Ref: 11030036
Title: 1.2.1 Maxess README File
date:  7/18/89

Copyright 3Com Corporation, 1991.  All rights reserved.

This README file contains important information which you will not
find in the manuals and other documentation provided as part of the
Maxess product package which you have received.  Please read through
this material completely before installing and using the Maxess
software.  If there is any question, the information in this README
file supercedes the information in the product manuals.

Directory
---------

    1. Product Questions and Assistance
    2. Installation and Configurations
    3. Troubleshooting
    4. BIOS Problems and Almost Compatible PCs
    5. Configuration Suggestions for Maxess Gateway Operation


PRODUCT QUESTIONS AND ASSISTANCE

As with any IBM communication product, most problems can be traced
to the original configuration of the software, either on the IBM
Host System or on the remote system, such as the PC in which Maxess
is installed.  The first resource you should use for assistance is
the product manuals and this READ.ME file.  The second most
immediate resource will be the IBM Host System Administrator who can
assist in diagnosing any configuration mismatches.

PLEASE have the following information available when you call so
that we can more quickly provide assistance:

    a. your Maxess SNA Gateway serial number
    b. the computer brand and model in which the Gateway is
       installed, and those which are used as workstations on your
       network.  Also, a description of any additional hardware or
       system (TSR) software which is installed.
    c. the Operating System and version number
    d. a description of the AUTOEXEC.BAT file and of the CONFIG.SYS
       file, both for the gateway machine and the workstation
       machines.
    e. a description of your IBM Host system configuration and the
       software version levels which are in use.
    f. a description of the communications equipment between you and
       your IBM Host system (for example, modems, modem eliminators,
       leased/switched lines, and line speeds).

INSTALLATION AND CONFIGURATIONS

The Maxess SNA Gateway contains many advanced features including a
the ability to switch between SNA 3270 Sessions and DOS
applications, with both remaining active.  This is done through
Terminate and Stay Resident (TSR) programs.

It is VERY important to follow the instructions for your networking
software and for Maxess, in creating your AUTOEXEC.BAT file.  The
order in which TSR programs are installed MUST be correct.  In the
case of Maxess, it must be installed LAST after all other TSRs in
order to operate correctly.


TROUBLESHOOTING

1. DOS Graphics Application screens.... A powerful feature of the
   Maxess SNA Gateway, is the ability to switch between a 3270
   Session and a DOS program with a simple "hot" key.  This allows
   you to have your IBM Host sessions active while you run your
   standard DOS programs.

   However, if you are using a DOS application which uses Graphics
   screens, you cannot "hot" key back to Maxess until the graphics
   program is stopped.  If you try, you will hear a beep when you
   type the "hot" key sequence.

2. Display Adaptors.... Certain machines such as the IBM PS/2 Model 30
   indicate that a color monitor is installed even when a monochrome
   monitor is attached.  Maxess screens will appear with incorrect
   highlighting when a system with a monochrome monitor is configured to
   Maxess as a color monitor.  If you have such a system, run the
   Workstation Configuration Program (WCP), choose the System/Components
   screen, and change the monitor type to mono. You will only have to do
   this procedure once (after the initial installation).

3. Token Ring Networks.... Pressing the PrintScreen key on a Maxess
   Gateway PC without a printer being attached will cause disconnections
   of 3270 sessions on the network. The PrintScreen function does not
   timeout soon enough to prevent the Workstations from timing out.

4. Novell NETBIOS.... The Novell implementation of NETBIOS does NOT
   support group names.  Consequently, the ability to define Gateway
   group names is not available when using Novell's NETBIOS.

5. Novell NETBIOS..... There are problems with session cleanup causing
   "Duplicate Network Name" errors.  These errors occur frequently when
   Maxess software is running and require you to cycle the machine's
   power and restart Maxess to recover.  Because of these Novell NETBIOS
   errors, we recommend that you use another NETBIOS such as the IBM PC
   adapter program (tokruei/netbuei) or the PC LAN Support Program
   drivers (dxma0mod.sys dxmc0mod.sys, and dxmt0mod.sys).

6. Maxess APPC...... There is a limit of 32K data length on individual
   APPC send and receive commands.  If an APPC partner system other than
   Maxess does send a Logical Record larger than 32K bytes, the Maxess
   Transaction Program (TP) can receive up to the first 32K in the first
   receive, and the rest of the Logical Record in subsequent receives. In
   this case, the What_Received parameter of the first receive indicates
   data_incomplete.  If the TP attempts to receive more than 32K bytes in
   a single receive, the data will be ignored and the receive length will
   be incorrect.

7. Tempus Link.... This popular file transfer facility works successfully
   with Maxess.  However, you can not use Tempus Link resident file
   transfer software concurrently with the same Maxess functions: the
   3270 SEND and RECEIVE file transfers commands.  Since both Maxess and
   Tempus Link use the same HLLAPI interface, conflicts arise which cause
   one or the other to time out.

8. Network Lock-Ups.... see below for possible BIOS/CPU problems.

9. HOMEBASE.... You can not use HOMEBASE V2.5 (TSR from Brown Bag
   Software) with any Maxess software.  When HOMEBASE is installed the
   machine locks up when Maxess software is running and requires you
   to cycle the machine's power and restart Maxess to recover.  You
   can use the HOMEBASE de-install program to unload HOMEBASE before
   running Maxess software.


BIOS/CPU PROBLEMS AND ALMOST COMPATIBLE PCS

Networking software makes extensive use of the machine facilities
contained in the ROM BIOS.  For some older IBM PCs and XTs, this
BIOS was found to contain bugs which prevent reliable operation with
networking software.  Maxess, which makes extensive use of this
networking software, is susceptible to these errors when running on
older machines.  However, the alternatives listed below are open to
you should you want to use an older IBM PC/XT as a workstation or
gateway on a network.

Also, on some very old IBM PCs, the CPU chip was flawed and did not
process Stack segment changes correctly.  This is rare and very few
of the machines were delivered, but they will cause problems, should
you try to use them on your network.

1. CPU Problems.... MMS will test for the presence of a bad
   8088. If found, the message "** BAD 8088 - replace immediately **"
   will be displayed and the program will terminate. You will not be
   able to use this PC as a Maxess workstation or gateway without
   replacing the CPU chip.

2. BIOS Problems.... You must have a version of the ROM BIOS dated
   1986 or later to reliably use networking software.  Most software
   will work normally for a time, but you may experience periodic
   errors on the network.  Some networking software is more sensitive
   to this problem than others.  These errors typically occur under
   heavy network traffic or workstation loading conditions.

   On the Maxess UTILITIES Diskette is a device driver called MAXTIMER.SYS.
   This driver fixes a bug in some ROM BIOS implementations, where pending
   interrupts are lost because the BIOS routine does not check the status of
   the interrupt controller before issuing a END OF INTERRUPT command. This
   bug is known to occur on IBM XTs and on pre-1987 ATs. For these systems,
   we recommend that you add the statement:

         DEVICE=MAXTIMER.SYS

   to your CONFIG.SYS file. MAXTIMER.SYS must be the FIRST device driver
   loaded! If MAXTIMER.SYS is not installed, then a warning message is
   displayed when MMS loads.

   Additional Alternatives:

      a. Update the BIOS ROM to the most recent IBM replacement part
         dated 1986 or later.
      b. Read the installation instructions for your networking
         software.  Some network products, such as IBM's Token Ring
         support, provide ".SYS" files which effectively "patch" the
         ROM BIOS to avoid some of these problems.  These fix files,
         unfortunately, do not completely eliminate the bugs in all
         areas of the BIOS.
      c. Contact your PC support representative about installation of a
         replacement ROM BIOS from various non-IBM vendors, which will
         have compatible BIOS parts.

3. Almost Compatible PC Problems.... There are many vendors of
   so-called "clone" PCs, each of which has a ROM BIOS installed in
   order to operate correctly.  In some cases in older models of these
   PCs, the ROM BIOS is not 100% compatible with the IBM BIOS, or was
   not written to support networking products.

   The Maxess SNA Gateway may experience problems on certain IBM
   "clones" because of these differences.  Check with your original
   equipment supplier for (a) the most recent version of the ROM BIOS
   which is available, and (b) the compatibility of the equipment for
   use with networking software.


CONFIGURATION SUGGESTIONS FOR MAXESS GATEWAY OPERATION

The Maxess product has extensive logging and diagnostic facilities which
can be configured by the System Administrator. In the case where the File
Server and the Maxess Gateway are on separate machines and logging is
directed to a File Server disk, an exceptional demand for network I/O
will be placed on the Server.

You may experience problems with some File Server implementations, which
are not capable of reliably processing this volume of server traffic. To
minimize these problems, it is HIGHLY recommended that the logging be
directed to a local drive as opposed to a network drive. See the Maxess
Gateway Administrator's Guide for more information on configuration.

    1. XID For Node Type 2.1 Operation - There is a documentation omission
    on page 5-6 of the Maxess SNA Gateway Administrator's Guide. The XID
    discussion is correct for host Node Type (NT) 2.0 data links, but there
    is no discussion of the required XID for NT 2.1 data links. For both
    switched (dial) and leased line NT 2.1 data links, you must supply a
    format type 3 XID rather than the format type 0 XID. Therefore with
    NT 2.1 data links, both switched and leased, you must specify digits
    one through four as 3200 rather than 0200.

    2. Maxess Compatibility with Other Adapters - The Maxess SNA Gateway
    Co-Processor Board is shipped with defaults settings. If these settings
    conflict with other hardware adapters installed in the same machine,
    then you must change either the Maxess board settings or the other
    adapter's settings; since only a Gateway machine contains the Maxess
    Co-Processor Board, Workstation machines are not affected by hardware
    adapters. Appendix A, B, and C of the Maxess SNA Gateway Administrator's
    Guide discuss the Maxess Co-Processor Board and its default settings.
    In particular, the following Maxess default settings may conflict with
    other hardware adapters:

         Interrupt Vector = 3
         I/O Addresses = 33C through 33F

    Appendix C of the Maxess SNA Gateway Administrator's Guide discusses
    how to customize the loadgw.bat startup file to reflect changes to
    Maxess Co-Processor board default settings. In addition, Appendix C
    points out that if the network adapter board in your Gateway machine
    requires DMA, then you must edit the loadgw.bat file and add the /d
    parameter to the Gateway Resident Support Program load statement:

          grsp /d

    Examples of network adapters that use DMA are the IBM PC Network
    adapter and the 3Com EtherLink Plus adapter.
