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WAL is a concept to achieve atomicity & durability - usually found in filesystems and database systems. Both atomicity (the “A” in ACID) and durability (the “D” in ACID) are properties of ACID - the set of properties used to describe database systems. What is atomicity & durability? Why do I want it? When you add or insert data to, say an SQL database, when the database system responds with “OK - I saved your data”, it has to be sure that even in the face of a power loss or application crash, the updated data is still found from the file.

Continue reading.. | Feb 23, 2017 by joonas.fi

Let’s learn some reverse-engineering with strace by inspecting how Docker interacts with its server API (Docker uses client-server model).

Docker has API documentation so it’s not like this is necessary, but this serves as a good example on how to reverse-engineer black boxes.

Continue reading.. | Jan 12, 2017 by joonas.fi

If you have not read my previous post on How do SSL certificates work?, go read it first! Moving on, this post is about setting up an certificate authority for company-internal use. “Company-internal” CA? Most CA setups are for company-internal usage, unless you are planning on starting multi-million dollar CA business by investing years and some serious cash to get through start-of-operation audits, periodical audits, setting up hardcore secure infrastructure with tight access controls, TPM modules and such.

Continue reading.. | Jan 9, 2017 by joonas.fi

In this article I try to explain how the increasingly encrypted internet works!

Continue reading.. | Jan 4, 2017 by joonas.fi

Buildbot is a build server like Jenkins, but stateless, super lightweight and aimed for building Dockerized apps.

Continue reading.. | Dec 28, 2016 by joonas.fi

function61.com got its website launched! Hope you enjoy it, and any feedback would be appreciated.

Continue reading.. | Dec 23, 2016 by joonas.fi

Every website will get hacked?

Yes. It is starting to look like every website - even the major ones, will get hacked. It is not a question of “if”, but “when”.

Just now in the news is that Yahoo was compromised and the result was a leak of names, usernames, passwords and other personal data of 500 million accounts - almost twice the United States population.

Here are examples of a few widely known breached websites (up to September 2016 - this list grows constantly):

Continue reading.. | Sep 23, 2016 by joonas.fi