This is just a note that I’ve substantially changed how the post sources are organized. I’ve tried to ensure that I preserve all the existing links, but if you spot something missing please feel free to leave a comment on this post.

While working on a pull request I will make liberal use of git rebase to clean up a series of commits: squashing typos, re-ordering changes for logical clarity, and so forth. But there are some times when all I want to do is change a commit message somewhere down the stack, and I was wondering if I had any options for doing that without reaching for git rebase.

It turns out the answer is “yes”, as long as you have a linear history.

OpenShift Container Storage (OCS) from Red Hat deploys Ceph in your OpenShift cluster (or allows you to integrate with an external Ceph cluster). In addition to the file- and block- based volume services provided by Ceph, OCS includes two S3-api compatible object storage implementations.

The first option is the Ceph Object Gateway (radosgw), Ceph’s native object storage interface. The second option called the “Multicloud Object Gateway”, which is in fact a piece of software named Noobaa, a storage abstraction layer that was acquired by Red Hat in 2018. In this article I’d like to demonstrate how to take advantage of these storage options.

Performance of the primary PyPi service has been so bad lately that it’s become very disruptive. Tasks that used to take a few seconds will now churn along for 15-20 minutes or longer before completing, which is incredibly frustrating.

I first went looking to see if there was a PyPi mirror infrastructure, like we see with CPAN for Perl or CTAN for Tex (and similarly for most Linux distributions). There is apparently no such beast,

The SYM-1 is a 6502-based single-board computer produced by Synertek Systems Corp in the mid 1970’s. I’ve had one floating around in a box for many, many years, and after a recent foray into the world of 6502 assembly language programming I decided to pull it out, dust it off, and see if it still works.

The board I have has a whopping 8KB of memory, and in addition to the standard SUPERMON monitor it has the expansion ROMs for the Synertek BASIC interpreter (yet another Microsoft BASIC) and RAE (the “Resident Assembler Editor”). One interacts with the board either through the onboard hex keypad and six-digit display, or via a serial connection at 4800bps (or lower).

Let’s say you have a couple of sensors attached to an ESP8266 running MicroPython. You’d like to sample them at different frequencies (say, one every 60 seconds and one every five minutes), and you’d like to do it as efficiently as possible in terms of power consumption. What are your options?

If we don’t care about power efficiency, the simplest solution is probably a loop like this:

import machine

lastrun_1 = 0
lastrun_2 = 0

while True:
    now = time.time()

    if (lastrun_1 == 0) or (now - lastrun_1 >= 60):
        read_sensor_1()
        lastrun_1 = now
    if (lastrun_2 == 0) or (now - lastrun_2 >= 300):
        read_sensor_2()
        lastrun_2 = now

    machine.idle()

If we were only reading a single sensor (or multiple sensors at the same interval), we could drop the loop and juse use the ESP8266’s deep sleep mode (assuming we have wired things properly):

I recently put together a short animation showing the spread of Covid throughout the Northeast United States:

I thought it might be interesting to walk through the process I used to create the video. The steps described in this article aren’t exactly what I used (I was dealing with data in a PostGIS database, and in the interests of simplicity I wanted instructions that can be accomplished with just QGIS), but they end up in the same place.

I found the following error from gpgv to be a little opaque:

gpgv: unknown type of key resource 'trustedkeys.kbx'
gpgv: keyblock resource '/home/lars/.gnupg/trustedkeys.kbx': General error
gpgv: Can't check signature: No public key

It turns out that’s gpg-speak for “your trustedkeys.kbx keyring doesn’t exist”. That took longer to figure out than I care to admit. To get a key from your regular public keyring into your trusted keyring, you can run something like the following:

Out of the box, OpenShift (4.x) on bare metal doesn’t come with any integrated load balancer support (when installed in a cloud environment, OpenShift typically makes use of the load balancing features available from the cloud provider). Fortunately, there are third party solutions available that are designed to work in bare metal environments. MetalLB is a popular choice, but requires some minor fiddling to get it to run properly on OpenShift.

I’ve had my eye on the Vortex Core keyboard for a few months now, and this past week I finally broke down and bought one (with Cherry MX Brown switches). The Vortex Core is a 40% keyboard, which means it consists primarily of letter keys, a few lonely bits of punctuation, and several modifier keys to activate different layers on the keyboard.

Physical impressions

It’s a really cute keyboard. I’m a big fan of MX brown switches, and this keyboard is really a joy to type on, at least when you’re working primarily with the alpha keys. I’m still figuring out where some of the punctuation is, and with a few exceptions I haven’t yet spent time trying to remap things into more convenient positions.