All posts by Philip O'Toole

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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Gaining Development Perspective from Field Trials

riverbed-logoAnother post, written by me, for the Riverbed Technology blog — this time about the value of Alpha and Beta testing.

Software developers, such as myself, can get very involved with a single part of the new software on which we are working, sometimes losing perspective. Helping customers deploy and test pre-release software helps us to design better products when we are reminded we need to create a solution, not just a box running some clever software.

You can read my latest post here.

My guidelines for reusable Django applications

djangoI came to Django development from much lower-level development — embedded software, device drivers, and system software. What has impressed me most about Django (and python in general) is the manner in which it guides you to do the right thing in terms of code construction. The framework and language naturally make you think about better ways to express your designs.

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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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Installing Fedora Core 12 on Chembook 2370VA

Fedora_verticalAfter a good experience with Fedora Core 8, and a reasonable experience with Fedora Core 11, I decided to install Fedora Core 12 on my Chembook laptop.

In summary, while FC8 and FC11 worked out of the box, FC12 failed to provide me with sound. I discovered later that the KDE mixer had set the center volume to mute. Once I unset that, I had sound.

Other than that, it worked pretty well.

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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.

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Yellow Dog Linux 6.1 on the PS3

Yellow Dog Linux on the PS3
Yellow Dog Linux on the PS3

I got around to installing Yellow Dog 6.1 using a DVD of the full distro. The installation went OK, and the installer fired up in graphical mode. However it proceeded to create the swap partition almost immediately because of low-memory concerns.

When it completed YDL was quite zippy – a much, much better experience than I got from FC12. I even had audio.

I may actually use this – it depends if I can get particular media players running on it.