File type of normal
application data on
1541 floppies. Comes from
SEQuential. Most applications write to SEQ files, some use
PRG or
USR. "Text files" were often saved as SEQs.
From C64 BASIC, a SEQ file can be opened for writing with something like:
open 2,8,2,"0:filename,seq,write"
Or perharps read to read.