Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!henry From: henry@utzoo.UUCP (Henry Spencer) Newsgroups: net.unix-wizards Subject: Re: Terminal paging in the kernel Message-ID: <3603@utzoo.UUCP> Date: Tue, 6-Mar-84 18:53:10 EST Article-I.D.: utzoo.3603 Posted: Tue Mar 6 18:53:10 1984 Date-Received: Tue, 6-Mar-84 18:53:10 EST References: <6841@cca.UUCP> Organization: U of Toronto Zoology Lines: 30 Our experiences with kernel paging here parallel Steve Zimmerman's: extensive skepticism in the beginning (including me), total acceptance after a little bit of real experience. Ours isn't even as fancy as Steve's, and we love it just the same. (Ours is essentially the one Geoff Collyer posted a while ago; he got it from us. We do not yet have a turn-paging-off-temporarily character, but plan to add one.) Try it, you'll like it. Really. I would like to add one thing to Steve's fairly complete rebuttal of the critics. Another criticism that has been seen is: The current kernel doesn't know anything about all the strange terminals out there. It is dreadfully unclean to add virtual-terminal stuff to it. Well, I would argue the last part at some length, if the virtual- terminal stuff is being added for some useful purpose like implementing a window system. But I don't need to argue that here, because the first part of this objection is full of s**t. Have you ever looked at the definition of, say, the NL1 delay bit? This is found in very nearly every Unix in existence, and it is custom-tuned for a terminal that nobody in his right mind has used for a decade. The V7 Unix kernel contains a fairly complete virtual-terminal system for hardcopy terminals circa 1972. About half the bits in the tty mode are dedicated to this exact purpose. So please don't complain about putting code that knows about terminals into the kernel; it's been there all along. The problem is that it was never updated to match modern terminals. -- Henry Spencer @ U of Toronto Zoology {allegra,ihnp4,linus,decvax}!utzoo!henry