> 8051s love talking to each other after all, otherwise USB would not exist.
Can anyone explain what the author meant by that? I thought 8051 is just an ISA, is there something special there for cross IC communication compared to other ISAs? And what the the connection to USB?
Awesome post! I'm confused about the schematics of the keyboard and I wonder if anybody here might point me in the right direction:
The HWB pin is pulled permanently low, so the MCU runs the default USB DFU bootloader on startup/reset.
Then the application firmware can be programmed using dfu-programmer.
But what happens after programming, when you unplug the keyboard and plug it back in? Since HWB is still pulled low, doesn't the MCU go back into the DFU bootloader instead of running the application?
How does the keyboard run the actual application firmware rather than the bootloader?
> Git is one of those technologies where it's super important to get a good grasp of how to internals work.
I fully agree, that's why I built a tutorial where you learn about Git internals by implementing Git yourself in Python:
https://www.leshenko.net/p/ugit/
Looks nice,
I wanted to submit a project and I spent time to fill the forms but I was greeted with a login wall after I filled all the details. There was no indication anywhere in the process that it would be required. It made me feel somewhat deceived.
I think it would be more honest towards your users to be upfront that you require login to submit a project.
I've seen people's Git skills improve after I taught them Git internals, but I taught them in a standard lecture format.
I didn't try teaching Git internals using code before, but I hypothesized it would be a good idea, and here is the result :) I'm curious about its effectiveness as well.
Yes! I'm going to adopt that wording.
Originally I tried to do a screencast about guided Git source code exploration but it didn't work because of that reason.
It was custom made for the tutorial. I didn't release it yet because I mostly focused on polishing the tutorial itself and not the code for the interface. Do you think people would be interested in the interface by itself?
Thanks! Note that ugit isn't supposed to be a custom compatible Git implementation, but rather a simplified Git-like implementation for teaching Git concepts. So even if ugit supported packfiles, it still won't be able to read a real Git repo.
I think it's important to distinguish between the concept of the init process vs specific implementations of the init process.
The article talks about the init process in general (the process that runs as PID 1 and picks orphaned processes).
There are different implementations of init (such as SysV-style, systemd, Upstart etc) but it doesn't make a difference for this article.
A restartable sequence is defined by a start and an end offset. If I write a restarable sequence in C I can't be absolutely sure that it's contiguous and I can't know where the commit instruction is...
Does it mean that I have to write it in assembly to make sure that I know where the sequence starts and where it ends?
The module takes an extra reference count to itself upon initialization and never decrements it, so rmmod will fail because the module will be "in use".