Released Feb 2003
WriteLED is a small display utility for the LED display panel of the IBM
PS/2 Server 95. It can be used to write a text made up of up to 8 characters to
the LED display panel. WriteLED can be used on DOS, OS/2, Windows 95/98 and
WriteLED for Windows NT requires the MCPOS driver to
operate properly. MCPOS must be started prior to the invocation of the program.
By contrast, WriteLED for DOS is a standalone DOS program and does not require
any additional drivers or utilities.
WriteLED uses the system LED display ports 108h thru 10Fh. Running WriteLED
on a machine without a LED display panel should not have any adverse effects on
the system integrity.
Program binaries and source code have been released for DOS and Windows NT.
The source code is common to DOS and Windows NT, where platform-dependent
sections are distinguished by the defined _WLEDDOS
This release of WriteLED provides video effects like scrolling and blinking
a text, and dumping a file to the LED display. The WriteLED package is
available for download.
WriteLED is controlled through a number of command line options. To list all
options and get a help information about the command line options, run
writeled -h. To run the built-in WriteLED demo,
execute writeled -d.
Always enclose text arguments in quotation marks. Text arguments are
required by the options -o (output), -s (scroll) and -f (file). For
example, this is a valid invocation: writeled -s "ooo
Welcome to the machine ooo". When you precede your scrolling text by
seven or more spaces, the text will enter the LED display from the rightmost
The options -m (machine), -u (user) direct WriteLED to write the computer resp. user name
on the display. Only the first 8 characters can be written, longer strings will
be truncated. These options are available only in WriteLED for Windows NT.
As a special feature, WriteLED includes a file dump facility. Yes, you have
read that correctly, you can dump the contents of any file to the LED display.
Select a file to dump and run writeled -f <file
name>, then enjoy your display. All control characters and repeating
spaces in the file are intercepted and removed, resp. replaced by a single
WriteLED will fail to write to the LED display panel of IBM Server 720. The
reason is that the LED display panel of Server 720 uses a different and unknown
to us display port address range.
Please report any problems or bugs.