Saturday, August 6, 2022

A/UX 3.1 - Setting up a 68K Macintosh (SE, Plus, PowerBook) as a Terminal

 

Apple A/UX 3.1

Also known as the Apple© Workgroup Server 95

"Setting up a 68K Macintosh (SE, Plus, PowerBook) as a Terminal"

Introduction

My Macintosh IIci does not have a network card but it does have a pair of serial ports. The printer and modem ports. Let's use them to setup a terminal over a serial cable. 

In the Apple A/UX 30 Local System Administration guide has a section on 7-14 for "Setting up a terminal". We'll be using this to guide us. 

Ingredients

  • See my prior post, Apple A/UX 3.1 - A Macintosh IIci Installation, as a prerequisite.
  • An Apple printer serial cable.
  • A second computer with serial ports such as an SE, Plus, or PowerBook. In other words, a 68K Macintosh with Din 8-pin serial connections.

Instructions

Caution

Remember to first power down your Macintosh computers before you plug in, or unplug a serial cable. You can damage your computers if you do this while powered on. 

Disable AppleTalk

Since A/UX was installed without a network card, it configured AppleTalk to work over serial. We need to disable that or it will interfere with our serial connection. The easiest way to accomplish this is to use the Chooser application. Start Chooser and change AppleTalk from "Active" to "Inactive" and close it. 

Configure Getty

Getty, short for "get tty", is a Unix program that manages terminals. TTY is short for teletype, teletypewriter, or teleprinter. A teletype is a device that can send and receive typed messages. As you can image, they have a long history of use starting with the telegraph. Getty detects a serial terminal connection, and then prompts the user to login. 

We need to enable getty, on the modem serial port. You'll need to login as root for this. 

First, make a backup copy of /etc/inittab just in case we mess it up. 

cd /etc
cp inittab inittab.old

Then, using vi or TextEditor, open the /etc/inittab file and look for a line referencing tty0, which is port 0, the modem. It should look something like this.

00:2:off:/etc/getty tty0 at_9600    # Port 0 (modem); set to "respawn"
01:2:off:/etc/getty tty1 at_9600    # Port 1 (print); set to "respawn"

Note, the lines in these files are not wrapped to multiple lines as they may appear on this page of text. Do not introduce extra newlines into the file.

You'll want to change "off" to "respawn" on tty0.

00:2:respawn:/etc/getty tty0 at_9600    # Port 0 (modem); set to "respawn"
01:2:off:/etc/getty tty1 at_9600    # Port 1 (print); set to "respawn"

Save your modified version of /etc/inittab and execute the init command to commit the changes you've made to the system.

init Q

You may also want to check the file /etc/gettydefs to be sure the parameters for co_9600 and tt_9600 are correct. I did not need to alter them.

co_9600 # B9600 # B9600 SANE TAB3 # ~MODEM ~DTR ~FLOW # \r\n\nApple Computer Inc. A/UX\r\n\nlogin: # co_4800

tt_9600 # B9600 # B9600 SANE TAB3 ~MODEM ~DTR ~FLOW # \r\n\nApple Computer Inc. A/UX\r\n\nlogin: # tt_4800

If all went well, you should now be able to start a terminal session over serial. 

Remember to first power down your Macintosh computers before you plug in or unplug a serial cable. You can damage your computers if you do this while powered on. 

To connect, use a terminal program such as MacTerminal. You'll want to configure the connection settings to use the "Serial Tool" method. The port settings should be:

Baud Rate: 9600
Parity: None
Data Bits: 8
Stop Bits: 1
Handshake: XON/XOFF

Make sure you are using the correct port. My PowerBook 520c has a combined Printer-Modem Port and an Internal Modem. I selected Printer-Modem Port. 

The terminal settings should be set for VT100. MacTerminal does not have that as an option, I selected "VT102 Tool". You can leave the rest of the setting the default unless you want to change the font size, for example.

Connect by selecting "Open Connection" under "Session" on the menu bar. You should be greeted by a login prompt. 



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