From owner-freebsd-questions Sun Apr 30 16:44:21 1995 Return-Path: questions-owner Received: (from majordom@localhost) by freefall.cdrom.com (8.6.10/8.6.6) id QAA07010 for questions-outgoing; Sun, 30 Apr 1995 16:44:21 -0700 Received: from cs.weber.edu (cs.weber.edu [137.190.16.16]) by freefall.cdrom.com (8.6.10/8.6.6) with SMTP id QAA07004 for ; Sun, 30 Apr 1995 16:44:18 -0700 Received: by cs.weber.edu (4.1/SMI-4.1.1) id AA04354; Sun, 30 Apr 95 17:37:48 MDT From: terry@cs.weber.edu (Terry Lambert) Message-Id: <9504302337.AA04354@cs.weber.edu> Subject: Re: [Q] NCONS vs. ptys To: pvinci@ix.netcom.com (Paul Vinciguerra) Date: Sun, 30 Apr 95 17:37:47 MDT Cc: questions@FreeBSD.org In-Reply-To: <199504300447.VAA11899@ix2.ix.netcom.com> from "Paul Vinciguerra" at Apr 29, 95 09:47:00 pm X-Mailer: ELM [version 2.4dev PL52] Sender: questions-owner@FreeBSD.org Precedence: bulk > What is the difference between virtual consoles and pty's? A virtual consle is like a pty, but contains device state information for the console hardware as well. For instance, scan code mode, memory containing screen contents, screen graphics mode, cursor location, current attributes, etc., etc.. A pty is just a pipe with cannonical processing on one end (the slave end) so that programs think they are using a tty. > I also understand that the number of xterms is limited by the number of > pty's. That's right. Xterms use pty's to make the programs running in them (like your shell) think they are talking to a physica device. Telnet, rlogin, screen, and other programs all use pty's to fool programs into talking to them. The 'p' in 'pty' stands for pseudo -- it's a pretend tty. Terry Lambert terry@cs.weber.edu --- Any opinions in this posting are my own and not those of my present or previous employers.