 For 7070 IOCS these are entries in the "File Specification Table" for tape files, each of which is generated by a DTF statement, or separate control blocks generated by DDF
DUF statements.In some other IOCS packages similar functions are provided by control cards.The above code defines a tape file on channel 1 called OUT, a sequential 1301/1302 disk file called DAFILE and a card file called CONSFILE.