Consider using fat-rs

[thejpster]

We should consider switching to FAT-rs (https://gitlab.com/susurrus/fat-rs/tree/master). No sense in duplicating work, if it:

• Works on #[no_std]
• Builds on stable
• Doesn't use alloc

[thejpster]

(https://github.com/rafalh/rust-fatfs fails this test because it uses core_io, which needs nightly, and uses alloc)

[twilco]

From fat-rs's README:

Eventually this will be migrated to use core_ios traits in order to be compatible with other libraries in the nascent no_std Rust ecosystem.

Looks like they might be moving towards core_io, too. Also, perhaps this is an ignorant question, but is it odd that these crates are moving towards core_io which requires alloc? Isn't the idea with embedded to avoid allocation whenever possible, meaning the utility of these crates becomes more limited by using implementations that require allocation?

Finally, I haven't been able to find a published crate on crates.io for fat-rs - perhaps I'm just missing it? 🙂

[rafalh]

Please note https://github.com/rafalh/rust-fatfs requires alloc only if you need LFN support.

[thejpster]

We have write support now. But we should keep an eye on what other crates are doing.