Best of Technical Support
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 firstname.lastname@example.org
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 email@example.com
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):
192.168.1.1 foo foo.bar.com
If your name is not fully qualified, sendmail will sleep for about one minute.
—Pierre Ficheux, Lectra Systèmes firstname.lastname@example.org
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: gethostbyaddr() failed for 192.168.0.1 Dec 21 18:33:47 keiko sendmail: 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 email@example.com
Practical Task Scheduling Deployment
July 20, 2016 12:00 pm CDT
One of the best things about the UNIX environment (aside from being stable and efficient) is the vast array of software tools available to help you do your job. Traditionally, a UNIX tool does only one thing, but does that one thing very well. For example, grep is very easy to use and can search vast amounts of data quickly. The find tool can find a particular file or files based on all kinds of criteria. It's pretty easy to string these tools together to build even more powerful tools, such as a tool that finds all of the .log files in the /home directory and searches each one for a particular entry. This erector-set mentality allows UNIX system administrators to seem to always have the right tool for the job.
Cron traditionally has been considered another such a tool for job scheduling, but is it enough? This webinar considers that very question. The first part builds on a previous Geek Guide, Beyond Cron, and briefly describes how to know when it might be time to consider upgrading your job scheduling infrastructure. The second part presents an actual planning and implementation framework.
Join Linux Journal's Mike Diehl and Pat Cameron of Help Systems.
Free to Linux Journal readers.Register Now!
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With all the industry talk about the benefits of Linux on Power and all the performance advantages offered by its open architecture, you may be considering a move in that direction. If you are thinking about analytics, big data and cloud computing, you would be right to evaluate Power. The idea of using commodity x86 hardware and replacing it every three years is an outdated cost model. It doesn’t consider the total cost of ownership, and it doesn’t consider the advantage of real processing power, high-availability and multithreading like a demon.
This ebook takes a look at some of the practical applications of the Linux on Power platform and ways you might bring all the performance power of this open architecture to bear for your organization. There are no smoke and mirrors here—just hard, cold, empirical evidence provided by independent sources. I also consider some innovative ways Linux on Power will be used in the future.Get the Guide