Volker Diels-Grabsch

Hi, I'm Volker Diels-Grabsch. I'm not just hacking around, but strive to create things with sustainable value.

Contact: v@njh.eu with PGP key 0xA29FBD515F8990AF

Find me at: GitLab, GitHub, Bitbucket, SourceForge, PyPI, StackOverflow

Articles Contests Fun Games Math Presentations Software Uni All

txt2pnm (extern)

by Volker Diels-Grabsch

Convert text to PNM.

Created 2023-12-01, Last updated 2023-12-01
Software

Bscp (extern)

by Volker Diels-Grabsch

Secure and efficient copying of block devices.

Created 2012-05-28, Last updated 2023-01-31
Software

Mathematische Spielereien

by Volker Diels-Grabsch

Material zu meiner Vortragsreihe „Mathematische Spielereien“.

Created 2006-04-28, Last updated 2022-08-04
Fun, Math, Presentations

OpenSSH: ssh_config equivalents of -N, -s, -n and -f

by Volker Diels-Grabsch

My contribution to the OpenSSH project.

Created 2016-08-29, Last updated 2021-08-20
Software

Means produced by distances

by Volker Diels-Grabsch, Mowaffaq Hajja and Panagiotis T. Krasopoulos

We describe a methodology that can be used to construct new distances which produce many famous means. Its main application is to construct a distance for the logarithmic mean, settling an old open problem. We also use it to construct alternative distances for already known means, such as the arithmetic and all quasi-arithmetic means. Moreover, we show how to construct distances for almost all means that can be obtained from Cauchy's Mean Value Theorem, and apply this to construct distances for all Stolarsky means. Finally, we show how to construct a distance for a mean Mq(a,b)=q-1(M(q(a), q(b))), where M is another mean for which a distance is already known, and q is a monotone bijection to a subinterval.

Created 2021-04-30, Last updated 2021-04-30
Articles, Math

Der IOCCC: Wie man mit schlechtem Code gewinnt (extern)

by Volker Diels-Grabsch

Vortrag im Datengarten 106 zur Vorstellung des International Obfuscated C Code Contest und Sezierung eines meiner Gewinner-Programme: Ankündigung, Folien (Folien-Quelltext), Video-Aufzeichnung.

Created 2020-01-14, Last updated 2020-01-14
Fun, Contests, Presentations

Domino-Chain (extern)

by Andreas Röver, Volker Diels-Grabsch, Roberto Lorenz and Harald Radke

Rearrange dominoes on different platforms to start a chain reaction.

Created 2008-11-15, Last updated 2019-12-29
Fun, Games, Software

Foxda (extern)

by Volker Diels-Grabsch

Foxda is a very old program that I created in 2001. Despite its age, it is still actively used and has been receiving a steady stream of small improvements over the years and decades.

Created 2001-06-16, Last updated 2019-10-06
Software

Ait – Android installation tool (extern)

by Volker Diels-Grabsch

Automate the installation of LineageOS as much as possible.

Created 2019-10-03, Last updated 2019-10-03
Software

Two winning entries at IOCCC 2019 (extern)

by Volker Diels-Grabsch

My two winning entries at the 26th International Obfuscated C Code Contest (IOCCC) 2019 in the categories "Best small program" and "Most self-aware". Announcements on twitter: Best small program, Most self-aware, Summary.

Created 2019-05-12, Last updated 2019-05-12
Contests, Fun, Software

Ganzzahlige Krähenfüße

by Volker Diels-Grabsch

Artikel für die Wurzel-Zeitschrift zur Klärung einiger Fragen, die Armin Singer in seinem Wurzel-Artikel „Höherdimensionale Krähenfüße“ aufwarf.

Created 2018-01-06, Last updated 2018-06-29
Articles, Math

LineageOS on Samsung Galaxy S II

by Volker Diels-Grabsch

How to install LineageOS on a Samsung Galaxy S II (GT-I9100, i9100).

Created 2018-02-09, Last updated 2018-02-15
Articles

Compile your own GPG

by Volker Diels-Grabsch

How to compile your own GPG locally.

Created 2017-09-13, Last updated 2017-09-13
Articles

Texcaller (extern)

by Volker Diels-Grabsch

Texcaller is a convenient interface to the TeX command line tools that handles all kinds of errors without much fuzz. It is written in plain C, is fairly portable, and has no external dependencies besides TeX.

Created 2010-12-28, Last updated 2017-08-30
Software

Surgical Team (extern)

by Volker Diels-Grabsch

What happened to the “Surgical Team” pattern from “The Mythical Man-Month”?

Created 2017-08-06, Last updated 2017-08-06
Articles

Private Keyserver on Debian

by Volker Diels-Grabsch

How to setup a private PGP/GPG keyserver on Debian.

Created 2014-01-27, Last updated 2017-07-05
Articles

Fingerprint (extern)

by Volker Diels-Grabsch

Print your GPG key fingerprint with LaTeX, and be better prepared for the next key signing party!

Created 2013-05-15, Last updated 2017-02-24
Software

Self-signed server certificate (extern)

by Volker Diels-Grabsch

How to create a self-signed server certificate for SSL/TLS with OpenSSL.

Created 2016-12-28, Last updated 2016-12-28
Articles

Handle GET and POST requests differently in Nginx (extern)

by Volker Diels-Grabsch

How to configure Nginx to use a different upstream depending on whether the request method is GET or POST.

Created 2016-12-28, Last updated 2016-12-28
Articles

Staticjoomla (extern)

by Volker Diels-Grabsch

Protect against Joomla security flaws by not running Joomla in public.

Created 2016-04-26, Last updated 2016-04-26
Software

Parallel reversal schedules

by Volker Diels-Grabsch

Diploma thesis in mathematics at the Humboldt University of Berlin:

Parallel reversal schedules using more checkpoints than processors

Created 2015-09-24, Last updated 2015-09-24
Articles, Math, Uni

SHA-1 implementation in C++ (extern)

by Steve Reid, Bruce Guenter and Volker Diels-Grabsch

SHA-1 implementation in C++ that is 100% Public Domain.

Created 2006-09-20, Last updated 2015-04-24
Software

Intel Wireless-N 7265

by Volker Diels-Grabsch

Solving connection issues with Intel Wireless-N 7265 under GNU/Linux.

Created 2015-02-23, Last updated 2015-02-23
Articles

Die Parabel von den zwei Programmierern

by Volker Diels-Grabsch

German translation of Neil W. Rickert's "The Parable of the Two Programmers" from 1985

Created 2008-11-26, Last updated 2015-02-18
Articles

Besondere Nutzung Luftraum

by Volker Diels-Grabsch

Diplomarbeit im Fachbereich Informatik der Humboldt-Universität zu Berlin:

Erarbeitung und Evaluierung von möglichen Lösungsarchitekturen für das System „Besondere Nutzung Luftraum“

Created 2014-06-11, Last updated 2014-06-11
Articles, Uni

Printer Drivers

by Volker Diels-Grabsch

Drivers for CUPS to get some printers working under GNU/Linux. These are PPD files as well as direct contributions to foomatic-db.

Created 2007-01-04, Last updated 2014-05-05
Software

Virtuelle Maschinen und IPv6 (extern)

by Volker Diels-Grabsch

Sehr einfache IPv6-fähige Netzwerkkonfiguration für virtuelle Maschinen (via KVM) in einem Linux-Host.

Created 2014-03-08, Last updated 2014-03-08
Articles

Mcpdf (extern)

by Volker Diels-Grabsch

Mcpdf fixes PDFtk's unicode issues, so you can write Łódź into your forms. It implements a small subset of PDFtk for which it implements compatible command line interface, so it can be used as a drop-in replacement for this subset of commands.

Created 2014-02-14, Last updated 2014-02-19
Software

drone-asciiview (extern)

by Volker Diels-Grabsch and Johann Philipp Strathausen

Live view of a drone camera in ASCII.

This was our competition entry at the NodeCopter birthday bash 2013.

Created 2013-09-13, Last updated 2013-09-13
Contests, Software

Bang Bang (extern)

by Shadab Ahmed, Robin Houston and Volker Diels-Grabsch

New sequence discovered: Number of bangbangs (!!) in shell substitution when starting with : '!!' and : "!!" '!!'.

This beautiful integer sequence was discovered by Shadab Ahmed and analyzed by Robin Houston. I registered it as A228162 in the OEIS.

Created 2013-08-16, Last updated 2013-08-17
Fun, Math

wwan-helper (extern)

by Volker Diels-Grabsch

wwan-helper is a script that establishes a UMTS connection using a Ericsson F3507g Mobile Broadband Module. It was designed to be used with a ThinkPad T420s. It takes care of resetting and reinitializing the modem if the hardware fails to get a WWAN connection, and retries as often as necessary until the UMTS connection is really established. It is meant to run as a hook script for the ifup / ifdown mechanism, but should also work on other networking systems.

Created 2013-07-11, Last updated 2013-07-11
Software

Kvmhosting (extern)

by Volker Diels-Grabsch

Script to manage KVM-based hosting, powered entirely by XSLT

Created 2012-11-21, Last updated 2013-06-05
Software

Bitcoinproof (extern)

by Volker Diels-Grabsch

Bitcoinproof creates a forgery-proof timestamp for your data, secured by the Bitcoin network. It allows you to prove that a certain event happened before a certain point in time. Maybe you want to prove that the damage in your flat already existed when you moved in, or that you were in possession of a great artwork before it was published, proving you are the author.

Created 2013-03-30, Last updated 2013-03-28
Software

Shasplit (extern)

by Volker Diels-Grabsch

Efficient backups by SHA-based data splitting: Shasplit takes a large data block, splits it into smaller parts, and puts those into an SHA-based content-addressed store. Reassembling those parts is a trivial "cat" invocation. Repeating parts (e.g. from previous split operations) are stored only once, which allows for efficient incremental backups of whole LVM snapshots via Rsync. Shasplit shows its strengths on encrypted block devices, but might be useful for non-encrypted data, too.

Created 2012-10-27, Last updated 2013-01-24
Software

Scs (extern)

by Volker Diels-Grabsch

Simple content-addressed store. This project is outdated, please have a look at Shasplit.

Created 2012-05-31, Last updated 2012-10-27
Software

How to contribute to OpenPrinting (extern)

by Volker Diels-Grabsch

How to contribute to OpenPrinting.

Created 2012-10-20, Last updated 2012-10-20
Articles

Redirect Savannah project (extern)

by Volker Diels-Grabsch

How to redirect the website of a Savannah project.

Created 2012-04-04, Last updated 2012-09-05
Articles

ASTERIX Parser (extern)

by Volker Diels-Grabsch

Draft of a parser for ASTERIX binary data such as CAT062, written in Python

Created 2012-06-19, Last updated 2012-06-20
Software

MXE (M cross environment) (extern)

by Volker Diels-Grabsch and many others

MXE (M cross environment) is a Makefile that compiles a cross compiler and cross compiles many free libraries such as SDL and Qt. Thus, it provides a nice cross compiling environment for various target platforms.

Created 2007-06-12, Last updated 2012-04-12
Software

Python vserver (extern)

by Volker Diels-Grabsch

Python interface to Linux-VServer for managing hosting systems.

Created 2009-09-15, Last updated 2012-03-22
Software

Nachtrag: Juniper-VPN unter Debian (extern)

by Volker Diels-Grabsch

Nachtrag: Juniper-VPN mit IcedTea-Web + OpenJDK unter Debian.

Created 2012-03-19, Last updated 2012-03-19
Articles

Binom Bijection

by Volker Diels-Grabsch

Storing k-Subsets Efficiently.

Created 2009-09-07, Last updated 2012-02-22
Articles, Math, Presentations, Software

Autoreload Bookmarklet (extern)

by Volker Diels-Grabsch

This bookmarklet reloads a website over and over again. It is written in the style of self-contained literate programming.

Created 2012-02-11, Last updated 2012-02-15
Software

Vim, Watch, Wmii

by Volker Diels-Grabsch

This is the summary of a short, unprepared talk I gave on 2012-01-17 at the Berlin PHP UserGroup. In that meeting, everyone was invited to present their favourite editor or IDE. So I demonstrated my current way of doing things.

Created 2012-01-17, Last updated 2012-01-17
Articles

Python tex (extern)

by Volker Diels-Grabsch

Convert LaTeX or TeX source to PDF or DVI, and escape strings for LaTeX.

Created 2009-08-21, Last updated 2012-01-06
Software

Juniper-VPN unter Debian (extern)

by Volker Diels-Grabsch

Juniper-VPN mit IcedTea-Web + OpenJDK unter Debian.

Created 2011-12-24, Last updated 2011-12-24
Articles

Java-Browser-Plugin unter Debian (extern)

by Volker Diels-Grabsch

Ich habe gerade sehr viel Zeit mit dem Einrichten von Java in meinem Browser verschwendet. Ich hoffe, mit diesem Posting andere davon abzuhalten, die gleichen Irrwege zu gehen.

Created 2011-12-23, Last updated 2011-12-23
Articles

beautify_git_hash (extern)

by Volker Diels-Grabsch

Beautify the Git commit hash! This is a little useless toy inspired by BitCoin's "proof of work" concept. It enables you to modify your Git commit to enforce a certain prefix on the Git commit hash.

Created 2011-10-01, Last updated 2011-11-14
Fun, Software

History of Everything / Geschichte von Allem

by Volker Diels-Grabsch

A bilingual short story, licensed under CC BY-SA 3.0.

Eine zweisprachige Kurzgeschichte, lizensiert unter CC BY-SA 3.0.

Created 2003-01-01, Last updated 2011-07-28
Articles, Fun

Volkers Sammlung von Standard-Floskeln (vssf)

by Volker Diels-Grabsch

Sammlung von Standard-Floskel-Sammlungen, inspiriert durch Dieter Brügmann.

Created 2011-04-03, Last updated 2011-07-27
Articles, Fun

DC-Rap

by Volker Diels-Grabsch

Technischer Import von medizinischen Bilddaten

Created 2007-11-09, Last updated 2011-05-05
Presentations

Abschaffung von Anglizismen im Berliner ÖPNV

by Volker Diels-Grabsch, Hauke Reddmann and Jochen Walerka

Der Verein zur aktiven Bekämpfung von Anglizismen – Lokalzirkel Berlin (VzaBvA-LB) fordert die Abschaffung von Anglizismen im Berliner öffentlichen Personennahverkehr.

Created 2008-08-04, Last updated 2011-04-03
Articles, Fun

ImageUpload (extern)

by Volker Diels-Grabsch

Small Qt program to upload images directly from the clipboard to a website. Its main purpose is uploading (possibly edited) screenshots to a documentation wiki.

Created 2010-12-15, Last updated 2010-12-21
Software

OCamlSDL Tutorial (extern)

by Volker Diels-Grabsch, Frank Prößdorf and an anonymous contributor

Getting started with SDL and Objective Caml

Created 2010-05-10, Last updated 2010-05-10
Articles

Schreiben – kurz gefasst

by Volker Diels-Grabsch, Tobias Florek and Berit Grußien

German translation of Paul Graham's "Writing, Briefly"

Created 2006-07-17, Last updated 2010-05-10
Articles

Freie Software veröffentlichen

by Volker Diels-Grabsch

Folien zum Vortrag „Freie Software veröffentlichen“.

Created 2009-11-21, Last updated 2009-12-08
Presentations

ELMA (Exim Ldap Mail Administrator) (extern)

by Sven Ludwig, Daniel Weuthen, Ruben Püttmann, Rudolph Bott, Volker Diels-Grabsch and Sven Lankes

The Exim Ldap Mail Administrator provides a comprehensive frontend to manage single server up to multiple server email sites.

Created 2007-03-28, Last updated 2009-11-19
Software

Firewall zu Hause

by Volker Diels-Grabsch

Anleitung zum Erstellen eines einfachen Firewall-Scripts "für den Hausgebrauch" mit iptables

Created 2006-03-23, Last updated 2009-01-24
Articles

tvscreen (extern)

by Volker Diels-Grabsch

Simple 64b intro that displays a TV screen. (tvscreen.zip)

Created 2009-01-02, Last updated 2009-01-02
Fun, Software

Self-contained Literate Programming

by Volker Diels-Grabsch

Demonstration of the technique of self-contained literate programming.

Created 2007-02-10, Last updated 2009-01-02
Articles, Software

ASCIImation (extern)

by Volker Diels-Grabsch and Carolin Grabsch

Animated ASCII art

Created 2008-09-05, Last updated 2008-12-16
Fun, Software

any2deb (extern)

by Volker Diels-Grabsch

Collection of shell scripts to create simple Debian packages.

Created 2006-03-07, Last updated 2008-12-14
Software

GnuWin32 Debian packages

by Volker Diels-Grabsch

Repository of Debian cross compiling packages based on GnuWin32. This repository has been superseded by the MXE project.

Created 2006-03-21, Last updated 2008-12-13
Software

How to write a self reproducing code (quine) (extern)

by Volker Diels-Grabsch

Answer to the StackOverflow question: "How to write a self reproducing code?"

Created 2008-09-20, Last updated 2008-10-01
Articles, Fun

VoPU – Volker's Python Utilities (extern)

by Volker Diels-Grabsch

This module contains various functions and classes which are very useful for my daily work with Python.

Created 2006-05-28, Last updated 2008-08-31
Software

Gedanken retten (extern)

by Volker Diels-Grabsch
Newsgroup: de.etc.schreiben.prosa
Message-ID: <g743o0$7hs$03$1@news.t-online.com>
Created 2008-08-03, Last updated 2008-08-03
Articles

Die Kunst, vor dem Schreiben nachzudenken (extern)

by Volker Diels-Grabsch
Newsgroup: de.soc.usenet
Message-ID: <g6pja7$f2f$02$1@news.t-online.com>
Created 2008-07-30, Last updated 2008-07-30
Articles

Risikomanagement

by Michael Berger, Volker Diels-Grabsch and Björn Schümann

Seminarvortrag an der Humboldt-Universität zu Berlin im Informatik-Seminar „Projektmanagement“.

Created 2008-06-27, Last updated 2008-06-27
Articles, Presentations, Uni

Recht für Software-Entwickler

by Volker Diels-Grabsch and Anne Pilchowski

Seminarvortrag an der Humboldt-Universität zu Berlin im Informatik-Seminar „Dimensionen der Softwareentwicklung“.

Created 2008-06-12, Last updated 2008-06-12
Articles, Presentations, Uni

Amdahlsches und Gustafsonsches Gesetz

by Volker Diels-Grabsch and Yves Radunz

Seminarvortrag an der Humboldt-Universität zu Berlin im Informatik-Seminar „Parallelisierung“.

Created 2008-05-26, Last updated 2008-05-26
Articles, Presentations, Uni

Einführung in IPv6 (extern)

by Frank Prößdorf and Volker Diels-Grabsch

Dieser Artikel ist eine Einführung in IPv6, das Internet Protokoll der nächsten Generation.

Created 2006-09-29, Last updated 2008-04-07
Articles

Minoren

by Volker Diels-Grabsch

Seminarvortrag an der Humboldt-Universität zu Berlin im Informatik-Seminar „Matroidtheorie“.

Created 2008-03-03, Last updated 2008-03-03
Articles, Uni

Make-crontab (extern)

by Volker Diels-Grabsch and Matthias Pohl

Manage different cronjobs with only one system user.

Created 2006-03-09, Last updated 2008-02-20
Software

Netzwerksimulation

by Volker Diels-Grabsch and Martin Schröder

Projektarbeit im Rahmen der Informatik-Vorlesung „Grundlagen der Rechnerkommunikation“ an der Humboldt-Universität zu Berlin.

Created 2008-02-18, Last updated 2008-02-18
Articles, Uni

XML, XPath, XQuery

by Volker Diels-Grabsch and Christine Janischek

Vortragsfolien im Rahmen der Informatik-Vorlesung „XML, XPath, XQuery“ an der Humboldt-Universität zu Berlin.

Created 2007-11-10, Last updated 2008-02-04
Articles, Uni

Lösung des 90-Zahlen-Problems

by Volker Diels-Grabsch

Lösung eines interessanten Problems, das an der Freien Universität Berlin gestellt wurde.

Created 2007-11-22, Last updated 2008-01-11
Contests, Math, Software

HTTP Proxy via INETD and Netcat

by Volker Diels-Grabsch

How to create a small, primive HTTP Proxy using just INETD and Netcat

Created 2007-11-21, Last updated 2007-11-21
Articles

Debian versions of qmail patches (extern)

by Volker Diels-Grabsch

Debian provides the qmail-1.03 source with some patches already applied. Thus, some other patches won't work. This site provides slightly modified versions of some popular patches that work with Debian's qmail sources.

Created 2007-03-02, Last updated 2007-03-02
Software

Projektarbeit Künstliche Intelligenz

by Volker Diels-Grabsch, Berit Grußien and Mario Krell

Projektarbeit im Rahmen der Informatik-Vorlesung „Künstliche Intelligenz“ an der Humboldt-Universität zu Berlin.

Created 2006-12-13, Last updated 2007-02-05
Articles, Uni

Einführung in Freie Softwaresysteme (extern)

by Manuel Blechschmidt and Volker Diels-Grabsch

Einführungs-Kurs in das Thema „Freie Software“ auf der CdE Sommerakademie 2006 in Kirchheim.

Created 2006-08-05, Last updated 2006-08-13
Presentations

LED-Anzeige

by Volker Diels-Grabsch, Berit Grußien and Mario Krell

Projektarbeit im Rahmen der Informatik-Vorlesung „Technische Informatik 2“ an der Humboldt-Universität zu Berlin.

Created 2006-07-05, Last updated 2006-07-05
Articles, Uni

SatNet-VY

by Yves Radunz and Volker Diels-Grabsch

3D-Simulation von Satelliten-Netzen im Rahmen des informatiCup 2005.

Created 2005-12-20, Last updated 2005-12-20
Contests, Software

Praktikums-Semesterarbeit Numerik

by Volker Diels-Grabsch and Mario Krell

Praktikums-Semesterarbeit zur Mathematik-Vorlesung „Numerik“ an der Humboldt-Universität zu Berlin.

Created 2005-07-24, Last updated 2005-07-24
Articles, Uni

Scoresheet for Kniffel / Yahtzee (extern)

by Volker Diels-Grabsch

This is a simple scoresheet for the game Kniffel which is also known as Yahtzee. The scoresheet has been created with LaTeX.

Created 2005-04-19, Last updated 2005-04-19
Games

mc4_sim

by Volker Diels-Grabsch

Simulator & Programm-Generator für den „MC4“ Microcomputer.

Created 2005-01-30, Last updated 2005-02-06
Software, Uni

Raucherverhalten von 16- bis 21jährigen

by Marie-Denise Huber and Volker Diels-Grabsch

Jugend forscht-Projekt über das Raucherverhalten von 16- bis 21jährigen.

Created 2004-11-18, Last updated 2004-11-18
Articles, Contests

VoJI (Volker's Java Improvements) (extern)

by Volker Diels-Grabsch

Would you like to have some facilities for database applications? Or are you looking for a stable log system? I want to offer you many features you probably miss in Sun's Java API.

Created 2001-01-07, Last updated 2003-09-21
Software

DAVIS (Dj's and Volker's IRC-Script) (extern)

by Volker Diels-Grabsch and Frank Prößdorf

DAVIS is an easy and useful language for IRC bots. It contains our own bots, some bots for demonstration, a parser that creates Java, C, Perl and IRC-Script code out of a DAVIS file, and an interpreter for DAVIS files.

In 2003 we entered the "Jugend forscht" (youth does research) contest with DAVIS as our project.

Created 2001-09-11, Last updated 2003-04-06
Contests, Software

Hosh (The Honk Shell) (extern)

by Volker Diels-Grabsch

Hosh is a shell for fun. There are commands like "make world" as well as "configure" which checks the whole machine – even the power status and the coffee temperature.

Created 2002-02-24, Last updated 2002-07-02
Fun, Games, Software

Murpi – Murphystic Pictures (extern)

by Volker Diels-Grabsch

It is possible to hang up a picture on two nails such that it falls down if only one of the two nails breaks. Since this is some kind of optimization of Murphy's law, I call such an arrangement "murphystic". This can be generalized to any number of nails and is a popular funny exercise on the theory of fundamental groups.

Murpi is a program that generates such arrangements and visializes them as PostScript files.

Created 2002-05-01, Last updated 2002-05-26
Fun, Math, Software

VoLT (Volker's LPC Tool) (extern)

by Volker Diels-Grabsch

VoLT is a nice tool for those who want to create MUDs with LPC. It makes it easy to create and edit rooms and worlds.

Created 2001-04-11, Last updated 2001-07-11
Games, Software