Thanks for the pointer, RB.

I had a little trouble bringing up the setup menu since CTRL+ALT+ESC gets interpreted by Ubuntu to switch windows. Reassigning ESC to the END key worked to get into setup.

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./mame apple2p -flop1 ~/Downloads/openemulator/UCSD\ Pascal\ 1.1_1.dsk -flop2 ~/Downloads/openemulator/UCSD\ Pascal\ 1.1_3.dsk -sl4 softcard -sl3 ssc -sl3:ssc:rs232 null_modem -bitb1 socket.

./mame tv995 -rs232a null_modem -bitb1 socket.

Now to get the system disk setup for Hazeltine 1500.

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