Editing Compatible Time-Sharing System (section)

===File system===
Each user had their own [[Directory (computing)|directory]], and there were also shared directories for groups of people with the same "problem number". Each [[Computer file|file]] had two names, the second indicating its type as did the [[Filename extension|extension]] in later systems. At first, each file could have one of four modes: temporary, permanent, read-only class 1, and read-only class 2. Read-only class 1 allowed the user to change the mode of the file. Files could also be symbolically linked between directories. A directory listing by ''listf'':
 	10 FILES	20 TRACKS USED
 DATE		NAME		MODE	NO. TRACKS
 5/20/63		MAIN	MAD	P	15
 5/17/63 	DPFA	SYMTB	P	1
 5/17/63 	DPFA	BSS	P	1
 5/17/63 	DPFA	FAP	P	2