# VFAT / FAT32
[](https://github.com/FedericoPonzi/vfat-rs/actions/workflows/CI.yml)
A simple VFAT implementation written in rust, and mostly tested against Linux's vfat driver.
It aims to be straightforward to understand and easy to use in a custom kernel.
It supports all the basic operations:
* File and directory creation,
* File reading and writing,
* Directory and file deletion,
* Metadata updates,
* Backup FAT writing
* Deleted clusters and directory entry slots are reused.
It needs better support for defragmentation — there is no defragmentation tool to consolidate free space.
## no_std
This component was first developed with `no_std` in mind. `std` is supported behind a feature flag, and it is used
for integration testing.
## Using it in your kernel
The exported apis are in the api module. The OS should provide:
* An implementation for the `TimeManagerTrait`. This is used for timestamping file creation and update.
* An implementation for the device trait. This is used to interact with the disk.
* `alloc` support — the library relies on the `alloc` crate (but not `std`) for heap-allocated types; like Box, Arc and String.
## Run example
The example runs in userspace. To run the example, first create a vfat fs using the script `tests/setup.sh`. This script:
* creates a vfat fs,
* mounts it,
* writes a bunch of files and directories (using your kernel's driver)
* unmounts it.
This file is also used for running integration tests. Your user needs sudo access for `mount` and `unmount` commands:
```text
fponzi ALL=(ALL) NOPASSWD: /usr/bin/mount,/usr/bin/umount
```
Then, you're ready to run the example file using:
```bash
cargo run --example simple --features std
```
### Benchmarks
CI runs benchmarks on every push to `master` and publishes historical results with trend charts to [the benchmark dashboard](http://gh.fponzi.me/vfat-rs/dev/bench/). If a benchmark regresses by more than 50%, an alert comment is created automatically.