Dear SCO Customer,
 
 Enclosed find Support Level Supplement (SLS) unx273.  This SLS resolves an 
 outstanding problem with the SCO UNIX System/V 386 Release 3.2 Operating
 System where heavy serial input would cause serial I/O degradation and
 system hang. It will install on machines running:
 
         SCO UNIX System V/386 Release 3.2 Operating System 
         SCO UNIX System V/386 Release 3.2 Operating System Version 2.0 
         Open Desktop Release 1.0 
 
 SLS unx273 will install on computers based on Industry Standard Architecture 
 and on computers based on Micro Channel Architecture (MCA).  This SLS is not
 applicable to operating systems with SCO MPX installed.
 
 To install this SLS, please take the following steps:
 
 (1) Reboot your system and enter System Maintenance mode.
 
 (2) Insert the floppy into your primary floppy drive and close the door.
 
 (3) Type:
 
       /etc/xinstall
         
     You will see the following message:
 
       For each volume in the distribution set, insert the
       floppy into the drive, enter 'y', and press <Return>.
       Enter the letter 'n' after the last volume.
     
       First Floppy? (y/n)
 
     At this point enter 'y' and press <Return>.  You will then see the 
     message:
 
       Extracting files...
     
     If you do not have the LINK kit installed, you will be prompted with
     the following message:
 
       You must install the LINK kit package for the Supplement
       Do you wish to install the LINK kit now (y/n)
 
     Enter 'y' and then <Return>.  
 
     You will see the message:
 
    backing up /etc/conf/pack.d/kernel/io.o as /etc/conf/pack.d/kernel/io.o.bak
 
 (4) You will then be prompted to build a new kernel with the message:
 
       You must create a new kernel to effect the driver change specified.
       Do you wish to create a new kernel now? (y/n)
 
     Enter 'y' and then <Return>.  You will then see the message:
 
       The UNIX Operating System will now be rebuilt.
       This will take a few minutes.  Please wait.
 
       Root for this system build is /
 
       The UNIX Kernel has been rebuilt.
 
       Do you want this kernel to boot by default? (y/n)
     
     Enter 'y' followed by <Return>.  You will see the message:
 
       Backing up /unix to /unix.old
       Installing new /unix
 
       The kernel environment includes device node files and /etc/inittab.
       The new kernel may require changes to /etc/inittab or device nodes.
 
       Do you want the kernel environment rebuilt? (y/n)
 
     Enter 'n' followed by <Return> and you will see the message:
 
       Device node or inittab changes associated with this new kernel have not
       been made. These changes should be made by running touch /etc/new_unix;
       /etc/conf/bin/mkenv.
 
       Next Floppy? (y/n)
 
     At this point, enter 'n' followed by <Return>.  
     
 (5) You must now reboot the system so that the changes made by SLS unx273
     can take effect.  To shut down your system, enter the command:
 
       shutdown -g0 -y
 
     SLS unx273 will take effect when your system is rebooted.  Note that if
     you re-install your LINK kit, you will need to re-install SLS unx273.

 If you have any questions, please call our SCO Customer Services Department
 at (800) 347-4381.  SCO Customer Service is available Monday through Friday,
 6:00 A.M. to 5:00 P.M., Pacific Time.

 We appreciate your business.

 SCO Support Services