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Using COM3 and COM4 in Tru64

Usually an Alpha system has one or two serial ports. The first port is often used as a serial console. AlphaVM currently supports only serial console. Thus, there is only one serial port left for other purposes. Often it is desired to have more serial lines. Therefore, since the 1.6 release our implementation supports additional COM3 and COM4. The guest OS (OpenVMS or Tru64) has to be configured to use these additional ports. The serial drivers have to be loaded.

The additional serial lines are serial ISA devices, the same as COM1 and COM2. Our implementation registers the devices in the ISA configuration table. When a serial driver is loaded, it uses the information from the ISA configuration table.

Below are the instructions.

  • Edit the kernel configuration /sys/conf/EMU. Add the new serial lines after ace0 and ace1.
controller ace2 at isa0 slot 2 vector aceintr
controller ace3 at isa0 slot 3 vector aceintr

  • Rebuild and copy the kernel.
# doconfig -c EMU
# cp /vmunix /vmunix.saved
# cp /sys/EMU/vmunix /vmunix
  • Create the device nodes.
# cd /dev
# ./MAKEDEV ace2 ace3
MAKEDEV: special file(s) for ace2:
tty02
MAKEDEV: special file(s) for ace3:
tty03
  • Optionally, enable the tty02 and tty03 for logging in. Add the following lines to /etc/inittab
tty02:23:respawn:/usr/sbin/getty /dev/tty02 9600 vt100
tty03:23:respawn:/usr/sbin/getty /dev/tty03 9600 vt100
  • Optionally, enable root login. Add /dev/tty02 and /dev/tty03 to /etc/securettys.
  • You may also need to edit /etc/remote. For instance, add
line2:dv=/dev/tty02:br#38400:pa=none

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