more on the HFC saga

Marc Weinstein mhw at fithp
Sat May 25 16:29:39 AEST 1991

>From article <1991May23.133742.560 at>, by dnichols at (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}!!fithp!mhw

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