At 18:06 Uhr +0100 17.10.2001, Matthew wrote:
>On Monday, October 15, 2001, at 06:13  pm, Matthew wrote:

>> I certainly am finding it a little slow, downloading things seems to
>> really throttle the connection.
>>
>> Oct 15 18:08:34 sonic /netbsd: zstty0: 6 silo overflows, 0 ibuf floods
>> Oct 15 18:10:15 sonic /netbsd: zstty0: 22 silo overflows, 0 ibuf floods
>>
>> I seem to be getting lots of these silo overflows. However, I have the
>> serial port speed set to "56700", should I decrease this? Will that not
>> throttle my modem even more than now?

"Depends".

Make sure you operate with hardware handshake - Macintoshes can do either
line control (DTR) or flow control (RTS) because they have only one
outgoing handshake line which is wired with both DTR and RTS in "hardware
handshake" modem cables. Make sure the modem ignores DTR -- usually AT &D0.

Use a lower MTU in your ppp setup to lose fewer data from a dropped byte.

I had a IIci running with an ISDN modem (max. 8 KByte/sec, interface speed
115KBit/sec) for a long time, and performance was fine as long as there
were no disk accesses.

I have my Q700 set up as a slip gateway for an old 486 notebook - again
with 115 KBit/sec. I see the occasional silo overrun, but no big problems.

>Okay... So, looks like there's no way to make it more acceptable!
>
>Fortunately, a friend and I built a PC from bits which we had around our
>respective bedroom floors (more from his than mine), and I now have an
>i386 NetBSD machine, which seems pretty good.
>
>Purely out of curiosity, now, can anyone explain why the performance
>isn't on par with that which Mac OS could provide on the same hardware?

The i386 most likely is equipped with a 16550 controller that has a 16 byte
fifo. The 85c30 in 68k Macs only has a 3 byte fifo which means that
transmission is much more sensitive to interrupt latency. Blocking
interrupts too long (disk access) means dropped bytes, and a single dropped
byte means a dropped packet dur for retransmission - worst case, 1500 Byte.

HTH,
	hauke

--
"Those who are willing to sacrifice essential liberties for
 a little order will lose both and deserve neither."
                                                   Benjamin Franklin