Dear SCO Customer,

Support Level Supplement (SLS) ptf4027b, the SCO UnixWare Streams Driver,
addresses several problems identified with the streams driver included in
SCO UnixWare Application Server and Personal Edition releases 2.1.1, 2.1.2,
and 2.1.3.  All of the problems listed below are addressed: 

SLS ptf4027a addressed these issue:

        -  select would return 'writeable' before a connection
           had been established on a socket

        -  tli applications may hang

        -  system panics occurring with kernel-mode address fault on user
           address 0x00D585D0

        -  writing to a named pipe using fprintf may create a deadly
           embrace after a period of time causing applications to hang

SLS ptf4027b additionally addresses this issue:

        -  Baan IV application fails on fast system 


SLS ptf4027b contains: 

        /etc/conf/pack.d/io/Driver_atup.o
        /etc/conf/pack.d/io/Driver_mp.o


Software Notes and Recommendations
----------------------------------

SLS ptf4027b should only be installed on:

        SCO UnixWare Application Server Release 2.1.1 2.1.2 2.1.3
        SCO UnixWare Personal Edition Release 2.1.1 2.1.2 2.1.3

SLS ptf4027b supersedes ptf4027a; however, it is not necessary
to remove ptf4027a prior to installing ptf4027b.


Installation Instructions
-------------------------

1. Download the ptf4027b.Z file to the /tmp directory on your machine.

2. As root, uncompress the file and add the SLS to your system using 
   these commands:

        $ su
        Password: <type your root password>
        # uncompress /tmp/ptf4027b.Z
        # pkgadd -d /tmp/ptf4027b
        # rm /tmp/ptf4027b

3. Reboot the system after installing this SLS.

The release notes, displayed prior to installation, can be found in:

        /var/sadm/pkg/ptf4027/install/ptf4027.txt


Removal Instructions
--------------------

1. As root, remove the SLS using these commands:

        $ su
        Password: <type your root password>
        # pkgrm ptf4027

2. Reboot the system after removing this SLS.


If you have questions regarding this SLS, or the product on which 
it is installed, please contact your software supplier.