Re: OT?: FAT32(/16?) Question: Max. files in top level
On Saturday 31 December 2016 09:16:10 Richard Owlett wrote:
> On 12/31/2016 7:49 AM, Gene Heskett wrote:
> > On Saturday 31 December 2016 08:01:15 Nicolas George wrote:
> >> Le primidi 11 nivôse, an CCXXV, Gene Heskett a écrit :
> >>> From personal experience decades ago, on a dos3.2 system, this is
> >>> correct. But I can't testify about the newer, or the now several
> >>> non-M$ versions of dos. I saw an announcement of yet another dos
> >>> release just a couple weeks back. I assume its getting better
> >>
> >> Think a little more about it: it is a limitation of the format, not
> >> the operating system. If an operating system extends the format, it
> >> is no longer compatible with the rest of the world, and then there
> >> is no reason to use FAT at all.
> >>
> >> Regards,
> >
> > Perhaps Nicolas, but ATM I am having it shoved down my throat
> > because I am playing with using a raspberrypi 3b to run a 1500 lb
> > metal lathe, and for some reason the boot partition is dos, but
> > mounted as /boot to armhf version of the debian jessie currently
> > installed. Seems to me the r-pi bios needs fixed to boot from an
> > ext4 file system. But I'm not in charge of such, can't even blow
> > the whistle. I'm still kicking the tires on the whole idea. Using
> > the SPI bus at 32 megabaud to talk to the peripheral driver that
> > runs the machine, I am finding that the noise radiated by the motor
> > supplies, which are switchmode, running at 17-19 kilohertz, have
> > enough radiated noise to wreck a 32 megabuad communications bus 7
> > inches long.
>
> Are you sure the problem is radiated noise.
> Could it be a ground loop?
> Prompted by vague recollections from decades past student days. YMMV
>
Some of both I think, I can clip the ground lead of the probe onto the
single point ground and find nearly 5 volts p-p, with sub 5ns rise and
fall times 3" away on a 60 volt psu cover whose ground braid comes back
to that bolt from the ground symbol on the psu terminal strip. Corcom
has a line filter they claim will reduce it at 30 mhz, by 50+ db. But it
needs to be at the line terminals, meaning one per supply and theres 3.
And the 30 mhz rating would be the most important since the spi bus is
running at 32 megabaud. Nominally $15 each. I built a box with two of
them from old computer psu's in it, but with output leads feet long, I
can see thats a waste of time. I can't believe a switchmode supply,
running at 17 kilohertz is making that much noise at 100+ megahertz. But
it is. If I buy some of the corcom filters, I can do some judicious
drilling and tapping and mount them right on the psu's with maybe 3/4"
connecting leads. Solder to the spade lugs and drop a chunk of heat
shrink over the input lugs. If I can attenuate the noise to around 1.25
v p-p, the bus seems bulletproof, but above 1.5 volts and its a coin
flip.
The FCC has rules about this, but all this crap is Chinese made now, and
no one AFAIK is checking what comes off the boat.
> > So I am cabbaging filter parts from
> > old computer psu's to see if I can quiet these power supplies down
> > to a dull roar. A film at 11 situation I fear.
> >
> > Cheers, Gene Heskett
Cheers, Gene Heskett
--
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-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
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