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Svn to Git

November 23, 2023

SVN to GIT migration Steps to migrate a svn repository into a git repository Environment variables In order to ease the reuse of these explanations let't define some variables: : https://server:port/svn/subpath : a fresh initialized git repository…

List of FOSS

August 25, 2023

Greatest Free and Open Source Software Quite often people hear or use software that is free of charge (freeware). Here I want to present great software that is additionally Open Source. This additional requirement is important to me as I like to have…

Ubuntu LUKS Rescue

June 28, 2023

Ubuntu LUKS rescue I had a 18.04 system running LUKS for data security purposes. After a starting from bionic I landed in jammy. I had a bunch of ppas and some combination of after and left me in a seemingly disastrous situation. After a reboot…

Ubuntu Remote Upgrade

January 22, 2023

Ubuntu Remote Release Upgrade Introduction Running a remote release upgrade can be dangerous, VPN, SSH can be updated or break during the upgrade process and leave a not bootable system as a result... This post shows how to mitigate the risks. NOTE…

C# Exception handling

January 14, 2023

C# Exception Handling Can I ignore exceptions? No. Exceptions are thrown by the .NET framework in many places, FileNotFoundException, FormatException on conversions, ... A ThreadInterruptedException may occur at any time. On function calls you might…

Mini DV Rescue

December 29, 2022

Mini-DV Cassette How to perform mini DV Grabbing with minimal and quantifiable quality loss. Pitfall: The FireWire interface used to perform grabbing is checking for transfer errors only, not content errors inside the grabbed data. Therefore the…

Networking: DNS lookup

September 30, 2022

DNS APIs There is no single API call to perform the lookup. Options are: libc getaddrinfo libc gethostbyname (OBSOLETE SPEC) libc resolver library (Low level DNS retrieval) direct interfacing to the dns servers via network calls The applications that…


September 02, 2022

Software Design Patterns Taken from Wikipedia, personal adaptations and additions made, shortened to be used as a small reference card, links back to wikipedia kept for details. See also Software Anti-Patterns. Architectural patterns Choice: How is…

Database Joins

July 01, 2022

Joins (INNER) JOIN The INNER JOIN keyword selects all rows from both the tables as long as the condition satisfies. This keyword will create the result-set by combining all rows from both the tables where the condition satisfies i.e value of the…

ZFS on linux

February 20, 2022

ZFS on Linux Installation on ubuntu 20.04 LTS Introduction: https://linuxhint.com/zfs-concepts-and-tutorial/ There are different levels of operation pool level: bundles several virtual devices vdev level: allows to define which redundancy is applied…

Number theory

January 31, 2022

Number Theory Links: https://oeis.org/ Definition: Arithmetic Function Functions from the natural numbers to the complex numbers $${ f(n) = c \vert n \in \mathbb{N}, c \in \mathbb{C} }$$ Definition: Multiplicative Function An arithmetic function $f…

MySQL queries

December 25, 2021

MySQL Report table sizes Replace with appropriate value. Find columns Replace , with appropriate values. Performance IN vs EXISTS Change into See https://dev.mysql.com/doc/refman/8.0/en/subquery-optimization-with-exists.html


December 19, 2021

Nintendo Infos Account passwort ändern (Verlust/Defekt/Diebstahl) Unterschiede Hauptkonsole & nicht Hauptkonsole erklärt Transfer Spiele/Daten zwischen Konsolen Spielestand Speicherung Speicherdaten übertragen Nintendo-Account Ein Nintendo-Account…

Database Terms

September 20, 2021

Database terms Definitions / Rules Entity <--> Database Table Naming convention: singular, uppercase Instance of an entity <--> Database Row (or Tuple or Record) Attribute <--> Database Column (or Field). Naming convention: singular, lowercase…


September 16, 2021

DOORS DXL Tips Deactivation of (dangerous) the auto-declaration feature (put it for example in ) Documentation https://www.ibm.com/docs/en/ermd/9.7.2?topic=function-extending-doors-dxl https://www.ibm.com/docs/en/SSYQBZ_9.7.2/com.ibm.doors…


June 07, 2021

Docker Ubuntu 20.04 setup Install docker Install basic support tools: Configure to restart docker on boot: Install docker-compose Download docker compose and make it executable (here 1.29.2, change accordingly) Check versions Permissions Give…

Backup with Borg

May 27, 2021

Borg Introduction Borg is a client server system allowing to backup remotely to repositories Risk analysis Scenario: Backup server compromised Confidentiality of all client data in danger if no encryption is used. Client encryption is a must, could…

Git-Annex: Compile

April 17, 2021

Introduction Git-Annex can be used to synchronize bigger files across networks that might not be very reliable or fast. Building git annex 64 bit version under windows Prerequisites cygwin 64 bit: gcc rsync git wget ssh gnupg git for windows 64bit…

Synology backup

December 20, 2020

Backup script Backup via shell Skript vom host zur NAS. Daten - Backup Wenn die Synology an ist, kann auf dem Backup (Nur Lesend) an diesem zugegriffen werden: \SYNDEHAAN\NetBackup Die Anmeldung erfolg mit dem mitgeteilten Benutzerkonto. Die Daten…


October 30, 2020

LG TV 2020 Einstellungen fürs TV Anschlüsse: Bild bei https://app.diagrams.net/ erstellt CEC Steuert das automatischen ein und ausschalten wenn man einen anderen Gerät ein oder ausshaltet. Overscan Sorgt dafür dass nichts von den Quelldaten…

GIMP shortcuts

October 10, 2020

GIMP Gimp toolbox They are customizable in the Edit -> Keyboard Shortcuts menu The default shortcuts are presented here (From version 2.6) NR Key Name Type Default Ctrl Shift Alt 01 Rectangular selection Selection Rectangle Center Square 0…

C# equality vs identity

October 05, 2020

C# Equality vs Identity Reference Microsoft: Guidelines for Overriding Equals() and Operator == Pay attention Equality means the objects have the same value, but are not necessarily the same instance Identity means the objects point to the one and…

vdi management

September 26, 2020

Introduction files are VirtualBox native virtual drive containers. These can have a fixed size or be dynamic, consuming as much space as is needed. "Hardware virtualization" deals with how to convert a real partition into a container for use within…

PC Build 2020

September 01, 2020

PC Build 2020 Requirements reduce noise (priority 1) reduce power (priority 2) optimized in processing videos code compilation Thoughts Opted for an air cooled 3950X against a water cooled system because of some doubts regarding maintenance and…

Risk analyis: data loss

July 24, 2020

Risk analysis: data loss Personal risk analysis and planned countermeasures. Initially I thought it would be a good idea to buy an ECC RAM enabled hardware but this looks like an adventure with consumer hardware. Reliable server component being both…

Radeon 4670 support

May 18, 2020

Radeon 4670 support Problem is a blank screen during and after startup. The BIOS boot logo can be seen correctly. Official Hardware Support ends But the open source driver is available (with some missing features) https://wiki.archlinux.org/index.php…


May 05, 2020

DIY NAS Requirements support 8 SATA disks support ECC reduce noise (prio 1) reduce power (prio 2) Components Component Price Size(s) Description Mainboard ~300€ uATX SUPERMICRO X10SRM-F Server Motherboard R3 (LGA 2011) Intel C612 Mainboard ~400€ ATX…

Backup solutions

April 30, 2020

Backup solutions Must haves chunk based deduplication) (not only file based) client / server (transfer to remote backup server) web viewer consistency check easy restoration (ro mountable) scriptable and customizable runs on Windows & Linux Nice to…

Backup with Bup

April 30, 2020

Backup with Duplicati

April 30, 2020

Backup with Restic

April 30, 2020

Ubuntu Tweaks

April 27, 2020

Ubuntu Tweaks BtrFS maintenance balance tree: weekly scrub: BtrFS snapshot settings https://wiki.archlinux.org/index.php/snapper is managing the snapshots there are a couple of systemd services to trigger snapshots Disable snapshot on boot: Edit to…

Windows Tweaks

April 20, 2020

Password in domain Password expiration info Renew password With NET USER Using powershell https://docs.microsoft.com/en-us/powershell/module/addsadministration/set-adaccountpassword?view=win10-ps Using smbpasswd (from ) Fix trust relationship…

Rsync Flags

April 08, 2020

Rsync Source https://stackoverflow.com/questions/4493525/what-does-f-mean-in-rsync-logs Options Often used flags during my sync jobs: Rsync flags Primer on the bit flags and how to get to output bit flags for all actions (it does not do this by…

Useful Bash Commands

March 22, 2020

Keyboard/Terminal Search in history: Restore lost echo: List logged in users Storage List block devices Network Scans arp, nmap, tcpdump Routing Manipulate routing table to route only a segment through a ppp0 tunnel and default to a route through…

Doomsday rule

March 17, 2020

Doomsday rule It takes advantage of each year having a certain day of the week, called the doomsday, upon which certain easy-to-remember dates fall; for example, 4/4, 6/6, 8/8, 10/10, 12/12, and the last day of February all occur on the same day of…


March 13, 2020

Integrals $a$, $b$, $c$, $\alpha$, $\beta$ are constants $f$, $g$, $u$ are functions of a variable $x$ Basic properties Properties $$ \int _a ^a f(x)dx = 0 $$ $$ \int _b ^a f(x)dx = - \int _a ^b f(x)dx $$ Chasles' theorem: $$ \int _a ^b f(x)dx + \int…


March 13, 2020

Trigonometry Relations $$\cos^2(a) + \sin^2(a) = 1$$ $$1 + \tan^2(a) = \frac{1}{\cos^2(a)}$$ Addition $$\cos(a+b) = \cos(a)\cos(b) - \sin(a)\sin(b)$$ $$\cos(a-b) = \cos(a)\cos(b) + \sin(a)\sin(b)$$ $$\sin(a+b) = \sin(a)\cos(b) + \cos(a)\sin(b…

CD Paranoia

March 13, 2020

CD Paranoia Bargraph Used to indicate things during read. The letters are hierarchical; for example if a transport error occurs in the same sector as jitter, the bargraph will print instead of . Character Meaning Two blocks overlapped properly, but…


March 12, 2020

Derivatives Definition $$f'(x)= \lim_{h \to 0} \frac{f(x+h) - f(x)}{h}$$ Formula $c$ is a constant $f$, $g$ are functions of a variable $x$ Basic properties Linearity $$(cf+g)'=cf'+g'$$ Product $$(f.g)'=f'.g + g'.f$$ Inverse (Quotient with $f=…

Test React

March 10, 2020

Test Test inlining a react component inside markdown. This component uses the hook. Embedded Counter component Source


March 09, 2020

Software Anti-Patterns Taken from Wikipedia, personal adaptations and additions made, shortened to be used as a small reference card, links back to wikipedia kept for details. See also Software Design Patterns. Organizational anti-patterns Detect…

Quotes (Finance)

March 08, 2020

Finance quotes NOTE (1): often and wrongly attributed to a private communication from a Rothschild investment house in London to an associate banking firm in New York dated June 25, 1863 NOTE (2): as quoted in Money and Class in America (1988) by…

Quotes (Computer)

March 08, 2020

Computer Quotes

Ubuntu Data Rescue

March 01, 2020

Ubuntu data rescue example 1: System does not boot anymore after an OS upgrade (kernel panic). Data is on a LVM. example 2: System does not boot anymore (HDD errors). Data is on an ext3 partition. Example 1 System does not boot anymore after an OS…

C# String formatting

February 27, 2020

C# String formatting Formatting is bound to a type, so depending on which type of object you pass to String.Format, you have different format specifiers. The index specifies the position of the parameter that shall be used for that format specifier…

C# Extending classes

February 11, 2020

Possible ways to extend a class Meaning providing additional methods to a class Extension methods "Extension methods enable you to "add" methods to existing types without creating a new derived type, recompiling, or otherwise modifying the original…

Programming Terms

February 02, 2020

Programming terms I often had trouble reading complicated explanations about some terms and the list here tries to make a definition that can be understood by normal human beings without theoretical mathematics and other higher level skills. Letter…


January 26, 2020

C# and performance of string building Introduction Strings are immutable in C#. That means that a string never gets modified by any operation. This implies that, when you call Replace for example the operation is never done in-place. Instead a new…


January 21, 2020

Perl programming language perl: Practical Extraction and Report Language Regular expressions are meta-characters (must be escaped) regexps consume as much input as possible (greedy by default) matches word boundary means not a word boundary start…

Haskell: category theory

January 07, 2020

Category Theory & Haskell programming language https://www.seas.upenn.edu/~cis194/spring15/lectures.html https://wiki.haskell.org/Learning_Haskell http://yogsototh.github.io/Category-Theory-Presentation https://bartoszmilewski.com/2014/10/28/category…

Chrome special pages

December 31, 2019

Chrome special pages The links were tested with google chrome version 42.0.2311.90 About pages for chrome page description Lists some of the about pages Shows up a blank page Lists all loaded dlls and their version information Terms of service…

Svn to Git

December 28, 2019

Backing up subversion repositories Introduction The source code is - as the name already tells - the real valuable data for software development. Therefore a proper backup of this important data is absolutely required. Backups shall provide…

BPMN plugin dokuwiki

December 24, 2019

BPMN IO plugin for Dokuwiki See https://www.dokuwiki.org/plugin:bpmnio Example

C# Detect if a process needs user input

December 21, 2019

C# Detect application wants user input Problem description Some time ago,I asked a question on stackoverflow.com. How to programmatically (C#) determine, if ANOTHER external application (native, java, .NET or whatever...) is currently demanding user…

Linux Containers

December 10, 2019

LXC - Linux containers Wikipedia: LXC LXC tutorial step by step LXC Overview Exploring LXC networking Getting started LXCs System containers to isolate servives LAMP in an LXC Ubuntu setup Install basic support tools: Check the configuration: List…

Set Top Box

May 15, 2019

Set Top Box GBUE 4K Hardware Important Features: GigaBlue UHD UE 4K 1x Full Band Capture DVB-C NIM 3128 FBC (8 tuner) 1x OUT Loop through Broadcom 7252s RAM 2GB DDR4 FLASH 4GB MMC 1x HDMI out 1 GB LAN Front: 1x USB 2.0 Rear: 1x USB 3.0 2x USB 2.0 1x…


March 13, 2019

Stdc - Helps porting C code to .NET Rationale Porting C code to .NET doesn't sound like being fun. And it is mostly for sure not funny... The mind breaking rewriting of formatting code to String.Format formats can cost a bunch of time and is error…

Windows Tweaks

January 10, 2019

Windows tips and tricks Windows 7 "god mode" This allows to see all system settings in one window. Create a folder named You can use anything in place of All Settings, the most important the point and what comes after the point. Energy options http…

Software metrics

January 09, 2019

Moving away from the old fashioned source code metrics Thanks to modern source code management, we are now able to collect not only spatial metrics on source code, but also temporal metrics. By spatial metrics, I mean the metrics measuring the…

Raspberry tweaks

January 09, 2019

Raspi Raspberry pi 2 OSMC installed as OS root account: ''osmc'', ''osmc'' by default Automatically expands to full SD size Enable WIFI: Internet radio: Added web-interface.chorus to have netbios resolution


January 09, 2019

REWORK NEEDED FUNANI GOAL: FUNANI is an open source project aiming at solving the management of large image and other media collections in a practical way. Finding the data you want in big data collections is usually a big pain and consumes a lot of…

Size Reporter

January 09, 2019

SizeReporter License Agreement. Introduction SizeReporter generates a CSV/TSV/XML report of the disk usage: CSV: Comma separated values (";") TSV: Tab separated values XML: XML format It runs from the console and can be triggered by scheduled jobs or…


January 07, 2019

Advanced Code Quality Center ACQC-Metrics License Agreement. **Quantify the quality of your code and develop higher quality code!\ ** ACQC Metrics computes typical source code file and function metrics. What are metrics good for? Well, it measures…

Test Bob

January 05, 2019

Test NOTE: disabled installation of svg bob at the moment (not used) remark-draw bob Illustration of svgbob capabilities Copied directly from the SvgBobRus repo.

Test Flowchart

January 05, 2019

Test remark-flowchart Normal With color Tribut to locize END

Test Graphviz

January 05, 2019

Test remark-draw graphviz Examples taken from the DOT pocket reference Example 1: Simple Graph Example 2: K6 Example 3: Simple Digraph Example 4: Full Digraph Example 5: Showing A Path Note that there's also a shorthand method as follows: Example…

Test Mermaid

January 05, 2019

Test remark-draw mermaid Gantt sequenceDiagram classDiagram gitGraph


January 05, 2019

Git Annex Introduction git-annex main project page GitMinutes #16: Joey Hess on git-annex File synchroniszation using git-annex assistant Large file management with git-annex NOTE: gitlab migrated from git-annex to git-lfs: https://docs.gitlab.com/ee…


January 03, 2019

Test Plantuml remark-draw dot Examples taken from the DOT pocket reference Example 1: Simple Graph Example 2: K6 Example 3: Simple Digraph Example 4: Full Digraph Example 5: Showing A Path Note that there's also a shorthand method as follows: Example…

GoF: Observer pattern

January 02, 2019

Observer Goal A subject object, maintains a list of its dependents, called observers, and notifies them automatically of any state changes. UML C# 2 alternatives (More information here): Using interfaces like and and make interface calls Use an…

GoF: Singleton pattern

January 02, 2019

Goal Restrict instanciation of a class to one object. UML {{http://upload.wikimedia.org/wikipedia/commons/thumb/f/fb/Singleton_UML_class_diagram.svg/200px-Singleton_UML_class_diagram.svg.png|UML Diagram}} C# Having a sealed class and private…

GoF: Visitor pattern

January 02, 2019

Visitor Goals Represent an operation to be performed on the elements of an object structure. Visitor lets you define a new operation without changing the classes of the elements on which it operates. This pattern usually makes use of a double…

Calling Conventions

January 02, 2019

Calling Conventions A calling convention defines how data exchange is handled during a function call between a caller and callee. How/where parameters are stored and in which order Who is responsible of cleaning up the storage area for the parameters…

Index page

January 01, 2019

Projects bpmnio plugin for Dokuwiki (open source) Funani is project aiming at managing large collections of pictures Stdc.Net helps to port C code to the .NET platform in an easy and fast way ACQC A platform for source code analysis Size Reporter…

Common shortcuts

January 01, 2019

Common shortcut Key names   = Control key = Break key (usually in the top-right area of the keyboard) = Print screen key (usually near break)    = Windows key (or linux key on some keyboards!) Trick How to bring back a window out of screen: right…

Blender shortcuts

January 01, 2019

Blender Links to the very nice Blender Wiki mainly for my own convenience. For more advanced help and details regarding blender, please refer to it. Getting started Wikibooks hotkeys Blender HotKeys In-depth Reference

Synology settings

January 01, 2019

Settings (DS415+) Storage Calculators Synology RAID calculator Data loss RAID calculator RAID 5 vs RAID 6 RAID 5 vs SHR (German) Don't use RAID 5 on small arrays RAID 5 stops working in 2009 RAID 6 stops working in 2019 Beware of URE (Unrecoverable…

C# numeric promotions

January 01, 2019

Promotion rules are in some situations quite tricky to understand. Here is the list of applied rules so the situations where an explicit cast is needed get clarified. From ECMA-334 Unary numeric promotions Unary numeric promotion occurs for…

Funani: Data Storage

January 01, 2019

Data storage Rationale Data is stored on disk, Metadata is stored in a database. How the data in the database is structured is defined in another blueprint: [metadata storage](metadata storage). The metadata in the database also contains a link back…

Funani: Other software projects

January 01, 2019

Other Projects Free projects dealing with media management: kphotoalbum (GPL) : tool to help me describe my images, and to search in the pile of images. http://iipimage.sourceforge.net/ (GPL) : light-weight streaming client-server system for the web…

Funani: Settings

January 01, 2019

Global Settings Rationale Global system settings have to be persisted. These settings are global to the whole system and allow administrators to steer and setup the global behavior of the system. Introduction By now it is not clear how many settings…

Funani: User Management

January 01, 2019

User Management Rationale Users must be declared and registered on the system to be able to access and record data on the system. Anonymous access can be granted to some extent with the exception of persisting all features and settings related to…


December 30, 2018

C# Stopwatch Assembly (reference) Using directive Code Note is equivalent to

C# Clipboard Custom Format

December 28, 2018

Clipboard custom format CF_HTML HTML Clipboard format Code to convert a standard valid HTML string into CF_HTML, the clipboard representation of HTML

C# Path Handling

December 28, 2018

Absolute and relative path manipulation Assembly (reference) Using directive Code to convert to an absolute path Converts path to an absolute path relatively to the basePath. The code also works properly if the path is already absolute. If the…

Git: Bare

December 28, 2018

Git Bare After that git fetch will update all branches. See SO: Git Fetch fails to work on bare repo, but git pull works on normal repo for details

Git: Tagging

December 28, 2018
 vcs git tag

Git Tagging retroactively

Visio shortcuts

December 27, 2018

Visio keyboard shortcuts Visio shortcuts are not directly visible in the GUI hence the difficulty to get them. This list was contributed by Reinmar Mück. Many thanks for the effort. NOTE: This is a subset of the shortcuts optimized to contain the…


December 27, 2018

C# SMTP Assembly (reference) Using directive Code: send an Email For details: http://msdn.microsoft.com/en-us/library/system.net.mail.smtpclient.aspx


December 27, 2018

IXmlSerializable Introduction Yeah, I know, this is yet another article about XML serialization... After having seen several issues in code using or demonstrating XML serialization on CodeProject (and having struggled with these issues myself!), I…

XML serialization

December 27, 2018

XML serialization Assembly (reference) Using directive Code: Creation of the serializer The following code generates a serialization assembly on the fly (on first execution). This assembly is then used to read and write objects of the specified type…

Funani: Rating

December 27, 2018

Rating Rationale The rating module enables users to rate an object in the Funani database: picture, video or just anything else. The rating enables a prioritization of the media being shown to users. Each user can modify his own rating and get…

Funani Technology

December 27, 2018

Introduction A set of standard tools has to be selected among a wide set of possibilities. What type of database to choose for storing and retrieving Metadata efficiently and scale with large amounts of data? Requirements Free and open source and…

Color of Code: License

December 26, 2018

FREEWARE SOFTWARE LICENSE AGREEMENT Copyright 2010-2021 Jaap de Haan, https://www.color-of-code.de NOTICE TO USER You may not use this software except in compliance with the License. Please, read this carefully. By using all or any portion of the…

Funani: Architecture

December 26, 2018

Global architecture Client/Server The overall architecture is client/server based. Several clients can access the server at the same time. The server is holding the data to be served. This content is the raw data that was uploaded (the files) and…

Funani: Rationale

December 26, 2018

Funani: Rationale Why yet another media management system? There are already great existing free software projects aiming at similar goals. None of them could satisfy all these requirements: Robustness against file renaming (many tools just link…

Text to Speech

December 25, 2018

C# Text to Speech Assembly (reference) Using directive Code: say "hello world" Code: list available voices