LJ Archive

Best of Technical Support

Various

Issue #77, September 2000

Our experts answer your technical questions.

Graphics on a Floppy

How do I create an image file from a floppy disk? I have tried to find this everywhere, with no success. —Bryan Hepkema, bhepkema@blsc.com

If I get your question correctly, to generate an exact copy of what is on a floppy disk, and store it on your hard disk, you can use the command dd if=/dev/floppy of=/tmp/floppy_image. You may have to input the correct device name for your floppy unit (possibly /dev/fd0). This will create a binary image of whatever is on the diskette in the file /temp/floppy_image. I would suggest you study the dd command with man (man dd). —Felipe E. Barousse Boué, fbarousse@piensa.com

If you need an image from a file, just insert the floppy and cat /dev/fd0 > file. The device representing the floppy is just a file representing the whole disk. That's true for hard drives as well. —Alessandro Rubini, rubini@linux.it

Web Fonts and Printing

How do I get Netscape to print fonts like the web pages actually show? Everything is defaulted to Times New Roman. How do I load and use True-Type fonts? —Greg Crutcher, madcrutch@earthlink.net

There is no short answer to your question. Many Xwindows configuration issues have to be addressed. The right answers can be found at the following URL: pegasus.rutgers.edu/~elflord/font_howto/html/index.html#toc1. It is also worth mentioning that Netscape has its own personality regarding fonts and behavior under X. —Felipe E. Barousse Boué, fbarousse@piensa.com

Check out the TrueType-HOWTO at www.moisty.org/~brion/linux/TrueType-HOWTO.html--Pierre Ficheux, pficheux@com1.fr

Sharing Files with Windows

I have installed Caldera's OpenLinux eDesktop 2.4 on my HP Pavillion 6630 computer. I can dual boot into either Linux or Win 98 and would like to be able to share files between operating systems. Under Linux, the file directory for Windows is visible under hda, and I browse through my Windows files and even open them, but I cannot write to this directory. Is there any easy way to set up a location on the hard drive where I can read and write to files from either Linux or Windows? —Tom Newman, newmanth@usa.net

It looks like you don't have permission to write to the files. That's what I would expect if you work as a user and the directory is automatically mounted at boot. Try adding “umask=0” in /etc/fstab, in the field where “default” appears to allow everybody to write the files. To have it be effective immediately, try umount /dos; mount /dos. —Alessandro Rubini, rubini@linux.it

PostgreSQL on Boot

How can I have PostgreSQL start automatically when my computer boots up? I must start the postgreSQL server with the command nohup postmaster -d 2 > logfile 2>&1 &, and I must start it as the user “postgres”. I can't figure out where in the /etc/rc.d scripts I should start it from. Thanks for your help! —Warren Killian, warrenk@in.net

The best way to start new programs is by writing a new script, just for them, in /etc/rc.d/init.d (talking RH-hierarchy, other distributions may be slightly different in the pathnames) and then link it from /etc/rc.d/rc3.d. The instructions to write those scripts in the right way should be part of the documentation for your distribution; another good way to do things is to learn (and copy) from what other scripts do. As far as links in /etc/rc.d/rc*.d, there is also a graphic tool to make those links, part of the control-panel tool. Note that Debian is already packaging Postres, so you can look at that script as well. —Alessandro Rubini, rubini@linux.it

The script should use a syntax such as

su postgres -c '/usr/bin/postmaster ...'

However, a “postgresql” init script is included in the distribution so that it is installed in the /etc/rc.d/inid.d directory. —Pierre Ficheux, pficheux@com1.fr

Trouble Logging In

I got Corel Linux installed alongside MS Win98 okay, but now, when I boot to Linux, the login screen flashes and accepts characters only when the screen is displayed (at about half-second intervals, on and off). I cannot catch the on part in order to successfully log in. What is wrong, and how is it fixed? I tried typing kde at the command prompt, but it cannot load x. It runs okay in VGA mode and logs in to kde okay. I am a total Linux newbie but am familiar with MS-DOS and CP/M (showing my age now!) Many thanks. —Adam Puk, adam-puk@cwcom.net

Your symptoms may mean that the system is driving the screen at incorrect frequencies (the PC world is too varied; it's not easy at all to devise things that work for all possible hardware), but there should be no relationship between that and reaction to keboard input. What you may try is booting in single user and then look for the command that corrupts things by executing the init scripts one at a time. Unfortunately, to do this kind of tracing, you'd need to already have good experience. I'm afraid your best bet is to look for a knowleadgeble neighbor. —Alessandro Rubini, rubini@linux.it

Cannot Access the Web

I am trying to make the system run on my cable modem. I have two other computers running on it, but they are Windows-operated. I have entered all the information that is needed, IP, Gateway, subnet mask, as well as host and domain. But every time I try to run Netscape and go to a web page, it gives me an error message that the web server cannot be found. I cannot seem to figure out what the problem might be; I have tried to follow all the documentation I could get my hands on. Hopefully you can help me. —Chirag Jay Patel, cjpagni@home.com

It looks like you have a routing problem. Try this command:

route add default gw <ip_of_your_cable_modem_host>

That is the IP address of the host that has attached the cable modem (or the IP address of the modem itself, depending on your hardware setup). What happens here is that this command tells Linux's TCP/IP to go out through the standard and default exit to the Internet, which is your cable modem. —Felipe E. Barousse Boué, fbarousse@piensa.com

Failure to Connect

When I try to connect to my ISP, I hear a dial tone but there is no connection. In /var/log/messages, there is the nex message: Peer is not authorized to use remote address x.x.x.x Where x.x.x.x is het number from the ISP. I searched the Internet for this but got very little information. Thank you in advance. —Wim van den Broeke, w.vd.broeke@hccnet.nl

Try adding the line

noauth

to the /etc/ppp/options file so the peer is allowed to set the route from the ISP assigned address, which is assumed not to be set at the moment of connection. Do a man pppd and check all options for the pppd daemon on the “options” setup file. —Felipe E. Barousse Boué, fbarousse@piensa.com

Configuration Questions

I am new to Linux, and I like it a lot. I would like to know how to do the following:1. Set the desktop display to conform to the monitor. 2. Set up the screen to be able to fit the size of my monitor. 3. Change the color scoop from 16bit to more colors. (Still monitor) 4. I am confused about Samba. Please advise on how to connect Samba file share with Windows. —Luke, godmatrix@godmatrix.com

1. The Xconfigurator command will guide you on the X setup. Use “custom” monitor and get the correct values of scan frequencies from your monitor manual specs.

2. The highest resolution can be achieved with Xconfigurator, as well. Make sure your monitor supports high resolutions!

3. After Xconfigurator, you can try editing /etc/X11/XF86Config to define default video modes, let's say 800x600 or 1024x768 on your video card's settings section. You have to make sure you have enough video memory to support high color depths.

4. You need to set up the IP and host name of your Windows PC on /etc/hosts. That is, host names must be correctly resolved. Edit /etc/smb.conf and add your workgroup name to the line: workgroup = YOUR_WORKGROUP_NAME. Then, add the server name to the line: server string = YOUR_SAMBA_SERVER_NAME. Finally, edit the line to say hosts allow = xxx.yyy.xxx. 127. You must write the first three number groups of your IP addresses (denoting the LAN address itself) immediately after a blank space and the “127.”, indicating the localhost. Note the trailing dots after network and localhost-network IP numbers. Lastly, share a directory from Linux to Windows, let's say:

[linuxtemp]
   comment = Linux /tmp directory
   path = /tmp
   public = yes
   writable = yes
   printable = no

This will share the /tmp directory under the “linuxtemp” name. Restart Samba with the command /etc/rc.d/init.d/smb restart and double click on the network neighborhood of your Windows box; you should see the Linux's share /tmp directory.

Samba is a complex service. I would suggest you look up further details from the Linux documentation project site at metalab.unc.edu/pub/Linux/docs/HOWTO/html_single/SMB-HOWTO--Felipe E. Barousse Boué, fbarousse@piensa.com

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