CHOST: i586 vs. i486 on AMD Geode LX

On my blog post about Installing Gentoo on ALIX.3D3 Mart Raudsepp made an interesting comment: He pointed out, that on AMD Geode CPUs it might be better to use i486 CHOST instead of my used i586, because the CPU is more like a i486 as far as instruction scheduling and times go.

This sounded interesting, so I googled for some benchmark test to measure differences. I found nbench, which measures performance by executing some typical algorithms and compares them to a Pentium 90 based system. So I installed it and run on the i586 CHOST system, then rebuild it completely to i486 CHOST and run it again. Continue reading

Updating BIOS on ALIX.3D3 within Linux

Usually BIOS updating means booting DOS and running a proprietary tool from the board vendor. A few days ago, coreboot's flashrom 0.9 has realeased. It's an open-source tool which supports program almost all flash chips used on x86 mainboards. Its compatibility list includes Geode™ CS5530/A, which can be found on the ALIX.3D3 board. So why not using flashrom to update ALIX.3D3 BIOS.

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Ethernet bonding with Linux and 802.3ad

2 NIC + SwitchNowadays, most desktop mainboards provide more than one gigabit ethernet port. Connecting them both to the same switch causes most Linux distros by default to get a individual IP on each device and route traffic only on the primary device (based on device metric) or round-robin. A single connection always starts at one IP and so all traffic goes through one device, limiting maximum bandwidth to 1 GBit.

Here comes bonding (sometimes called (port) trunking or link aggregation) to play. It connects two ore more ethernet ports to one virtual port with only one MAC and so mostly one IP address. Wheres earlier only two hosts (with the same OS running) or two switches (from the same vendor) could be connected, nowadays there's a standard protocol which makes it easy: LACP which is part of IEEE 802.3ad. Continue reading

Installing Gentoo on ALIX.3D3

When I ordered the ALIX.3D3 board I thought installing Gentoo on this should be a piece of cake, but finally there were some stumbling blocks and that's why I want to summarize how I got gentoo running.

First of all, I recommend installing Gentoo on a normal desktop to get to know the installing process, which is a bit different from graphical installers of mainstream distros. The Gentoo Handbook is a great documentation how this done.

To install gentoo, you have to boot a minimal or "rescue" linux usually from cd/dvd. I tried to convice the bios to boot from a usb cd-rom drive, but I hadn't any success. Continue reading

commenting iptables rules

I often use iptables (or ip6tables, the IPv6 version of iptables) to implemented firewall rules on my linux systems.

In earlier times I used a commented bash script to setup the rules after booting, but using Gentoo nowadays there is a nice init script saving and restoring my tables. Using this I stopped commenting the firewall rules, but yesterday I found a very nice solution for this problem.

Iptables has a special "match" for comments. Continue reading