Sunday, June 7, 2020

The Safe Way to test Thermal Runaway Protection on 3D Printers

  1. Disconnect the heater cartridge from the main board
  2. Start heating the hot end
  3. Expect machine to error out after ~10 seconds and shut down 

Thursday, May 28, 2020

Writing useful commit comments

Some thoughts on writing useful [concise, descriptive, contextual] commit comments. Applies to all SCM systems (Git, Subversion, etc.)

A properly formed Git commit subject line should always be able to complete the following sentence:

  • If applied, this commit will your subject line here
For example:
  • If applied, this commit will refactor subsystem X for readability
  • If applied, this commit will update getting started documentation
  • If applied, this commit will remove deprecated methods
  • If applied, this commit will release version 1.0.0
  • If applied, this commit will merge pull request #123 from user/branch
Chris Beam

Thursday, May 14, 2020

Don't name ANYTHING AUX, or NUL, or...

Further to my earlier post, I discovered 'aux' is not just a bad choice for folder names, it's bad for ANY file name on Windows!

Apparently back in the Dark Ages (1974 or so) when Bill Gates invented computers, the Interwebs and everything else digital, AUX, NUL, COM3, etc. were deemed names reserved for the OS, "magical files" if you will. That decision lives on through backward-compatibility (c'mon, 1974?! CP/M?! DOS?!?!?).

While working on my project, MS Visual Studio Code happily agreed to let me name a file"aux.yaml". Even though this ominous warning appeared, it let me continue once I appended "yaml" to the name:

 Everything went fine until I tried to add the file to the project's working copy in Subversion. For some reason, no matter how many times I pressed "Add..." in TortoiseSVN, the file refused to appear in the commit list, and failed to adopt its stroppy little blue plus sign in Windows Explorer.

Hmm, let's open it with Notepad++ to make sure the file is OK - nope, Notepad++ complained bitterly about the file when I tried to open it:

So at this point I figure the file was somehow corrupted by my attempts to add it or move it around in the Subversion working copy, let's just nuke it and start over:

OK this is definitely weird.

A few minutes googling produced the answer: open an admin command prompt and delete or rename the file. The command ren \\.\C:\path\to\file\aux.yaml auxiliary.yaml put everything right again - TortoiseSVN happily added the file, Notepad++ opened it with nary a whimper, and Visual Studio Code - well, let's just say it has it's own opinion on file names.


How a 1974 bug still bites Win10 and Azure users

Monday, May 11, 2020

Windows error naming folder 'aux' - wat?!

Windows complained, unjustly I thought, when I tried to name a folder 'aux'. Turns out this is one of a number of restricted MSDOS device files:

LST (only in 86-DOS and DOS 1.xx)
KEYBD$, SCREEN$ (only in multitasking MS-DOS 4.0)
$IDLE$ (only in Concurrent DOS 386, Multiuser DOS and DR DOS 5.0 and higher)
CONFIG$ (only in MS-DOS 7.0-8.0)