diff --git a/src/interrupts.s b/src/interrupts.s
index f1211a5..ab43a8c 100644
--- a/src/interrupts.s
+++ b/src/interrupts.s
@@ -204,8 +204,6 @@ cop_jump_table:
 	.word .word0 dir_open
 	.word .word0 dir_close
 	.word .word0 dir_read
-	.word .word0 dir_first
-	.word .word0 dir_next
 
 ; -----------------------------------------------------------------------------
 sys_reset:
@@ -306,7 +304,8 @@ con_puts:
 	rts
 
 ; -----------------------------------------------------------------------------
-; Read a line of input from stdin, storing as a NULL-terminated string.
+; Read a line of input from stdin, storing as a NULL-terminated string. That is,
+; standard input is read until a newline is encountered.
 ;
 ; Arguments:
 ;		A: Bank of destination buffer
@@ -340,7 +339,8 @@ sh_exec:
 
 ; -----------------------------------------------------------------------------
 ; Exit the running user program, returning to the shell with an exit code. This
-; function does not return.
+; function does not return. If there is no shell specified in the kernel's
+; memory, then the kernel will load and run a PGZ binary stored in ROM.
 ;
 ; Arguments:
 ;		A: Exit code
@@ -778,11 +778,23 @@ dir_open:
 dir_close:
 	rts
 
+; -----------------------------------------------------------------------------
+; Given a pointer to a structure populated by dir_open and a pointer to a file
+; information structure buffer, read the next directory item from the directory.
+; Repeated invocations of this function on a single directory read the items
+; one at a time, until the last one, at which point the read item will have
+; a NULL name; reading will then loop back to the beginning. The arguments are
+; passed in a data structure with the following layout:
+;
+; struct dir_read_s {
+;		void *dir;
+;		void *file_info;
+; };
+;
+; Arguments:
+;		A: Bank of argument
+;		Y: Address of argument
+; Return value:
+;		A: Error code
 dir_read:
 	rts
-
-dir_find_first:
-	rts
-
-dir_find_next:
-	rts