Re: Read from /dev/lp, new patch against 2.1.27/28

Carsten Gross (
Tue, 11 Mar 1997 19:09:25 +0100 (MET)

Ted ( wrote on Mar 10 1997:
> You realize there is a parallel-port SCSI driver for the ZIP interface
> already, right?
Yes, I know this. It's just a question if it (the ZIP drive for example) is
an IEEE1284 compatible device and is detected via the device detection
according to the IEEE standard.

My enhancements are not for driving a parallel ZIP drive or a parallel port
CD-ROM, but for use with various HP printers (mainly newer "laserjet"
models). These printers are using a protocol defined by IEEE standard no.
1284. This standard describes the "centronics" printer interface with some
enhancements to read data from the printer (or another peripheral device
attached to the printer port) using special readback operations. Among other
features there is a command available to "auto-detect" the attached printer
- in my driver available via an ioctl. Auto-detect means here, you are
requesting a device id and the printer/peripheral responses with a unique
string describing manufacturer, model and some other features.

Please correct me if I'm wrong, but I always thought Windows allows you to
use a ZIP drive and a parallel printer on the same port. At the moment this
is not possible with Linux, as I know. But it would be nice if the kernel
auto-detects other hardware, for example the ZIP drive, or a parallel CD-ROM
- I saw a driver for this too - and blocks the use as normal printer port or
gives you a small hint.

I just would like to now if the ZIP drive or other hardware are returning a
"device id" like the HP printers do. Therefore my first posting was a little
bit misleading. I'm sorry about it.


Carsten Gross		Internet:
Wohnheim Heilmeyersteige:  Sebastian Kneipp Weg 6, 89075 Ulm