more on the HFC saga
Marc Weinstein
mhw at fithp
Sat May 25 16:29:39 AEST 1991
>From article <1991May23.133742.560 at ceilidh.beartrack.com>, by dnichols at ceilidh.beartrack.com (DoN Nichols):
> In article <1991May22.042143.13250 at fithp> mhw at fithp (Marc Weinstein) writes:
>>From article <103431 at becker.UUCP>, by bdb at becker.UUCP (Bruce D. Becker):
>
>>> Doing compression in the
>>> modem seems wasteful of resources due
>>> to the fact that uncompressed data gets
>>> pumped thru the serial interface with
>>> an interrupt service routine invocation
>>> for each character!
>>
>>Hmmm - don't understand the logic here. If I want to send a file to
>>someone, and I know my modem will compress the file anyway, then I don't
>>have to bother with compressing the file before the fact. Less wory,
>>less bother.
>
> If you pre-compress the file, that's fewer characters through your
> serial interface, and therefore fewer interrupts. And, since the
> transmission speed between modems is fixed (after compression), the fewer
> interrupts per unit time (on the average). It's the high rate of interrupts
> that really brings the system to its knees.
True enough. In this context, I agree. I just don't see this as an
argument for turning off compression in the modem by default.
--
Marc Weinstein
{simon,royko,tellab5}!linac!fithp!mhw Elmhurst, IL
-or- {internet host}!linac.fnal.gov!fithp!mhw
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