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Reviving my old blog from backups...

Spectrum Scale has support for end-to-end checksumming if you have an ESS, but not with non-ESS storage. As a poor man's checksumming, one can store file checksums in the extended attributes. Storing checksums here can be useful for validating if there has been bitrot at a later point, without leaving around .md5sum-files everywhere. Manually this can be done with the “mmchattr” command:

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These were the steps I needed to perform to run pi-hole in a podman container on Centos8/RHEL8:

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I had the unifi controller running under debian, but finally re-softet my machine to run Centos-8 instead. Before doing that I made a backup of the Unifi controller.

After installing Centos-8 I tried setting up and running the unifi container from https://github.com/jdoss/unifi simply by running:

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Together with Miguel Gomez Gonzalez and Ahmad Y Hussein, I did an IBM Redbooks residency in Poughkeepsie, New York, to write a book about High-Performance computing on the IBM AC922 platform. In the book we try to document and share some insights about how to implement CORAL style HPC clusters. Download it from http://www.redbooks.ibm.com/abstracts/sg248422.html

Starting with OpenSSH v3.9 there was a new feature that allowed one to run several sessions over the same ssh connection. The benefit of connection sharing is that only the first time you connect to a host you'll need to exchange keys, authenticate, negotiate encryption, etc. Skipping all this initial connection setup, makes any additional sessions to a host you've already connected to very quick.

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Here's a port of http://www.cs.umd.edu/users/harry/jotp/ to Java 2 Platform Micro Edition (J2ME), so that it can be used on mobile phones that supports Java. I made this so that I can securely connect to our ssh-server from insecure internet cafees, where people might be trying to sniff my passsword. The midlet supports md5-hashing, since that's what I'm using. Adding md4 should be trivial, if anybody needs it.

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How to calculate CPUTime of a function with Java

I've wanted to know the cputime used in java functions, but it turned out that this was a bit too low level for java. Therefore I had to create a JNI (Java Native Interface) function for it. The code for this example is at http://tanso.net/CPUtest.tar.gz , and here's how to do it:

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