added ipfs and fsspec

lectures/file-and-data-systems/slides.qmd

@@ -381,9 +381,16 @@ The file system becomes an independent system.
 
 # Shotgun buffet
 
-## IPFS
+## IPFS (InterPlanetary File System)
+* Content addressable storage on the internet (the hash of the data identifies a *file*.
+* Distributed index tables.
+* You either provide the data online or pay others to do so.
+* Automated methods of caching and replication.
+
 
 ## fsspec
+* Python package that provides pseudo-filesystems on various backends.
+* Unifies access to various implementations.
 
 ## Symbolic links (symlinks)