GETTING TO AND USING COMPUTER SCIENCE DEPARTMENT MACHINES WITHOUT A WORKSTATION Gary T. Leavens Department of Computer Science, Iowa State University $Date: 1997/08/20 21:49:56 $ This document describes how to get into a Computer Science (Com S) department machine from someplace other than a Com S department workstation. 1. PUBLIC WORKSTATIONS AND TERMINALS Although it's easiest to use the workstations in 115 and 116 Atanasoff Hall for this class, you can also work from other places on campus. There are also workstations in 139 and 248 Durham center, as well as those listed in the following URL. http://www.cc.iastate.edu/olc_answers/information/facilities/public_labs.html A list of public terminal sites is available in URM 108, which you can get from 195 Durham center. If you see the ``DIAL:'' prompt on a terminal, it's available and hooked up to the Iowa State Network (ISN); so type ``enet'' (without the quotes), then hit ``return''. You will see a menu of selections. Select the number for ``telnet to remote host'' and then type the name of the computer you wish at the prompt (e.g., popeye.cs.iastate.edu), followed by a ``return''. For more details see the Project Vincent User's Guide or URM 108. 2. DIALING IN BY A MODEM At any hour of the day or night, remote access is possible if you have a modem and a computer or terminal. Modems are amazingly cheap (at least to someone who remembers what they used to cost); you can get a 36K baud modem for peanuts, and slower ones for even less. If you are not familiar with this modems etc., look at URM 39, which you can get from 195 Durham Center, it has more details than the following discussion. To connect with a modem, use 8 bits, no parity, and dial 268-3638 (that's 268-ENET). At the prompt choose option 1 (``telnet to remote host'') by typing ``1'' and then the ``return'' key, you will then be prompted for a host name; type the name of the machine you want, press ``return'' a few times, and then you can log in. If you live in a dorm room, you can get the Iowa State Network (ISN) hooked up directly to your room. Talk to the ISU Telecommunications Office about it. 3.1 USING THE ISN If you are getting to the Com S department machines as described above, you are using the ISN. The ISN allows you to freeze (stop) output from the computer, and then to thaw output (let it continue). This is done by using the control characters C-s and C-q. Try the following experiment. At the shell prompt, type sh -c 'while true; do echo hi; sleep 1; done' This starts an infinite loop, printing hi on your screen once every second. While this is going on, type a C-s (press ``control'' and ``s''). You will see the sequence of printing stop. Now type a C-q. You will see several his print all at once, these were saved while ISN was waiting for you to type the C-q. Then you see the normal printing process resume. Try typing C-q now; what happens? After you understand how this works, stop the printing completely by typing a C-c; this kills the Unix process that is printing hi. The point of this is twofold. You can use C-s to stop output. More subtly, if you accidentally type C-s, output will stop. So if you are expecting output and none is forthcoming, try typing C-q to get it started. 3.2 USING EMACS OVER THE ISN Emacs also uses C-s and C-q, but unfortunately it does not use C-s and C-q in the same way that ISN does. Normally (i.e., not using the ISN) C-s means ``incremental-search'' and C-q ``quoted-insert'' and these both work fine. However, the ISN does not transmit C-s and C-q to emacs, but interprets them to mean stop (freeze output) and start (thaw output) before emacs sees them. This section describes some ways to get around that problem. 3.2.1 The Easiest Way You can avoid the ISN entirely by dialing in to enet directly. Try calling 268-3638. Unfortunately, that line is often busy. 3.2.2 Another Way The easy way is, after starting emacs, execute the command ``M-x isn-mode''. (That is, hit the ``escape'' key (labeled ESC), then type ``x'', then at the prompt type ``isn-mode'', all without the quotes.) This makes emacs swap the keys C-\ and C-s, and also C-q and C-^. That is, to get emacs to do an incremental search, you type C-\ instead of C-s, and to look for the same thing again, type C-\ again. Instead of typing C-x C-s to save a file you type C-x C-\ . (Or just type C-x s to save all your files.) To get a quoted insert, type C-^ instead of C-q. If you often or usually use the ISN, you can have ``isn-mode'' invoked automatically, every time you use emacs, by putting the following line in your ``~/.emacs'' file. (isn-mode) This has the side effect of using ISN mode even on workstations, but if you use ISN often enough, it is just as easy to learn these keys as the standard ones. 4 CONNECTING FROM A MICROCOMPUTER On some personal computers (micros) and perhaps on some Macintosh computers you can connect using ``telnet''. To do this double click on the telnet icon or type telnet popeye.cs.iastate.edu (or whatever machine you want). The micro will then act as a terminal. 5. GETTING MORE INFORMATION For more information about details of using the Com S department machines, such as how to forward your mail to/from project Vincent, how to get your files to/from Vincent (use ftp), how to customize your X windows or how to display X windows stuff from a Vincent workstation, use your web browser (such as the program ``mosaic'') and get to the URL http://www.cs.iastate.edu/help/index.html Information about Project Vincent is also available from that URL, and from the following URL. http://www.cs.iastate.edu/