Tag Archives: programming

Monitoring Storm Kafka Spouts using Python

kafka-logo-tallWhen running a large real-time processing system, monitoring is critical. But it does more than allow you to keep an eye on your system. During development it allows you test hypotheses about how it works, how it performs when certain parameters are changed, and takes the guessing out of working with dynamic systems.

Storm, a real-time computational framework open-sourced by Twitter, is such a system and comes with a Spout, allowing messages to be streamed from a Kafka Broker.

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A simple host system for a 6502 emulator

2000px-CBM_Logo.svgCPU emulation, particularly of older processors, is an interesting topic.

While emulation source code for various CPU cores is easily available, I wanted to better understand how to interface the emulated CPU with my host machine. Therefore I decided to write a simple example of a host system for an emulated MOS Technology 6502 microprocessor.

The goal would be to have the emulated 6502 write “Hello, world” to the console of my linux desktop machine.

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gdb, inline source, and stepping through your code

I really like having inline source when using gdb. Code Complete, by Steve Mcconnell has an entire chapter explaining how you should proactively step through all code you write — and not just when you’re actively debugging an issue. Having followed this practice for a few years now, I can testify that it increases your productivity enormously. I simply can’t imagine not doing so before committing any code.

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Valgrind, blessed be its name

Valgrind comprises a bunch of very useful tools for detecting problems with your programs. I first came across it a couple of years back and find it to be excellent. In particular I use its memory profiler, which helps you catch errors such as memory leaks and invalid accesses. In my experience these types of errors sometimes indicate logic errors, not just areas where you’ve forgotten to free some previously allocated memory — which is another reason why it is such a great tool. Continue reading Valgrind, blessed be its name