TECHNICAL BULLETIN
                                Bulletin #1-266

Date:  April 4, 1990

                                 NetBIOS Patch

NetBIOS may hang under heavy network traffic conditions because of the following:  An outbound packet is acknowledged while IPX is in the process of sending that packet.  The acknowledge code attempts to cancel the outbound packet and, if successful, sends the next outbound packet.  

Previous versions of NetBIOS incorrectly report a successful cancel in this situation and then re-use the outbound packet's ECB to send the next packet, with dire consequences.  This problem has been fixed in a patched copy of NetBIOS.  This file is available on NetWire and is called NB215C.ZIP.  

If you have the version of NetBIOS that came with NetWare v2.15, revision C, you can patch the NetBIOS emulator yourself.  Listed below is the patch for the NETBIOS.EXE file (the file is dated July 20, 1989 and contains 21,219 bytes).  The patch fixes this specific problem only.

	copy netbios.exe netbios.tmp
	debug netbios.tmp
	-e cs:0947 <CR>
	XXXX:0947  0A.0C <SPACE> 		(you will need to enter the 0C and press the space bar)
	XXXX:0948  C0.FF <CR>			(you will need to enter the FF and then press the enter key)
	-e cs:1620 <CR>
	XXXX:1620  0A.0C <SPACE> C0.FF <CR>	(you will need to enter the 0C and press the space bar.  It will return with the C0.  You will enter the FF and press ENTER.)
	-w <CR> Writing XXXX bytes		(write the change)
	-q <CR>					(quit)

If the stated values are not returned where indicated, do not proceed with the patch.  Use the pre-patched copy of NetBIOS (available on NetWire).