INT10FIX DOCUMENTATION

       Published by:
       PC Enterprises
       2400 Belmar Blvd,  Wall NJ  07719
       Authors: P. Joseph Calabria and Kurt J. Stampone


       A small percentage of jrExcellerator customers have reported
       that their PCjr occasionally beeps and ignores key-presses
       when the jrExcellerator is used in "fast" mode.  Although this
       problem is encountered by very few PCjr users, it is a
       definite problem that has a solution.

       The problem is caused by improperly written code in the
       PCjr's ROM BIOS.  That's why replacing the jrExcellerator can
       not correct this problem.  Instead, the solution is to use the
       FIXBEEP program to correct the PCjr's ROM BIOS.  If you are  
       not experiencing a keyboard beeping problem then there is no 
       benefit in running the FIXBEEP program.

       The keyboard beeping problem is caused by bugs in the PCjr's
       ROM BIOS routine used to handle keyboard input.  The BIOS
       routine incorrectly uses the Intel 8253 timer chip which is
       decodes keyboard transmissions.  Intel, the manufacturer of  
       the timer chip, specifies that the chip must be allowed at   
       least one microsecond to settle after each read
       or write operation.  The PCjr's ROM BIOS clearly violates this
       specification.

       In most cases, Intel's timer chips are actually much better
       than their specifications indicate.  That's why the violation
       rarely causes a problem when the PCjr is operated at 4.77MHz.
       However, when the PCjr is operated at 9.54MHz, these bugs
       prevent some of Intel's timer chips from working properly.

       The FIXBEEP program provides the solution.  It allows
       the PCjr to comply with the timer chip's specifications by
       allowing a microsecond wait after reading or writing to the
       chip.  The FIXBEEP program has been placed in the Public
       Domain and we encourage you to share it with other PCjr users
       who encounter a keyboard beeping problem.

       If you are using the PC Enterprises Keyboard Buffer Cartridge
       be sure to run the JRSYNC or JRSYNCNP program before you run
       FIXBEEP.

       To use the FIXBEEP program we recommend you copy the program
       to your boot disk and include the FIXBEEP /I command in your
       AUTOEXEC.BAT file.  By doing this the keyboard beeping
       corrections will be made automatically each time you boot
       your computer.

       FIXBEEP must be run from high memory (memory above 128KB)
       because it is timing dependent.  If FIXBEEP is not run from
       high memory, the wait states added by the PCjr's video
       circuitry would prevent your keyboard from working.  To      
       avoid this problem, if you attempt to install FIXBEEP in low 
       memory, the program will refuse to load, and a message will  
       tell you why. 

       If you receive the  "Program is not being loaded into
       fast memory" message, it means you tried to load FIXBEEP in 
       slow (internal) memory.  There are at least two ways you can
       correct this problem.  

       One method that will force FIXBEEP, and all your software    
       to load in the PCjr's "fast" memory is to modify the command 
       you are using to install your memory management software.  If 
       you are use jrConfig this means do not use the -S option at  
       all, or use the -S option with a value of 91 or larger.

       For a quick and easy solution, simply use the jrExcellerator's 
       FASTMEM command before you run FIXBEEP.  FASTMEM will not do 
       anything at all if all of your PCjr's slow memory has already 
       been set aside.  However, if slow memory is still available,
       FASTMEM will set it aside for you.  You may wish to include  
       the FASTMEM command in your AUTOEXEC.BAT file, as long as it 
       appears before FIXBEEP.

       If your jrExcellerator ROM BIOS is revision 3.0 or later the 
       FIXBEEP program is built into the jrExcellerator.  This offers
       several advantages.  First, the FIXBEEP command becomes an   
       internal DOS command, which means it never needs to be on your 
       diskette drive.  Second, the version of FIXBEEP built into the 
       jrExcellerator BIOS, always runs from ROM instead of RAM.  In 
       other words, you'll never need to worry about slow memory    
       because programs built into ROM run faster than programs which 
       execute from RAM.

       Unfortunately, jrExcellerators that use an earlier ROM BIOS  
       can not be upgraded without returning the jrExcellerator to  
       PCE.  The reason is that the FIXBEEP program requires a larger 
       EPROM and modifications must be made to the jrExcellerator   
       to use the new EPROM.  

       The diskette version of FIXBEEP requires the /I option before
       it will install.  To install FIXBEEP type: FIXBEEP /I
    
       To see the help screen type: FIXBEEP /?

       In addition to these options FIXBEEP also provides parameters 
       for diagnostic test purposes.  In the unlikely event that    
       FIXBEEP does not correct a beeping problem that you          
       experience, install FIXBEEP using the /D or /S parameters.  In 
       this mode, any time a beep is produced, FIXBEEP will display 
       information PCE can utilize to determine what caused the beep. 
       If this happens, write down any codes produced in diagnostic 
       mode, then contact PCE.  (Remember: It is normal for the PCjr 
       to beep while the diskette drive light is on unless you have 
       a Keyboard Buffer Cartridge installed).

       For more information contact:

           PC Enterprises
       "The jrProducts Group"

       Customer Service: 1-908-280-0025
       Order and Catalog Hotline: 1-800-922-PCjr


       The PCjr Lives
       There is a Reason!