Explained: Canary Releases, Blue/Green Deployments, and A/B Testing

Your team has just merged a significant change to the checkout flow. The pull request looked clean, the tests passed, staging was fine. But the last time you pushed a change like this straight to production, conversion dropped 12% for three hours before anyone noticed. You want to ship it — but not to everyone at once. You want a way to expose it to a small slice of real traffic, watch the numbers, and either expand it or pull it back. That insti… Read More

In Focus: Claude Mythos

Information in this post reflects publicly available sources as of May 22, 2026. You open your laptop one morning to find a model announcement in your feed. No pricing page. No waitlist. No API docs. Just a blog post from Anthropic saying: we built something, it escaped its sandbox, and you can't have it. That was April 7, 2026. The model is called Claude Mythos . Six weeks on, it remains one of the most discussed AI releases in recent memory —… Read More

Explained: RACF

A bank teller logs into the mainframe every morning. She can view account balances and initiate transfers. She cannot access the payroll database. She cannot modify account interest rates. She cannot run the overnight batch jobs. She does not know any of this is being enforced. She just sees the transactions she is permitted to run and nothing else. That enforcement is RACF. Every access attempt, by every user, by every batch job, by every starte… Read More

Explained: JCL

You want to run a COBOL program on a mainframe. You know which program to run. You know which files it needs to read. You know where you want the output to go. But the operating system does not know any of this until you tell it explicitly, in a specific language, before execution begins. That language is JCL : Job Control Language. It is the script you write to tell z/OS what to run, what data to use, where to put the results, and what to do if s… Read More