RTLGuard
========

For Elbox Mediator busboards with an RTL8139 based network card and
Elbox's FastEthernet.device.

Under heavy network traffic the network can stop for good: downloads
end with a timeout, network volumes hang, and only a reset helps. The
Amiga itself keeps running.

The cause is the receive configuration register of the RTL8139. After
an invalid packet header, FastEthernet.device 1.25 restarts the card's
receiver, which clears that register, but does not write it again. The
card stays switched on and accepts no packets.

RTLGuard runs in the background, checks the card twice a second and
restores the register when it finds it cleared. The driver itself is
not changed. The number of repairs is kept in an ENV variable.

The fault appears under heavy load, most of all with several transfers
at once, and fast accelerators seem to make it more likely. It was
found and tested on an A1200 with a PiStorm32-lite (Emu68) and a
Mediator 1200 TX, with FastEthernet.device 1.25 and pci.library 13.15.


Installation
------------

Copy "RTLGuard" to C: and add this line to S:User-Startup, after the
network is started:

    Run >NIL: C:RTLGuard QUIET

Everything else is in RTLGuard.guide.


Disclaimer
----------

This software is provided "as is", without warranty of any kind. You
use it entirely at your own risk. The author cannot be held
responsible for any loss of data or damage to software or hardware.

RTLGuard is by Andreas Winkler, 2026, and is freeware. It may be copied
and distributed freely as long as the archive stays complete and
unchanged and no money is charged for it beyond the cost of the medium.

Mediator, pci.library and FastEthernet.device are products of Elbox.


History
-------

1.2 (21.10.2026)  First public release.

 PERMSSN    UID  GID    PACKED    SIZE  RATIO METHOD CRC     STAMP          NAME
---------- ----------- ------- ------- ------ ---------- ------------ -------------
-rw-r--r--  1000/513      3078    5160  59.7% -lh5- 946e Oct 21 17:07 RTLGuard/RTLGuard
-rw-r--r--  1000/513      3334    8369  39.8% -lh5- 748a Oct 21 16:57 RTLGuard/RTLGuard.guide
-rw-r--r--  1000/513      1112    2138  52.0% -lh5- 8f2a Oct 21 17:07 RTLGuard/RTLGuard.readme
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total         3 files    7524   15667  48.0%            Oct 22 00:34