Date: Mon, 09 Oct 1995 10:47:48 -0700 From: Paul Traina <pst@cisco.com> To: Stu Phillips <stu@cisco.com> Cc: hackers@freebsd.org Subject: Re: FleeBSD and XNTPD Message-ID: <199510091747.KAA02148@puli.cisco.com> In-Reply-To: Your message of "Mon, 09 Oct 1995 09:28:38 PDT." <199510091628.JAA21052@feta.cisco.com>
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That's utterly bizzare that async IO isn't working on the serial lines, I seem to recall using it way back a million years ago. What version of FreeBSD are you using? I assume 2.0.5R, right? > Date: Mon, 9 Oct 1995 09:28:38 -0700 > From: Stu Phillips <stu@cisco.com> > To: pst@cisco.com > Subject: FreeBSD and XNTPD > Cc: dkatz@cisco.com > > Spent a frustrating weekend trying to get one of the clock drivers for > XNTPD working - of course, to hook up my GPS using NMEA as a first pass > to determine just what level of accuracy it might produce. > > Turns out that FleeBSD doesn't seem to support asynchronous IO on serial > ports. All the software built just fine but ioctl() or fcntl() calls on > the serial file handle trying to set the process id to be signalled (ie > using F_SETMODE or TIOCSPGRP) barfed with 'inappropriate ioctl for device). > > After a lot of kernel code reading I confess to confusion.... the tty driver > itself definetly supports async IO and the appropriate ioctl operations > but the sio driver does not. I thought that the tty driver was always > layered on top but alas seems not to be the case. > > So, bottom line, failed to get xntp to recognize the clock - its way too > much work to change the logic to poll since the whole enchilada is built > around async io. Futz! > > On a more positive note, the G-45 can be interogated for the time of day > using its own protocol - the answer has 4 uS resolution - date/time plus > a 256Kbbps sync'd clock. Of course with the serial link this degrades > significantly but should be good enough for roughly 1-2 mS precision. > > Sucks for a real GPS but for $300 LAN clock doesn't look too bad. > > Stu >
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