Re: developing plustek driver-- questions
Antal Novak (afn@weevil.net)
Wed, 22 Jul 1998 10:56:37 -0400 (EDT)
> On Tue, 21 Jul 1998, Antal Novak wrote:
> > I don't like low-level OS-dependent... I've got FreeBSD and Linux, and I'm
> > sure many others use different OSes; it would be too hard to develop
> > low-level drivers for every OS. It's much simpler to have to manually
> > specify an I/O port (and in the future, it might be auto-detectable)...
>
> But surely the low level driver code has to live in kernel space in order
> to make use of interrupts and not busy wait on the port? If the driver
> runs in user space, even if it is run as root and niced to a high priority
> it isn't going to get the snappy response that a kernel module could get?
> Especially seeing as the standard parallel port doesn't come with DMA so
> the processor has to be involved in every byte transfered? Whilst
> effectively hanging the machine whilst a scan is in progress is OK in the
> Windoze world, I don't think it sounds terribly nice for the UNIX
> environment. Or is there a cunning way of doing an efficient, platform
> independent, user space, low level driver that I've missed?
Well... maybe further down the line. At this point, all I'm interested in
is a working SANE driver.
Do other parallel port drivers require kernel support?
afn
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