[SunRescue] Help with IPC serial ports...
james at foonly.com
Tue Dec 28 22:12:27 CST 1999
On Tue, 28 Dec 1999, Kurt Mosiejczuk wrote:
> This is where the problems are. Anything greater than 9600 baud
> ends up with serial input overruns. I even recompiled the kernel to
> take out the cruft I don't need. Still problems.
> So, I started searching the net for help. Seems that I may just be out
> of luck. Apparently the zs8530s on almost all sparcs have just a 3-byte
> FIFO, no DMA, and require LOTS of CPU intervention. After all this, I'm
> amazed my IPX had no problems at 38400.
I've got three words for you, and they're probably not what you want to
The zs serial port driver in SunOS 4/5 can sustain 38400bps on an IPC
class machine with no problem, and 76800bps is doable on an IPX or faster.
*BSD and Linux can't do this on the same hardware. For most things they
are more lightweight and perform better on low-end hardware, but they are
lacking in zs serial port performance.
I used a SS1+ as my dialup PPP gateway at 38400bps for over 2 years. No
overruns or other problems. Ran both SunOS 4.1.3u1 and Solaris 2.4, along
with ipfilter, the Harvest Cache and a boatload of other daemons. For a
NAT router, you can fit the OS and everything else on a 100MB disk with a
bit of work, and 24MB RAM is sufficient. 16MB would work if you went with
SunOS 4, but given the lack of support and number of patches I wouldn't
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