Re: ECP port driver

["RollingHillsObs \(Shawn Dvorak\)" <rollinghillsobs@cfl.rr.com>]

My 486 Linux box was retired some months ago, but I gave this a try on a
Pentium 166 running Redhat 6.2 (= kernel 2.2.14).  After just a bit of
twiddling to get the "short" module to compile, I got the following results
from three runs:

[root@homebase /dev]# time dd if=/dev/short0s bs=16 count=1000000 >/dev/null
1000000+0 records in
1000000+0 records out
3.12user 26.53system 0:32.38elapsed 91%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (100major+14minor)pagefaults 0swaps

[root@homebase /dev]# time dd if=/dev/short0s bs=16 count=1000000 >/dev/null
1000000+0 records in
1000000+0 records out
2.89user 27.38system 0:33.10elapsed 91%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (100major+14minor)pagefaults 0swaps

[root@homebase /dev]# time dd if=/dev/short0s bs=16 count=1000000 >/dev/null
1000000+0 records in
1000000+0 records out
3.37user 26.28system 0:32.42elapsed 91%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (100major+14minor)pagefaults 0swaps

Average clock time was 32.6 seconds, and CPU utilization was solid at 91%.
Although a 486 w/ Linux has generally been the agreed-upon platform for
running the cameras, I don't think that an old Pentium like one I used would
be much of a stretch for any budget today.  There isn't much price
difference on EBay or the like for a 486 vs. an ancient Pentium.  And,
Pentium motherboards generally accept DIMMs as opposed to the much-pricier
SIMMs required by most (all?) 486s.

Shawn


----- Original Message -----
From: "Robert Creager" <robert@carolinecreager.com>
To: "Fraser Farrell" <fraser@trilobytes.com.au>; "Robert Creager"
<robert@carolinecreager.com>
Cc: <tass@listserv.wwa.com>
Sent: Thursday, September 06, 2001 4:56 PM
Subject: Re: ECP port driver


>
> Hey,
>
> I'm hoping some fine person, with a slow box
> (486/Pentium) and a 2.2 kernel can run a simple test.
> On the link below is a tarball of examples from the
> Linux Device Drivers 2nd edition book.  Within said
> tarball is a driver called short.  While it doesn't
> run the parallel port in ECP mode, it should give a
> rough idea of if the computer is capable of
> downloading the data in a timely manner.  After
> building and loading the module (by using make and
> then short_load), execute the following statement:
> time dd if=/dev/short0s bs=16 count=1000000 >
> /dev/null
>
> What this will do is execute 1 million 16 byte
> transfers (using insb), trashing the results.  The
> /dev/short0s is the device which uses the insb macro,
> vs inb.  If the time of this command is less than 40
> seconds, the computer might (should?) be able to keep
> up.
>
> For comparison, my AMD K6-2 500Mhz (roughly a Pentium
> II), will execute the above in about 31 seconds, using
> 85% CPU (it's almost CPU bound, but not quite).
>
> http://examples.oreilly.com/linuxdrive2/
>
> ---- Fraser Farrell <fraser@trilobytes.com.au> wrote:
> > Robert (and list),
> >
> > >Hmmm... 2.2 you say.  I was shooting for 2.4 - it
> > >makes supporting devfs easier to do - no need for
> > >IFDEFS.  Any particular reason you indicate 2.2?
> >
> > The ECP port was introduced around the era of the
> 486; so I was
> > thinking of a scenario where a 486/Pentium-class
> computer sits outside
> > in the cold & damp to run the Mark IV. Most of the
> prebuilt distros
> > with kernel 2.4 are a bit overwhelming for older
> hardware. Or won't
> > run at all.
> >
> > OTOH you may need a powerful box with kernel 2.4 to
> run the image
> > analysis software.
> >
> >
> > >If there are serious requests for 2.2, is anyone
> > >willing to test some code on their platform?
> Although
> > >I can grab another version of the kernel, my server
> is
> > >my playground, and I dislike rebooting often :-)
> >
> > My server had its second reboot for this year two
> days ago. A power
> > cut which outlasted the UPS. I used this opportunity
> to replace a
> > noisy fan :)
> >
> >
> > >Speaking of distribution specific, what
> architectures
> > >might someone use this on, and would that someone
> be
> > >willing to test some code?
> >
> > Hmmm...of the boxes with ECP ports here; I can do
> Redhat 6.1 (kernel
> > 2.2.12) Mandrake 8.0 (kernel 2.4.something) or
> Slackware 7. I've also
> > got Redhat 7.1 but nowhere to install it yet. I
> could also try it out
> > with a couple of the mini-distros such as Dragon or
> Phat.
> >
> > What I don't have is a Mark IV (or something that
> can simulate a Mark
> > IV).
> >
> > It may be worth developing a utility that can run
> under DOS (or Linux)
> > to simulate a Mark IV on any computer with an ECP
> port. Including the
> > output of known "test pattern" images for
> verification of your setup
> > and data analysis.
> >
> > The ability to swap in a known-to-be-working
> replacement is very
> > helpful for troubleshooting. But having two Mark
> IV's at every
> > location probably isn't Tom's idea of effective
> surveying! A simulator
> > would also be useful for anyone without the camera
> who wants to write
> > control software for it.
> >
> > Apologies if all this has been discussed before.
> >
> >
> >
> > cheers,
> > Fraser Farrell
> >
> >
> >
> >
>