RE: [CAD_CAM_EDM_DRO] Re: LinuxCNC laptops

Drifting a bit off-topic here but if you think Compaq laptops and Desktops
are a bother, check out their Servers.

Gorgeous machines, bulletproof, very high performance and incredible bang
for the buck (I worked with a lot of them about eight to twelve years ago)

In order to make any and I do mean __any__ changes to the configuration, you
had to have a proprietary CD-ROM disk for that model of machine.

No disk + hardware change = bricked machine until you could get a
replacement disk and reformat.

Change RAM, add another HD - you needed that disk.

They used to be available for free download but now they are available only
as a part (re: $$$) and the older ones are no longer available.

If you ever get the chance to buy a Compaq server on eBay or wherever, you
will not be dissapointed but it needs to come with that CD-ROM.

Dave
(who owns and loves three Compaq 1850Rs)

> -----Original Message-----
> From: CAD_CAM_EDM_DRO@yahoogroups.com
> [mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of Yahoo
> Sent: Tuesday, March 04, 2008 7:52 AM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: [CAD_CAM_EDM_DRO] Re: LinuxCNC laptops
>
> I used to work at Intel, and I still know people who work at
> Intel, and I
> can tell you this kind of problem continues to get worse. The
> good news is,
> with higher processor speeds the system management tasks take
> less time. The
> bad news is, laptop makers continue to get more and more
> proprietary in
> their designs. You may have noticed that laptops almost
> always ship with a
> "special" version of Windows. I once had a Compaq laptop that
> wouldn't work
> any more if you formatted the hard drive. (Of course they did
> that with
> their desktops as well, but we all know what happened to
> Compaq.) Add to
> that VMX from Intel and SVM from AMD, and the target keeps
> moving. Bottom
> line is you never know until you try, and laptops are most
> likely to have
> problems with any real-time application because they were not
> made for that.
> Not that PCs were made for that either. The days when all PCs
> conformed to
> the IBM PC/AT specification are long gone.
> --
> Phil Mattison
> http://www.ohmikron.com/
> Motors::Drivers::Controllers::Software
>
> ----- Original Message -----
> From: Stephen Wille Padnos <spadnos@...>
> To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> Sent: Monday, March 03, 2008 8:18 PM
> Subject: Re: [CAD_CAM_EDM_DRO] LinuxCNC laptops
>
>
> > Hi there.
> >
> > (I'm not sure if you're the same person who asked this
> question on the
> > EMC-users list, but just in case you're not, here goes ... )
> >
> > Laptops are particularly susceptible to having problems due to power
> > management. Intel built a special mode into their
> processors, starting
> > somewhere in the 386/486 release cycle. It's called SMM or System
> > Management Mode. The SMI interrupt is what puts the
> processor into this
> > mode, and that interrupt can't be turned off. (even though some
> > chipsets may allow it to be turned off, this is actually
> out of spec for
> > the chip since thermal management is done in this mode, among other
> things)
> >
> > So here's the problem: every 64 seconds, and whenever a "system
> > management event" occurs, the processor will stop whatever
> it's doing,
> > and go off to take care of "system-y things". This can take several
> > hundred milliseconds to complete. I'm not sure why it's so slow,
> > considering that 300ms is about a billion cycles these
> days, but that's
> > the kind of latency we've measured. If this happens when
> you're trying
> > to output steps at a rate of 15 KHz, the step stream will
> suddenly stop
> > (no deceleration) and then start up again a while later (with no
> > acceleration), which is likely to cause the motors to
> stall, or at least
> > to lose steps.
> >
> > This isn't a problem with EMC2 specifically, it should
> happen to other
> > programs as well, including Mach3 (due to Windows), and
> possibly even
> > TurboCNC (since SMI is supposed to be enabled by default).
> Sometimes
> > you can get acceptable performance by tweaking the BIOS and
> testing (a
> > lot). I don't know of any solutions that "just work",
> especially for
> > many different CPUs and chipsets. If anyone has a good, general
> > solution (for Windows or for Linux), I'd like to hear about
> it so we can
> > incorporate it into EMC2.
> >
> > There are sometimes other problems with latops as well, such as
> > insufficient drive strength from the parallel port, or no
> parallel port
> > at all :)
> >
> > - Steve
> >
> > marcin_ose wrote:
> >
> > >Dear Group,
> > >
> > >Can you suggest what brands of laptops have good compatibility with
> > >LinuxCNC, and what distribution of Linux you would recommend? I'm
> > >looking for a laptop, and want to make sure that it will work well
> > >with LinuxCAD for an CNC acetylene torch table that we're building.
> > >
> > >Thanks,
> > >
> > >Marcin
>
>
>
>
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