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Date: Thu, 16 Nov 1995 00:27:23 +1100
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199511151327.AAA05338@godzilla.zeta.org.au>
To: hsu@cs.hut.fi, j@uriah.heep.sax.de
Subject: Re: ISP state their FreeBSD concerns
Cc: bde@zeta.org.au, current@FreeBSD.org
Sender: owner-current@FreeBSD.org
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>> Bruce Evans writes:
>>  > >+ #ifndef RS_IBUFSIZE
>>  > >  #define       RS_IBUFSIZE     256
>>  > >+ #endif

>>  > Your setup is very special.

>Yes, but Bruce, why can't we insert the simple #ifndef?  It doesn't
>break anything, but would allow interested people (with a `very
>special setup') to override it from the config file instead of hacking
>the sources over and over again.

Because ifdefs are evil and simply changing RS_IBUFSIZE is not sufficient.
It must satisfy the following:

	TTYHOG - 2*RS_IBUFSIZE > 0 (much greater, < TTYHOG/2 would be silly)
	RS_IBUFSIZE - 11520 * (1.0/hz + max_softtty_interrupt_latency) >= 0

Bruce