Fritz: All Fritz/All Fritz.zip/All Fritz/FILES/UTILREEN/ZENO21.LZH/ZENO21.DOC

Text File | 1989-01-23 | 8KB | 158 lines

Author's Documentation:

ZENO.COM:  M. Lazarus, June 11, 1986

          ZENO is a small, fast, core-resident program that
speeds up certain screen writes.  The actual increase in speed is
almost three-fold, but the increase you see on the screen depends
on the application program in use.  An example:  with BCOMM
operating at 9600 bps, the increase is approximately 20-30
percent.  Only certain programs take advantage of ZENO; but those
that don't (including PC-Write) are usually fast enough without
it.

          ZENO reduces available memory by about 900 bytes.

          ZENO operates with all screens.  On some color screens,
however, it may cause snow -- harmless but annoying.  If that
happens, remove ZENO with the instructions below.

          Important:  Do not change back and forth between
monochrome and color displays while ZENO is installed.  Users of
monochrome graphics boards:  this includes you.

          To load:  At the DOS prompt, type ZENO.  A message will
appear.

          To remove:  At the DOS prompt, type ZENO/K (use no
spaces; must be capital K).  A message will appear.  Important:
First remove all core-resident programs loaded after ZENO.

Additional Comments:

          (1)  ZENO, like many other fast screen programs,
eliminates the wait for the retrace.  But ZENO also trys to speed
up the BIOS routines in other ways as well.  For details, see the ASM
listing.  Roughly speaking, ZENO assumes that the underlying
program is trying to use the BIOS call in the most likely manner;
it tests for that, and if the assumption is right, uses a faster
method.  If ZENO's assumptions are wrong, the test of the
assumption slows down ZENO's performance in comparison to a
program that only eliminates the retrace delay.  Therefore, if
the underlying program's use of INT 10 is extremely unusual,
there may well be faster screen speedup programs faster than
ZENO.  But that is likely to be true only of very rare programs.

          (2)  TEST.COM does nothing but a series of BIOS screen
writes, counting timer interrupts.  It then writes out the number
of timer interrupts that have elapsed.  Useful for comparing fast
screen programs, although, obviously, it does not test them under
all conditions.

          (3)  Comments and suggestions are best addressed to me,
David Seidman, on Bob Blacher's bulletin board, 202-547-2008.

CHANGES by Ron Tansky:
Fixes: ZENO would hang the computer if 40-character mode was used.  I
modified the program to bypass the speed-up in 40-character mode.
I also modified the program to accept /k or /K on the command line
to kill ZENO.
   Also changed message to say 'may cause snow', as the other message
('may cause interference') really worried some users.

Second set of changes by Ron Tansky:
The first set of changes fixed the hang if 40-character mode turned on,
but I later discovered that the ZENO speed-improvement was permanently
turned off afterwards ('til next boot).  I also found out that the same
was true for graphics mode with the original ZENO; i.e.  if you ever
go into graphics mode, ZENO won't come back to speed afterwards.
This set of changes fixes both of these problems.  ZENO goes to sleep
during modes that it can't handle, but wakes back up and again
speeds up 'normal' screen output.  I put a version number into the startup
message (version 1.1), so that you can recognize this latest fix.

P.S.  I've tried to send the changed ZENO back to David Seidman,
on Bob Blacher's bulletin board, 202-547-2008.  I've never been able to
get anything but a busy signal.  If anyone knows another way to get these
fixes back to the original author, we'd both appreciate it.

Changes by Chris Blum - CompuServe 76625,1041     1/28/87

     Added code to support TTY mode output ( AH = 0EH ). Needed because
some clone BIOSs ( mine is DTK/ERSO ), do not update cursor position
through BIOS call in this mode. Without the changes, ZENO loses its
place in the display memory and the display goes out to lunch with some
BIOS configurations. I tried to follow the technique and spirit of the
existing code as much as possible. Updated version number ( now 1.2 ).

Changes by Lynn Ransdell                          5/29/87

     As written, ZENO versions 1.1 & 1.2 worked with all my software
except KEDIT 3.51 (Mansfield Software Group, Storrs, CT).  I managed
to circumvent the problem by changing the values loaded/tested in the
AX register.  Former values were 00F0h,,, replacement values were
FEFEh.  I made the assumption that KEDIT was sending the former values
(for reasons unknown to me) and that ZENO was misinterpreting them as
its signal to KILL itself.  I further assumed that the AX values might
have been arrbitrarily chosen, and thus could be arbitrarily changed.
So far, this has proven (with the software that I use) to be satis-
factory, but may conflict with someone else's software.

     I have labeled this version as 1.3 in order to distinguish it
from the prior versions.  I have not seen any other versions later
that ver. 1.2.

     The program, ZENOTEST.COM, is included in the archive for
comparing screen I/O speed before/after installing ZENO.  It is also
useful for benchmarking different "ansi"-type video drivers.  The
best combo I've found is NANSI286.SYS with ZENO13.

Changes by Glenn K. Smith    CompuServe 70357,1136    12/14/88

    ZENO 1.3 was just what the doctor ordered!  ZENO 2.0 is
basically the same as the previous versions, however, this one has the
ability to do snow checking.  I managed to get around the problem of
snow by using some nifty code to put characters on the CGA screen.  The
only cost in performance was a loss in speed. ZENO 2.0 runs around 2.5
times slower with snow checking on than without.  This means that
ZENOTEST on my computer went from 28 seconds to 67 seconds.  Its still
faster than the 147 seconds that ZENOTEST records without ZENO being
installed.

    I modified the program to handle a new switch (/S) for snow
checking.  I also made a couple changes to the messages and to the NO
ACTION message.  It now displays the valid switches.

     I have labeled this version as 2.0 in order to distinguish it
from the prior versions.  I have not seen any other versions later
that ver. 1.3.

Changes by Glenn K. Smith    CompuServe 70357,1136    01/15/89

    Oops, I guess ZENO wasn't done.  I had several complaints that
PROCOMM+, Turbo Pascal and a few other programs wouldn't work right when
ZENO (any version) was installed.  This turned out to be a problem on
their part, not with ZENO.  Those programs modified the bios cursor
without going through ZENO.  The kept track of the cursor location
internally and stored the result when they were done.  As a result, ZENO
was unaware that anything had happened.  The change was minor, I just
used the bios cursor position and re-calculated a new screen offset
everytime a character was placed on the screen.  As a result, these
programs now work, however ZENOTEST now runs about 4 seconds slower.

    Good News!  A played with the snow checking code and was able to
speed it up quite a bit.  ZENOTEST used to give me a reading of 66
seconds at 10 mhz.  The new code returns a value of 46 seconds.  Not
too bad.  Only 12-13 seconds slower than without snow checking.

     I have labeled this version as 2.1 in order to distinguish it
from the prior versions.  I have not seen any other versions later
that ver. 2.0.

P.S. I've noticed that PROCOMM+ now runs quite a bit faster than it did
before.  When you have snow checking enabled, the program called bios to
place the characters on the screen.  Now ZENO does that.  You'll still
get snow if you disable snow checking in PROCOMM+ or with ZENO.