diff --git a/src/development/design/filesystem.md b/src/development/design/filesystem.md
index 3259573..ab3129e 100644
--- a/src/development/design/filesystem.md
+++ b/src/development/design/filesystem.md
@@ -24,19 +24,22 @@ It's identified simply by numerical order.
 const BOOT_SIZE: u64; // How large the BOOT partition will be
 const LABEL_SIZE: u64; // Number of characters that can be used in the partition label
 
+let NUM_CHUNLKS: u64; // Number of chunks in a specific partition
 struct PartitionHeader {
     boot: bool, // Boot flag
     label: [char; LABEL_SIZE], // Human-readable label. Not UTF-8 though :/
-    num_chunks: u64, // Chunks in this partition
+    index: [(u64, Uuid); NUM_CHUNKS], // Array of tuples mapping Actor UUID's to chunk indexes
+    // TODO: What if a Uuid is on multiple chunks?
+    num_chunks: NUM_CHUNKS, // Chunks in this partition
 }
 ```
 
 ### Chunk
 Small pieces that each partition is split into.
-Contains fixed-length metadata (checksum, extension flag, uuid) at the beginning, and then arbitrary data afterwards.
+Contains fixed-length metadata (checksum, extension flag) at the beginning, and then arbitrary data afterwards.
 If the saved data exceeds past a single chunk, the `extends` flag is set.
 
-Additionally, it has a **UUID** generated via [lolid](https://lib.rs/crates/lolid) to enable identifying a specific chunk.
+<!-- Additionally, it has a **UUID** generated via [lolid](https://lib.rs/crates/lolid) to enable identifying a specific chunk. -->
 
 ```rust
 const CHUNK_SIZE: u64; // Example static chunk size
@@ -45,7 +48,6 @@ struct ChunkHeader {
     checksum: u64,
     extends: bool,
     encrypted: bool,
-    uuid: Uuid,
     modified: u64, // Timestamp of last modified
 }
 
@@ -75,6 +77,7 @@ Basically, `part1_offset = BOOT_PARTITION_SIZE`, `part1_data_start = part1_offse
 ### Writing
 Writing uses a similar process. An *Actor* can request to write data. If it has proper capabilties, we serialize the data, allocate a free chunk[^free_chunk], and write to it.
 We *hash* the data first to generate a checksum, and set proper metadata if the data extends past the `CHUNK_SIZE`.
+Then the `ParitionHeader` *index* is updated to contain the new chunk(s) being used.
 
 ### Permissions
 Again, whether actors can:
@@ -116,6 +119,6 @@ struct PackedExecutable {
 
 [^encryption]: Specific details to be figured out later
 
-[^find_chunk]: Currently via magic. I have no idea how to do this other than a simple search. Maybe generate an index, or use a **UUID**?
+[^find_chunk]: The `PartitionHeader` has a tuple `(Uuid, u64)` which maps each `Actor` to a chunk number, allowing for easy finding of a specific chunk from an actor-provided `Uuid`.
 
-[^free_chunk]: Again, no idea how.
+[^free_chunk]: Because we know which chunks are used, we know which ones aren't.