kaypro arrow keys for +/- scrolling and right and
; left margin control
;
; BISHOW is a  buffered,  bidirectional  version  of  SHOW.ASM
; which first appeared in Interface Age, November, 1981.  That
; program  could  only  scroll  forward  in  a  file, and read
; sectors from disk one at a time as they  were  sent  to  the
; console.   I  used SHOW frequently to take a quick look at a
; file without loading a  big  text  editor,  and  to  examine
; another  file  with the RUN command while in Wordstar.  TYPE
; does not work since it is not a file that Wordstar can  load
; and run.
;
; It was annoying when I went past the point I was looking for
; in a file with SHOW, and could not go backwards.  Thus, this
; bidirectional  version  which  uses  random access reads. In
; addition, buffering was added so that  the  number  of  disk
; reads  would  be  reduced,  and  moving  back and forth in a
; moderate sized file would be speeded up.  There is  a  trade
; off between the size of the buffer and the length of time it
; takes to refill the buffer which should be set to the user's
; preference.
;
; There are several customizing items in this program.  One is 
; the equate "maxsec" which sets the buffer size.   Another is 
; the  string  in the subroutine "clrscr" just after  the  org 
; statement.   This should be changed to erase the screen  and 
; home  the cursor for the user's terminal.   The program,  as 
; written,  requires a terminal with an erase screen and  home 
; cursor  function.   Some  terminals  do not allow  the  80th 
; column  to be filled without going to the  next  line.   For 
; this reason, the screen width ("maxchr") initially is set to 
; 79.   The screen sizes can be changed using the "S" (screen) 
; command.  The parameters that can be changed are the maximum 
; column  displayed ("maxchr"),  the minimum column  displayed 
; (allowing  you  to "window" the output),  and the number  of 
; lines ("scroln").   A zero for the maximum column  displayed 
; will  give and unlimited screen width.   The maximum  column 
; displayed  and  the number of lines can be set when  calling 
; BISHOW,  e.g.,  "BISHOW file.nam 79 24" will give 79 columns 
; and 24 lines,  and "BISHOW file.nam 79" will give 79 columns 
; with the default number of lines.  The last customizing item 
; is the "short" equate.   If this is chosen, the multiplicity 
; of command forms is not allowed (see the beginning to change 
; the  commands  used),  and certain messages  are  shortened.  
; This will allow BISHOW to fit into a 1K area.  If "short" is 
; false, the program is slightly over 1K.  Finally, direct I/O 
; to the console is used to avoid echoing the commands to  the 
; console as the CP/M write console function does.
;
; Just  a  small contribution to the public domain software as
; partial payment for the many fine and  educational  programs
; the system has given me.  Phil Cary.