I currently have two parallel ports in my PC (one at address 0x3bc and
one at 0x378) and was wondering if it is possible to use them simultaneously
_without_ using more than one interrupt. I've read that in DOS, most printing
is not interrupt-driven, but instead is accomplished by polling. Having read
the Printing-HOWTO, I have learned that it is possible (under Linux) to toggle
between an interrupt driver and a polling driver for each parallel port
(/dev/lp0, /dev/lp1) using a utility called "tunelp". I was wondering if any
of the following configurations are possible for simultaneous use of the two
1) Have both ports share IRQ7.
2) Have both ports run with the polling driver (using no interrupts).
3) Have one port using IRQ7 and the other port running with the polling driver.
I know that I can set the two parallel ports up using separate interrupts, but
the card with the second parallel port only allows use of IRQ7 or IRQ5 (it's
an 8-bit I/O card), and IRQ7 is already used by my first parallel port (it's
integrated onto the motherboard and its IRQ is not changeable) and IRQ5 is
being used by an old MIDI interface card (whose IRQ is also not changeable).
Any comments/suggestions are greatly appreciated!