Jens Rehsack-Technical Product Owner

Development of a mobile app to slow down the progression of dementia

Coordination of software development (TPO – Technical Product Owner)

agile requirements management (agile requirements engineering)

prioritization of tasks in consultation with stakeholders

stakeholder management

documentation and management of the software architecture

conducting PoC for technology decisions

Documentation as Code

docToolchain, arc42, req42, aim42, tpo42, C4 model, Archimate

ADR, Architecture Decision Records

Docker

Pre-Commit, Conventional Commits, Semantic Versioning

Liberating Structures, Agile Principles, Holacracy, Sociocracy 3.0

Mobile frameworks

AI developing interfaces, LLM

Cordova, Unity

Google Gemini, OpenAI, Character.AI

Prompt development

Setup of a continuous integration platform for distributed product development

consulting, concept development and development of platform software

consulting on the transformation from manual integration to automated integration

git coaching

pair/crowd programming

Agile Coach support

support for team self-organization (Agile Coaching)

running agile ceremonies

preparation of "Agile Snacks"

Product Owner support

GitHub Actions, GitHub Workflows

Documentation as Code

docToolchain, arc42, C4 model, Archimate

ADR, Architecture Decision Records

Confluence, Jira, ConceptBoard

Liberating Structures, Agile Principles, Holacracy, Sociocracy 3.0

Docker, Podman

Azure Cloud

Pre-Commit, Conventional Commits, Semantic Versioning

BOM, SBOM

HiL, Hardware-in-the-Loop simulation

SiL, Software-in-the-Loop simulation

SAFe, LIFe

Agile transformation

System architect embedded product development

analyze and assess existing architecture

develop architecture optimizations

develop implementation optimizations

identify gaps in knowledge management

reverse engineering

agile ceremonies

arc42, PlantUML, C4 model

BitBucket, Confluence, Jira

agile architecture principles

doctoolchain, asciidoctor

PlantUML standard library

connect cloud IoT platforms with Yocto (MQTT, Kafka, Azure)

connect an energy industry gateway with a smart home gateway (e.g. matter)

Docker, Kubernetes, K8s, ArgoCD, Ansible2

Engineer/Architect Container Platform – Private Cloud Technology

Capturing and documenting architecture decisions using arc42

PoC for needed services in Tanzu Kubernetes clusters

Design of services according to cloud-native principles

Agile consulting, support with agile transformation

Legacy communication

infrastructure architecture

K8s, cloud-native

requirements analysis

GitLab, GitLab Runner

secret management, ACME (Automated Certificate Management Environment)

GitOps

SAFe / agile transformation

Helm charts

SAP Jam

Let’s Encrypt

step-ca

Nexus OSS

repository manager

supply chain management

Helm chart

TOGAF

HashiCorp Vagrant, Packer & Vault

Architecture and implementation support during the introduction of a micro-service architecture

Analysis of the existing solution and comparison with application requirements

Team grooming to capture tribal knowledge

Capturing and documenting requirements using arc42

Creation of specifications in Confluence & draw.io

Review of requirements & specifications in the team and in the architecture board

Support in creating CI/CD-based development workflows

Coaching in building a company-wide software architecture

object-oriented analysis & design

requirements analysis / requirements engineering

object-oriented design

system architecture

management consulting

preparation of decision templates

SpringBoot

Jenkins, GitLab

OpenVPN

Consulting and support for the migration of embedded solutions from Windows CE to Yocto Linux

Analysis of the existing solution and comparison with the requirements of the application on the current device generation

Gathering requirements

Running a Yocto workshop

Documenting requirements

Creating specifications

Reviewing requirements and specifications in the team and in the architecture board

NXP i.MX6, phyCard

Yocto, Open Embedded

eSDK

VNC

Requirements engineering

Architecture

Scrum of Scrum

Windows CE

Subversion

Management consulting

Creating decision templates

Creation of a lab version for an embedded Linux operating system platform with cloud support

Porting IEC 61499-compatible embedded software to an embedded industrial PC for cloud integration

Packaging the software and support components

Creating Docker containers

Basic operating concept and cloud concept for Composer and Kubernetes

Test scenarios to verify real-time capability

Documentation of the situation

Review of concepts and source code delivered by third parties

Docker, Docker Composer

Software defined network

Cross-compilation, cross-compile SDK

Kata containers

TCP, UDP, Ethernet

Perl6 / Raku

crosstools-NG

LLVM, CLang

Jira, Confluence, BitBucket

GitLab, GitHub

IEC 61499, IEC 61131

BACnet, CAN-BUS, LON, DALI, FBUS, SBUS, MBUS

Enocean, ZigBee, KNX

Kafka, Kubernetes

Real-time capability

RS232, RS485

Consulting/coaching to improve code quality

Designing quality control processes based on stakeholder requirements

Improving workflow integration into the Scrum processes in use

Coaching skills in dealing with Git, Git processes, and Github

Analysis of the existing workflows

Recording the existing quality issues

Identifying the weak points in the existing processes

Developing full workflows including quality control stages

Visual representation of the workflows

Creating a cheat sheet for the git commands needed for the work

Creating a report on further improvement opportunities

Linux extension for Windows 10

git, Github, Jira, Confluence

Scrum

LaTeX

Redmine

Windows 10

Dia

Adding, updating, and fixing packages for OE-Core, OpenEmbedded, and Java, especially Perl5 (OE-Core), Samba (OpenEmbedded: meta-networking), Nginx (OpenEmbedded: meta-webserver), and OpenJDK-8 (meta-java)

Maintenance of a custom layer for Perl modules, as offered on CPAN (meta-cpan)

Maintenance of layers for systemd replacement (meta-sysinit)

Maintenance of a layer for provisioning and updates, e.g. OTAU (meta-prd-flash)

Porting & packaging of OpenJDK-8

Safety, Reliable Boot System, Read-Only Filesystem

Development and adaptation of BSPs (Board Support Packages)

Development of an SDN for workshops and development/integration/test stages

Yocto, OpenEmbedded

git, mercurial, subversion

Patch Management

Patch evaluation

Bootloader

Docker, Linux Container (LNX), qemu, KVM, VirtualBox, VMware, Vagrant

Managed switches, single-tagged Ethernet VLANs

llvm 3.5, llvm MCJIT

Java8 Hotspot, Java8 Shark (Zero/Shark)

Samba 4 (especially waf), dnsmasq, systemd

Design and implementation of a fully update-capable Linux-based operating system for embedded home automation to prevent security gaps at the end customer

Analysis of available frameworks for cross-compiling custom Linux distributions with a focus on long-term availability of updates

Assembly of the distribution for the home automation system

Integration and system testing of the Board Support Packages (BSP)

Modularization of images for optional installation of Kodi / media players

Design of full updates using a rescue system

Design of update strategies for legacy devices in the field

Release management

Technical support for application development

Refactoring of the BSPs to harmonize interfaces across all platforms

Agile transformation: introduction via Kanban to Scrum

Agile coach, establishment of the Product Owner role

Migration from Subversion to git (GitHub, BitBucket)

Design & implementation of a Software-Defined Network for development (IT), test (IT), test (business department), production (plant), goods receipt (plant)

Administration of build environment (OpenZFS on Ubuntu)

Yocto, Open-Embedded

System Security & Reliability

Linux 3.0, 3.10, 3.14, 4.1

FreeScale i.MX6, Globalscale GuruPlug, Marvell Kirkwood

Cross-compilation

Packaging of Perl, Java (OpenJDK), Collecd, RRDTool, CPAN modules, Google V8

libstatgrab, daemontools, daemontools-encore

Moo, MooX::ConfigFromFile, IO::Async, Dancer2

Wireshark / tcpdump

git, mercurial, subversion, nginx

Kanban, Scrum

Jenkins

Linux Firewall (nftables)

RAID-Z2

ZFS performance optimization

Network segmentation with VLAN (separation of developer networks), single-tagged Ethernet

Managed Network

ARM Assembler, NEON

LLVM, MCJIT

ARMv7 optimization, ARM5-TE cross-compile fixes, ARM5 assembler, Thumb

U-Boot (bootloader)

Z-Wave, DuoFern

Jira, Confluence, BitBucket, GitHub

gcc 4.8, 4.9, 5.2

Ant, Maven, Groovy

Scrum Master

GPG, OpenVPN

Development of an SNMP agent for use on railway tracks

MIB design and implementation

Programming sensor measurements

Test and acceptance support

technical documentation

Debian Linux, µCLinux

net-snmp

gcc

cross-compilation

embedded Linux (ucLinux or µcLinux)

Ethernet control

Development of a web application

Taking over an existing, unfinished application

Adapting the components to customer needs

database optimization

RHEL (RedHat Enterprise Linux) 6.1

MySQL 5.1

Apache Web Server 2.1

Support for the Linux operations team in the data center

Development of Perl scripts to support Linux administration

Installation of 3rd party applications (e.g. Tivoli Monitoring Agent)

Design of a DBIx::Class-based database for managing the installations

Interface to the systems management team

Support for Subversion installations

Documentation in MediaWiki

Red-Hat Enterprise-Linux 5, 6

Red-Hat Network AddOns (Satellite, HA cluster)

Open Cluster Framework

Tivoli Monitoring

Perl (Module::Build, Satellite API, DOM::XML)

dmidecode, systool

Kerberos

XIV, EMC, IBM Storage Cluster

Tivoli Storage Manager

Multipath

VMware ESX, KVM

Support for OS and application monitoring in the data center

3rd-level support for Unix operations

Development of a multi-threaded SNMPv3 server for Unix and Linux in C++

Software architecture and design according to Booch with UML

Design and further development of the Management Information Base (MIB)

Implementation of a proof of concept for the SNMP server

Implementation of the required statistics collectors (as a library) for Linux, Solaris, AIX and HP-UX in C

Porting the C++ libraries snmp++ and agent++ to any Unix environment using autotools

Development of SNMP plugins for Nagios in C++

Development of SNMP daemon plugins for additional application monitoring in Perl

Creation of automated tests in C++ and Perl

Packaging software for systems management using epm

Creation and maintenance of CFEngine rules

Debugging (trace analysis, gdb, valgrind, ...)

Documentation (LaTeX, Doxygen)

Data center operations

HP-UX 11.11-11.31 (HP PA-Risc & IA64)

SuSE Linux Enterprise Server 9-11

Solaris 8-10 (Sparc & x86)

Operating system and application virtualization

AIX 5.2-6.1

Programming languages C, C++, Perl, Shell script

GNU Compiler Collection 4.2 (gcc 4)

CFEngine, RedHat Package Manager (rpm – SLES, RHEL), Licensed Program Products (lpp, bff – AIX), Software Bundles (swinstall – HP-UX) & Packages (pkg – Solaris)

Standard Template Library (STL), Boost

snmp++, agent++

libstatgrab, POSIX system API, vendor system API

libjson, libConfuse

autoconf, automake (GNU Autotools)

Ethernet parameters, controller parameters, disk parameters

Kerberos, LDAP, NDS

Perl5 (5.8)

Migration of a CRM application

Provision of a Perl 5.10 environment including multi-threading on HP-UX 11.23

Provision of DBI/DBD modules for database access

Performance optimization (databases, Perl)

Multi-thread programming with Perl

HP-UX 11.23

GNU Compiler Collection 4.2 (gcc 4)

Perl 5.10

DB2 8.5, Oracle 10i, PostgreSQL 8.3

Log::Log4perl

DBI 1.609, DBD::DB2, DBD::Oracle

Profiling with Devel::NYTProf

Data center automation in HACMP and SAP environments (concept/design, architecture & programming)

Development of core functions used by all scripts

Establishment of build, test, and release management via RPM and tagging using a CVS wrapper (ITIL requirement)

Concept development of required functions to involve additional team members (lead development)

Creation of applications for configuration and operations tasks for SAP, Uniq, Oracle, and HACMP

Management of virtual machines (Linux) and logical partitions (LPAR, AIX)

Perl 5.8, Perl 5.10, CPAN

Red Hat Enterprise Linux 4 (RHEL4), Red Hat Enterprise Linux 5 (RHEL5), gcc 3.4

Operation of Linux server farms, virtualization using Shared-Root Image

AIX 5.2, 5.3, HACMP 5.4, xlC 10, LPAR/WPAR/CoD

Template::Toolkit, SQL::Statement, DBI, DBD::Oracle, ...

Eclipse 3.3, Eclipse 3.4, Eclipse 3.5

EPIC (Eclipse Perl Integration), Active State Perl, SQL-Explorer, Mylyn, Subclipse

Bugzilla 3, CVS, Subversion 1.5 and Subversion 1.6 (svn)

pkgsrc for own Perl distribution

Rational Software Architect 7.5

XS (C interface for Perl) to speed up Perl modules and connect C/C++ libraries

Packaging/package conversion of software using pkg, rpm, and lpp (installp, bff) and ppd

Creating reports using Template::Toolkit & LaTeX, Template::Toolkit plugins

Single Sign-On with Kerberos

SAP Basis administration 4.6, 6.4, 7.0 (backup with backint and rman, virtualization, distributed systems, monitoring, SLA (Service Level Agreement), ...) for R3/ABAP systems, J2EE, and dual-stack instances

Oracle 10 under SAP

Oracle GRID, Oracle RAC

NetApp cluster (NAS)/HP StorageWorks XP (SAN) administration for SAP/Oracle installations

Virtualization of Linux guests with VMware, KVM, and Xen (proof of concept)

SAP NetWeaver (with sapnwrfc) for managing administrative SAP users

Maintenance and further development of Perl modules

API documentation

Development, planning, and execution of tests (manual and CI)

Patch management (collaborator management)

subversion, git

compiling OSS on various operating systems

Perl package management (CPAN)

IBM XL C/C++ v10/v11 for AIX

Oracle Studio 12.1 for Solaris (Sun Studio)

GNU Compiler Collection 4.x (gcc/g++ 4.2, 4.4, 4.6, 4.7, 4.8, 4.9, 5.2, 6.0, 7.0, 8.0)

MS Visual Studio for C++ 2008, 2015

XCode 3.3, 4.5, 5.1, 6.1, 7.3 (Clang, LLVM), 9.1, 10.1

GNU make, BSD make, GNU Auto-Tools (autoconf, automake, libtool, ...)

Microsoft Windows Services for Unix (WSU, Interix), Windows Subsystem for Linux

Solaris 10 & Solaris 11 (OpenSolaris, Solaris Express), AIX, HP-UX, NetBSD, FreeBSD, Mac OS X, Debian: Lenny, Squeeze, SuSE Linux (SLES, SLED), RedHat Enterprise Linux

Intel x86 (i386, i586, i686), x86_64, amd64, Sparc, PowerPC, MIPS, ARM, DEC Alpha

Monitoring sensors / operating system statistics / internal OS structures (process tables, network/interface configuration, libstatgrab, ...)

ANSI SQL

Maintenance of SQL::Statement (SQLite & PostgreSQL as reference), DBD::CSV and DBD::File (DBI), DBI::Test

PostgreSQL, MySQL

Test automation, parallel tests, Test Anything Protocol

Porting open-source software to AIX, HP-UX, NetBSD, FreeBSD, and Mac OS X

ASN.1 encoding / decoding, SNMP

D-Bus for reacting to system events

Continuous integration

WxGTK, gtk2

Programming for Unix

Embedded development (data transfer), driver programming

Software design

Unit tests, regression tests

Quality assurance

Network administration

Software packaging & software distribution

Seminar leadership, training

ANSI C (C89, C99)

C++ (C++98), STL, Boost

Perl5, CPAN, DBI

Oracle, Toad, DB2, MySQL, PostgreSQL

Microcontroller NEC CAN3+ (e.g. µPD780828, ...), ARM (e.g. PXA270)

GNU C/C++, IBM CSet for C/C++ (Visual Age, xlc), IAR embedded Workbench, Watcom C/C++, ...

XML (DOM, XML-RPC, SAX, XSLT, SOAP)

Linux, Solaris, AIX, FreeBSD, OS/2, Windows 2000, Windows NT 4.0, MS-DOS

ClearCase, Subversion, CVS, RCS, MSK SI, TeamConnection

Rational Rose

Microsoft Office (incl. Visio)

DHCP, BOOTP, SMTP, UDP, TCP, FTP, SSH, ICMP, ESCON

Sockets, POSIX threads (pthreads)

Andrew Filesystem / Kerberos administration

HACMP