Date: Thu, 25 Apr 1996 09:03:15 -0400 From: "Frank E. Terhaar-Yonkers" <fty@mcnc.org> To: sos@FreeBSD.org Cc: bde@zeta.org.au, current@FreeBSD.org, freebsd-current@FreeBSD.org Subject: Re: minor syscons bogon Message-ID: <199604251303.JAA09174@robin.mcnc.org.mcnc.org>
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>> Does anything actually use this kludge? Like, how would an application >> even know that /dev/ttyv[MAXCONS] == /dev/console ? This is very ugly. > Obviously. >NO vty is the same as /dev/console, period. But by changing the MAXCONS >define you break the logic in syscons that deals with this. Exactly my point. Tying a kernel define to a minor device # is stupid. >NO application is supposed to know ANYTHING about MAXCONS, its an internal >define to syscons, and it shouldn't be tampered with (except you know Then document it as such. >EXACTLY what you are doing). It is a hack that solves an old problem >in the way interaction with the console is done internally in the kernel. >There was a time when it defined the number of consoles available, but >that is long gone, as that is done dynamically now. >It has nothing to do with the physical /dev/console device which is >alwas on the same major/minor no matter what MAXCONS is set to. >So don't change MAXCONS, and don't make more than the 16 vty's >that MAKEDEV allows you to, or something VERY UGLY is going to happen. It's not unreasonable to whittle down defines to say, get a kernel (and enuf utils) to fit on a 1.44 floppy for "fixit" purposes. This define seemed to fit the bill. A "few bytes" here and there makes a huge difference not only here but in a production system where it may make the difference between a process page thrashing or not. >I wouldn't advise that you go change random defines all over the >place or you are in for some REAL trouble. > > >-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- >Soren Schmidt (sos@FreeBSD.org) FreeBSD Core Team > So much code to hack -- so little time. > \\\\////\\\\////\\\\\////\\\\\////\\\\////\\\\////\\\\////\\\\////\\\\////\\\\ Frank Terhaar-Yonkers, Manager High Performance Computing and Communications Research MCNC PO Box 12889 3021 Cornwallis Road Research Triangle Park, North Carolina 27709-2889 fty@mcnc.org voice (919)248-1417 FAX (919)248-1455 http://www.mcnc.org/hpcc.html
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