Re: [PARPORT] The simplest of all FAQs

David Campbell (
Thu, 8 Oct 1998 12:31:42 +0800

Date sent: Wed, 07 Oct 1998 23:50:39 -0400
Organization: @Home Network Member
To: David Campbell <>
Subject: Re: [PARPORT] The simplest of all FAQs

> OK, sorry I didn't know how to read the /proc/ioports. Anyway,
> here's its output.
> 0000-001f : dma1
> 0020-003f : pic1
> 0040-005f : timer
> 0060-006f : keyboard
> 0080-009f : dma page reg
> 00a0-00bf : pic2
> 00c0-00df : dma2
> 00f0-00ff : npu
> 01f0-01f7 : ide0
> 02f8-02ff : serial(auto)
> 0378-037f : lp
> 03c0-03df : vga+
> 03e8-03ef : serial(auto)
> 03f0-03f5 : floppy
> 03f6-03f6 : ide0
> 03f7-03f7 : floppy DIR
> 03f8-03ff : serial(auto)
> 6400-647f : Digital DC21041 Tulip
> /dev/lp is using that address. I guess I missed the
> line about chaining devices.

<CHANT> parport, parport, parport </CHANT>

Sorry about that, parport is the parallel port sharing code available in the
2.1.x kernels for 18(??) months and will be available in the Linux 2.2.x
kernels (real soon - I hope).

Support for sharing the parallel port under Linux 2.0.x is available on a
harasment basis (harass the developers enough and they will supply a
patch, sometimes...).

Your options are:
1) Use a Linux 2.1.x kernel
2a) Disable the lp driver (use "lp=0" as a kernel boot option)
2b) "rmmod lp" if the lp driver is a module, use "lsmod" to check
3) Try the Linux 2.0.x parport patch (requires kernel rebuild - not for newbies)
4) Wait for Linux 2.2.x to arrive (supposedly only a month or two away)

> In my machine at the office, I don't have a printer on /dev/lp
> because the printer is on the ethernet, so they aren't
> set up identically even if running same kernel.
> Would that do it?

*nod vigourously*

The lp driver is one of the drivers that tends to cause people grief when trying
to use the paride suite. (eg: it is loaded and they don't even realise)

> Windows has no trouble with having the printer connected at the
> same time [but it is windows, nevertheless :0) ]

(cough) Umm... you obviously haven't heard about the "problems" with HP
printers and various pass through parallel port devices under Win95?
Yes, windows does do parallel port sharing (but there is the odd "feature" or
two which causes problems).

> Is there a workaround?

see above

URLs to get you started: Linux parallel port devices Linux parallel port sharing

David Campbell

Current project list:
a) Maintain Linux ZIP drivers
b) Create Linux chipset specific parport drivers
c) Start on ParSCSI drivers

Any assistance to clearing this list most welcome

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This archive was generated by hypermail 2.0b3 on Wed 30 Dec 1998 - 10:18:32 EST