Re: msdosfs oddity?

[Jason Thorpe <thorpej%me.com@localhost>]

> On Nov 29, 2024, at 12:39 PM, Mouse <mouse%Rodents-Montreal.ORG@localhost> wrote:
> 
> Someone at work recently gave me a Raspberry Pi Pico.  This is an ARM
> SoC.  It's way too small to run NetBSD (less than a meg of RAM); I
> wanted to build my own bare-metal code for it.  The reason I'm writing
> is that I'm having trouble accessing it as a USB device.  This is on
> 5.2; I don't know whether the msdosfs support is different.  If anyone
> can tell me what I might need to do differently, I can experiment.

I do a lot of hobby stuff with RPi Pico, so I’m pretty familiar with its inner workings.

The file system on the Pico (and all of the RP2040 devices) is completely virtual.  There is no actual file system on the device.  The boot ROM snoops the writes and looks for blocks written in a specific format described by the UF2 specification and in turn writes them to the correct location in the on-board flash.

> bootsig0 0 bootsig1 0
> msdosfs_mountfs 22
> 
> and sd0d gives me
> 
> bytespersec 0 secperclust 0 secpertrack 0
> msdosfs_mountfs 22
> 
> Of course, it works fine on Linux.  I'm so sick of "just use Linux and
> it all works" instead of actually bloody _documenting_ things.

It works fine on macOS, too :-)

Anyway, figure out where it’s returning the EINVAL?

-- thorpej