Very simple question: how to add a serial port on old sysvr4(at&t 386 2.1)?
I have tried "mknod /dev/tty01 c 4 0" and create it,but is "dead".
Some suggestion?
Thanks

edit1: i see on fresh installation serial are recognized both

It's been a long time but you need to edit /etc/inittab and insure you have the "getty" process assigned to the serial device (you can assign other functions to it for serial interfaces - getty prompts for login)

If you have man pages on the system look at:
man inittab
man getty
man init

I found man pages and at http://unixhelp.ed.ac.uk/CGI/man-cgi?inittab+5 found examples for getty for serial devices:
http://unixhelp.ed.ac.uk/CGI/man-cgi?inittab+5

I forget the exact syntax we used to use for making serial interfaces to other systems. All I really recall about that was we'd do redirect in and out of the device and usually set it to xon/xoff (software flow control) if possible or would cable it for hardware flow control (rts/cts pins in addition to others) if not pssible to do software flow control.

Thanks,Already know of getty,tty,inittab.
My problem is another,the serial is not recognized,only tty00(first serial)
is present.
I have tried to mknod,but when i try the test
echo "prova" > /dev/tty01,give me error

Check for IRQ and DMA conflicts, its usually the source of the errors you will get when trying to talk to a serial interface

2 members found this post helpful.

IRQ conflicts is a good suggestion. You only have two interrupts (3 and 4) for default serial.

How did you determine the major, minor (4,0) to use for this device?

Does "stty </dev/tty01" give any output?

Most of what I used to do used port cards and/or muxes to provide the additional ports so they weren't using the default serial port setups.

1 members found this post helpful.

Yes was irq conflict,virtualbox assign irq 4 on tty00 and irq 3 on the next tty!
mknod /dev/tty01 c 3 0
and echo prova > /dev/tty01
now works fine.
Thanks

Glad you got it fixed.

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