Fun with recursion in Java

Hanoi.java contains a routine textbook solution to the familiar Towers of Hanoi problem. Upon compiling it and running it ( java Hanoi > out.txt), the execution times for the various numbers of discs are printed out as follows

A tale of two SCNs

A few weeks ago, I had the opportunity to investigate an issue on a live system where a regular J2EE web application was hitting the well-known error ORA-01555: snapshot too old: rollback segment number <number> with name <name> too small. But in this particular case, it was accompanied by an ORA-02063, which means that the error was received from a database link. Folks with Oracle dblink experience are probably aware that unexpected traps lurk beneath the attractive abstraction that dblinks provide. A snapshot too old on a dblink - that had to be interesting !

A signed root zone and an NSEC adventure

On 15-July-2010, the root zone of the Domain Name System was DNSSEC-enabled. The details of this effort, which was underway for some time, are outlined at http://www.root-dnssec.org. The signing of the root is regarded as an important step towards a broader DNSSEC deployment across the internet.

ssh Timeouts

Some time back I was encountering annoying timeouts on ssh sessions and came to know some useful details in the process of getting it resolved.