Best of Technical Support

Our experts answer your technical questions.
Programming with Shared Memory Segments

I have some processes that create shm segments and others that link to those segments. The problem is that some processes create shm segments with a key, but the addresses of the attachment are the same as that of previous shm segments created by other processes with different keys. —Christian Grunfeld, cgrunfeld@uolmail.com.ar

There is a good Linux shared memory tutorial at www.acm.uiuc.edu/lug/presentations/shm/shm.html. —Felipe E. Barousse Boué, fbarousse@piensa.com

Nice Keyboard, but Where Are the Accent Marks?

How do I enter a foreign/high-ISO8859 character, for instance ê, from inside an X Windows System? At a console screen, I can do Alt+237 and get that character. Various documents talk about the “Compose” key, but I'm unable to get results by following any of those instructions. —Kevin Goess, knet@goess.org

I was able, by building an .Xmodmap (notice leading dot) file, to remap all the keys in order to accept Spanish, English, Portuguese and French characters by using dead-keys, CTRL, ALT and ALTGR sequences. I will put my /usr/lib/X11/xinit/.Xmodmap on-line at http://www.piensa.com/xmodmapfile/. This file is “run” whenever X is initialized. You can run it manually with the xmodmap command. —Felipe E. Barousse Boué, fbarousse@piensa.com

A GUI utility to pick special characters is the Gnome Character Map, available at http://www.gnome.org/. —Paul Christensen, pchristensen@penguincomputing.com

Login Won't

I'm running a small home network with Linux/Win95/WinNT all coexisting. Recently, the Linux machine stopped allowing Telnet sessions or direct (text) logins on the console. I'm receiving this message: /sbin/login: /lib/libc.so.6: version `GLIBC_2.1.3' not found (required by /sbin/login)

The file /lib/libc.so.6 is linked to /lib/libc-2.1.1. Can you tell me what I am missing? —Larry Busse, ljb@one.net

It looks like you upgraded /bin/login (probably through the util-linux RPM), and you now have a dependency problem since your binary was built for glibc 2.1.3, and you have glibc 2.1.1. I'm not quite sure how the RPM was installed, considering that it should have complained due to library incompatibility. One possibility you should be looking at is that someone accessed your system without your knowledge and installed a modified /bin/login to compromise your system. If that's not the case, re-install the util-linux package that came with your RH 6.0 distribution (rpm -U --force) and you should be okay. —Marc Merlin, marc_bts@valinux.com

CD-ROM Mounts...but Where?

I'm trying to install Sun StarOffice 5.1 on my machine. I mount the CD-ROM (mount /mnt/cdrom), but when I go to the cd-rom directory (/cd) to try to see the files, nothing is there. —Luis Embalo, zulobaby@hotmail.com

Make sure you're looking in the right directory. If mount /mnt/cdrom doesn't give you any errors you should be looking in /mnt/cdrom for the contents of the CD-ROM. One thing you can try is using the mount command with no arguments. On my system it returns this line:

/dev/hdc on /mnt/cdrom type iso9660 (ro)

This tells me that my CD-ROM drive (hdc) is mounted at /mnt/cdrom. If you would like to mount your CD at /cd, try:

mount /dev/cdrom /cd
--Paul Christensen, pchristensen@penguincomputing.com

Full-Duplex or Not?

In an HP-UX system, to find out a duplex status of an Ethernet card, one simply issues a command: lanadmin -x lan0. This will report if a card is in full-duplex 100MB mode or not. I've been trying to find out for a long time what would be an equivalent of something similar in Linux but cannot find it. —Boleslaw Mynarski, bman@bolek.com

Sure, you have two of them: mii-tool and mii-diag. One place you get those from is: ftp://ftp.valinux.com/pub/support/flory/mii-tool/. —Marc Merlin, marc_bts@valinux.com

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