Jens Rehsack
System Architect, Enterprise Architect
Experience
The Linux Foundation / Yocto Project
- 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)
- Maintaining a custom layer for Perl modules as offered on CPAN (meta-cpan)
- Maintaining layers for systemd replacement (meta-sysinit)
- Maintaining a layer for provisioning and updates, e.g., OTAU (meta-prd-flash)
- Porting & packaging OpenJDK-8
- Safety, Reliable Boot System, Read-Only Filesystem
- Developing and adapting BSPs (Board Support Packages)
- Designing an SDN for workshops and development/integration/test stages
Skills:
- Yocto, OpenEmbedded
- git, mercurial, subversion
- Patch management
- Evaluating patches
- Bootloader
- Docker, Linux Containers (LNX), qemu, KVM, VirtualBox, VMware, Vagrant
- Managed switches, single-tagged Ethernet VLANs
Insights:
- llvm 3.5, llvm MCJIT
- Java8 Hotspot, Java8 Shark (Zero/Shark)
- Samba 4 (esp. waf), dnsmasq, systemd
The NetBSD Foundation
- Adding and updating 3rd party applications in the pkgsrc environment for AIX, Linux, Windows, Solaris, HP-UX, Mac OS X (Darwin), FreeBSD, and NetBSD
Skills:
- PkgSrc, packaging
- Package conversion
- cvs, subversion, git, mercurial, fossil
- compiling OSS on different operating systems
- Security patch management, security risk management
- Vulnerability management
- IBM XL C/C++ v10/v11 for AIX
- Oracle Studio 12.1 for Solaris (Sun Studio)
- GNU Compiler Collection 4.x (gcc/g++ 4.2-4.9, 5.2, 6.0, 7.0, 8.0, 11.0, 13.0)
- 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, ...)
- Solaris 8-11 (OpenSolaris, Solaris Express), AIX, HP-UX, NetBSD, FreeBSD, Mac OS X, Debian: Lenny, Squeeze, SuSE Linux (SLES, SLED), RedHat Enterprise Linux
- Porting open-source software to AIX, HP-UX, NetBSD, FreeBSD, and Mac OS X
- Intel x86, x86_64, amd64, Sparc, PowerPC, MIPS, ARM, DEC Alpha
- Deploy management
Insights:
- graphviz
Perl Comprehensive Archive Network (CPAN)
- Maintaining and further developing Perl modules
- API documentation
- Developing, planning, and executing tests (manual and CI)
- Patch management (managing collaborators)
Skills:
- subversion, git
- compiling OSS on different 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 / OS statistics / OS internal structures (process tables, network/interface configuration, libstatgrab, ...)
- ANSI SQL
- Maintaining 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 system event reactions
- Continuous integration
Insights:
- WxGTK, gtk2
Summary
Simplicity is the result of maturity. – Friedrich Schiller
My work doesn’t follow a rigid plan but flexibly aligns with an evolving project goal – always in harmony with the company’s mission. By choosing small, deliberate steps, we create the openness needed to respond properly to unforeseen events and required adjustments. This approach focuses not only on technical requirements but also on business goals, stakeholder interests, and existing organizational structures.
In this iterative process, usable interim results have more value than just quickly reaching an originally set target. With each step, our understanding of the real needs and constraints grows.
Simplicity thus doesn’t come from making things simpler, but from maturity: the result of continuous reflection, honest communication, and the ability to distinguish the essential from the nonessential. It’s the mark of a solution that not only works but endures – because it has grown through the interaction of all influencing factors.
Languages
Education
Martin Luther University Halle-Wittenberg
Computer Science · Germany
Mathematics, Science & Technical Specialized School
University entrance qualification · Germany
Certifications & licenses
Polarion Basic Training & Advanced Training
Requirements Engineering / Requirements Management
PostgreSQL Administration (Replication, Stored Procedures, Application Migration to PostgreSQL)
Postgres.eu
ITIL Processes
Samba (incl. LDAP, Domain Controller, Network Planning, Active Directory, ...)
vxWorks 6.3 & WindRiver Workbench 2.5
WindRiver
TFC Training Level 1
TFC
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