Oliver Wehrens
Seasoned Technology Leader. Mentor. Dad.

Hi, I'm Oliver Wehrens.

For over 20 years I shaped Technology & Product in companies ranging from startups to major cooperations. I started my career in software engineering and moved to technology leadership in roles like Head of Architecture, CTO and VP Engineering. I transform technology and shape cultural changes in organizations. I am a proponent of the fact that every change in technology, product and organisation triggers a change in the other areas.

Beyond that, I like to share my expertise and learnings at the Mentoring Club as well as in articles here.

Enjoy

Publications

Clean code ... should you DRY?

Clean code ... should you DRY? Don't repeat yourself. This is a core principle of programming. Right? Or? Why not?
article 2 min read

Why you need a macro architecture

Why you need a macro architecture What is a macro architecture and what is important?
article 3 min read

Can AI replace me as a consultant?

Can AI replace me as a consultant? Can an AI replace my job? What would it take?
article 3 min read

Whisper: Nvidia RTX 4090 vs M1Pro with MLX (updated with M2/M3)

Whisper: Nvidia RTX 4090 vs M1Pro with MLX (updated with M2/M3) How fast is my Whisper Benchmark with the MLX Framework from Apple? Nvidia 4090 / M1 Pro / M2 Ultra / M3
article 5 min read

Artifacts for effective alignment

Artifacts for effective alignment Which artifacts are at least needed for an effective alignment in your organization?
article 6 min read

Podcast time

Podcast time Ivan of dev.env Podcast invite me to talk about my way in the IT industry.
interview 1 min read

OpenAI Whisper Performance on Nvidia RTX 4090

OpenAI Whisper Performance on Nvidia RTX 4090 How fast is OpenAI whisper on a RTX 4090?
article 1 min read

Semantic Search with Cosine Similarity

Semantic Search with Cosine Similarity Search through text with semantic search using machine learning.
article 3 min read

OpenAI Whisper Benchmark Nvidia Tesla T4 / A100

OpenAI Whisper Benchmark Nvidia Tesla T4 / A100 I ran a benchmark on an Nvidia Tesla T4 / A100 to see how well OpenAI Whisper performs.
article 3 min read

OpenAI Whisper on Apple M1

OpenAI Whisper on Apple M1 How good runs the C++ implementation of OpenAIs Whisper on Apple Silicon?
article 4 min read

What does it take to become a software architect?

What does it take to become a software architect? I got together with Eberhard Wolff to discuss and answer questions about what it takes to become a Software Architekt on Software Architektur TV.
interview 6 min read

How hands-on should a CTO be?

How hands-on should a CTO be? Should a CTO code?
article 2 min read

Sketch Book Summary: No Estimates

Sketch Book Summary: No Estimates Sketch Book Summary: No Estimates
article 1 min read

Four weeks of home office

Four weeks of home office On March 12th we decided to send everybody into Home office. We were partially already working remotely but we never tried to be 100%. Now we were forced to.
article 4 min read

Sketch Book Summary: Good Strategy, Bad Strategy

Sketch Book Summary: Good Strategy, Bad Strategy A sketch on the book to remember.
article 1 min read

2019

2019 Lots of things have changed for me in 2019. So let’s look back.
article 2 min read

Technical Agility

Technical Agility What, why, where & how to react to changes
article 16 min read

Wardley Mapping Canvas

Wardley Mapping Canvas A simple Canvas for creating Wardley Maps.
article 1 min read

Using Sketch Book Summary (SBS) to remember content what matters to me.

Using Sketch Book Summary (SBS) to remember content what matters to me. Drawing important things from books keeps my memory fresh.
article 2 min read

Sketch Book Summary: Atomic Habits

Sketch Book Summary: Atomic Habits A summary sketch about the book 'Atomic Habbits'.
article 1 min read

CD und DevOps im Expertencheck

CD und DevOps im Expertencheck Grau ist alle Theorie. Wir haben daher verschiedene Experten zum Thema Continuous Delivery und DevOps befragt – wir wollten wissen, wie ihre Erfahrungen mit den eigenen Teams und Unternehmen verlaufen sind. Oft stellte sich heraus, dass die Technik an sich nicht das größte Problem ist.'.
print 1 min read

Warum wir auf DevOps setzen

Warum wir auf DevOps setzen Die Konkurrenz ist groß, jeder will beim Ausliefern der Software der schnellste sein. Warum wir dabei auf DevOps setzen? Das sind die Argumente.
print 1 min read

2017-90 - Random Tech Links

2017-90 - Random Tech Links
article 1 min read

Service Discovery For Machines And Humans

Service Discovery For Machines And Humans
article 1 min read

Microservices bei der E-POST

Microservices bei der E-POST Microservices sind in aller Munde, und auf Konferenzen versprechen Migrationsszenarien und technische Details gut besuchte Vorträge. Eine Folie, die fast immer auftaucht, ist eine Feststellung von Melvin Conway aus dem Jahr 1968, die besagt, dass „Organisationen, die Systeme entwerfen, […] auf Entwürfe festgelegt sind, welche die Kommunikationsstrukturen dieser Organisationen abbilden.“ (Conways Law). Das heißt konkret, dass sich die Organisation der Firma und der Teams ­direkt auf den Code und die Architektur auswirkt.
print 1 min read

Der Real-Life-Check

Der Real-Life-Check Über Microservices wird momentan viel in Theorie geschrieben und gesprochen. Doch wie sieht es in der wahren Welt dort draußen aus? Wir haben die Autoren dieses Themenschwerpunkts und weitere Experten aus der Branche gefragt, wie ihre Microservices-Erfahrungen aus der Praxis sind.
print 1 min read

How is your microservice architecture doing?

How is your microservice architecture doing?
article 10 min read

Entwicklung verteilter Systeme - Herausforderungen nicht nur an die Architektur

Entwicklung verteilter Systeme - Herausforderungen nicht nur an die Architektur
talk 2 min read

Wider den Monolith - Am Ende wird alles gut

Wider den Monolith - Am Ende wird alles gut
talk 1 min read

Migrating a monolith

Migrating a monolith
article 5 min read

If you don't fight it you end up with a monolith

If you don't fight it you end up with a monolith
article 4 min read

A Monolith could be good for you

A Monolith could be good for you
article 3 min read

How you might know that you have a monolith

How you might know that you have a monolith
article 2 min read

How failing tests can be green

How failing tests can be green
article 2 min read

Getting Faster

Getting Faster
talk 1 min read

Mit Puppet und RPM

Mit Puppet und RPM „It works on my machine“ hat sicher jeder schon einmal gehört. In der Entwicklung verhält sich die Software wie erwartet. Bis diese in der Produktion ist, dauert es lange. Einmal live, treten dann unerwartete Fehler auf, während die Softwareentwicklung längst an einer ganz anderen Stelle ist. Wie kann dieser Spagat umgangen werden? Dieser Artikel reflektiert, wie wir mit diesem Problem auf Basis einer paketorientierten Deployment Pipeline umgehen.
print 1 min read

Doing a Sprint Review with a Review Fair

Doing a Sprint Review with a Review Fair
article 2 min read

Using KVM and Virt-Manager via XQuartz on MacOSX (and solving the keymapping trouble)

Using KVM and Virt-Manager via XQuartz on MacOSX (and solving the keymapping trouble)
article 1 min read

Getting started with veewee and vagrant

Getting started with veewee and vagrant
article 3 min read

From Development to Production

From Development to Production
talk 1 min read

Do not use Javadoc

Do not use Javadoc
article 2 min read

Javascript testing for Java projects

Javascript testing for Java projects
article 3 min read

Realtime Push Events zum Browser

Realtime Push Events zum Browser WebSockets sind in aller Munde, im Java Magazin sind sie nun sogar Titelthema. Aber es geht auch einfacher: Wer Echtzeit-Events zum Browser schicken will, kann es sich leicht machen. Dieser Artikel zeigt, wie.
print 1 min read

Cucumber-jvm for Java

Cucumber-jvm for Java
article 3 min read

One assert per test, really

One assert per test, really
article 2 min read

Spring 3 MVC, Ajax and jQuery Magic (or better: simplicity)

Spring 3 MVC, Ajax and jQuery Magic (or better: simplicity)
article 3 min read

Busy Programmers Guide on where to buy eBooks

Busy Programmers Guide on where to buy eBooks
article 3 min read

How to detect if your server is down when making jQuery Ajax calls

How to detect if your server is down when making jQuery Ajax calls
article 2 min read

Lightweight Web Prototyping for the Framework loving (Java) Developer

Lightweight Web Prototyping for the Framework loving (Java) Developer
article 4 min read

How we switched from Subversion to Git

How we switched from Subversion to Git
article 7 min read

5 code metrics you need to watch

5 code metrics you need to watch
article 3 min read

Name your objects right

Name your objects right
article 2 min read

One year of blogging

One year of blogging
article 2 min read

What's your preferred development infrastructure stack?

What's your preferred development infrastructure stack?
article 2 min read

Using Selenium2 for web testing (and not Selenium IDE)

Using Selenium2 for web testing (and not Selenium IDE)
article 6 min read

Story based daily stand-up meeting

Story based daily stand-up meeting
article 2 min read

Integrate early, integrate often

Integrate early, integrate often
article 3 min read

Concordion vs. Cucumber and Java based Acceptance Testing

Concordion vs. Cucumber and Java based Acceptance Testing
article 5 min read

Test JBoss Rules 5 (or Drools) with TestNG

Test JBoss Rules 5 (or Drools) with TestNG
article 4 min read

How pair programming can help you to get into Test Driven Development

How pair programming can help you to get into Test Driven Development
article 2 min read

4 ways to test your code

4 ways to test your code
article 3 min read

How to get your developers to pay more attention to the burn down chart (and have fun)

How to get your developers to pay more attention to the burn down chart (and have fun)
article 1 min read

Two upgrades to cut down development time

Two upgrades to cut down development time
article 3 min read

Getting started with JSF 2 (and Maven)

Getting started with JSF 2 (and Maven)
article 3 min read

Update on Quant TestTester

Update on Quant TestTester
article 1 min read

Quant - Check your Tests

Quant - Check your Tests
article 3 min read

Jetbrains released a Google App Engine plugin for IntelliJ

Jetbrains released a Google App Engine plugin for IntelliJ
article 1 min read

IntelliJ Idea Plugin Property Sorter updated

IntelliJ Idea Plugin Property Sorter updated
article 1 min read

How to test Spring Webflow 2 (with parent flows)

How to test Spring Webflow 2 (with parent flows)
article 2 min read

Getting the Browsers GeoLocation with HTML 5

Getting the Browsers GeoLocation with HTML 5
article 3 min read

A Quick Look at Google App Engine for Java

A Quick Look at Google App Engine for Java
article 4 min read

Coloring your IDE

Coloring your IDE
article 2 min read

IE7 caches rendered elements?

IE7 caches rendered elements?
article 2 min read

Using TestNG with DataProviders to cover more test cases

Using TestNG with DataProviders to cover more test cases
article 2 min read

How to refactor Spring Webflow variables in your JSF pages with IntelliJ IDEA

How to refactor Spring Webflow variables in your JSF pages with IntelliJ IDEA
article 2 min read

Updated Scrum Board Cheat Sheet with Story Owner

Updated Scrum Board Cheat Sheet with Story Owner
article 1 min read

SOLID Development Principles In Motivational Pictures (enhanced)

SOLID Development Principles In Motivational Pictures (enhanced)
article 1 min read

Why our current Sprint commitment will fail

Why our current Sprint commitment will fail
article 3 min read

Three reasons why you don't want to use a Spring context in unit tests

Three reasons why you don't want to use a Spring context in unit tests
article 5 min read

Sorting your properties files in IntelliJ Idea

Sorting your properties files in IntelliJ Idea
article 1 min read

The ScrumBoard Cheat Sheet

The ScrumBoard Cheat Sheet
article 3 min read

Extreme visibility in an agile environment

Extreme visibility in an agile environment
article 3 min read

My MacBook Pro loves 4 GB

My MacBook Pro loves 4 GB
article 1 min read

IntelliJ IDEA Rulezzz with code completion

IntelliJ IDEA Rulezzz with code completion
article 1 min read

IntelliJ IDEA 8.1

IntelliJ IDEA 8.1
article 1 min read

Behavior driven development with EasyB (and vs. TestNG)

Behavior driven development with EasyB (and vs. TestNG)
article 3 min read

Starting again

Starting again
article 0 min read