Hi, In MemoryFileSystem the class MemoryWriteStream seems dead code. Agreed ? In class MemoryFileWriteStream the IV writeStream seems to be used and could be removed. Agreed ? MemoryFileWriteStream>>#close must first do a #flush. Right ? I need these for fixing https://pharo.fogbugz.com/f/cases/22466/Add-readWriteStream-and-readWriteStr... but these are actually a bit independent. Sven