selawdivad

One of the first real programs I wrote was a program to display telemetry data from a CAN bus. I was on the solar car team at uni, and we wanted to be able to view the data from the various systems live during the race. The CAN network was connected to a CAN-ethernet converter, which sent UDP packets over a wireless ethernet link to our lead car. I had no experience with networking, or UDP or CAN at all, but I had some documentation and a lot of free time, so I got to work.

Each device on the CAN network had a bit mask to identify it. For example, the bit mask for the motor controller might have been 0x1200. This meant that any packet starting with 0x12 belonged to the motor controller. For example, 0x1201 was one type of message, and 0x1202 another type, but both belonged to the motor controller.

There was specific logic for each device on the network, so you needed to first figure out which device owned a packet using the bit mask, then apply the relevant logic to decode the packet.

Looking back, I realise the correct way to approach this would be to have a list of bit masks:

0x1200
0x1300
0x1400

Then simply bitwise & any incoming packet with 0xff00, and lookup the result in the list of bit masks.

Not knowing better however, what I actually did was create a giant dictionary of every possible packet value, so I could lookup any packet and determine which system it came from. This was so repetitive that I had to make use of my newfound super-power – vim macros – to complete the 8000 line dictionary…

Excerpt from real code below:

{
    0x102:
    {
        'name':             'SHUNT_CMU_STATUS_TEMPERATURE_AND_VOLTAGE_1_2',
        'data':
        [
            'cell_0_voltage',
            'cell_1_voltage',
            'cell_2_voltage',
            'cell_3_voltage',
        ],
        'unpack_string':    'intle:16, intle:16, intle:16, intle:16'
    },

    0x103:
    {
        'name':             'SHUNT_CMU_STATUS_TEMPERATURE_AND_VOLTAGE_1_3',
        'data':
        [
            'cell_4_voltage',
            'cell_5_voltage',
            'cell_6_voltage',
            'cell_7_voltage',
        ],
        'unpack_string':    'intle:16, intle:16, intle:16, intle:16'
    },
}

Reformed Christian. I was raised in a Christian family, and always believed in the basic concepts of God, heaven, hell, etc. But I mistakenly thought Christianity was about trying to be “good enough” for God until my mid teens. Around this time I realised that I couldn’t be perfect, which was super distressing for a time. But then I read Ephesians 2:8-9 which says:

For it is by grace you have been saved, through faith—and this is not from yourselves, it is the gift of God— not by works, so that no one can boast.

This was a big relief, as it meant that I didn’t need to rely on trying to be good enough for God. I just needed to accept God’s free gift of salvation. That’s the moment I would say I became a Christian.

Since then, I’ve had times where I’ve questioned it all, but I always come back to the resurrection of Jesus. I find the non-miraculous explanations of the resurrection account to be so implausible that it makes more sense to accept that it’s a historical fact. And if the resurrection’s true, then it makes sense to believe the rest of it as well.

What are your hobbies? Most people struggle to learn programming until they find a project that they are interested in. You mentioned an interest in music. Perhaps you could try Sonic Pi, which is a live coding environment where you can create music from code. It comes with a built-in tutorial, and a bunch of pre-written example code-music. It’s built with the ruby language.

Use RSS. Find good independent blogs which meet your standards of good open web content and subscribe to them. Some places to look:

• https://search.marginalia.nu/
• !weblogs@lemm.ee
• https://news.ycombinator.com/

Also, start your own website/blog and link to other websites and blogs.

I just use the KeePassXC password generator. :)

My 3 year old daughter has a 2010 MacBook running AntiX. She knows how to boot it, press Enter on the dual-boot screen, and is getting close to being able to select Stardew Valley from the app menu. She also enjoys playing GCompris.

The first step is to make sure your hardware is supported. I’ve found the linux hardware database to be invaluable getting new systems configured. The site is overwhelming at first, but the easy path is to just click the big ‘Probe your computer’ button and follow the instructions. Once you’ve done a probe, you’ll get a web-page with a listing of all your computer’s hardware and the support status. Even better, you get links to additional drivers or kernel modules required to get stuff working which isn’t supported out of the box.

I mainly use Python, so my workflow is the same on every OS: Neovim and a shell, usually one of each in a vertical split. This transfers nicely to remote SSH sessions too, and even works in Termux on my phone!

Have you investigated whether it’s possible to test your cross-compiled builds in Qemu, rather than copying them to the host?

Don’t forget apk! It’s FAST!

I have a git repository in ~/dotfiles, and symbolic link the ones I want as I need them. I’ve only just started tracking my dotfiles and I’m not super disciplined with it yet, so I still have slightly different setups on each system.