diff --git a/toolbox/os.cpp b/toolbox/os.cpp
index e6c3877..daf3414 100644
--- a/toolbox/os.cpp
+++ b/toolbox/os.cpp
@@ -52,7 +52,7 @@
 #include "os_internal.h"
 #include "toolbox.h"
 #include "stackframe.h"
-
+#include "fs_spec.h"
 
 using ToolBox::Log;
 
@@ -339,6 +339,31 @@ namespace OS
 
 	uint16_t Open(uint16_t trap)
 	{
+
+		enum {
+			/* IOParam */
+			_qLink = 0,
+			_qType = 4,
+			_ioTrap = 6,
+			_ioCmdAddr = 8,
+			_ioCompletion = 12,
+			_ioResult = 16,
+			_ioNamePtr = 18,
+			_ioVRefNum = 22,
+			_ioRefNum = 24,
+			_ioVersNum = 26,
+			_ioPermssn = 27,
+			_ioMisc = 28,
+			_ioBuffer = 32,
+			_ioReqCount = 36,
+			_ioActCount = 40,
+			_ioPosMode = 44,
+			_ioPosOffset = 46,
+
+			_ioDirID = 48,
+
+		};
+
 		uint32_t d0;
 
 		int fd;
@@ -348,25 +373,54 @@ namespace OS
 
 		Log("%04x Open(%08x)\n", trap, parm);
 
-		uint32_t namePtr = memoryReadLong(parm + 18);
+		uint32_t namePtr = memoryReadLong(parm + _ioNamePtr);
+		uint32_t ioDirID = memoryReadLong(parm + _ioDirID);
 
-		uint8_t ioPermission = memoryReadByte(parm + 27); 
+		uint8_t ioPermission = memoryReadByte(parm + _ioPermssn); 
 
 		std::string sname = ToolBox::ReadPString(namePtr, true);
+		sname = FSSpecManager::ExpandPath(sname, ioDirID);
+
+
 
 		fd = Internal::FDEntry::open(sname, ioPermission, false);
 		d0 = fd < 0 ? fd : 0;
 		if (fd >= 0)
 		{
-			memoryWriteWord(fd, parm + 24);				
+			memoryWriteWord(fd, parm + _ioRefNum);				
 		}
 
-		memoryWriteWord(d0, parm + 16);
+		memoryWriteWord(d0, parm + _ioResult);
 		return d0;
 	}
 
 	uint16_t OpenRF(uint16_t trap)
 	{
+
+		enum {
+			/* IOParam */
+			_qLink = 0,
+			_qType = 4,
+			_ioTrap = 6,
+			_ioCmdAddr = 8,
+			_ioCompletion = 12,
+			_ioResult = 16,
+			_ioNamePtr = 18,
+			_ioVRefNum = 22,
+			_ioRefNum = 24,
+			_ioVersNum = 26,
+			_ioPermssn = 27,
+			_ioMisc = 28,
+			_ioBuffer = 32,
+			_ioReqCount = 36,
+			_ioActCount = 40,
+			_ioPosMode = 44,
+			_ioPosOffset = 46,
+
+			_ioDirID = 48,
+
+		};
+
 		uint32_t d0;
 
 		int fd;
@@ -376,20 +430,22 @@ namespace OS
 
 		Log("%04x OpenRF(%08x)\n", trap, parm);
 
-		uint32_t namePtr = memoryReadLong(parm + 18);
+		uint32_t namePtr = memoryReadLong(parm + _ioNamePtr);
+		uint32_t ioDirID = memoryReadLong(parm + _ioDirID);
 
-		uint8_t ioPermission = memoryReadByte(parm + 27); 
+		uint8_t ioPermission = memoryReadByte(parm + _ioPermssn); 
 
 		std::string sname = ToolBox::ReadPString(namePtr, true);
+		sname = FSSpecManager::ExpandPath(sname, ioDirID);
 
 		fd = Internal::FDEntry::open(sname, ioPermission, true);
 		d0 = fd < 0 ? fd : 0;
 		if (fd >= 0)
 		{
-			memoryWriteWord(fd, parm + 24);				
+			memoryWriteWord(fd, parm + _ioRefNum);				
 		}
 
-		memoryWriteWord(d0, parm + 16);
+		memoryWriteWord(d0, parm + _ioResult);
 		return d0;
 	}