Block Symbol File (.bsf)

A symbol file (with the extension .bsf) created with the Quartus^® II Symbol Editor. You can read and edit a symbol, which represents a macrofunction, primitive, megafunction, or design file, in a BSF, and add the symbol to a Block Design File (.bdf) with the Symbol Editor. You can also specify the ports and parameters of a symbol. The Symbol Editor allows you to open LMFs; however, you must make the read-only LMFs writable before you edit them.