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Our experts answer your technical questions.
Geometry Mismatch Error

I am having a problem with LILO. It hangs after the letters “LI”. I read the MINI-HOWTO, and it says that the first boot loader was able to load the second boot loader but has failed to execute it. Then it goes on to say that the cause is a “geometry mismatch”. Any suggestions?

—Jim Mendoza Red Hat 4.2

LILO loads its second-stage loader and then the kernel by accessing disk blocks based on their disk location (CHS: Cylinder, Head, Sector). A “geometry mismatch” is what happens when LILO's map uses CHS values that are not those used by the BIOS; this happens with modern BIOSes that play dirty games with disk geometry to overcome a limitation built in Microsoft programs. Add a “disk =” section to your /etc/lilo.conf to specify disk geometry as Linux sees it.

—Alessandro Rubini

Undetected Modem

Linux does not detect my modem at com4 (/dev/cua3, address as 0x02e8) which works fine in Win95. Each time I reboot the system, it automatically detects only serial port number 1 (/dev/cua0, at 0x03f8) and port number 2 (/dev/cua1, at 0x02f8). My modem is internal, non-plug-and-play, 33.6Kbps and manufactured by PC tel.

—Jianzhong Ding Red Hat 4.2

Use setserial to tell the serial driver about the location of your ports. “Plug-and-play” is an ugly specification, and most of the time it creates problems. To look for your PnP devices and configure them, run the isapnp package.

—Alessandro Rubini

Sendmail Pause

During startup, there is a long pause while sendmail starts. I can only assume that a request is timing out while trying to contact something on the network (the network, of course, isn't up yet).

Is there a way to shorten the time-out period for sendmail or otherwise correct the situation?

—David Moulton Red Hat 4.0

This may be a problem with your machine name in the /etc/hosts file. Recent versions of sendmail need your name to be a FQDN (including a domain name): foo

If your name is not fully qualified, sendmail will sleep for about one minute.

—Pierre Ficheux, Lectra Systèmes

The pause is most likely a name server lookup that is timing out. Have a look in your maillog (probably /var/log/maillog) and search for lines that look like these two:

Dec 21 18:33:46 keiko sendmail[4547]:
 gethostbyaddr() failed for
Dec 21 18:33:47 keiko sendmail[4553]:
 starting daemon (8.8.5): SMTP+queueing@00:05:00

What's happening is sendmail is trying to resolve the IP address of the machine it's running on. Name server calls take a relatively long time to timeout, thus the delay you are experiencing. The quick solution is to add an entry for this IP address into /etc/hosts or into your name server configuration. sendmail starts very quickly after you have done this.

—Keith Stevenson