CPU 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.
Another post, written by me, for the Riverbed Technologyblog — 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.
I 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.
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.
expect is a tool built using Tcl which allows you to automate many tasks that would otherwise mean tedious repetition at the command line. While many tools come with a command line interface, they don’t lend themselves well to scripting — telnet is the classic example. But with expect you can script these tools as easily as bash.
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.
I cannot praise the revision-control tool git highly enough, and often use it as a buffer between SVN and me. Much of my professional work flow involves fixing a bug here, fixing a bug there — lots and lots of small changes in many different branches. git is the perfect tool for this kind of work. And it is fast.
A colleague at work gave me the idea of storing metadata for each photo on my brother’s site inside its EXIF data. I liked this idea as I originally thought I would need another text file on disk, which described the photos. Tying data to an object by adding it to the object itself is also much more robust.
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.
In between bouts of Wipeout HD, I net-installed english-language 64-bit PowerPC Fedora Core 12 on my 80GB PS3. Installation with PetitBoot didn’t present any problems, though audio didn’t seem to work. However FC12 is quite slow on my PS3, so I ain’t going to use it – it seems it’s paging to disk a lot.