sceSaveDataSetSaveDataMemory2 read the whole slot file, patched it and
replaced it through a temporary file on every call, so each call cost a
full rewrite of the slot (up to 32 MiB). The changed ranges now go to a
small journal that is staged through the slot's temporary file and
renamed into place, then written into the slot file in place, and the
journal is removed. A journal left by an interrupted call is replayed by
the next setup, get, set or sync of that slot.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>