We ran into a couple of interesting problems with modules. The first one dealt with SCSI emulation with IDE drives. You need SCSI emulation if you want to write to your IDE CD-ROM with Linux tools. In the past, we have recompiled the kernel with SCSI emulation, but it is so much easier if you […]

Building from source is fun, but it’s easier to distribute RPMs to a bunch of machines. You may recall that we recently built and installed the OpenTDS libraries and SQSH, a dandy little command line tool for use with MS SQLServer. These built nicely on my RedHat 7.3 system, and I have a bunch of […]

[or… how I learned to stop worrying and love the /etc/group file] On Red Hat, the default permissions for a serial port are: ls -l /dev/ttyS1 crw-rw—- 1 root uucp This means that root is the owner and group is uucp. No others have access to the serial port. In order for a non-root user […]

Urbana used to work with a guy who routinely shut down GNU/Linux by typing: sync sync halt That just sounded plain crazy. Why not use shutdown? Well, we just figured he was just a little old-school. The command appeared to work (manpage for sync, manpage for halt). Now, our robocoop is running a giagd system, […]

In this article, we showed how to build a serial port multiplexer that allows up to 16 different servers to be controlled from one serial port. We needed to upgrade our servers to 8.0, and, of course, we wanted to use the serial port to do it rather than lug a monitor and keyboard over. […]

We knew the answer to this question once, back when the world was young and full of truth. Without hesitation, we’d have spouted “Just take the output of lsof | wc -l!” And it’s true enough, in a general sort of way. But if you asked me the same question now, my answer would be: […]

In this article I struggled with a Barracuda ST15150N drive that had problems with Tagged Command Queueing. Well, it is nice to have an install diskette that works with a serial console and works with the ST15150N. This article will guide you through the modification of a stock RedHat install boot disk. I will start […]

Red Hat’s maintenance policy is nasty. On the one hand, they need to make money, and maintaining distributions is expensive. On the other hand, for those of us who use Red Hat in budget environments, we can’t really afford their advanced server product, and can’t afford to change to a new version every year. One […]

We all have fat fingers sometimes and mistype commands, often transposing letters in a word or leaving letters out. When using Bash, you can fix it with the magic carets instead of retyping the whole command. example: [root@pippi opt]# usradd -u 666 -g 100 udergahad bash: usradd: command not found Oops, it should be “useradd”. […]

Check out Bruce Perens’ analysis here, and ESR’s An Open Letter to Darl McBride.

Samba 3.0 allows Linux to authenticate against Active Directory and access shared resources on a Windows 2000 server. Samba 3.0 is still beta. For info on the status, see the status page at samba.org. This article will detail the procedure to get this running with Red Hat 8.0. First, get the Samba distribution from samba.org. […]

It has been awhile since we powered up the Sparc64 box we loaded Gentoo on in this article. Well, links was not on the box, and we wanted it. Emerge failed: srv-44 scsi # emerge links . . . !!! Couldn’t download links-2.1_pre2-patch.tar.bz2. Aborting. Doh! We have to emerge portage and sync it: srv-44 scsi […]

Buoys and gulls, I’d like to introduce the lsof command. Say that you were moving a whole bunch of files, and there was no indication of what file was currently being moved? lsof shows (lists) open files. For instance, if you were moving a bunch of files from directory sales, you could see exactly what […]

We ran across an interesting problem when using our trusty loadlin boot diskette to boot one of our machines when we had a grub freakout: Uncompressing Linux… ran out of input data — System halted_ It turns out that this happens when the kernel is over 1 meg. There are a couple of options. There […]

The System V init scripts are a bear to configure by hand. We discussed using chkconfig in this article. Ksysv, part of KDE, provides an easy to use GUI interface. Just drag the services to the appropriate place. The priority number, K/S prefix, and symlinks will all be set up automatically. Backup up all of […]

I was reading Wired last night, and there was an interesting article about Torvalds. You can read the article here. There was a blurb in it about the Stallman GNU/Linux debate that bothered me. Stallman is a crank in the finest sense. This means that when he says something, it is usually true, you just […]

It is a good idea to test this and upgrade to it if you are running a 2.4 kernel. There have been some problems with virtual memory with some of the 2.4 releases. There was also a nasty bug with symlinks w/ 2.4.11. Get it from: Kernel.org Mirrors. Seems to work fine for us. We […]

Minicom is a simple terminal program. We use it to access our servers via our serial port mux. Most likely your GNU/Linux distribution has Minicom as an available package. If not, or you would rather compile yourself, grab minicom from here. Unpack the sources in your favorite spot and compile: # cd mini* [minicom-2.00.0]# ./configure […]

We have a Sony Cyber-shot model DSC-U20 camera. We had to add USB filesystem support and generic SCSI support to our kernel, but besides that, using the camera with GNU/Linux was quite easy. After your kernel is happy, just plug in your USB device and run dmesg: root@srv-1 u-1 # dmesg . . . hub.c: […]

There are two main bootloaders you can use with Linux these days: LILO and GRUB. Red Hat uses GRUB by default now. Most distributions used LILO until quite recently. We built a fairly souped up Linux workstation w/ a large Maxtor IDE drive. We decided to use Sorcerer GNU/Linux; however, we had a horrid time […]