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After reading "Optimizing NT RAS" (May 1998), Taed Nelson asked me
why the Windows NT 4.0 serial.sys driver installs with the default first in,
first out (FIFO) values of 8 for the receive buffer (RX) and 1 for the transmit
buffer (TX). I decided to investigate the matter in the Microsoft Windows NT
Server 4.0 Resource Kit.
The resource kit's Registry documentation refers you to a nonexistent
Knowledge Base article (Q112559), making the mystery even stranger. You can't
help but wonder why Microsoft removed this article. And you are still left
wondering why Microsoft selected the NT 4.0 default values of 8 for RX FIFO and
1 for TX FIFO, especially when Windows 95 uses the default values of 8 and 16,
respectively.
You can improve modem performance by increasing the TX FIFO value to 16. In
regedit, change the TX FIFO value in the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Serial subkey to 16. However, before you
experiment with this modification, make sure you have backed up your Registry.
In addition, be aware that modifying the TX FIFO value is a global change that
affects all serial ports on the system. As a result, this change might cause
problems for other types of devices (such as plotters, mouse devices, and
digitizing tablets) attached to serial ports. After you change the TX FIFO
value, verify whether all the serial-based devices are working properly.
If you encounter any problems with particular devices on other component
object model (COM) ports, you can make the following change, which is specific
to a particular serial port. In the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Serial subkey, create an additional Registry subkey
for a specific serial port number by adding a Serialn key (where n
is the number of the COM ports connected to the dial-up adapter) under this
key's Parameters subkey.
For example, a specific entry for COM1 is HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Serial\Parameters\Serial. Inside this
newly created key, create the same REG_DWORD value for TX FIFO as that found in
the Serial subkey and set it to the desired value for that port (e.g., 16
decimal). You can also create custom values to this port for other entries, such
as RX FIFO.
—Sean Daily
sean@ntsol.com
Try Before You Buy
I have been testing Symantec's pcANYWHERE32 8.0 for Windows NT 4.0, NT 3.51,
and Windows 95 in a development lab to determine its compatibility and
functionality with my company's legacy systems. In particular, I wanted to test
pcANYWHERE32's ability to upload and download files to and from distributors'
bulletin board systems (BBSs) using Pulsar Systems' ZMODEM.
My company has been running pcANYWHERE32 on UNIX servers in its US systems.
For several years, I have used a script to automate the ZMODEM transfers.
However, my company plans to replace the UNIX boxes with NT. Initially, I
believed that I could still use pcANYWHERE32 with NT to maintain the BBS file
transfers to the distributors. But when I tested pcANYWHERE32 for NT and Win95,
I discovered that Symantec has not incorporated the functionality of the earlier
versions into version 8.0. This version doesn't support script-based file
transfers to legacy BBSs.
Calls to Symantec have been fruitless. No one seems concerned that this
feature doesn't work with NT. (It works with other platforms, however.) And no
one appears to know whether this feature will ever be functional. So buyer
beware. Before you part with your hard-to-come-by IS budget and purchase a
product, make sure it works.
—Robert J. Birkett
Remotely Change the LMHOSTS Table
Suppose you have a network of Windows NT workstations at local and remote
sites (some of which are far away). You don't have either fixed IP addresses or
Windows Internet Naming Service (WINS), so whenever you install a new computer,
you must change the LMHOSTS table. You can perform this task remotely by using
the .reg file in Listing 1 to change the Registry keys.
In Listing 1, Elnk31 and AMDPCN1 are network adapters that might exist in a
computer. Although this file contains entries for several adapters, NT will use
only the appropriate one.
To install the changes in the Registry, use the .bat file in Listing 2, put
in the logon script, and reboot. The script in Listing 3 will not only implement
the Registry changes but also implement the WINS and Domain Name System (DNS)
policy. Before you use this listing, change the IP and domain names to the ones
in your network.
—Jose Abel Aguiar
jose_aguiar@hotmail.com