Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site mit-eddie.UUCP Path: utzoo!watmath!clyde!burl!ulysses!harpo!ihnp4!mit-eddie!barmar From: barmar@mit-eddie.UUCP (Barry Margolin) Newsgroups: net.unix-wizards Subject: Re: Terminal paging in the kernel Message-ID: <1417@mit-eddie.UUCP> Date: Sat, 10-Mar-84 23:15:25 EST Article-I.D.: mit-eddi.1417 Posted: Sat Mar 10 23:15:25 1984 Date-Received: Sun, 11-Mar-84 07:05:57 EST References: <6841@cca.UUCP> <690@ihuxx.UUCP> <216@masscomp.UUCP> <334@dual.UUCP> Organization: MIT, Cambridge, MA Lines: 37 If there were a way to obtain this information for each terminal WITHOUT hardcoding it into the kernel, this portion of the paging dispute would go away - but I don't see any way to do that..... Sure there is - the user tells the kernal how many lines and columns there are. I have seen references to "stty page 24". You could simplify it by allowing "stty type vt100"; stty would look vt100 up in termcap to find out the number of lines, and then make the appropriate system call. This way you don't need the type table in the kernal, just the ability to make use of the information in the table. In some cases you can even do better than requiring the user to use stty: many terminals have a recognizable answerback, so when it dials up Unix can send an ENQ and see if it recognizes the answerback. Those of you who are against terminal paging in the kernal have not been very constructive. Anyone have any suggestions for a way to get this affect without doing it in the kernal? I am very sympathetic to those who believe that the kernal should only be used for the low-level device control that requires privileged instructions. However, the pipe mechanism doesn't provide enough functionality to do what we want. I just experimented with ncsh|more and discovered that I didn't see anything until I filled up a page or sent EOF (which was better than what happened when I tried csh|more which didn't even echo and didn't recognize ^D). In addition, there is no way to perform ioctl's on filters (I could be wrong - I am not that much of a wizard), and many programs use isatty, which will fail on pipes. I suppose it could be done with pseudo-tty's, but that will put a much larger burden on the system than one would want. So, either put up or shut up. The fact is that someone has made very minor kernal modifications to add a very useful feature. -- Barry Margolin ARPA: barmar@MIT-Multics UUCP: ..!genrad!mit-eddie!barmar