Date: Thu, 31 Jan 2013 11:04:03 -0700 From: Warner Losh <imp@bsdimp.com> To: Ian Lepore <ian@FreeBSD.org> Cc: freebsd-arm@FreeBSD.org Subject: Re: SD card -image- for the beaglebone Message-ID: <EE9BDFB7-324F-4C22-9A08-88294F6DC6E4@bsdimp.com> In-Reply-To: <1359646574.93359.327.camel@revolution.hippie.lan> References: <510A4F5B.7000407@g7iii.net> <1359646574.93359.327.camel@revolution.hippie.lan>
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On Jan 31, 2013, at 8:36 AM, Ian Lepore wrote: > On Thu, 2013-01-31 at 11:02 +0000, Iain Young wrote: >> Hi Folks, >>=20 >> I have just taken delivery of a few Beaglebones that I am intending = to >> do some NTP Work. With FreeBSD having one of the better reputations >> with regards to Time and PPS etc, I thought I would install FreeBSD = on >> at least one of them. >>=20 >> Unfortunately, all of the guides I've found all assume you have a >> FreeBSD box already running. Unfortunately, I don't, and nor do I = have >> a spare x86 box to do so. >>=20 >> Does anyone have an *image* of a base install for a 4 Gig microSD >> card that I can download ? Preferably with ssh and dhcp installed >> (yes, I know about blowing away the keys), as that would avoid having >> to rely on the console. >>=20 >> Quite happy to rebuild the kernel and world afterwards (yes, I know I >> need an 8 Gig SD card), but it's just this bootstrapping problem = thats >> an issue... >>=20 >=20 > So you're interested in a PPS driver for BeagleBone? That would be = fun > to play with, I wonder what the BB's timer hardware looks like? It'd = be > easy enough to do with a gpio interrupt I suspect, but the timing geek > in me can't resist going for the nanosecond-accurate measurements when > possible, even if it is kind of pointless for millisecond-accurate = NTP. You can drive ntpd's accuracy to microsecond or tens of microseconds = with appropriate hardware. nanosecond accuracy help to steer the = frequency estimate the kernel uses for time keeping, but that only helps = a little since its frequency estimates are computed over hundreds of = seconds. Warner=
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