Linux Gazette... making Linux just a little more fun! Copyright © 1996-98 Specialized Systems Consultants, Inc. _________________________________________________________________ Welcome to Linux Gazette! (tm) _________________________________________________________________ Published by: Linux Journal _________________________________________________________________ Sponsored by: InfoMagic S.u.S.E. Red Hat Our sponsors make financial contributions toward the costs of publishing Linux Gazette. If you would like to become a sponsor of LG, e-mail us at sponsor@ssc.com. Linux Gazette is a non-commercial, freely available publication and will remain that way. Show your support by using the products of our sponsors and publisher. To subscribe to Linux Journal, click here. _________________________________________________________________ Table of Contents March 1998 Issue #26 _________________________________________________________________ * The Front Page * The MailBag + Article Ideas + Help Wanted + General Mail * More 2 Cent Tips + Apache SSL extensions... + Locate + Re: Printing Problems + Re: LG25, Netscape on the Desktop + Re: Linux and VAX 3400 and 3300 + Binary File Access with dd + Follow up to find 2c-tip + ispell & Pine 3.96 + XVSCAN: Combining different parts together + 2c-tip: Netscape on the Desktop + Linux and Win95 + My $0.02 tip: Graphical su + Easter Eggs in Netscape + Core Dumps * News Bytes + News in General + Software Announcements * The Answer Guy, by James T. Dennis + Can't Telnet to Red Hat 5.0 Server + Use the Source, Luke! + 'ifconfig' to Troubleshoot Dropped Ethernet Packets? + Cthugha + xdm Login doesn't! * Clueless At The Prompt, by Mike List * EMACSulation, by Eric Marsden * Graphics Muse, by Michael J. Hammel * Linux on a Kapok 7200, by Alessandro Usseglio Viretta * Low Cost Macintosh-Linux Networking at Home, by Dr. Richard L. Dubs * New Release Reviews, by Larry Ayers + Tcd and Gtcd * Setting up Your In-Home (or In-Office) Network, by Tom Kunz * The Yorick Programming Language, by Cary O'Brien * The Back Page + About This Month's Authors + Not Linux The Answer Guy The Weekend Mechanic will return. _________________________________________________________________ TWDT 1 (text) TWDT 2 (HTML) are files containing the entire issue: one in text format, one in HTML. They are provided strictly as a way to save the contents as one file for later printing in the format of your choice; there is no guarantee of working links in the HTML version. _________________________________________________________________ Got any great ideas for improvements? Send your comments, criticisms, suggestions and ideas. _________________________________________________________________ This page written and maintained by the Editor of Linux Gazette, gazette@ssc.com "Linux Gazette...making Linux just a little more fun!" _________________________________________________________________ The Mailbag! Write the Gazette at gazette@ssc.com Contents: * Help Wanted -- Article Ideas * General Mail _________________________________________________________________ Help Wanted -- Article Ideas _________________________________________________________________ Date: Sun, 01 Feb 1998 21:43:23 -0800 From: Bradley Akey, bakey@slip.net Subject: Creative Labs SB-16 & Sony CDU76E-S I am attempting to install RedHAt Linux ver 4.2 from a Sony CDU-76E-S CD-ROm connected to a Sound Blaster 16 via an IDE interface at base io 0x1E8, IRQ 15. Waht is the correct boot parameter to get this CD-ROM to function properley _________________________________________________________________ Date: Tue, 3 Feb 1998 08:25:32 -0500 (EST) From: Michael Stutz, stutz@dsl.org Subject: Help Wanted: recording audio data Is there any way to read and save the data that is currently being played by the soundcard, regardless of the sound source? (There is a program in alpha which does this called paudio, at http://web.syr.edu/~jdimpson/proj/. It creates a readable /proc/audio -- but I haven't yet gotten it to work with the OSS-compatible driver produced by the Linux Ultrasound Project which I use.) Michael Stutz _________________________________________________________________ Date: Mon, 09 Feb 1998 14:18:49 -0500 From: Todd Blake, tbb@enterprise.aacc.cc.md.us Subject: Help Wanted I like most people am the only person to use my linux system at home. What I'd like to do is when my system is done booting to have me automatically login as my main user account(not as root though) on one virtual console(the first) and leave all other consoles and virtual consoles alone, so that someone telnetting in will get a login prompt like normal, just that I won't. I'd still like the other vc's have login's for others to login and other reasons. I've tried just putting /bin/sh in /etc/inittab and that didn't work, and I'm stumped. Does anyone have any ideas on this? Todd Blake _________________________________________________________________ Date: Mon, 09 Feb 1998 17:47:08 -0600 From: peter smith, psmith@computek.net Subject: Problems with Linux through Wingate Socks I'm having a few problems accessing the internet through Wingate v2.0 on my Windows95 machine using my Linux Redhat 4.2 installation. I've had this SOCKS server set-up for quite some time on my internet dial-out machine and have previously had no problems accessing the internet through this server via my second machine's installation of Windows95 or even WindowsNT. The problem is directly related to DNS lookups. If I access a domain-name from my Linux machine that seems to get redirected, I will receive an error that the DNS address does not exist. For instance, if I attempt to open the web page http://www.kernel.org (which gets redirected to http://linux.kernel.org) my browser (Netscape v4.04 for Linux 2.0* i386 rpm) reports a DNS error. However if I instead attempt to open the redirected web page http://linux.kernel.org my browser will open it ok, without error. I'm baffled by this behavior and have tried a number of different things! I can provide more detailed information if needed. Thanks in advance to any who try to help! ;) I love Linux Gazette and have a great time browsing all the cool suggestions and tips! Keep up the ideas and info! PeterS _________________________________________________________________ Date: Mon, 09 Feb 1998 19:04:42 -0500 From: Melmac88, smegan@erols.com Subject: Shadow passwords Can someone do a clear explanation on how to set up a shadow password file, and exactly how it works? I've seen this recommended for security purposes in many books and articles, but there never seems to be an explanation on how to do this. _________________________________________________________________ Date: Wed, 09 Dec 1998 04:38:06 -0900 From: David Lev, dlev@polarnet.com Subject: my dual pentium My name is David Lev, I have a problem with my second CPU. I am currently using a Caldera OpenLinux Standard with Kernel (2.0.29-2). After I install the system I try to enable the 2 CPU and my computer FREEZE or I loss my DeskTop and it takes for ever to do one process. but with one CPU the computer work fine no problems at all. I ask for your help. If you can help me also on how to enable 2 modems and run them as one. My computer content: ATX Dual Motherboard - GA-586DX with SCSI on board Adaptec 7880 CPU - 2x 233MMX Pentium 128M RAM EDO 2x 3.1G HDD - W.D - IDE 2x 8X CD-ROM - IDE 2x 56K Modem ESS Sound card _________________________________________________________________ Date: Sat, 14 Feb 1998 15:00:34 EST From: Andreas M. Weiner, HGuAWeiner@aol.com Subject: Linux and AMD K6 Processor - any Problems? This is my hardware configuration. Support answered that there would be problems with using the K6 with Linux; for instance a crash. What dou you know about this problem ? Could you send me a some informations to solve this problem ? Are there Kernel patches available ? I'm looking forward of getting the answers from you Andreas M. Weiner _________________________________________________________________ Date: Sun, 15 Feb 1998 10:26:36 -0800 From: David, elvii@writeme.com Subject: X without a Mouse? Been searching around the net and ldp, and can't seem to find anything on this one. Trying to be able to use X WITHOUT a mouse. Yes, I know, it works bets with a mouse, but I'd like to be able to get at least limited x funcationality without it. Any help is greatly appreciated, and being waited. Also, is there any was to do mouse emulation without a mouse? I found a program that translated ps/2 to a standard serial mouse, for before x supported ps/2, i assume... anyone know if a program has been written to allow the keypad to do mouse, ie, translate keypad input to /dev/mouse? Thanks for your time, hoping some kind linux guru's out there can help. :) David _________________________________________________________________ Date: Mon, 16 Feb 1998 21:59:04 -0700 From: Todd Jamison, jamisont@littoneos.com Subject: Help with Sound Card I currently am running RedHat 5.0 on a Pentium 150 W/48 MB Ram. I = cannot get my ESS ES1868 plug and play sound card to work. I am very = new to linux and am still learning. If anyone can help me i would = really appreciate it. Todd _________________________________________________________________ Date: Tue, 17 Feb 1998 16:41:49 -0600 From: John Gorman, John.H.Gorman@MCI.Com Subject: HP4 & font I just installed a HP LaserJet 4L on RedHat 4.2 Intel and when I print postscript (from emacs, etc), it prints at about a size 24 font. How to I set my font where I want it. Thanks John Gorman _________________________________________________________________ Date: Fri, 20 Feb 1998 08:46:12 +0100 From: Jeroen Bulters, jbulters@scoutnet.nl Subject: Changing XDM windows Can I change the XDM login window/screen? I have a cool house logo so i want to use it in my own Home Network. And at my school they want to know to so. Is it possible. If yes, how? If no, WHY NOT. Jeroen Bulters, The netherlands _________________________________________________________________ Date: Tue, 17 Feb 1998 01:36:30 +0000 From: Mackenzie St. Louis, mstlouis@tiac.net Subject: New Motherboards A lot of motherboards have been coming out lately with built in graphics and sound. Any plans to cover them. I just bought a TX-Pro-II board with graphics and sound. However I think I will be returning it since I can't get the sound to work. It has a SoundPro chip. Can not also get XFree 3.3.1 to run properly. It will only come in 8 bit 320x200, even though the graphic chip is supposed to be AGP. If you could point out where I can get some info. I would gladly write an article for the Gazette in case any else comes across this same problem. Please email me with any info or questions. _________________________________________________________________ Date: Tue, 24 Feb 1998 16:28:09 -0800 From: chewey nougat, daiger@usc.edu Subject: HELP-Installing Linux on a FAT32 Drive I'm interested in installing linux on a machine I built recently, but = when I installed Win95(b), I idiotically opted to format the drive using = FAT32, which in a 95-only environment is great, but linux can't read it = for greek. I've looked around for utilities to effectively un-FAT32 the drive, = which I will then partition with Partition Magic to use the freespace as = a native ext2 partition, etc., but am having little luck. Reformating is = a disheartening prospect I would rather not face, but am fully prepared = to do so if I don't find any help here. much thanks, nate daiger _________________________________________________________________ Date: Thu, 26 Feb 1998 13:47:06 -0500 From: Brian O. Bush, bbush@xtdl.com Subject: question on motor control Does anyone know how to interface and control two motors from a Linux box? I am looking for a simple solution (in circuit at least). Thanks, Brian _________________________________________________________________ Date: Fri, 27 Feb 98 14:16:13 -0500 From: Bill R. Williams, brw@ETSU.Edu Subject: Wanting HELP! First off: I can *not* believe I am the only one bitten by this. In the process of getting a System installed I upgraded from the original CD-ROM install of (Intel) RedHat 4.2 to the new RedHat 5.0 CD-ROM. One of the significant items on this system is the mars-nwe Netware emulator. Under the RedHat 4.2 with mars-nwe 0.98pl8-1 the mars package ran fine, but logged copious errors about there being "too many connections -- increase the number in config.h". But it ran, and I *liked* the way it happily did Netware duties! (Especially the printer part.) The *new* RedHat 5.0 with mars-nwe 0.99pl2-1 offered some very desirable abilities, not the least of which is the move of some items (such as number of connections) to the run-time config file (/etc/nwserv.conf under RedHat, probably nw.ini on other distributions.) Now the bad news... Of lesser, but still irritating, importance is the fact that the mars package won't shutdown without some hard kills. This may be related to the really important problem which is: This new package spawns out nwconn processes with an empty parenthesis as the last token instead of the USERID ('nwconn ... ()') until all connection slots are eaten, and then, of course, will not recognize any new attempts. Any users already logged into the nwserv(ice) are Ok. Since I am neither a Netware guru nor a mars guru I can only hazard a guess, but since the nwconn(s) are children of the ncpserv daemon I suspect that ncpserv is the source of the troubles. I have tried every combination of parameter twiddling in the run-time config file that can think of, but to no avail. One thing I have noticed, the 2.0.32 linux kernel /usr/src/linux/.config no longer has the 'CONFIG_IPX_INTERN' setting (should be unset according to mars-nwe docs) which existed in 2.0.27. This may or may not have anything to do with the problem. Checking the kernel sources, it appears that the RedHat rpm of the 2.0.32 kernel has the mars patches incorporated into the source. Anyone who has solved this problem, please share the secret. BTW: I attempted resolution through the RedHat Support system as a registered RedHat customer, and if anybody wants a good laugh I'll be happy to share the "circle of correspondence" from RedHat support. I did learn from the attempt that no *human* at RedHat actually ever sees the E-Mail to the support team or 'Bugs' team. (The "auto answer" mechanism will get right back to you, though, and tell you not to expect an answer.) As I said, I can *not* believe I am the only one bitten by this, because I've looked on the news groups and seen several posts with "Mars and RedHat 5.0" in the Subject fields. These were all on the French os.linux.... lists, and unfortunately I do not read French! Sorry for the rambling on... Bill R. Williams _________________________________________________________________ Date: Sat, 7 Feb 1998 13:03:24 +0100 (CET) From: Manfred Lemke, lema0019@FH-Karlsruhe.DE Subject: Support for IBM Ethernet card? I'm frantically searching for some kind of support for IBM's LAN Adapter/A for Ethernet. Does any of you know of a driver in the Linux Kernel that works? Best regards and thanks in advance, Manfred Lemke _________________________________________________________________ General Mail _________________________________________________________________ Date: Fri, 27 Feb 1998 00:09:33 +0100 (MET) From: Radoslav Dejanovic, rdejanov@public.srce. Subject: Linux Journalists International Linux Journalists International is an effort to make a meeting point for journalists who use Linux or simply write about it. It is also a place where other journalists and other people can take a look what is going on with Linux and media that supports it. There will be info pages about magazines/media and journalists who use Linux and/or write about Linux & related software. I am editor in one croatian computer magazine (http://www.pcchip.hr) and this is my effort to give the Linux community something that lacks: popularity in media and a chance to boost media coverage of Linux. The homepage is at http://www.purger.com/~rado/lji.html - please take a look at it. LJ and LG are the strongest "Linux inside" media :), so your support in this project is essential. Rado _________________________________________________________________ Date: Wed, 4 Feb 1998 10:02:08 -0500 (EST) From: Paul Lussier, plussier@LanCity.COM Subject: Retraction Re: Linux and routing It was just called to my attention that this came across a little to strongly and I'd like to clarify what I had previously written. On Tue, 6 Jan 1998, I wrote: Some words of caution. DO NOT HAVE YOUR LAN CONNECTED AT THE TIME OF THE CABLE MODEM INSTALLATION!!!! [Comapany names removed], and most of the other cable companies (we deal with them all here) will refuse to connect a LAN to their broadband network. Simply remove your hub or coax cable from view, and let them do what they need to do, then connect everything else up after they leave. This was probably a little of an overstatement. I know only of 1 company that has this as a policy, but have heard of people having problems with some of the others. I have even recently been informed of one company that is *quite* Linux friendly and will "encourage the use of Linux as firewall/routers" as well as "allow and assist individuals & companies to setup there own Web servers, either at their permises or ours. We offer web hosting and will assist in registering a domain name". So, I obviously made an improper, blanket statement which does not represent the attitudes or policies of all companies. Some other interesting tidbits of information about cable modems and cable companies: 1. Do not expect support for running a LAN over the cable modem from the cable company. They don't want you to do it, they won't help you do it. 2. Do not expect to put up a web server to be accessed by from the internet. You are a client, not a server. This technology,though fully capable of performing in this manner, is not being deployed for use this way. Again, this is a blanket statement that *does not* apply to all cable companies. There is a good reason for those companies who do hold this policy, and perhaps I should have gone into more detail. When you get a cable modem from a cable company, *typically* you are agreeing to lease the equipment from them under similar agreement as you rent the TV set top box for cable television reception. The agreement typically states that you are not allowed to run the cable to any other TV for which you do not rent a box. The same goes for the cable modems. They are agreeing to lease you 1 modem for 1 computer. Setting up a firewall/proxy server to enable other systems access is exactly like placing a diplexor on you TV set, and running the cable to another television. That is a violation of the agreement, and is illegal, immoral, and unethical; it's stealing. And again, I re-iterate, this is not true for *all* companies. Check with your cable company, they should be happy to explain their policies to you. I don't really think you *should* expect to be able to do either of these though, unless the cable company has provisions in place. You are agreeing to connect one computer to their network as a client. Anything more, you should expect to pay more, as they are providing you with increased capabilities. Just like the phone company charges more per added service (*69, caller ID, etc) so should the cable companies. Personally, I think that average rate of US$40-$50 a month for the equivalent of a T1 to my house is an awesome deal. If I want more capability, I should expect and be willing to pay more. Cable companies WILL shut you down for running a server of anykind on your end of the network, and it can be *forever* :( Again, I spoke without clarification. Obviously it depends upon the policies of your local cable company. I know of 2 or 3 instances where this has been the case. By stating the above, I was trying to warn of the possible consequences of violating the contract with the cable company. If the cable company specifies in the contract what you are allowed to do and what you are not allowed to do, you should expect to deal with the consequences of violating the agreement. Spammers love cable/broadband networks. There have been several cases where a broadband network customer has been used by spammers and were subsequently shutdown for life by the cable company. What happens is the person decides to connect their private LAN to the cable modem but sets the firewall up incorrectly. Spammers search cable/broadband networks for proxy servers/firewalls (Usually Win95/NT) that allow incoming connections and then use that system to spam the entire cable/broadband network making the spam appear as if you sent it. Spammers love any insecure system or network. Broadband Technology though, for the first time has allowed people more extensive and closer contact with other people on the internet. When you dial into an ISP with a normal modem, it's a little more difficult for devious minded people to take advantage of other users. But with cable modems, you now have hundreds and/or thousands of people all on the same private network, all with similars IP addresses, many of whom, now leave their systems connected for much longer periods of time. This makes it much easier for crackers, and other mischievous people, to take advantage of anyone who isn't running a properly secured system. Usually you will be given 1 warning by the cable company, but there have been cases where none was given and the customer was completely shut down. I have heard of this happening on several occasions, where usually the person was running an improperly configured firewall, and spammers used their system to launch e-mail to thousands of people connected to cable companies' private broadband networks. If I'm paying $40 or $50 a month for this service, I, as a paying customer do not want to receive solicitous e-mail (spam) from some one else, especially if they are on the same broadband network as I. I would complain to my cable company about it and expect them to do something. It was these exact circumstances that has led to several people having their cable modems permanently removed. Current modems are capable of transmitting at 10Mbs in both directions, but are usually deployed throttled back to a trasmit speed of 300Kbs and a recieve speed of 1.5Mbs. You want more bandwidth, they'll be happy to charge you more money :) Personally, I think this is very fair. The cable companies are providing us with a service. We, as consumers, have to pay for this service. Just like my electric bill, if I use a lot of electric service, I pay a lot of money; or like the telephone company, if I have more features or want a T1, I pay more money than if I only had a normal telephone line. It's the same with cable modem technology, the capability is there for 10Mbps bandwidth in both directions. The technology is also there to regulate that flow. I expect the cable companies to use that technology. If I want LAN speeds to my house, I should expect to have to pay for it. Again, I want to apologize for not clarifying my previous statements a little more. Please check with your local cable company before you do anything like connecting your private LAN to theirs. There are as many different policies as there are cable companies, so make sure to explicitly ask if what you want to do is permitted. This is a great technology and has tremendous benefits. Playing by the rules that the cable company has put in place will only help the technology spread. By violating the rules, you run the risk of losing access to it, as well as making it more difficult for the cable comapanies to contiue selling this service. Like any other market driven product, if there's no money in it, or it costs too much to implement, it will fall by the wayside, and no one benefits. By not folling the rules, we as customers can make it cost prohibitive for implementation, and conversely, by following the rules, we create more market demand, which in turn, continues pushing the technology forward, and everyone benefits. #include I don't pretend to know all the policies of all the cable companies. I don't assume to speak for any of the,, nor do I tell them how to operate. My opinions are my own, and no one else's. Dammit Jim, I am a Unix sysadmin, not a sales rep :) Please feel free to send me questions, comments, criticisms, etc. Paul _________________________________________________________________ Date: Thu, 5 Feb 1998 15:01:30 -0500 From: Jack Chaney, JAC14@chrysler.com Subject: New Direction I heard on the radio last night, an announcement that IBM has just successfully masked, produced and tested their newest piece of silicon. The processor is based on the PowerPC design and is reported to run at 1000MHz. Knowing what I know about the PowerPC and its various flavours, I think it would do to examine the idea of porting Linux in a native coded version to this processor platform. The pricing of this chip with a heavy duty operating environment could give the Alpha a real run for its money. The PowerPC (for those who don't know) is a RISC based processor with three major operation blocks, each capable of independent operation. This enables the instruction flow to become parallelized so as many as three instructions can be done simultaneously, and because it is a RISC processor the instructions have been optimised so most occur in only one or two cycles. The other element of the design is to have an extremely large cache memory on-board the processor to reduce fetch time for instructions. To give an idea of the improvement in speed realised by this method, a PowerPC emulates the Intel part by keeping an interpreter block in the cache memory of the chip and interprets the Intel object code at comparable speeds of the Intel parts. The lure of creating a native Linux for this processor has crossed my mind on a number of occasions prior to the IBM announcement, and now I hope with encouragement this can move from fantasy to fact. Jack Chaney _________________________________________________________________ Date: Fri, 6 Feb 1998 08:50:00 -0500 From: Hampton, Mike, hamptom1@INDY.NAVY.MIL Subject: Picking a nit Maybe I should have called the subject of this "pet peeve" or something like that. What I am writing about is a simple grammatical error that I have seen many people make, but one that shouldn't appear in the Gazette or any published effort and that is the incorrect use of "it's" when the author should have used "its." An example is in the following sentence from a recent issue: "This was necessary in order for a *nix version to behave to applications like it's counterparts so applications could run everywhere." If you take the "it's" and expand it, the sentence would read: "This was necessary in order for a *nix version to behave to applications like it is counterparts so applications could run everywhere." The sentence no longer makes sense. Authors should remember that "it's" is a contraction of "it is." If they want a possessive of "it," they should use "its." I have also seen instances of authors using the apostrophe-s when they intended to form a plural but made a possesive instead (for example, using menu's, a possesive, instead of menus, the proper plural form). Like I said before, these are very simple and common errors, but ones which I feel can hurt the author's credibility. Before anybody gets too defensive, let me say that as an employee of a major defense contractor, I have made the above error and have had it pointed out to me. Maybe that's why it stands out so much when I see it now. Now I'll put down my pen and let others point out my errors. Mike Hampton _________________________________________________________________ Date: Fri, 06 Feb 1998 08:12:09 -0600 From: Tyree Gwyn, bounti@myriad.net Subject: love your site!! i very much enjoy the information found on LG!! even though i am posting from a windows machine, i use linux(redhat 5.0) the majority of the time. i just happen to be at work, at this time. anyway, being a newbie to this whole linux scheme, i have used your site, dejanews, oreilly books, and many howto's to get my system up to my specs. linux is very exciting, and has alot of promise. please keep up the good work. Tyree _________________________________________________________________ Date: Sun, 08 Feb 98 17:34:41 -0500 From: Leon C. Isaacson, lci2@global.co.za Subject: Incomplete Book Reviews In Linux Gazette 25, the review of "A Practical Guide to Linux" , by Mark Sobell, fails to supply the publishers name, publication date, and price. I enjoyed the review, but surely this information should be included as a matter of course. Given your reviewers laudatory comments, how or where can the rest of us hope to acquire this book? Leon (I agree. He should have included that information. Here's what I know: Publisher: Addison Wesley Longman, info@awl.com, http://www.awl.com/ Price: $38.00 US ISBN: 0-201-89549-B -- Editor) _________________________________________________________________ Date: Fri, 21 Nov 1997 18:59:53 -0500 From: Timothy D. Gray, timgray@lambdanet.com Subject: Getting Linux to the public... Has anyone noticed that when your friends see your neat-o Linux system with the nice 17 inch monitor, high quality video card, and fast computer that when they say, "Wow! that is nice, and you can do almost anything on that!" you cringe with the fact that they are going to want you to put it on their system? now mind you, I dont cringe on sharing the best O/S on the planet, In fact I want everyone to use Linux. It's just that almost all X windows software is written for 1024 X 768 or higher resolution video screens and that 99% of those wanting to use Linux and X windows only have a 14" monitor that can barely get past 640X480 at 256 colors. I tried several times to get friends into Linux and X but to no avail because the software developed for X is for those that have Gobs of money for good video boards and humoungous monitors. It's not a limitation of Linux or X, it that the software that is developed for these platforms are by professionals or professional users that can afford that new 21 inch monitor at the computer store. We as a group might want to see software scaled back to the 640X480 crowd.. then Linux would take the world by storm.. Until then It's going to be limited to us pioneers and Scientists... Tim Gray _________________________________________________________________ Date: Wed, 25 Feb 1998 15:42:09 +0000 From: Jaime E. Villate,villate@fe.up.pt Subject: uptime record In Issue 25 (February 98) Sean Horan wrote about a Linux system that ran continously for 274 days. Here is a quote from Bruce Perens (president of Debian, works at Pixar) that I took from http://www.debian.org "I thought three months without a reboot was a big deal. When I mentioned it to our developers, one of them showed me details about his system. It was up for 458 days, and was halted to move it to another floor. The network and disk device drivers had handled tens of millions of interrupts in that time." It would be interesting to know what the record is for other operating systems older than Linux. Jaime Villate, University of Porto, Portugal http://www.fe.up.pt/~villate/ _________________________________________________________________ Published in Linux Gazette Issue 26, March 1998 _________________________________________________________________ [ TABLE OF CONTENTS ] [ FRONT PAGE ] Next This page written and maintained by the Editor of Linux Gazette, gazette@ssc.com Copyright © 1998 Specialized Systems Consultants, Inc. "Linux Gazette...making Linux just a little more fun!" _________________________________________________________________ More 2¢ Tips! Send Linux Tips and Tricks to gazette@ssc.com _________________________________________________________________ Contents: * Apache SSL extensions... * Locate * Re: Printing Problems * Re: LG25, Netscape on the Desktop * Re: Linux and VAX 3400 and 3300 * Binary File Access with dd * Follow up to find 2c-tip * ispell & Pine 3.96 * XVSCAN: Combining different parts together * 2c-tip: Netscape on the Desktop * Linux and Win95 * My $0.02 tip: Graphical su * Easter Eggs in Netscape * Core Dumps _________________________________________________________________ Apache SSL extensions... Date: Fri, 27 Feb 1998 15:49:41 -0800 From: Glenn D'mello, glenn@arbornet.org From Frank: My problem is this one ... I've gone bananas in trying to find a document that explains how to install, in a step by step fashion, the Apache SSL "extensions" to one of my Apache WWW Webservers (the performance increase is awesome) can you or anyone that reads this help... This is how I did it: 1. Get SSLeay 0.8.0 or later from ftp://ftp.psy.uq.oz.au/pub/Crypto/SSL 2. Build and test and install it! 3. Get Apache 1.2.5 source 4. Get Apache SSLeay extensions from ftp://ftp.ox.ac.uk/pub/crypto/SSL/apache_1.2.5+ssl_1.13.tar.gz 5. Unpack it in the apache-1.2.5 source directory and patch Apache as per the README. 6. Configure and build it. 7. Read the docs before building (set your paths, etc, etc) Worked the first time too! Hope this helps: Glenn. _________________________________________________________________ Locate From: John Corey, norm@comanche.dyn.ml.org One of my annoyances with the locate program have been that with it, users can see files they have no access to otherwise. So, I have deviced a little patch to the original sources to fix that, along with a few other annoyances. It inherently does a few other things as well. It will only list files that do currently exist (not just files that existed when updatedb was last run). Also, it adds the option -l to locate which simply performs a ls -l on the files returned. To compile, get the sources from ftp://prep.ai.mit.edu/pub/gnu/findutils-4.1.tar.gz . Extract that, then apply the attached diff to it with: patch The only file modified is locate.c, so you can skip the installation process if you already have updatedb/locate installed, and just simply replace your existing locate binary with the new one (keeping a backup of the original, should anything evil happen). Enjoy _________________________________________________________________ Re: Printing Problems Date: Wed, 04 Feb 1998 22:05:40 +0100 From: M.H.M. Verhoeven, leeuweri@stad.dsl.nl Anyone that can help me. I'd love to hear it. I try running lpr, but everytime I get no name for local machine. How do I set this and/or what is the problem. -- Manish Oberoi I had the same problems with printing (no name for local machine). You should put a entry for your machine in /etc/hosts, and your problem is solved. In my case, the name of my computer had changed, but /etc/hosts still contained the old name for my machine. Gertjan _________________________________________________________________ Re: LG25, Netscape on the Desktop Date: Thu, 05 Feb 1998 00:26:03 +0100 From: Soenke J. Peters, peters@on-line.de I use a similar trick to start up the browser-/mail-/news-window from three different buttons in my windowmanager's panel. For the mail-window, you have to start the script with 'mailbox:' as the url parameter, for the news-window simply use 'news:'. For urls beginning different from the above, netscape opens the normal browser window. Soenke J. Peters, Hamburg, Germany _________________________________________________________________ RE: Linux and VAX 3400 and 3300 Date: Thu, 05 Feb 1998 10:11:00 -0700 From: James Gilb, p27451@email.sps.mot.com To: dennis.j.smith@ArthurAndersen.com I have just purchased a MicroVAX 3400 and 3300. I would like to put Linux on these two systems. Can you provide any help in this aspect. I believe those are MIPS 3000 boxes, try the Linux VAX Port Homepage at http://ucnet.canberra.edu.au/~mikal/vaxlinux/home.html and the Linux/MIPS project at http://lena.fnet.fr/ My guess is that you will need to get your hands dirty on this one. You could also try NetBSD, they may have a port now. If they are not MIPS boxes, then you could have a real challenge on you hands, but then isn't that half the fun of Linux? James Gilb _________________________________________________________________ Binary File Access with dd Date: February 9, 1998 From: Leonard R Budney lbudney@fore.com dd stands for Disk Dump. Or if it doesn't it should. The "main" use for dd is to duplicate a floppy disk, bit for bit, to a file. You probably used it to create boot disks when you installed Linux for the first time, unless you used its much less functional cousin rawrite. If you're sick of keeping boxes of floppies around, you can use dd in reverse, and throw the floppy away. Depending on permissions, you might have to do this as root. dd if=/dev/fd0 of=quicken_install_disk_1.img bs=1440k The if argument specifies an input file (which defaults to the standard input). Naturally, the of argument names the output file (which defaults to the standard output). Finally, the bs argument tells dd what block size to use. Here we set the block size equal to the size of a floppy disk, and let dd read one block of data. The man page says that the purpose of dd is to "convert a file while copying it." In English, that means that dd does not assume a file is made of text! It doesn't look for carriage returns to delimit lines, it doesn't stop reading at the first binary zero, nothing! This gives us the power to read files exactly, byte for byte. It allows us to read a fixed number of bytes, or physically to overwrite a file. As just one example, consider /dev/random. That's a nifty Linux innovation--a pseudo device that accumulates randomness. Would you like to read 10 bytes of random data from /dev/random? It's a snap. dd if=/dev/random of=/tmp/random.bin bs=1 count=10 Note that /dev/random provides binary data, so if we omit the of argument then that data will probably trash our display. Alternately, we could have omitted the of argument, but piped the output through cat -v to escape any non-printable characters. In addition to the arguments explained above, we use the count argument to specify the number of blocks to read. In conjunction with a blocksize of 1, count=10 tells dd to read exactly 10 bytes. Here's a final example, for the paranoid. When you delete a file using rm, you only delete the inode pointing to your data. The data is still there, on the disk, waiting for somebody with a "Disk Doctor" utility to resurrect and read. Does that bother you? Well, you should delete your data, not just your file. Again, dd comes to the rescue. Normally dd truncates its output file before writing. The argument conv=notrunc overrides that behavior, and causes dd to write over any existing data. The following shell script combines all of these ideas, and wipes out your file by overwriting it five times with pseudorandom data, and then deleting it. #!/bin/sh FILE=$1 SIZE=`ls -l $FILE | awk -- '{print \$5;}'` { for iteration in 1 2 3 4 5 do dd if=/dev/urandom of=$FILE bs=${SIZE} count=1 conv=notrunc sync done } && rm -f $FILE Enjoy! Len. _________________________________________________________________ Follow-up to find 2c-tip Date: Tue, 10 Feb 1998 19:20:44 +0000 From: Markus Pilzecker, mp@rhein-neckar.netsurf.de in your December issue, one of the 2-cents about find had been: A shorter and more efficient way of doing it uses backticks: grep "string" `find . -type f` Note however, that if the find matches a large number of files you may exceed a command line buffer in the shell and cause it to complain. The solution to this is using xargs: find -print0 | xargs -0 grep . xargs only puts as much onto grep's [or whatever else's] command line as fits without overflow. Only in the latter case will it start a new instance of grep. The trick of the first proposal to add ``/dev/null'' to grep's command line to make it print the name of the file in work is [mostly] superfluous then, since xargs [mostly] puts more than one filename onto grep's command line. The find option ``-print0'' and the xargs option ``-0'' work together to assure correct handling of odd filenames. Markus _________________________________________________________________ ispell & Pine 3.96 Date: Fri, 13 Feb 1998 08:39:34 -0800 (PST) From: Peter Struijk To use ispell in Pine, go into Pine SETUP (press S, then C), search using WhereIs for "speller" (press W) and make sure the value set there is "ispell". That will do it. Peter _________________________________________________________________ XVSCAN: Combining different parts together Date: Sat, 13 Sep 1997 01:04:29 -0500 From: Earl Fryman, fryman@io.com To: xvscanlist@tummy.com Is it possible to combine two (or more) different parts from different pages on same fig? For example, if I scan pages and want to print transparencies from small part of the text enlarged. Now, if the part 1 is at the end of a page and the part 2 is on the following page, I have not been able to combine them on one single fig (part 1 and below it part 2). How could I do that with xvscan? If the parts are on the same page I have used cut, past and crop. -- Juha Perkkio, juha.perkkio@mikkeliamk.fi Yes it is posible. Load the first image and select the portion of the image to cut. Press Alt-C (hold down Alt key and press C). Load the second image and press Alt-V. A frame window the size of the cut in the first image will appear. Position the frame where you want the image to be pasted, then press Alt-V (again). This even works if the two image are of different type (bmp, jpg, gif, etc.). Earl Fryman _________________________________________________________________ 2c-tip: Netscape on the Desktop Date: Sun, 15 Feb 1998 19:43:58 -0100 From: Victor-A. Bruessow, Christian.Bruessow@t-online.de I'm using this little bash script to start Netscape: #!/bin/sh if [ $1 ] ; then REMOTE_COMMAND="openURL($@,new-window)" else REMOTE_COMMAND="openBrowser" fi netscape -remote $REMOTE_COMMAND || netscape $@ I think it has some advantages over the script from Tim Hawes: * no need to look for a lock file, which means: * it even starts Netscape, if there is a stale lock file from a crashed browser session :-) * you can call it without any arguments, it doesn't matter if there is a running Netscape or not ("openURL($@,new-window)" will cause an error, if "$@" is empty, so I use "openBrowser" instead) Christian _________________________________________________________________ Linux and Win95 Date: Wed, 18 Feb 1998 14:55:22 +1300 From: Justin Lodge, justin.lodge@optimation.co.nz Rexson Re: Your Question e-mail to Linux Gazette Your big problem is that Win95 has probably helped itself to the entire drive already - so there is no space left available to install extra Linux partitions. What you really should do first is to back up all the existing partitions using a tape or a Zip or a Jaz drive. Let me guess you don't have one of these..... if you can beg/borrow/steal one temporarily and back everything up before you do anything that would be good. Maybe your D: partition doesn't hold much and you can transfer the data to the C: drive where Win95 is installed - this will allow you to re-use the D: partition for Linux. Next - buy/beg/borrow/steal a recent copy of Red Hat for Linux (make sure you get the book and the floppy disks that come with the CD) and the Doctor Linux book. Red Hat has a beginners book with it that explains a lot that you need to know to install Linux and a set of excellent scripts that lead you though the installation. doctor linux has good beginners sections and more complex ones about dual booting Win95 and Linux I would recommend that you DO NOT try to make the machine dual boot - it could cock-up the win95 installation but these articles will help you understand the mechanics around this area. The HOWTO articles in Doctor Linux are all available on the Internet if you don't want to buy a book but having a hard copy to reference is much easier. once you have re-located any useful data off the D: to the C: then use the disk partitioning tool that comes with red hat to de-allocate the D: partition and then create the root, usr, swap and home (and any others) in this area. From memory I believe that the root partition has to be in a primary partition but all the rest can be logical partitions contained in a single "extended" partition. This re-allocation of partitions is EXTREMELY dicey - make absolutely sure you understand which partition is C: and which is D: IF you de-allocate C by mistake then it is almost definitely un-recoverable unless you have Norton for Win95 or something similar that can repair the damage. Create a boot diskette using red hat so that when you want to run Linux you just plug it in and re-boot the machine - booting off the floppy may seem awkward but it is much much faster than any version of Windoze. Any one else using the family using the machine will not have this boot diskette and will not be able to see your partitions from Win95 and won't even know that Linux is there. This is how I keep my family off my copy of Linux. Justin _________________________________________________________________ My $0.02 tip: Graphical su Date: Wed, 18 Feb 1998 22:01:25 +0100 (CET) From: Andreas Kostyrka, andreas@rainbow.studorg.tuwien.ac.at Sometimes one want to do su but be able to use X11 programs like RH control-panel. There are several ways to accomplish this: *) The hard way: su - and copy&paste the xauth: $ xauth list $DISPLAY # mark the output $ su - # xauth add # export DISPLAY= or ftp://sunsite.unc.edu:/pub/Linux/apps/financial/investment/. The sources are free for non-commercial use. The program tsinvest is for quantitative financial analysis of equity values. An optimal portfolio investment strategy for multiple equities is computed. The program decides which of all available equities to invest in at any single time, by calculating the instantaneous future value of all equities, and using statistical estimation techniques to estimate the accuracy of the calculated values. Entropic techniques are used throughout. A tutorial is presented in the man(1) pages. A companion equity market simulation program is included. For more information: John Conover, conover@netcom.com _________________________________________________________________ Linux Logo 1.04 - shows system info with a linux logo 9 Feb 1998 linux_logo outputs a color ansi version of a penguin, accompanied by system info gathered from proc. SUPPORTS Linux, SMP, Atari m68k, and even some non-Linux OS's USES [instructions included]: * Have a boot-up penguin in userspace [avoid kernel bloat] * Impress your friends with a fancy color penguin login/motd * Have a "penguin" port on your computer * Use your imagination! WHERE TO GET LINUX_LOGO: http://www.glue.umd.edu/~weave/vmwprod/linux_logo-1.04.tar.gz http://sunsite.unc.edu/pub/Linux/Incoming/linux_logo-1.04.tar.gz -- at first http://sunsite.unc.edu/pub/Linux/logos/penguin/linux_logo-1.04.tar.gz Check out other programs at http://www.glue.umd.edu/~weave/vmwprod For more information: Vince Weaver, weave@eng.umd.edu, http://www.glue.umd.edu/~weave/ _________________________________________________________________ xfpovray v1.3 - An X interface for POV-Ray raytracer 16 Feb 1998 I would like to present a new version (1.3) of my xforms interface to the ray tracer POV-Ray. If you have ever used POV-Ray from the command line, you might find this program useful. Check: http://cspar.uah.edu/~mallozzir/ Source code is available in tgz, bzip2, and rpm formats. For more information: Robert S. Mallozzi, mallors@crazyhorse.msfc.nasa.gov http://cspar.uah.edu/~mallozzir/ University of Alabama _________________________________________________________________ Casio Digital Diary Backup/restore v2.2 17 Feb 1998 Casio Diary is a package that allows communication to the CASIO series of hand-held organizers based on a protocol posted by Knut Radloff, knut@krhh.hanse.de. Version 2.2 has been tested on Linux2.x , Solaris2.x, sunos4.x. For both the BOSS and ILLUMINATOR models and is released under the GPL. It is provided as is i.e. jamal is not to be responsible for any damages it causes to you, your CASIO or your environment. Primary-site: http://sunsite.unc.edu/pub/Linux/apps/comm/ 100kB casio22.tgz, 1kB casio.lsm Alternate-site: ftp://ftp.cyberus.ca/pub/users/hadi/casio/casio22.tgz For more information: Jamal Hadi Salim, hadi@cyberus.ca Ottawa, Canada _________________________________________________________________ Telnet98 - updated telnet source distribution 18 Feb 1998 Telnet98 is a new release of the ubiquitous "telnet" utility, based on the 1995 MIT telnet distribution from ftp.cray.com and net-dist.mit.edu. Telnet98 adds some new features to the distribution including new 'configure' based build and install scripts and support for additional authentication and encryption types. Telnet98 can be downloaded from ftp://quasimodo.stanford.edu/pub/telnet/, and US/Canadian users can find instructions there for downloading source with strong (128-bit) encryption enabled. For more information: Thomas Wu, tjw@xenon.stanford.edu Stanford University: Computer Science Department, CA USA _________________________________________________________________ Subject: fetchmail-4.3.7 - mail retriever for POP and IMAP 18 Feb 1998 The 4.3.7 release of fetchmail is now available at the usual locations, including http://earthspace.net/~esr/fetchmail/. Here are the release For more information: Eric S. Raymond, esr@snark.thyrsus.com Organization: Eric Conspiracy Secret Labs, http://earthspace.net/~esr _________________________________________________________________ leap 1.1.9 - A free RDBMS 20 Feb 1998 LEAP is a free RDBMS (Relational Database Management System) that has been used as an educational tool in Universities around the world to aid students as they learn database theory. It allows relational algebra expressions to be entered directly into the system, and the results to be queried. It supports relational closure, so complete expressions can be deeply nested. Examples are included from popular database texts, including C.J.Date's "An introduction to database systems". LEAP is entirely free (it is distributed under the terms of the GNU General Public License), and is very easy to install. All distributions contain the full 'C' source code. Versions exist for all Unix implementations, and Windoze 95/3.1/NT. Full documentation is included in the distribution, and is available on the web. LEAP is in active development (on a Linux 2.0 slackware system) by the author. Full details, including links to the main ftp archives, are available on the LEAP web page: http://www.dogbert.demon.co.uk/leap.html http://www.brookes.ac.uk/~e0190404/leap.html Strictly speaking LEAP 1.1.9 is BETA software, but extensive testing has shown no major problems. For more information: Richard Leyton, rleyton@acm.org _________________________________________________________________ WMF - WebMailFolder 1.0.1 mail folder to html converter 20 Feb 1998 This tool is for converting mails to html and can be used for mailinglist archive. It can be found on: ftp://sunsite.unc.edu/incoming/Linux/ or ftp://sunsite.unc.edu/pub/Linux/Incoming/ should be moved to ftp://sunsite.unc.edu/pub/Linux/apps/www/converters/ ftp://ftp.lugs.ch/incoming should be moved to ftp://ftp.lugs.ch/pub/linux/mail For more details see the doc/ChangeLog or Norbert Kuemin, Swisscom, Norbert.Kuemin@gd2.swissptt.ch http://www.lugs.ch/LUGS_Members/norbert.kuemin/wmf.html _________________________________________________________________ bash Book Released 27 Feb 1998 New Edition of the "Definitive Guide to bash" released--O'Reilly's Learning the bash Shell By Cameron Newham & Bill Rosenblatt now covers Version 2.0. This second edition covers all of the features of bash Version 2.0, while still applying to bash Version 1.x. New features include one-dimensional arrays, parameter expansion, and more pattern-matching operations. In addition, bash 2.0 is POSIX.2 conformant. This updated edition covers new commands, security improvements, additions to ReadLine, improved configuration and installation, and an additional programming aid, the bash shell debugger. For more information: O'Reilly & Associates, info@ora.com, http://www.oreilly.com/ _________________________________________________________________ Published in Linux Gazette Issue 26, March 1998 _________________________________________________________________ [ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next _________________________________________________________________ This page written and maintained by the Editor of Linux Gazette, gazette@ssc.com Copyright © 1998 Specialized Systems Consultants, Inc. "Linux Gazette...making Linux just a little more fun!" _________________________________________________________________ The Answer Guy By James T. Dennis, linux-questions-only@ssc.com Starshine Technical Services, http://www.starshine.org/ _________________________________________________________________ Contents: * Can't Telnet to Red Hat 5.0 Server * Use the Source, Luke! * 'ifconfig' to Troubleshoot Dropped Ethernet Packets? * Cthugha * xdm Login doesn't! _________________________________________________________________ Can't Telnet to Red Hat 5.0 Server From: Brad Lackey, lackeyb@holly.colostate.edu I am trying to set up a LINUX web server for Colorado State = University - CIS Dept. I have Red Hat 5.0 Installed with user accounts = set up but I cannot telnet to the machine. I get the login prompt, but = none of the user accounts that I have created seem to work, including = root. they all give me "Login incorrect". I was wondering how to fix = this validation problem... Thanks, Brad First I'll have to assume that you installed RH5 on a fresh x86 machine with no previous OS, and that you've just installed the package from a CD and have yet to apply any upgrades or patches to it. If that's the case -- fire up the old browser and go to Red Hat's "Errata" pages at: http://www.redhat.com/support/docs/rhl/rh50-errata-general.html There are about 30 upgrade packages there -- including fixes for the utils package (fixes 'vipw' command), and glibc (the core c libraries which most of your other programs depend upon through the magic of shared libraries). I don't see a specific entry for the problem that you're describing -- and I haven't upgraded any systems to RH5 yet -- so I don't know if this problem is generic. A quick search of Yahoo!/Alta Vista and DejaNews doesn't show a match to exactly this problem either -- but it does show that telnet to RH5 boxes is working for many people. (Many of the problems reported have to do with long delays, caused by the "double-reverse lookup" that TCP Wrappers uses to prevent most varieties of spoofing). So, given that the search string "+red +hat +5 +telnet +login" didn't give us an easy answer we'll have to do some troubleshooting. Let's start with some questions: Does your syslog (/var/log/messages or /var/log/security) tell you anything? Have you run pw5conv to enable shadow passwords? If you run 'vipw' ('vi' the /etc/passwd file) do the password hashes appear there? Have you installed a different PAM (pluggable authentication modules) or modified its configuration (any of the files under /etc/pam.d/)? I didn't see a new PAM RPM up at the site listed above -- though things like the initscripts package and the glibc package might help. If these questions don't help you find the problem and resolve it I'd suggest that you grab a Red Hat 4.2 or a S.u.S.E., Debian or other distribution and install that. If you use Red Hat 4.2 you'll want to fetch all the upgrades for that -- and you might be able to install specific RH5 rpms (including the glibc which *should* co-exist cleanly with the libc 5.x that most (almost all) Linux distributions prior to RH5 rely on). As a support volunteer I find Red Hat's decision to push the release of "Hurricane" out the door at the end of last year to be abominable. I suggested to them that they do a 4.5 first -- and wait until about March of this year for a 5.0 (hoping that glibc would be better understood, that PAM would move much closer to 1.0, and that the 2.2 kernel *might* ship by then).* *** Please note: I don't have any "inside" hints as to when any of these event will occur. I don't know how long it will take to go from the 2.1.8x kernels through the inevitable 2.1.99.x flurry and get to 2.2. I read the kernel mailing list and cross my fingers like everyone else. Obviously Red Hat Inc (the company) and Caldera, and Yggdrasil, and many other organizations and individuals can help. If I were a programmer I might be able to help more. However, I was sure that 5.0 was too soon -- and the 34 Mb of upgrades and patches that were available as of last November needed to be released on CD to save the 'net a bunch of bandwidth. (I occasionally cut these and similar new stuff onto CD's using my ISDN line and my CD-R and give them away. I'm hoping to give one or two away at tonight's SVLUG (Silicon Valley Linux User's Group) meeting where we'll be hearing from Bruce Perens of the Debian project, and Eris S. Raymond, whose paper on the "Crystal Cathedral" was cited as a key part of Netscape's decision to release their sources)). I'd like to see Red Hat adopt a subscription model, where I can get monthly update of their "updates" and "contrib" mirrors for about $10/month. (I suppose it doesn't *have* to be Red Hat to do this, anyone with a CD-R and a reasonable trickle feed from the 'net could do it. Though the economies of scale don't work until we get a few hundred subscribers). Heck, if there's enough interest I'll do it. In any event, I hope one of these methods works. At the risk of starting serious flame wars and raising questions about my "loyalty to the cause" (which cause we're not sure) I'd also suggest that you look at the OpenBSD (and FreeBSD and NetBSD) distributions if you don't have a specific reason for picking Linux for this application. Linux is the most popular of the free Unix' -- but it's not the only one -- and it's not necessarily the best for all applications. OpenBSD, in particular, seems to be very well suited to multi-user "student use" and "computer lab" use. This is because Theo de Raadt and his team have found and corrected a large number of buffer overflows and other vulnerabilities in the sources for FreeBSD and NetBSD (and probably in the sources of many Linux utilities as well). Obviously this depends quite a bit on your intended applications. However, if I was setting up a general use shell account system for a school lab, an ISP, or a USENIX "terminal room" I'd probably suggest OpenBSD. For personal workstations I think Linux holds the edge in performance and applications availability. --Jim _________________________________________________________________ Use the Source, Luke! From: SuatChoo Lua, suatchoo@yahoo.com Here there something that maybe you can answer me. From where i can get the information about Linux File system,memory managemant,and scheduling algorithm. Thank you! coco In many ways I'm not the best person to answer this question. Remember that I am not a coder -- and I haven't contributed any programming to the Linux kernel (which I'm sure we all appreciate). However, I've read a bit of it -- and will offer some opinions. If you want deep information about -- technical details -- about Linux filesystem, memory management, and scheduling internals than the obvious thing to do is to read the sources. /usr/src/linux/kernel/sched.c is about 1700 lines long (about 80 pages). There are about 30 .c files under /usr/src/linux/fs (the filesystems directory) -- and about 160 .c files under that whole tree. Linux supports many different filesystems -- although the one that is considered to be "native" to Linux is the ext2fs. A variant of this filesystem has been adopted by the FSF for their ongoing HURD project (which is a microkernel OS for which rms and the Free Software Foundation developed gcc, GNU emacs, and most of the applications and utilities that make Linux possible). The code for ext2fs is about 5000 lines. Probably the simplest filesystem that ships with Linux is the Minix compatible one. Minix is a simple microkernel operating system written by Andrew S. Tanenbaum for inclusion with (and publication in) his text book on "Operating Systems: Design and Implmentation." That book is one of the seminal works on the topic -- and has probably been studied by every major contributor to Linux. The memory management code is in /usr/src/linux/mm. It probably shows off the greatest innovations in the Linux kernel. The aggressive strategies here allow a Linux kernel to operate within a pretty modest footprint despite the "freeping creaturism" that some of its detractors lament. Where to begin: * I'd start by reading Tanenbaum's book (there's a second edition where he's joined by Albert S. Woodhull). Just read the first half to get all the key concepts. The latter half of the book are the sources for Minix; which don't relate to Linux. * I'd then pick up a copy of the The Linux Kernel Hacker's Guide by Micheal K. Johnson (should be at any good LDP -- Linux Documentation Project -- mirror site). * Then grab a copy of The Linux Kernel by David A. Rusling and LINUX Kernel Internals by Michael Beck et al. (This last one is published by Addison Wesley -- the others are available online -- and published/printed in various editions of _The_Linux_Bible_, _Dr._Linux_, etc). After you've read some of those the kernel sources will hopefully make sense. Keep in mind that many of these things are still changing in the form of patches and in the newer 2.1.x kernels. For example there is a "evolution scheduler" which allows you to experiment with different scheduling algorithms for your Linux system. You can learn quite a bit about current Linux limitations by perusing Kurt Huwig's collection of "unofficial" Linux patches at http://linuxhq.sigkill.org/ or http://www.huwig.de if you'd like to read them in the original German. These include several experimental shedulers and memory management tweaks (like one that search for duplicated pages and aliases them to one another on the fly). I hope you find all those interesting and informative. --Jim _________________________________________________________________ 'ifconfig' to Troubleshoot Dropped Ethernet Packets? Uh-Unhg! From: Chris Oliphant, Chris.Oliphant@nextel.com I have a HP Vectra XM2 4/100i computer with an onboard PCnet/32 ethernet chip running Red Hat Linux 4.0, kernal version 2.0.18. I currently am having problems communicating over the ethernet connection for the last three days. I want to use IFCONFIG to troubleshooting the problem, but don't understand how to use the command's output. My problems are excessive receive packets being dropped and excessive transmit errors. I am able to ping the onboard chip, and the port connect is good with other systems connected to it. But when I connect my Linux system to the port, I have problems. Please advise. Thanks for any assistance you may provide. --Chris Oliphant 'ifconfig' is the "interface configuration" utility. It isn't a troubleshooting tool. I'd usually 'ping', 'tcpdump' and 'netcat'* or 'kermit'* for troubleshooting this sort of problem. * netcat is at ftp.avian.org (It is a little "swiss army knife" for TCP/UDP -- providing a simple facility for scripted TCP connections and transfers). * kermit (C-Kermit) is at kermit.columbia.edu (Aside from being a venerable file transfer protocol and serial communications packages, C-Kermit is also a telnet/rlogin client -- offering file transfers, scripting, debugging, and log-to-file features over TCP connections). Based on your question here's a few standard support questions to echo back: "for the last three days"? What happened then or before then? Did the link work fine before then? Did you upgrade your kernel? Change drivers? Add a new video card? Did this kernel/driver/module ever work acceptably with this ethernet card? With this system's mixture of other components? With a similar (so-called "identical") system? Excessive errors on an ethernet line suggests the following sorts of problems: 1. high collision rates -- Are there other boxes on your LAN segment that might be utilizing an excessive amount of the bandwidth? How many systems are on this segment? What applications are they running (particularly network intensive)? As an example if you put a few xterminals or diskless workstation on a network and they fetch all of their X resources, binaries and libraries over the wire (rather than tftp to a local RAM disk for example) then you can flood an unswitched ethernet segment in no time. 2. hardware problems with your card or someone else's (on the same network segment) -- It is possible that some ether card on your segment is broken and "chattering" (generating spurious signals which corrupt the data frames (network layer "packets") from other cards. This is likely to show symptoms across the entire segment (all the machines will be affected). It is also possible that any particular card is damaged. It is also possible for the problem to be in a particular wire (are you using 10BaseT, coax/thin net, or (heaven forbid!) thicknet?), or even a particular port on one of your hubs (repeater, concentrator, whatever the "term du jour" for that thingie-me-bob is). It could be as simple as "someone kinked the wire by running it over with their chair wheel." A good way to test for this is to get an ethernet "cross over" cable (sort of a "null modem" for 10BaseT) and plug it between the problem system and a known good one. This bypasses all the intervening components to help isolate the problem. (Basic troubleshooting 101: identify all components, eliminate as many as possible for testing, continue simplifying the configuration -- and possibly the tests -- until something works, re-add components back until failure. That isolates the problem.) 3. bad driver or configuration -- If this has never worked under Linux (or under the specific kernel your working with) you should boot under some other OS and use whatever diagnostic utilities HP provides. If those work and Linux still fails it suggests a software configuration or driver problem. If you had an older kernel that did work without a problem, try booting with it and running your tests -- it's always possible that the card is broken in someway that only shows up under conditions that don't occur from DOS or Win '95. It's also possible that something in your kernel is broken. Naturally you'll also want to try a 2.0.33 or 2.0.34 kernel to see if that helps. As I've pointed out -- you need to do basic troubleshooting in situations like this. You also want to ask yourself: "Have I provided enough information for anyone (short of a psychic) to answer this question?" --Jim _________________________________________________________________ Cthugha From: kim angel, angelk@cadvision.com Could you please tell me when Cthungha will be available for Win95? Thanks! Kim Angel Sorry. Can't be much help there. I presume you mean Cthugha (no 'n') which would be the audio/video amusement (turn your $3K multi-media system into a $40 "discoteque" light). Hmm....I detect a tad of dissatisfaction with the product! I've never run it. I have a lack of interest in the class of software. I had to look it up in the LSM (software map) to remember what it was -- since I mis-remembered it as a "game"). I have no idea if or when it would be available for Win '95 -- or even why anyone would port it. However, I'd contact the author/maintainer (should find his/her/their name(s) in the man pages or docs). What I am seeking is a program that is capable of applying digitized animation choreographed to audio sequences. Could you help me with this? I'm the "Linux Answer Guy" (or, to be more specific and a little less pretentious, the "Linux Gazette Answer Guy"). It appears that Cthugha *is* just what you want -- for Linux. I'm not the "Windows '95 Answer Guy." A role which I probably would be wholly inadequate at since I don't run it on any of my systems and I don't like what little of it I've had to run. Despite this I can offer you a pretty simple piece of advice: Ask the author. Another possibility is that you could try the port yourself. I'm not sure what the licensing of Cthugha and its sources is -- but it's probably GPL. That license lets you port it to any OS or platform you like -- or pay anyone else to perform the port to your specs. If you should find that the port to native Windows API's is too difficult you could try DESQview/X (which offers X Windows API's over DOS) or you could try OpenNT (from Softway Systems at www.softway.com). OpenNT offers reasonably complete Unix API's -- and some X Windows if I heard correctly -- and runs under NT. I have also heard of several developers tools that purport to compile Unix/X Windows code into native MS Windows API's. However I don't have any experience with them, nor any personal interest in them. -- Jim _________________________________________________________________ xdm Login doesn't! From: Cesar Augusto Kant Grossmann, ckant@fazenda.gov. I run my Linux Box in the "graphics mode" (changing inittab accordling) = bu I can't login as normal user. When I try to login as normal user, the = screen flickers like a logout in the X, and the login screen comes back. This is also referred to as "using 'xdm'" (X Display Manager) which provides a GUI login to X. You don't mention what sort of system you have (which distribution what architecture/platform, what packages you've installed or updated, etc). You also don't mention whether you can login via a text mode console (VC/VT) or via telnet or a serial line. If you can, the problem is likely to be a mismatch between your 'xdm' binary and the authentication model/settings that you have for your other 'login' modes. This is one area where the FreeBSD crowd definitely had a better model. Under Linux you can use the old-fashioned (traditional -- and insecure) authentication mode where the hashes of your passwords are stored in the /etc/passwd. Alternatively you can install or enable some variation of the "shadow" suite. This removes the password hashes from the /etc/passwd file and stores them in a different file -- one which is only accessible to privileged (SUID) programs -- and not readable by normal users. The purpose of all that is to make the system more resistant to dictionary and cryptanalytic (brute force or otherwise) attacks. In other words using the 'shadow' options is more secure than allowing normal users to just snarf the hashes up, and copy them to a machine running 'crack'. The problem is that there are many programs that authenticate users under Unix/Linux. In addition to login there's xdm, ftpd, xlock, vlock, screen's lock feature, popd, imapd, the passwd command etc. In FreeBSD they modified the libraries -- and ensured that all the programs were linked against the same shared library. This hides the details -- because the library calls that "getpwent()" (get password file entries) automatigically merge the passwd hash from the shadow file (called /etc/pwdb.master? or somethine like that -- in FreeBSD) if that file exists and is readable. Thus unprivileged files on a shadow enabled get pw entries with an "obscured" password field (usually just a "x") while privileged (SUID) program get a merged one that's suitable for comparison to a properly crypted/hashed password as provided by an alleged user. The other advantage to the FreeBSD method is that changing the hashing algorithm (from the traditional 56-bit DES on a string of zeros -- to a MD5 sum) is relatively easy -- only has to be supported in one place (the shared libraries) and doesn't require that all the other programs be changed. (Another feature of the FreeBSD password/account management libraries is that they support dbm hashes of the account names -- meaning that *huge* lists of accounts are possible without suffering a "linear" increase in login/authentication response times) For now Linux has three different, and partially incompatible account/authentication schemes: * Traditional /etc/passwd files * Shadow suite (still with flat text files) * PAM and libpwdb (dbm files and modular authentication model). The frustrating thing is that these can all work together do some degrees -- a pwdb system maintains a set of text flatfiles that are sync'd to the dbm/hash tables (these hashes are the indexed/search type -- as opposed to the cryptographic variety that I referred to earlier -- like 56-DES and MD5). Although Red Hat has shipped their last 2 or three releases with PAM -- it isn't quite all there yet. The most recent version of PAM is about 0.63 (beta). However -- if you installed a recent Red Hat Linux (4.2 or 5.0 with patches) you should be able to use its xdm and all of their stock utils without trouble. If you compiled your own 'xdm' or fetched it from somewhere you should consider recompiling it -- but looking for options that relate to "shadow" support. What seems to happen? Where I can find more informations about these? A FAQ or something like... I'd start by reading the Shadow HOWTO. I'd also suggest a web search on PAM (pluggable authentication modules): Here's some URL's I have for them: * Andrew Morgan's Page: http://www.kernel.org/pub/linux/libs/pam/ * The Linux-PAM System Administrators' Guide: http://www.math.muni.cz/linux/Linux-PAM/html/pam.html * PAM - Pluggable Authentication: http://www.redhat.com/linux-info/pam/ * PAM specs -- OSF RFC 86.0: http://sysadm.sorosis.ro/devel/pam/rfc86.0.txt It's a good idea to read about PAM since several other Unix flavors are also moving towards it (currently appearing in Solaris and HP-UX, at least). Sorry for my bad English, but I think it's better than your Portuguese... Undoubtedly your English is better than my Portugese -- or even my French (I've never studied the former and only had a couple of high school years of the latter). --Jim _________________________________________________________________ Copyright © 1998, James T. Dennis Published in Linux Gazette Issue 26 March 1998 _________________________________________________________________ [ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next "Linux Gazette...making Linux just a little more fun!" _________________________________________________________________ Clueless at the Prompt By Mike List, troll@net-link.net _________________________________________________________________ [INLINE] Welcome to installment 6 of Clueless at the Prompt, Here's this month's account of the triumphs, trials and tribulations that I caused myself or encountered since the last time, and a couple tips that may come in handy and increase your understanding of linux. _________________________________________________________________ *Splitvt and Screen: Last month, I suggested splitvt as a substitute for virtual consoles when using a serial terminal. I still recommend splitvt since you can work in two separate windows that are in sight of each other- cut and paste with gpm is a snap for scavenging previously written scripts or.... But several people wrote to tell me about screen, which is an even better substitute for virtual consoles when using that dumb terminal. I'm still working on making screen work fluidly, Alt-F* took a little getting used to at first. Instead of the A-F* combination you use the C-a* keys to open a new window. There are some other features that I have only read about, the only difference between screen and virtual consoles is that each new screen is already logged on. Like I said, I'm not familiar with all of screen's features, but to use it, basically you type: screen progname and your screen session is started in VT0. To add more VTs you can use: Ctrl-a c and to change from one screen to another: Ctrl-a 0-9 and you can change from screen to screen, depending on how many you have opened. Note that the screens are numbered 0-9 rather than 1-10, the only clumsy feature of this program, IMHO. _________________________________________________________________ *Back to basics: Some friends of mine, the nefarious UGD folks have a page "User Guide Dog"which details many, if not most of the usual commands that a new user might find useful but not clearly documented. I don't have to tell you that man pages can be pretty hostile to a gnubee (ever wonder what that picture was?), but if you check them out after using the programs to do the things you most commonly need to do, you will most likely achieve enlightenment - the information is suddenly much more clear. The UGD Project is shaping up as a good vehicle for this journey, if you can take the ride. Bring along your sense of humor, one of the guys is a Canadian from out on the tundra ; ). _________________________________________________________________ *Some stuff you may not hear anywhere else (so basic they forgot to tell you): Here's some stuff you probably already know about, if you've been into Linux (or other unices)for a while. * Filename Completion : If you aren't an enthusiastic typist, you'll find this of value. Just type enough of the filename to make it unique, then hit tab it will complete the filename so you can get on with your life and file manipulation.Play with this feature, if you haven't typed enough of the name to be unique, it will sit and stare at you, try another character or two.Likewise, if you specified the wrong directory,you'll get nada. * Quick cd : Another keystroke saving apparatus is: .. and its close relative . The details for a quick cd areas follows: as you may be already aware, the dots represent your current directory(single dot) and parent directory (double dot).By CDing to .. you will be magically transported to the parent directory, ie from /usr/bin to /usr.You can use: cd - to return to the previous directory, and to go up two or more levels: ../../and so on will work. The single dot is not as useful in terms of cd, but it does have its use. If you are in a directory that's not in your path, or dont have . in your path statement, you must give a path to run an executable file. This is easily accomplished by typing: ./execuname which will give the relative pathname, allowing it to be found and run. There are a few good reasons why using the single dot in your path statement isn't a good idea, suffice to say, if you'd like more info on that subject, you should read up on system security. * GPM : This has been so basic to my linux experience that I would be crippled without it, in fact once when I flubbed an installation and didn't have it running, it became my first priority to correct that little oversight. The mere fact that the non unix OS seem not to have this is reason to upgrade to Linux, although I found a dos program that allows a similar use of the mouse on simtelnet. In a related matter, if you dual boot(most home boxes, I'd imagine)you might find yourself using ls -aF when you actually meant to type dir or cp when what you wanted was copy you can create batch files(like shell scripts) named for your favorite unix commands, using your favorite switches. Not as cool as dosemu or just plain staying in Linux, but ya gotta do what ya gotta do. _________________________________________________________________ *Errata: No I don't really do "make dev" when I make a kernel (maybe I could blame it on my keyboard)make dep is what I meant. _________________________________________________________________ If you have a subject that you would like to see covered or have any corrections, comments or flames let me know, and I'll look into the matter. troll@net-link.net See you next month! _________________________________________________________________ Copyright © 1998, Mike List Published in Issue 26 of Linux Gazette, March 1998 _________________________________________________________________ [ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next _________________________________________________________________ "Linux Gazette...making Linux just a little more fun!" _________________________________________________________________ EMACSulation by Eric Marsden _________________________________________________________________ This column is devoted to making the best use of Emacs, text editor extraordinaire. Each issue I plan to present an Emacs extension which can improve your productivity, make the sun shine more brightly and the grass greener. Internet-ready! You've probably heard the hype about ``Internet-ready'' operating systems where you can access the Internet with a click of your mouse. Well, users of the customizable Emacs user interface have had the Net only a keypress away since as early as 1989! Emacs has built-in networking capability, which it uses for connecting to news or SMTP servers and for web browsing. To illustrate its use, here is a bit of code which opens a TCP connection to port 13 of your local machine to request the current time : ;; usage: M-x display-date (defun display-date () (interactive) (let ((stream (open-network-stream "DAYTIME" nil "localhost" "daytime")) ) (set-process-filter stream 'my-process-filter)) (defun my-process-filter (proc string) (message "Current date is %s" (substring string 0 -1))) This code --which assumes you're running inetd-- should display something like the format of date in the minibuffer. The rich set of primitives and the integrated error management provided by Emacs make it easy to program useful utilities; consider how many lines of code would have been required to provide the equivalent functionality in C. Ange-ftp Ange-ftp is a package by Andy Norman which allows Emacs to see the entire Internet as a virtual filesystem. It adds remote editing capability by mapping requests for remote files to FTP commands. For example, if you ask Emacs to open a file named /marsden@ondine.cict.fr:~/.emacs then ange-ftp will spawn an FTP process, connect to the host salines.cict.fr as user marsden, CWD to my home directory, GET my Emacs initialization file and display the file as if it were on your local filesystem. If ange-ftp needs a password it will read one from the minibuffer. If you make changes to the file and save it, it will be PUT back to the server for you. You can even copy files from one remote machine to another by typing M-x copy-file RET /user1@host1:/path/to/file1 RET /user2@host2:/path/file2 ; ange-ftp looks after opening two ftp connections for you. Ange-ftp comes pre-installed with Emacs (XEmacs features efs, a complete rewrite by the same author). The only customization you might need to make is to configure a gateway, if you don't have direct Internet access. You can use ~/.netrc to configure default logins for oft used hosts in the traditional way (and even passwords if you're foolhardy). Perhaps the most elegant feature of ange-ftp is its seamless integration with Emacs; the only visible change it introduces is the extended filename syntax. Filename completion (by pressing TAB in the minibuffer) is available on remote hosts in the same way as on your local machine. Ange-ftp works well with Dired, the directory editor, allowing you to browse though distant machines, operate on several remote files at once, etc. It also works with bookmarks, so you can memorize an interesting spot on your favorite ftp server, and jump back to the same spot next week with ease. Take a typical usage: ask Emacs to open the following directory (with C-x C-f or from the Files menubar) : /anonymous@ftp.kernel.org:/pub/linux/kernel/ You will be presented with a directory listing many different releases of Linux kernels (if you have a line like default login anonymous password user@site in ~/.netrc then ange-ftp can infer the anonymous@ for you automatically). Type C-x r m to bookmark the location. There's more on bookmarks in Jesper Pedersen's article in issue 7 of the Linux Gazette. Web browsing Emacs-w3 (also referred to by some as Gnuscape) is a web browser written by William Perry in Emacs Lisp. It is fairly sophisticated in certain respects, having been the first production browser to support cascading style sheets. It understands tables, and can display images inline under XEmacs, or by invoking external viewers when hosted by GNU Emacs. Its author notes that Emacs-w3 is yet another reason never to leave the comfort of the One True Editor, but to me it serves more as a reminder of the deficiencies of Emacs Lisp : it is slow, and has a tendency to block while waiting on a slow link (unfortunately Emacs is not multi-threaded, though you can set the variable url-be-asynchronous to t to reduce this annoyance). If you want to try it out get the latest version from the betas directory, which has many improvements over the version distributed on most Linux CDROMs. browse-url is an nifty Emacs extension which can dispatch references to URLs to Mozilla or to Emacs-w3. It does this by using Netscape's remote invocation protocol, which as a side note even works when you're running the browser on a distant machine (the implementation uses the X11 inter-application communication protocol). Emacs features its own remote control mechanism which lets you send commands to a running Emacs (even on another machine), called gnuserv/emacsclient, which I might talk about another time. Recent versions of Emacs are set up to use browse-url in mail and news reading modes. URLs should be highlighted when you pass the mouse over them, and you can click on them with the middle mouse button to invoke your favorite browser. Here's how you can set up browse-url to use Mozilla when you're running X11 and Emacs-w3 otherwise : (if (eq window-system 'x) (setq browse-url-browser-function 'browse-url-netscape browse-url-new-window-p t) (setq browse-url-browser-function 'browse-url-w3)) Another more indirect use of browse-url is WebJump by Neil W. Van Dyke. This Emacs plugin provides a programmable hotlist of interesting web sites with which to feed your browser. Perhaps its most interesting feature is the ability to send a query to Internet search engines such as AltaVista and Yahoo! without having to load the first page of ads, but it also includes features for dispatching searches to FAQ and RFC archives, to the online Webster or Thesaurus, or to bring up an appropriate page of the Java API. Naturally (this is Emacs) you can extend it to include your own favorite sites. You might find yourself using it more than your browser's bookmarks. Files at your Fingertips ffap is a powerful package which extends the find-file command (the one which prompts for a file name in the minibuffer, normally bound to C-x C-f). It searches the text around the cursor position for something which might represent a filename -- a file in the current directory, a C #included file, a newsgroup reference, an ange-ftp style reference to a file on a remote machine or an URL -- and prompts you either to open that file, or to send the URL to a browser (via browse-url). Once experiencing this you quickly get sick of typing filenames into the minibuffer, and may find yourself inserting ``hyperlinks'' in strategic places in your files to save typing. ffap is distributed with both Emacs and XEmacs; I bind it to the F3 key as follows : (autoload 'find-file-at-point "ffap" nil t) (define-key global-map [(f3)] 'find-file-at-point) or if you prefer you can simply override the traditional find-file by saying (autoload 'find-file-at-point "ffap" nil t) (define-key global-map [(control x) (control f)] 'find-file-at-point) ffap is pretty good at determining interesting filenames; it even knows how to recognize RFC names, and from which server they may be obtained. It goes to the trouble of pinging remote machines to determine whether they are alive, and can naturally be extended to recognize personal types of filename references. To conclude on filename shortcuts, you might enjoy Noah Friedman's fff (Fast File Finder) which helps you find files hidden somewhere deep in inode-space by querying your locate database (part of the GNU findutils). Feedback Several people wrote to me with comments on last month's article on jka-compr. Chistopher B. Browne told me he prefers crypt++, which provides on-the-fly decryption and encryption as well as automatic compression and decompression. Whereas jka-compr trusts the filename extension, crypt++ reads the first few bytes of the file to determine its type. The package also has functions for dealing with DOS-style linefeeds which you might find useful if you have to exchange files with other operating systems, although you could just as well say (standard-display-ascii 13 ""), which simply hides those ^M characters. Crypt++ is not a standard part of Emacs (it's not included in the GNU Emacs distribution, though it is bundled with XEmacs). I haven't tested its cryptographic capabilities, because As a French citizen I am prohibited from using any form of encryption. In France encryption requires authorization from the President, which is accorded only to large military companies and to financial institutions (and then only if the keys are held in escrow). These laws are one of the reasons holding back the incorporation of kernel-level support for encryption in Linux. Before accusing France of being backward, please consider the fact that countries su