Method and apparatus for managing data such as in a flash memory. In some embodiments, a memory module electronics (MME) circuit writes groups of user data blocks to consecutive locations within a selected section of a non-volatile memory (NVM), and concurrently writes a directory map structure as a sequence of map entries distributed among the groups of user data blocks. Each map entry stores address information for the user data blocks in the associated group and a pointer to a subsequent map entry in the sequence. A control circuit accesses a first map entry in the sequence and uses the address information and pointer in the first map entry to locate the remaining map entries and the locations of the user data blocks in the respective groups. Lossless data compression may be applied to the groups prior to writing.