Date: Sat, 2 Sep 2000 19:58:26 -0600 (MDT) From: Nate Williams <nate@yogotech.com> To: Allen Campbell <allenc@verinet.com> Cc: Ian Smith <smithi@nimnet.asn.au>, freebsd-stable@FreeBSD.ORG Subject: Re: bad 16550A maybe? Message-ID: <200009030158.TAA01926@nomad.yogotech.com> In-Reply-To: <39B19295.3D66E41@verinet.com> References: <Pine.BSF.3.96.1000902074531.8872A-100000@gaia.nimnet.asn.au> <39B19295.3D66E41@verinet.com>
next in thread | previous in thread | raw e-mail | index | archive | help
> > > Maybe. silo overflows happen because the machine is too slow to > > > service the interrupt before the buffer overflows (but unless it is a > > > 386SX25 you should have enough CPU power). It can also be caused by > > > baud rate mismatches, but that's fairly rare and unusual (you usually > > > get framing errors from a 16550A in this case). This can also be > > > caused by other hardware misbehaving and blocking interrupts. > > > > I ran a 386SX16 under DOS 5 / DESQView (~10 tasks in 6Mb) using David > > Nugent's BNU FOSSIL driver as a Fidonet mailer/BBS for almost 9 years, > > hardly ever seeing 16550A overflows at 14 byte thresholds, albeit 14.4k. > > You actually run a 386SX25? I have a 486/133 that has always > experienced intense SILO overflows (yes, it is a true 16550, bought > specifically to address this,) under FreeBSD. Which version of FreeBSD? I've been running (well, I quit the company, but the box is still up) a 486/66 with 4 16550A's running full-blast @ 115K on the modems with nary a problem. The box is a firewall, DNS, email, and modem server for a small office, and is working great. The only modifications were to continually upgrade the software such as BIND and SENDMAIL where remote root exploits were possible, but otherwise it's a stock FreeBSD 2.2.8 system. (No X, of course.) > I suspect the problem is exasperated by PIO mode IDE and an ISA > NE2000. Anyhow, the threshold most definitely MUST be lowered when > communicating at >50Kbps with my USR modem. We're running the same setup (PIO IDE and a NE2000), and I've ran all 4 modems (2 USR Sportsters and 2 USR V.Everythings) full-blast one day to see how well it would handle it. Not once did it even hiccup or lose packets. > I would kill for a kernel option that makes patching unnecessary but > the attitude, as expressed above, that anything faster than a 386SX25 > can not possibly be too slow seems to preclude this. I'm with Rod Grimes in stating that something happened in later releases of FreeBSD that makes this difficult or impossible. Nate To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200009030158.TAA01926>