diff --git a/toolbox/os.cpp b/toolbox/os.cpp
index 15f34de..06e6976 100644
--- a/toolbox/os.cpp
+++ b/toolbox/os.cpp
@@ -1,24 +1,55 @@
 #include "os.h"
-
+#include "toolbox.h"
 
 #include <cpu/defs.h>
 #include <cpu/CpuModule.h>
 #include <cpu/fmem.h>
 
 #include <string>
+#include <cerrno>
 
 #include <sys/xattr.h>
 #include <sys/stat.h>
 #include <sys/paths.h>
 #include <stdlib.h>
 
+namespace {
+
+	using namespace OS;
+
+	uint16_t errno_to_oserr(int xerrno)
+	{
+		switch (xerrno)
+		{
+			case EBADF: return rfNumErr;
+			case EIO: return ioErr;
+			case EACCES: return permErr;
+			case ENOENT: return fnfErr;
+			case ENOTDIR: return dirNFErr;
+			case EISDIR: return notAFileErr;
+			case ENOTSUP: return extFSErr;
+			case EROFS: return wPrErr;
+
+			case EDQUOT: return dskFulErr;
+			case ENOSPC: return dskFulErr;
+
+
+			default:
+				return ioErr;
+		}
+
+	}
+}
+
 namespace OS
 {
 
 	uint16_t GetFileInfo(uint16_t trap)
 	{
-		uint32_t parm = cpuGetAReg(0);
 
+		uint16_t d0;
+
+		uint32_t parm = cpuGetAReg(0);
 
 		fprintf(stderr, "%04x GetFileInfo(%08x)\n", trap, parm);
 
@@ -39,12 +70,7 @@ namespace OS
 				return bdNamErr;
 			}
 
-			int l = memoryReadByte(ioNamePtr);
-			sname.reserve(l);
-			for (unsigned i = 0; i < l; ++i)
-			{
-				sname.push_back(memoryReadByte(ioNamePtr + 1 + i));
-			}
+			sname = ToolBox::ReadPString(ioNamePtr);
 
 			// todo -- how are absolute, relative, etc paths handled...
 
@@ -53,8 +79,10 @@ namespace OS
 
 			if (::stat(sname.c_str(), &st) < 0)
 			{
-				memoryWriteWord(bdNamErr, parm + 16);
-				return fnfErr;
+				d0 = errno_to_oserr(errno);
+
+				memoryWriteWord(d0, parm + 16);
+				return d0;
 			}
 
 			// finder info
@@ -126,4 +154,79 @@ namespace OS
 		return 0;
 	}
 
+	uint16_t SetFileInfo(uint16_t trap)
+	{
+		std::string sname;
+		uint16_t d0;
+
+
+		uint32_t parm = cpuGetAReg(0);
+
+		fprintf(stderr, "%04x SetFileInfo(%08x)\n", trap, parm);
+
+		uint32_t ioCompletion = memoryReadLong(parm + 12);
+		uint32_t ioNamePtr = memoryReadLong(parm + 18);
+		uint16_t ioVRefNum = memoryReadWord(parm + 22);
+		uint8_t ioFVersNum = memoryReadByte(parm + 26);
+		//int16_t ioFDirIndex = memoryReadWord(parm + 28);
+
+		// + 32 = finder data - 16 bytes.
+
+		uint32_t ioFlCrDat = memoryReadLong(parm + 72);
+		uint32_t ioFlMdDat = memoryReadLong(parm + 76);
+
+		// currently, only sets finder info.
+
+		if (!ioNamePtr)
+		{
+			memoryWriteWord(bdNamErr, parm + 16);
+			return bdNamErr;
+		}
+
+		sname = ToolBox::ReadPString(ioNamePtr);
+
+		// check if the file actually exists
+		{
+			struct stat st;
+			int ok;
+
+			ok = ::stat(sname.c_str(), &st);
+			if (ok < 0)
+			{
+				d0 = errno_to_oserr(errno);
+				memoryWriteWord(d0, parm + 16);
+				return d0; 
+			}
+
+
+		}
+
+		// finder info is actually 32 bytes, so read and update the first 16.
+		{
+			uint8_t buffer[32];
+			int ok;
+
+			std::memset(buffer, 0, sizeof(buffer));
+
+			ok = ::getxattr(sname.c_str(), XATTR_FINDERINFO_NAME, buffer, 32, 0, 0);
+
+			// only 16 bytes copied.
+			std::memcpy(buffer, memoryPointer(parm + 32), 16);
+
+			ok = ::setxattr(sname.c_str(), XATTR_FINDERINFO_NAME, buffer, 32, 0, 0);	
+
+			if (ok < 0)
+			{
+				d0 = errno_to_oserr(errno);
+				memoryWriteWord(d0, parm + 16);
+				return d0; 				
+			}
+		} 
+
+		d0 = 0;
+		memoryWriteWord(d0, parm + 16);
+		return d0;
+	}
+
+
 }
\ No newline at end of file
diff --git a/toolbox/os.h b/toolbox/os.h
index ddeefe4..3d71a37 100644
--- a/toolbox/os.h
+++ b/toolbox/os.h
@@ -74,7 +74,7 @@ namespace OS
 		wrgVolTypErr = -123,                            /*Wrong volume type error [operation not supported for MFS]*/
 		volGoneErr = -124                               /*Server volume has been disconnected.*/
 	};
-	
+
 	enum {
 		fidNotFound = -1300,                            /*no file thread exists.*/
 		fidExists = -1301,                              /*file id already exists*/
@@ -100,6 +100,7 @@ namespace OS
 
 
 	uint16_t GetFileInfo(uint16_t trap);
+	uint16_t SetFileInfo(uint16_t trap);
 }
 
 #endif
diff --git a/toolbox/toolbox.cpp b/toolbox/toolbox.cpp
index 8904478..0cd55c7 100644
--- a/toolbox/toolbox.cpp
+++ b/toolbox/toolbox.cpp
@@ -11,11 +11,17 @@
 #include "mm.h"
 #include "os.h"
 
+#include <string>
+
 // yuck.  TST.W d0
 extern "C" void cpuSetFlagsNZ00NewW(UWO res);
 
 namespace ToolBox {
 
+
+
+
+
 	void dispatch(uint16_t trap)
 	{
 		// todo -- check/remove extra bits for save a0, toolglue, etc.
@@ -26,6 +32,9 @@ namespace ToolBox {
 			case 0xA00C:
 				d0 = OS::GetFileInfo(trap);
 				break;
+			case 0xa00d:
+				d0 = OS::SetFileInfo(trap);
+				break;
 
 			// BlockMove (sourcePtr,destPtr: Ptr; byteCount: Size);
 			case 0xa02e:
@@ -62,4 +71,31 @@ namespace ToolBox {
 		cpuSetFlagsNZ00NewW(d0);
 	}
 
+	std::string ReadCString(uint32_t address)
+	{
+		std::string tmp;
+
+		if (address)
+		{
+			tmp.assign((char *)memoryPointer(address));
+		}
+
+		return tmp;
+	}
+	
+	std::string ReadPString(uint32_t address)
+	{
+		std::string tmp;
+
+		if (address)
+		{
+			unsigned length = memoryReadByte(address);
+		
+			tmp.assign((char *)memoryPointer(address + 1), length);
+		}
+
+		return tmp;
+	}
+
+
 }
\ No newline at end of file
diff --git a/toolbox/toolbox.h b/toolbox/toolbox.h
index 3bc2471..600391c 100644
--- a/toolbox/toolbox.h
+++ b/toolbox/toolbox.h
@@ -1,9 +1,15 @@
 #ifndef __mpw_toolbox_h__
 #define __mpw_toolbox_h__
 
+#include <string>
+
 namespace ToolBox
 {
 	void dispatch(uint16_t trap);
+
+
+	std::string ReadCString(uint32_t address);
+	std::string ReadPString(uint32_t address);
 }