“I can do any thing. I can’t do everything.”
The sheer number of projects and problem domains covered by OpenStack was overwhelming. I never learned several of the other projects under the big tent. One project that is getting relevant to my day job is Ironic, the bare metal provisioning service. Here are my notes from spelunking the code.
Continue readingOne of my friends wrote a bunch of music back in high school. The only remaining recordings are on a cassette tape that he produced. Time has not been kind to the recordings, but they are audible…barely. He has a device that produces MP3s from the tape. My job has been to try and get them so that we can understand them well enough to recover the original songs.
I have the combined recording on a single MP3. I’ve gone through and noted the times where each song starts and stops. I am going to go through the steps I’ve been using to go from that single long MP3 to an individual recording.
Continue readingConcrete weighs 5 pounds per quart.
Continue readingAnother question from the Reddit Theory board. Here is my answer.
Continue readingWhen you start looking at Jazz lead sheets, you might notice a Chord with the Alt modification. This is an altered chord.
Continue readingThe key piece of persisted data in an DHCP server is the lease. A lease is a the mapping between a MAC address and an IP address, limited in time. A Lease typically has a start time and an end time, but can be renewed. Because I am still living in an IPV4 world, I have to deal with arbitrarily small pools of IP addresses. Thus, the design needs to strike the balance between static and dynamic: a machine should generally get back the same IP address each time. However, if addresses get tight, address reuse should be aggressive.
Continue readingTo capture DHCP packets I ran:
tcpdump port 67 -i vnet0 -vvvv -w /tmp/packets.bin
That gave me a binary file 940 bytes long. This is actually 2 packets: the request and the response. This has the IP header, the UDP header, and the DHCP packet payload in it.
Continue readinghexdump boot-packet.bin -e'"%07.8_ad " 8/1 "%03d " " " 8/1 "%03d " " |"' -e'16/1 "%_p" "|\n"' -v |
The Extract Function refactoring is the starting point for much of my code clean up. Once a “Main” function gets sufficiently complicated, I pull pieces of it out into their own functions, often with an eye to making them methods of the involved classes.
While working with some rust code, I encountered an opportunity to execute this refactoring on some logging code. Here’s how I executed it.
Continue readingSomeone asked (on Reddit) how to swing eighth notes. Here’s my response, somewhat cleaned up and expanded.
Don’t. If you try to swing them, they will be over done.
Play straight eighth notes. The “swing is done via articulation.