I have been writing software since 1984, when I typed my first program into an 8-bit Amstrad CPC 464. I have been paid to do it since 1991. In between I taught myself QuickBasic, Turbo Pascal, C, and MASM assembly from manuals and magazines, because that is what you did before the internet.
Today I work in Domain-Driven Design, CQRS, and Event Sourcing, and I help businesses move software off platforms that are running out of road.
What I am working on
Legacy to Modern LLC. I founded it in 2025 to do one thing well: take MS-DOS, Visual Basic, Delphi, and legacy .NET Framework applications and move them onto current platforms without losing the business rules that took decades to get right. That last part is the whole job. The code is replaceable. The accumulated knowledge of every edge case is not.
A book on Event Sourcing and CQRS. More than 400 pages across 18 chapters, built on a production-grade .NET reference implementation with four interchangeable event store backends. Every pattern in it was proven in working code before it was written about. It is the book I wanted when I started.
A course. Build an Event Store in C# .NET for CQRS and Event Sourcing, for people who learn by building rather than reading.
The longer version
Thirty-five years across fourteen vertical markets: real estate, criminal justice, retail, banking, manufacturing, automotive, legal, aviation, travel and leisure, wealth management, electronic payments, health sciences, professional sports, and pharmacy automation.
That has meant work for American Airlines, UBS, PayPal, Capital One, AWS, the NFL, and Royal Caribbean, alongside a lot of businesses whose names you would not recognise but whose software runs something you depend on.
My first professional role, in 1991, was residential property management software at Real Estate Software Company. The MS-DOS flagship managed more than a million properties. Systems of exactly that vintage are what I spend my time on now, thirty-five years later, which I find funnier than I probably should.
Why I still care about old software
Legacy is not a synonym for bad. A system that has run a business for twenty years has survived every edge case the business could throw at it, and those rules were paid for once, in production, by people who found the exceptions the hard way. That is the most valuable thing in the building, and it is the first thing a careless rewrite destroys.
Software should be easy to use, performant, reliable, and replaceable. It should not matter how old or new it is. It is all about the end user.
Elsewhere
- Legacy to Modern — legacy modernization consultancy
- X
- Writing here since 2006. The archive is mostly CQRS, Event Sourcing, and Domain-Driven Design, with some detours.
Thomas Jaeger 
I kinda liked DOS 6.0 myself…I sat in front of my Commodore Vic20 sipping bad coffee back in the days when I wrote my first “choose your own adventure” game. But I ran out of memory…3.5K doesnt go very far…
DUDE! send me an email…
I saw your profile on Monster, and then was curious to the link you left and have done a little snooping. Its very clear that you love technology. You have a passion for what you do. This is precisly the kind of mind set we look for in our employees. I have already sent you an email, and our location may preclude you from considering us, but I wanted to take the time to tell you this is a great site and you do a wonderful and creative job in your descriptions. Well done!
Thomas,
Over the years, i have known you i am and have always been amazed at the insight you have brought to the development community. there are those of us that are greatfull for teachings you have given us, and students like myself will long remember things that you have said and shown to us.
Regards
your Friend
Matthew G. Tutor
Hi Thomas,
I attended the iPhone seminar last nigt and you mentioned you had a reference list of URLs that were helpful in your development. please send me those when you have an opportunity. i would sincerely appreciate it.
Thanks,
GQ Lewis
Just a note from a past user of Aczar, showing appreciation for a nice piece of software.
Hey, I would really like to have the czarlist library file, I hope it’s discountued since it’s 16 years old. I am a big VBDOS fan and have programmed alot of things in it, I made an advanced graphing calculator, I also put some forms together and make an operating system. Even today it’s still so interesting. Thanks!!
Visual MASM is the best assembler IDE I saw so far, it’s damn nice and shiny. Thanks for this tiny jewel.
Just a big thank you for easystroke,years later and nothing better tossed it out yet!
and it look not too hard to support…
…a daily user .
where can I buy the “Architecting And Designing Event Based Microservices”, paid course. I couldn’t find a link to it.
Hi!
I can’t open the program group, what should I do?
Sincerely : Laszlo.
Thomas, Get in touch with me please, email is still the same. my # has changed.
Its Matt Tutor
Hi Matt, I just saw this comment. I usually do not check my WordPress site that often. What is your email?