1 files changed, 51 insertions, 0 deletions
diff --git a/system/dos/1986/src/open b/system/dos/1986/src/open
new file mode 100644
index 0000000..92e81e9
--- /dev/null
+++ b/system/dos/1986/src/open
@@ -0,0 +1,51 @@
+PACKET open DEFINES                             (* Copyright (C) 1986 *)
+                                                (* Frank Klapper      *)
+  open  action,                                 (* 20.03.86           *)
+  close action,
+  action opened,
+  action closed,
+  init check rerun,
+  check rerun:
+
+BOOL VAR open;
+INT VAR old session;
+
+INITFLAG VAR packet := FALSE;
+
+PROC open action:
+  open := TRUE
+
+END PROC open action;
+
+PROC close action:
+  open := FALSE
+
+END PROC close action;
+
+BOOL PROC action opened:
+  IF NOT initialized (packet)
+    THEN close action
+  FI;
+  open
+
+END PROC action opened;
+
+BOOL PROC action closed:
+  NOT action opened
+
+END PROC action closed;
+
+PROC init check rerun:
+  old session := session
+
+END PROC init check rerun;
+
+PROC check rerun:
+  IF session <> old session
+    THEN close action;
+         error stop ("Diskettenzugriff im RERUN")
+  FI.
+
+END PROC check rerun;
+
+END PACKET open;