When I initially switched the computer portion of my rhythm stage setup over to a Raspberry PI I went with a 32GB SD card because that's recommended. But I don't need very much space for what I'm doing and a bigger SD card makes copies slow: the cheap cards I've been using take me over an hour to write with my Mac's card reader.

I recently made some changes to my setup, removing support for bass whistle on the PI (now that I have an arduino-based version) and adding support for more foot-bass options. This normally means round of re-imaging all of my SD cards: I have a bunch of them because SD card corruption is probably the most common reason my system breaks [1], and it's easy to have extra cards. I'm pretty sick of 82-minute waits, however, so I decided to go down to four-GB SD cards.

I imaged a card with Raspberry Pi OS Lite (64-bit), started setting it up, and immediately ran out of space. Turns out apt-get update and apt-get upgrade can use a lot of space. After apt-get purge and apt-get clean, however, I had about 300MB to spare. It would probably be possible to get a lite distribution to go a lot smaller than this, since the only actually large thing I need is the sound font, fluid-soundfont-gm at 145MB, but this seems to work fine.

Regardless, it works great, and I can now image a card in 15min:

$ time sudo dd if=~/Desktop/rpi-4gb.dmg of=/dev/disk4
7782400+0 records in
7782400+0 records out
3984588800 bytes transferred in 877.723067 secs (4539688 bytes/sec)

real       14m41.556s
user       0m3.299s
sys        0m28.741s

[1] This used to happen a lot, but now mostly doesn't. The hardware hasn't changed, so I think the reason it has stopped happening is that my Raspberry PI is no longer responsible for the bass whistle. My MIDI router doesn't write to the file system, and doesn't read beyond initialization, while the bass whistle version used the file system to persist settings across reboots.