diff --git a/OpenSim/Framework/IImprovedAssetCache.cs b/OpenSim/Framework/IAssetCache.cs
similarity index 92%
rename from OpenSim/Framework/IImprovedAssetCache.cs
rename to OpenSim/Framework/IAssetCache.cs
index a853e9015d..8477116403 100644
--- a/OpenSim/Framework/IImprovedAssetCache.cs
+++ b/OpenSim/Framework/IAssetCache.cs
@@ -29,7 +29,7 @@ using OpenSim.Framework;
 
 namespace OpenSim.Framework
 {
-    public interface IImprovedAssetCache
+    public interface IAssetCache
     {
         /// <summary>
         /// Cache the specified asset.
@@ -38,6 +38,12 @@ namespace OpenSim.Framework
         void Cache(AssetBase asset);
 
         /// <summary>
+        /// Cache that the specified asset wasn't found.
+        /// </summary>
+        /// <param name='id'></param>
+        /// <summary>
+        void CacheNegative(string id);
+
         /// Get an asset by its id.
         /// </summary>
         /// <param name='id'></param>
@@ -61,4 +67,4 @@ namespace OpenSim.Framework
         /// </summary>
         void Clear();
     }
-}
\ No newline at end of file
+}
diff --git a/OpenSim/Framework/WearableCacheItem.cs b/OpenSim/Framework/WearableCacheItem.cs
index af28abc74c..966a6bc290 100644
--- a/OpenSim/Framework/WearableCacheItem.cs
+++ b/OpenSim/Framework/WearableCacheItem.cs
@@ -50,7 +50,7 @@ namespace OpenSim.Framework
             return retitems;          
         }
 
-        public static WearableCacheItem[] FromOSD(OSD pInput, IImprovedAssetCache dataCache)
+        public static WearableCacheItem[] FromOSD(OSD pInput, IAssetCache dataCache)
         {
             List<WearableCacheItem> ret = new List<WearableCacheItem>();
             if (pInput.Type == OSDType.Array)
@@ -100,7 +100,7 @@ namespace OpenSim.Framework
 
         }
 
-        public static OSD ToOSD(WearableCacheItem[] pcacheItems, IImprovedAssetCache dataCache)
+        public static OSD ToOSD(WearableCacheItem[] pcacheItems, IAssetCache dataCache)
         {
             OSDArray arr = new OSDArray();
             foreach (WearableCacheItem item in pcacheItems)
diff --git a/OpenSim/Region/Application/OpenSim.cs b/OpenSim/Region/Application/OpenSim.cs
index 3cb999bee5..d9fdcde732 100644
--- a/OpenSim/Region/Application/OpenSim.cs
+++ b/OpenSim/Region/Application/OpenSim.cs
@@ -206,6 +206,7 @@ namespace OpenSim
             MainServer.Instance.AddStreamHandler(new OpenSim.XSimStatusHandler(this));
             if (userStatsURI != String.Empty)
                 MainServer.Instance.AddStreamHandler(new OpenSim.UXSimStatusHandler(this));
+            MainServer.Instance.AddStreamHandler(new OpenSim.SimRobotsHandler());
 
             if (managedStatsURI != String.Empty)
             {
diff --git a/OpenSim/Region/Application/OpenSimBase.cs b/OpenSim/Region/Application/OpenSimBase.cs
index 90505e193f..b8363ab789 100644
--- a/OpenSim/Region/Application/OpenSimBase.cs
+++ b/OpenSim/Region/Application/OpenSimBase.cs
@@ -898,6 +898,26 @@ namespace OpenSim
             }
         }
 
+        /// <summary>
+        /// handler to supply serving http://domainname:port/robots.txt
+        /// </summary>
+        public class SimRobotsHandler : BaseStreamHandler
+        {
+            public SimRobotsHandler() : base("GET", "/robots.txt", "SimRobots.txt", "Simulator Robots.txt") {}
+
+            protected override byte[] ProcessRequest(string path, Stream request,
+                                 IOSHttpRequest httpRequest, IOSHttpResponse httpResponse)
+            {
+                string robots = "# go away\nUser-agent: *\nDisallow: /\n";
+                return Util.UTF8.GetBytes(robots);
+            }
+
+            public override string ContentType
+            {
+                get { return "text/plain"; }
+            }
+        }
+
         #endregion
 
         /// <summary>
diff --git a/OpenSim/Region/ClientStack/Linden/UDP/LLClientView.cs b/OpenSim/Region/ClientStack/Linden/UDP/LLClientView.cs
index a69b670cd7..55050d9de4 100644
--- a/OpenSim/Region/ClientStack/Linden/UDP/LLClientView.cs
+++ b/OpenSim/Region/ClientStack/Linden/UDP/LLClientView.cs
@@ -621,7 +621,11 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             GroupsInView.Clear();
 
             if(m_scene.GetNumberOfClients() == 0)
-                GC.Collect();          
+            {
+                GC.Collect();
+                GC.WaitForPendingFinalizers();
+                GC.Collect();
+            }
         }
 
         public void Kick(string message)
diff --git a/OpenSim/Region/CoreModules/Agent/TextureSender/J2KDecoderModule.cs b/OpenSim/Region/CoreModules/Agent/TextureSender/J2KDecoderModule.cs
index 47dcbcd3ff..6d1f0c2ab1 100644
--- a/OpenSim/Region/CoreModules/Agent/TextureSender/J2KDecoderModule.cs
+++ b/OpenSim/Region/CoreModules/Agent/TextureSender/J2KDecoderModule.cs
@@ -57,13 +57,13 @@ namespace OpenSim.Region.CoreModules.Agent.TextureSender
         /// <summary>List of client methods to notify of results of decode</summary>
         private readonly Dictionary<UUID, List<DecodedCallback>> m_notifyList = new Dictionary<UUID, List<DecodedCallback>>();
         /// <summary>Cache that will store decoded JPEG2000 layer boundary data</summary>
-        private IImprovedAssetCache m_cache;
-        private IImprovedAssetCache Cache
+        private IAssetCache m_cache;
+        private IAssetCache Cache
         {
             get
             {
                 if (m_cache == null)
-                    m_cache = m_scene.RequestModuleInterface<IImprovedAssetCache>();
+                    m_cache = m_scene.RequestModuleInterface<IAssetCache>();
 
                 return m_cache;
             }
diff --git a/OpenSim/Region/CoreModules/Asset/CenomeAssetCache.cs b/OpenSim/Region/CoreModules/Asset/CenomeAssetCache.cs
index ebec9d2d74..14b0280cd5 100644
--- a/OpenSim/Region/CoreModules/Asset/CenomeAssetCache.cs
+++ b/OpenSim/Region/CoreModules/Asset/CenomeAssetCache.cs
@@ -91,7 +91,7 @@ namespace OpenSim.Region.CoreModules.Asset
     /// </code>
     /// </example>
     [Extension(Path = "/OpenSim/RegionModules", NodeName = "RegionModule", Id = "CenomeMemoryAssetCache")]
-    public class CenomeMemoryAssetCache : IImprovedAssetCache, ISharedRegionModule
+    public class CenomeMemoryAssetCache : IAssetCache, ISharedRegionModule
     {
         private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
         
@@ -192,7 +192,7 @@ namespace OpenSim.Region.CoreModules.Asset
                 expirationTime);
         }
 
-        #region IImprovedAssetCache Members
+        #region IAssetCache Members
 
         public bool Check(string id)
         {
@@ -221,6 +221,11 @@ namespace OpenSim.Region.CoreModules.Asset
 
         }
 
+        public void CacheNegative(string id)
+        {
+            // We don't do negative caching
+        }
+
         /// <summary>
         /// Clear asset cache.
         /// </summary>
@@ -308,7 +313,7 @@ namespace OpenSim.Region.CoreModules.Asset
         public void AddRegion(Scene scene)
         {
             if (m_enabled)
-                scene.RegisterModuleInterface<IImprovedAssetCache>(this);
+                scene.RegisterModuleInterface<IAssetCache>(this);
         }
 
         /// <summary>
diff --git a/OpenSim/Region/CoreModules/Asset/CoreAssetCache.cs b/OpenSim/Region/CoreModules/Asset/CoreAssetCache.cs
index f72074851e..82bc5ccebb 100644
--- a/OpenSim/Region/CoreModules/Asset/CoreAssetCache.cs
+++ b/OpenSim/Region/CoreModules/Asset/CoreAssetCache.cs
@@ -40,7 +40,7 @@ using OpenSim.Services.Interfaces;
 namespace OpenSim.Region.CoreModules.Asset
 {
     [Extension(Path = "/OpenSim/RegionModules", NodeName = "RegionModule", Id = "CoreAssetCache")]
-    public class CoreAssetCache : ISharedRegionModule, IImprovedAssetCache
+    public class CoreAssetCache : ISharedRegionModule, IAssetCache
     {
         private static readonly ILog m_log =
                 LogManager.GetLogger(
@@ -98,7 +98,7 @@ namespace OpenSim.Region.CoreModules.Asset
         public void AddRegion(Scene scene)
         {
             if (m_Enabled)
-                scene.RegisterModuleInterface<IImprovedAssetCache>(this);
+                scene.RegisterModuleInterface<IAssetCache>(this);
         }
 
         public void RemoveRegion(Scene scene)
@@ -110,7 +110,7 @@ namespace OpenSim.Region.CoreModules.Asset
         }
 
         ////////////////////////////////////////////////////////////
-        // IImprovedAssetCache
+        // IAssetCache
         //
         public bool Check(string id)
         {
@@ -124,6 +124,11 @@ namespace OpenSim.Region.CoreModules.Asset
                 m_Cache.Store(asset.ID, asset);
         }
 
+        public void CacheNegative(string id)
+        {
+            // We don't do negative caching
+        }
+
         public AssetBase Get(string id)
         {
             return (AssetBase)m_Cache.Get(id);
diff --git a/OpenSim/Region/CoreModules/Asset/FlotsamAssetCache.cs b/OpenSim/Region/CoreModules/Asset/FlotsamAssetCache.cs
index b6dd5652c7..84e13a0d9d 100644
--- a/OpenSim/Region/CoreModules/Asset/FlotsamAssetCache.cs
+++ b/OpenSim/Region/CoreModules/Asset/FlotsamAssetCache.cs
@@ -55,7 +55,7 @@ using OpenSim.Services.Interfaces;
 namespace OpenSim.Region.CoreModules.Asset
 {
     [Extension(Path = "/OpenSim/RegionModules", NodeName = "RegionModule", Id = "FlotsamAssetCache")]
-    public class FlotsamAssetCache : ISharedRegionModule, IImprovedAssetCache, IAssetService
+    public class FlotsamAssetCache : ISharedRegionModule, IAssetCache, IAssetService
     {
         private static readonly ILog m_log =
                 LogManager.GetLogger(
@@ -78,6 +78,7 @@ namespace OpenSim.Region.CoreModules.Asset
         private static ulong m_RequestsForInprogress;
         private static ulong m_DiskHits;
         private static ulong m_MemoryHits;
+        private static ulong m_weakRefHits;
 
 #if WAIT_ON_INPROGRESS_REQUESTS
         private Dictionary<string, ManualResetEvent> m_CurrentlyWriting = new Dictionary<string, ManualResetEvent>();
@@ -91,9 +92,15 @@ namespace OpenSim.Region.CoreModules.Asset
         private ExpiringCache<string, AssetBase> m_MemoryCache;
         private bool m_MemoryCacheEnabled = false;
 
+        private ExpiringCache<string, object> m_negativeCache;
+        private bool m_negativeCacheEnabled = true;
+        private bool m_negativeCacheSliding = false;
+
         // Expiration is expressed in hours.
-        private double m_MemoryExpiration = 0.001;
+        private double m_MemoryExpiration = 0.016;
         private const double m_DefaultFileExpiration = 48;
+        // Negative cache is in seconds
+        private int m_negativeExpiration = 120;
         private TimeSpan m_FileExpiration = TimeSpan.FromHours(m_DefaultFileExpiration);
         private TimeSpan m_FileExpirationCleanupTimer = TimeSpan.FromHours(1.0);
 
@@ -107,6 +114,10 @@ namespace OpenSim.Region.CoreModules.Asset
         private List<Scene> m_Scenes = new List<Scene>();
         private object timerLock = new object();
         
+        private Dictionary<string,WeakReference> weakAssetReferences = new Dictionary<string, WeakReference>();
+        private object weakAssetReferencesLock = new object();
+        private bool m_updateFileTimeOnCacheHit = false;
+
         public FlotsamAssetCache()
         {
             m_InvalidChars.AddRange(Path.GetInvalidPathChars());
@@ -134,6 +145,7 @@ namespace OpenSim.Region.CoreModules.Asset
                 if (name == Name)
                 {
                     m_MemoryCache = new ExpiringCache<string, AssetBase>();
+                    m_negativeCache = new ExpiringCache<string, object>();
                     m_Enabled = true;
 
                     m_log.InfoFormat("[FLOTSAM ASSET CACHE]: {0} enabled", this.Name);
@@ -152,6 +164,11 @@ namespace OpenSim.Region.CoreModules.Asset
                         m_MemoryCacheEnabled = assetConfig.GetBoolean("MemoryCacheEnabled", m_MemoryCacheEnabled);
                         m_MemoryExpiration = assetConfig.GetDouble("MemoryCacheTimeout", m_MemoryExpiration);
                         m_MemoryExpiration *= 3600.0; // config in hours to seconds
+
+                        m_negativeCacheEnabled = assetConfig.GetBoolean("NegativeCacheEnabled", m_negativeCacheEnabled);
+                        m_negativeExpiration = assetConfig.GetInt("NegativeCacheTimeout", m_negativeExpiration);
+                        m_negativeCacheSliding = assetConfig.GetBoolean("NegativeCacheSliding", m_negativeCacheSliding);
+                        m_updateFileTimeOnCacheHit = assetConfig.GetBoolean("UpdateFileTimeOnCacheHit", m_updateFileTimeOnCacheHit);
     
     #if WAIT_ON_INPROGRESS_REQUESTS
                         m_WaitOnInprogressTimeout = assetConfig.GetInt("WaitOnInprogressTimeout", 3000);
@@ -212,7 +229,7 @@ namespace OpenSim.Region.CoreModules.Asset
         {
             if (m_Enabled)
             {
-                scene.RegisterModuleInterface<IImprovedAssetCache>(this);
+                scene.RegisterModuleInterface<IAssetCache>(this);
                 m_Scenes.Add(scene);
             }
         }
@@ -221,7 +238,7 @@ namespace OpenSim.Region.CoreModules.Asset
         {
             if (m_Enabled)
             {
-                scene.UnregisterModuleInterface<IImprovedAssetCache>(this);
+                scene.UnregisterModuleInterface<IAssetCache>(this);
                 m_Scenes.Remove(scene);
                 lock(timerLock)
                 {
@@ -255,12 +272,23 @@ namespace OpenSim.Region.CoreModules.Asset
                         }
                     }
                  }
+                if (m_MemoryCacheEnabled)
+                    m_MemoryCache = new ExpiringCache<string, AssetBase>();
+            
+                lock(weakAssetReferencesLock)
+                    weakAssetReferences = new Dictionary<string, WeakReference>();
             }
         }
 
         ////////////////////////////////////////////////////////////
-        // IImprovedAssetCache
+        // IAssetCache
         //
+        private void UpdateWeakReference(string key, AssetBase asset)
+        {
+            WeakReference aref = new WeakReference(asset);
+            lock(weakAssetReferencesLock)
+                weakAssetReferences[key] = aref;
+        }
 
         private void UpdateMemoryCache(string key, AssetBase asset)
         {
@@ -327,6 +355,7 @@ namespace OpenSim.Region.CoreModules.Asset
             if (asset != null)
             {
                 //m_log.DebugFormat("[FLOTSAM ASSET CACHE]: Caching asset with id {0}", asset.ID);
+                UpdateWeakReference(asset.ID, asset);
 
                 if (m_MemoryCacheEnabled)
                     UpdateMemoryCache(asset.ID, asset);
@@ -336,6 +365,17 @@ namespace OpenSim.Region.CoreModules.Asset
             }
         }
 
+        public void CacheNegative(string id)
+        {
+            if (m_negativeCacheEnabled)
+            {
+                if (m_negativeCacheSliding)
+                    m_negativeCache.AddOrUpdate(id, null, TimeSpan.FromSeconds(m_negativeExpiration));
+                else
+                    m_negativeCache.AddOrUpdate(id, null, m_negativeExpiration);
+            }
+        }
+
         /// <summary>
         /// Updates the cached file with the current time.
         /// </summary>
@@ -354,6 +394,25 @@ namespace OpenSim.Region.CoreModules.Asset
             }
         }
 
+        private AssetBase GetFromWeakReference(string id)
+        {
+            AssetBase asset = null;
+            WeakReference aref;
+
+            lock(weakAssetReferencesLock)
+            {
+                if (weakAssetReferences.TryGetValue(id, out aref))
+                {
+                    asset = aref.Target as AssetBase;
+                    if(asset == null)
+                        weakAssetReferences.Remove(id);
+                    else
+                        m_weakRefHits++;
+                }
+            }
+            return asset;
+        }
+
         /// <summary>
         /// Try to get an asset from the in-memory cache.
         /// </summary>
@@ -476,13 +535,38 @@ namespace OpenSim.Region.CoreModules.Asset
         {
             m_Requests++;
 
-            AssetBase asset = null;
+            object dummy;
+            if (m_negativeCache.TryGetValue(id, out dummy))
+                return null;
 
-            if (m_MemoryCacheEnabled)
+            AssetBase asset = null;
+            asset = GetFromWeakReference(id);
+            if (asset != null && m_updateFileTimeOnCacheHit)
+            {
+                string filename = GetFileName(id);
+                UpdateFileLastAccessTime(filename);
+            }
+
+            if (m_MemoryCacheEnabled && asset == null)
+            {
                 asset = GetFromMemoryCache(id);
+                if(asset != null)
+                {
+                    UpdateWeakReference(id,asset);
+                    if (m_updateFileTimeOnCacheHit)
+                    {
+                        string filename = GetFileName(id);
+                        UpdateFileLastAccessTime(filename);
+                    }
+                }
+            }
 
             if (asset == null && m_FileCacheEnabled)
+            {
                 asset = GetFromFileCache(id);
+                if(asset != null)
+                    UpdateWeakReference(id,asset);
+            }
 
             if (m_MemoryCacheEnabled && asset != null)
                 UpdateMemoryCache(id, asset);
@@ -494,6 +578,12 @@ namespace OpenSim.Region.CoreModules.Asset
                 GenerateCacheHitReport().ForEach(l => m_log.InfoFormat("[FLOTSAM ASSET CACHE]: {0}", l));
             }
 
+            if(asset == null)
+            {
+
+
+            }
+
             return asset;
         }
 
@@ -530,6 +620,9 @@ namespace OpenSim.Region.CoreModules.Asset
 
                 if (m_MemoryCacheEnabled)
                     m_MemoryCache.Remove(id);
+
+                lock(weakAssetReferencesLock)
+                    weakAssetReferences.Remove(id);
             }
             catch (Exception e)
             {
@@ -553,7 +646,12 @@ namespace OpenSim.Region.CoreModules.Asset
             }
 
             if (m_MemoryCacheEnabled)
-                m_MemoryCache.Clear();
+                m_MemoryCache = new ExpiringCache<string, AssetBase>();
+            if (m_negativeCacheEnabled)
+                m_negativeCache = new ExpiringCache<string, object>();
+            
+            lock(weakAssetReferencesLock)
+                weakAssetReferences = new Dictionary<string, WeakReference>();
         }
 
         private void CleanupExpiredFiles(object source, ElapsedEventArgs e)
@@ -911,28 +1009,34 @@ namespace OpenSim.Region.CoreModules.Asset
             List<string> outputLines = new List<string>();
 
             double invReq = 100.0 / m_Requests;
+
+            double weakHitRate = m_weakRefHits * invReq;
+            int weakEntries = weakAssetReferences.Count;
             
             double fileHitRate = m_DiskHits * invReq;
+            double TotalHitRate = weakHitRate + fileHitRate;
+
             outputLines.Add(
-                string.Format("File Hit Rate: {0}% for {1} requests", fileHitRate.ToString("0.00"), m_Requests));
+                string.Format("Total requests: {0}", m_Requests));
+            outputLines.Add(
+                string.Format("unCollected Hit Rate: {0}% ({1} entries)", weakHitRate.ToString("0.00"),weakEntries));
+            outputLines.Add(
+                string.Format("File Hit Rate: {0}%", fileHitRate.ToString("0.00")));
 
             if (m_MemoryCacheEnabled)
             {
                 double HitRate = m_MemoryHits * invReq;
-
                 outputLines.Add(
-                    string.Format("Memory Hit Rate: {0}% for {1} requests", HitRate.ToString("0.00"), m_Requests));
+                    string.Format("Memory Hit Rate: {0}%", HitRate.ToString("0.00")));
 
-                HitRate += fileHitRate;
-
-                outputLines.Add(
-                    string.Format("Total Hit Rate: {0}% for {1} requests", HitRate.ToString("0.00"), m_Requests));
+                TotalHitRate += HitRate;
             }
+            outputLines.Add(
+                string.Format("Total Hit Rate: {0}%", TotalHitRate.ToString("0.00")));
 
             outputLines.Add(
                 string.Format(
-                    "Unnecessary requests due to requests for assets that are currently downloading: {0}", 
-                    m_RequestsForInprogress));
+                    "Requests overlap during file writing: {0}", m_RequestsForInprogress));
 
             return outputLines;
         }
diff --git a/OpenSim/Region/CoreModules/Asset/GlynnTuckerAssetCache.cs b/OpenSim/Region/CoreModules/Asset/GlynnTuckerAssetCache.cs
index 5f76ac2c9e..195bdaa43f 100644
--- a/OpenSim/Region/CoreModules/Asset/GlynnTuckerAssetCache.cs
+++ b/OpenSim/Region/CoreModules/Asset/GlynnTuckerAssetCache.cs
@@ -41,7 +41,7 @@ using OpenSim.Services.Interfaces;
 namespace OpenSim.Region.CoreModules.Asset
 {
     [Extension(Path = "/OpenSim/RegionModules", NodeName = "RegionModule", Id = "GlynnTuckerAssetCache")]
-    public class GlynnTuckerAssetCache : ISharedRegionModule, IImprovedAssetCache
+    public class GlynnTuckerAssetCache : ISharedRegionModule, IAssetCache
     {
         private static readonly ILog m_log =
                 LogManager.GetLogger(
@@ -100,7 +100,7 @@ namespace OpenSim.Region.CoreModules.Asset
         public void AddRegion(Scene scene)
         {
             if (m_Enabled)
-                scene.RegisterModuleInterface<IImprovedAssetCache>(this);
+                scene.RegisterModuleInterface<IAssetCache>(this);
         }
 
         public void RemoveRegion(Scene scene)
@@ -112,7 +112,7 @@ namespace OpenSim.Region.CoreModules.Asset
         }
 
         ////////////////////////////////////////////////////////////
-        // IImprovedAssetCache
+        // IAssetCache
         //
 
         public bool Check(string id)
@@ -126,6 +126,11 @@ namespace OpenSim.Region.CoreModules.Asset
                 m_Cache.AddOrUpdate(asset.ID, asset);
         }
 
+        public void CacheNegative(string id)
+        {
+            // We don't do negative caching
+        }
+
         public AssetBase Get(string id)
         {
             Object asset = null;
diff --git a/OpenSim/Region/CoreModules/Avatar/AvatarFactory/AvatarFactoryModule.cs b/OpenSim/Region/CoreModules/Avatar/AvatarFactory/AvatarFactoryModule.cs
index 41a3f5239e..67256ee685 100644
--- a/OpenSim/Region/CoreModules/Avatar/AvatarFactory/AvatarFactoryModule.cs
+++ b/OpenSim/Region/CoreModules/Avatar/AvatarFactory/AvatarFactoryModule.cs
@@ -288,7 +288,7 @@ namespace OpenSim.Region.CoreModules.Avatar.AvatarFactory
             if (bakedTextures.Count == 0)
                 return false;
 
-            IImprovedAssetCache cache = sp.Scene.RequestModuleInterface<IImprovedAssetCache>();
+            IAssetCache cache = sp.Scene.RequestModuleInterface<IAssetCache>();
             if(cache == null)
                 return true; // no baked local caching so nothing to do
 
@@ -705,7 +705,7 @@ namespace OpenSim.Region.CoreModules.Avatar.AvatarFactory
                 return 0;
 
             int texturesRebaked = 0;
-//            IImprovedAssetCache cache = m_scene.RequestModuleInterface<IImprovedAssetCache>();
+//            IAssetCache cache = m_scene.RequestModuleInterface<IAssetCache>();
 
             for (int i = 0; i < AvatarAppearance.BAKE_INDICES.Length; i++)
             {
diff --git a/OpenSim/Region/CoreModules/Avatar/UserProfiles/UserProfileModule.cs b/OpenSim/Region/CoreModules/Avatar/UserProfiles/UserProfileModule.cs
index 3f7a8ee7a9..df5265cbe8 100644
--- a/OpenSim/Region/CoreModules/Avatar/UserProfiles/UserProfileModule.cs
+++ b/OpenSim/Region/CoreModules/Avatar/UserProfiles/UserProfileModule.cs
@@ -69,7 +69,7 @@ namespace OpenSim.Region.CoreModules.Avatar.UserProfiles
         Dictionary<UUID, UUID> m_classifiedCache = new Dictionary<UUID, UUID>();
         Dictionary<UUID, int> m_classifiedInterest = new Dictionary<UUID, int>();
         ExpiringCache<UUID, UserProfileCacheEntry> m_profilesCache = new ExpiringCache<UUID, UserProfileCacheEntry>();
-        IImprovedAssetCache m_assetCache;
+        IAssetCache m_assetCache;
 
         private JsonRpcRequestManager rpc = new JsonRpcRequestManager();
         private bool m_allowUserProfileWebURLs = true;
@@ -221,7 +221,7 @@ namespace OpenSim.Region.CoreModules.Avatar.UserProfiles
         {
             if(!Enabled)
                 return;
-            m_assetCache = Scene.RequestModuleInterface<IImprovedAssetCache>();
+            m_assetCache = Scene.RequestModuleInterface<IAssetCache>();
         }
 
         /// <summary>
diff --git a/OpenSim/Region/CoreModules/ServiceConnectorsOut/Asset/HGAssetBroker.cs b/OpenSim/Region/CoreModules/ServiceConnectorsOut/Asset/HGAssetBroker.cs
index 9eb41f94f6..31d112925f 100644
--- a/OpenSim/Region/CoreModules/ServiceConnectorsOut/Asset/HGAssetBroker.cs
+++ b/OpenSim/Region/CoreModules/ServiceConnectorsOut/Asset/HGAssetBroker.cs
@@ -48,7 +48,7 @@ namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.Asset
                 LogManager.GetLogger(
                 MethodBase.GetCurrentMethod().DeclaringType);
 
-        private IImprovedAssetCache m_Cache = null;
+        private IAssetCache m_Cache = null;
         private IAssetService m_GridService;
         private IAssetService m_HGService;
 
@@ -176,7 +176,7 @@ namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.Asset
 
             if (m_Cache == null)
             {
-                m_Cache = scene.RequestModuleInterface<IImprovedAssetCache>();
+                m_Cache = scene.RequestModuleInterface<IAssetCache>();
 
                 if (!(m_Cache is ISharedRegionModule))
                     m_Cache = null;
diff --git a/OpenSim/Region/CoreModules/ServiceConnectorsOut/Asset/LocalAssetServiceConnector.cs b/OpenSim/Region/CoreModules/ServiceConnectorsOut/Asset/LocalAssetServiceConnector.cs
index 5f3445068b..d5d6667504 100644
--- a/OpenSim/Region/CoreModules/ServiceConnectorsOut/Asset/LocalAssetServiceConnector.cs
+++ b/OpenSim/Region/CoreModules/ServiceConnectorsOut/Asset/LocalAssetServiceConnector.cs
@@ -44,7 +44,7 @@ namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.Asset
     {
         private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
 
-        private IImprovedAssetCache m_Cache = null;
+        private IAssetCache m_Cache = null;
 
         private IAssetService m_AssetService;
 
@@ -128,7 +128,7 @@ namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.Asset
 
             if (m_Cache == null)
             {
-                m_Cache = scene.RequestModuleInterface<IImprovedAssetCache>();
+                m_Cache = scene.RequestModuleInterface<IAssetCache>();
 
                 if (!(m_Cache is ISharedRegionModule))
                     m_Cache = null;
diff --git a/OpenSim/Region/CoreModules/ServiceConnectorsOut/Asset/RemoteAssetServiceConnector.cs b/OpenSim/Region/CoreModules/ServiceConnectorsOut/Asset/RemoteAssetServiceConnector.cs
index e6eeacfaf6..ff04f9d66e 100644
--- a/OpenSim/Region/CoreModules/ServiceConnectorsOut/Asset/RemoteAssetServiceConnector.cs
+++ b/OpenSim/Region/CoreModules/ServiceConnectorsOut/Asset/RemoteAssetServiceConnector.cs
@@ -48,7 +48,7 @@ namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.Asset
                 MethodBase.GetCurrentMethod().DeclaringType);
 
         private bool m_Enabled = false;
-        private IImprovedAssetCache m_Cache;
+        private IAssetCache m_Cache;
 
         public Type ReplaceableInterface 
         {
@@ -111,7 +111,7 @@ namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.Asset
 
             if (m_Cache == null)
             {
-                m_Cache = scene.RequestModuleInterface<IImprovedAssetCache>();
+                m_Cache = scene.RequestModuleInterface<IAssetCache>();
 
                 // Since we are a shared module and scene data is not
                 // available for every method, the cache must be shared, too
diff --git a/OpenSim/Region/Framework/Scenes/Scene.cs b/OpenSim/Region/Framework/Scenes/Scene.cs
index e44f11a54e..d7a4ca46aa 100755
--- a/OpenSim/Region/Framework/Scenes/Scene.cs
+++ b/OpenSim/Region/Framework/Scenes/Scene.cs
@@ -1581,6 +1581,8 @@ namespace OpenSim.Region.Framework.Scenes
                 m_heartbeatThread = null;
             }
 
+            GC.Collect();
+            GC.WaitForPendingFinalizers();
             GC.Collect();
             // tell physics to finish building actor
             m_sceneGraph.ProcessPhysicsPreSimulation();
@@ -1856,13 +1858,9 @@ namespace OpenSim.Region.Framework.Scenes
 
                     if (!LoginsEnabled && Frame == 20)
                     {
-                        // m_log.DebugFormat("{0} {1} {2}", LoginsDisabled, m_sceneGraph.GetActiveScriptsCount(), LoginLock);
-
-                        // In 99.9% of cases it is a bad idea to manually force garbage collection. However,
-                        // this is a rare case where we know we have just went through a long cycle of heap
-                        // allocations, and there is no more work to be done until someone logs in
                         GC.Collect();
-
+                        GC.WaitForPendingFinalizers();
+                        GC.Collect();
                         if (!LoginLock)
                         {
                             if (!StartDisabled)
@@ -1887,6 +1885,7 @@ namespace OpenSim.Region.Framework.Scenes
                                 // LoginLock can currently only be set by a region module implementation.
                                 // If somehow this hasn't been done then the quickest way to bugfix is to see the
                                 // NullReferenceException
+
                                 IRegionReadyModule rrm = RequestModuleInterface<IRegionReadyModule>();
                                 rrm.TriggerRegionReady(this);
                             }
diff --git a/OpenSim/Region/OptionalModules/Materials/MaterialsModule.cs b/OpenSim/Region/OptionalModules/Materials/MaterialsModule.cs
index 7312bc39a8..b259f52f8f 100644
--- a/OpenSim/Region/OptionalModules/Materials/MaterialsModule.cs
+++ b/OpenSim/Region/OptionalModules/Materials/MaterialsModule.cs
@@ -63,7 +63,7 @@ namespace OpenSim.Region.OptionalModules.Materials
         
         public Type ReplaceableInterface { get { return null; } }
 
-        IImprovedAssetCache m_cache;
+        IAssetCache m_cache;
         private Scene m_scene = null;
         private bool m_enabled = false;
         private int m_maxMaterialsPerTransaction = 50;
@@ -207,7 +207,7 @@ namespace OpenSim.Region.OptionalModules.Materials
         {
             if (!m_enabled) return;
 
-            m_cache = scene.RequestModuleInterface<IImprovedAssetCache>();
+            m_cache = scene.RequestModuleInterface<IAssetCache>();
             ISimulatorFeaturesModule featuresModule = scene.RequestModuleInterface<ISimulatorFeaturesModule>();
             if (featuresModule != null)
                 featuresModule.OnSimulatorFeaturesRequest += OnSimulatorFeaturesRequest;
diff --git a/OpenSim/Region/OptionalModules/Scripting/RegionReadyModule/RegionReadyModule.cs b/OpenSim/Region/OptionalModules/Scripting/RegionReadyModule/RegionReadyModule.cs
index 870c0bbce9..1725eb4f0c 100644
--- a/OpenSim/Region/OptionalModules/Scripting/RegionReadyModule/RegionReadyModule.cs
+++ b/OpenSim/Region/OptionalModules/Scripting/RegionReadyModule/RegionReadyModule.cs
@@ -214,6 +214,10 @@ namespace OpenSim.Region.OptionalModules.Scripting.RegionReady
             m_scene.EventManager.OnEmptyScriptCompileQueue -= OnEmptyScriptCompileQueue;
             m_scene.LoginLock = false;
 
+            GC.Collect();
+            GC.WaitForPendingFinalizers();
+            GC.Collect();
+
             if (!m_scene.StartDisabled)
             {
                 m_scene.LoginsEnabled = true;
diff --git a/OpenSim/Services/Connectors/Asset/AssetServicesConnector.cs b/OpenSim/Services/Connectors/Asset/AssetServicesConnector.cs
index a6e8eb424b..bdc3befb08 100644
--- a/OpenSim/Services/Connectors/Asset/AssetServicesConnector.cs
+++ b/OpenSim/Services/Connectors/Asset/AssetServicesConnector.cs
@@ -49,7 +49,7 @@ namespace OpenSim.Services.Connectors
         const int MAXSENDRETRIESLEN = 30;
 
         private string m_ServerURI = String.Empty;
-        private IImprovedAssetCache m_Cache = null;
+        private IAssetCache m_Cache = null;
         private int m_retryCounter;
         private bool m_inRetries;
         private List<AssetBase>[] m_sendRetries = new  List<AssetBase>[MAXSENDRETRIESLEN];
@@ -233,7 +233,7 @@ namespace OpenSim.Services.Connectors
             }
         }
 
-        protected void SetCache(IImprovedAssetCache cache)
+        protected void SetCache(IAssetCache cache)
         {
             m_Cache = cache;
         }
@@ -260,8 +260,13 @@ namespace OpenSim.Services.Connectors
                 asset = SynchronousRestObjectRequester.MakeRequest<int, AssetBase>("GET", uri, 0, m_Auth);
 
  
-                if (asset != null && m_Cache != null)
-                   m_Cache.Cache(asset);
+                if (m_Cache != null)
+                {
+                    if (asset != null)
+                        m_Cache.Cache(asset);
+                    else
+                        m_Cache.CacheNegative(id);
+                }
             }
             return asset;
         }
diff --git a/OpenSim/Services/Connectors/Inventory/XInventoryServicesConnector.cs b/OpenSim/Services/Connectors/Inventory/XInventoryServicesConnector.cs
index d80e660553..2ddd7a2f55 100644
--- a/OpenSim/Services/Connectors/Inventory/XInventoryServicesConnector.cs
+++ b/OpenSim/Services/Connectors/Inventory/XInventoryServicesConnector.cs
@@ -54,6 +54,8 @@ namespace OpenSim.Services.Connectors
 
         private string m_ServerURI = String.Empty;
 
+        private int m_maxRetries = 0;
+
         /// <summary>
         /// Timeout for remote requests.
         /// </summary>
@@ -100,6 +102,7 @@ namespace OpenSim.Services.Connectors
             m_ServerURI = serviceURI;
 
             m_requestTimeoutSecs = config.GetInt("RemoteRequestTimeout", m_requestTimeoutSecs);
+            m_maxRetries = config.GetInt("MaxRetries", m_maxRetries);
 
             StatsManager.RegisterStat(
                 new Stat(
@@ -700,10 +703,20 @@ namespace OpenSim.Services.Connectors
 
             RequestsMade++;
 
-            string reply 
-                = SynchronousRestFormsRequester.MakeRequest(
+            string reply = String.Empty;
+            int retries = 0;
+
+            do
+            {
+                reply = SynchronousRestFormsRequester.MakeRequest(
                     "POST", m_ServerURI + "/xinventory",
                      ServerUtils.BuildQueryString(sendData), m_requestTimeoutSecs, m_Auth);
+                
+                if (reply != String.Empty)
+                    break;
+
+                retries++;
+            } while (retries <= m_maxRetries);
 
             Dictionary<string, object> replyData = ServerUtils.ParseXmlResponse(
                     reply);
diff --git a/OpenSim/Services/Connectors/SimianGrid/SimianAssetServiceConnector.cs b/OpenSim/Services/Connectors/SimianGrid/SimianAssetServiceConnector.cs
index 9ad4a7a56f..531939f2cc 100644
--- a/OpenSim/Services/Connectors/SimianGrid/SimianAssetServiceConnector.cs
+++ b/OpenSim/Services/Connectors/SimianGrid/SimianAssetServiceConnector.cs
@@ -55,7 +55,7 @@ namespace OpenSim.Services.Connectors.SimianGrid
         private static string ZeroID = UUID.Zero.ToString();
 
         private string m_serverUrl = String.Empty;
-        private IImprovedAssetCache m_cache;
+        private IAssetCache m_cache;
         private bool m_Enabled = false;
 
         #region ISharedRegionModule
@@ -65,7 +65,7 @@ namespace OpenSim.Services.Connectors.SimianGrid
         {
             if (m_cache == null)
             {
-                IImprovedAssetCache cache = scene.RequestModuleInterface<IImprovedAssetCache>();
+                IAssetCache cache = scene.RequestModuleInterface<IAssetCache>();
                 if (cache is ISharedRegionModule)
                     m_cache = cache;
             }
diff --git a/bin/config-include/FlotsamCache.ini.example b/bin/config-include/FlotsamCache.ini.example
index c0d743093b..2b5d37e0e0 100644
--- a/bin/config-include/FlotsamCache.ini.example
+++ b/bin/config-include/FlotsamCache.ini.example
@@ -22,7 +22,44 @@
     ; Set to false for no memory cache
     ; assets can be requested several times in short periods
     ; so even a small memory cache is useful
-    MemoryCacheEnabled = true
+    MemoryCacheEnabled = false
+
+    ; If a memory cache hit happens, or the asset is still in memory
+    ; due to other causes, update the timestamp on the disk file anyway.
+    ; Don't turn this on unless you share your asset cache between simulators
+    ; AND use an external process, e.g. cron job, to clean it up.
+    UpdateFileTimeOnCacheHit = false
+
+    ; Enabling this will cache negative fetches. If an asset is negative-cached
+    ; it will not be re-requested from the asset server again for a while.
+    ; Generally, this is a good thing.
+    ;
+    ; Regular expiration settings (non-sliding) mean that the asset will be
+    ; retried after the time has expired. Sliding expiration means that
+    ; the time the negative cache will keep the asset is refreshed each
+    ; time a fetch is attempted. Use sliding expiration if you have rogue
+    ; scripts hammering the asset server with requests for nonexistent
+    ; assets.
+    ;
+    ; There are two cases where negative caching may cause issues:
+    ;
+    ; 1 - If an invalid asset is repeatedly requested by a script and that asset is
+    ;     subsequently created, it will not be seen until fcache clear
+    ;     is used. This is a very theoretical scenario since UUID collisions
+    ;     are deemed to be not occuring in practice.
+    ;     This can only become an issue with sliding expiration time.
+    ;
+    ; 2 - If the asset service is clustered, an asset may not have propagated
+    ;     to all cluster members when it is first attempted to fetch it.
+    ;     This may theoretically occur with networked vendor systems and
+    ;     would lead to an asset not found message. However, after the
+    ;     expiration time has elapsed, the asset will the be fetchable.
+    ;
+    ; The defaults below are suitable for all small to medium installations
+    ; including grids.
+    NegativeCacheEnabled = true
+    NegativeCacheTimeout = 120
+    NegativeCacheSliding = false
 
     ; Set to false for no file cache
     FileCacheEnabled = true
@@ -32,7 +69,7 @@
     ; this is good if memory is not a problem.
     ; if memory is a problem then a few seconds may actually save same.
     ; see hit rates with console comand: fcache status
-    MemoryCacheTimeout = .001 ; 3.6s ie around 4s (1s resolution)
+    MemoryCacheTimeout = .016 // one minute
 
     ; How long {in hours} to keep assets cached on disk, .5 == 30 minutes
     ; Specify 0 if you do not want your disk cache to expire
diff --git a/bin/config-include/GridCommon.ini.example b/bin/config-include/GridCommon.ini.example
index 0922cf5a4a..10a5b474d9 100644
--- a/bin/config-include/GridCommon.ini.example
+++ b/bin/config-include/GridCommon.ini.example
@@ -85,6 +85,7 @@
     ; Change this to your grid-wide inventory server
     ;
     InventoryServerURI = "${Const|BaseURL}:${Const|PrivatePort}"
+    ;MaxRetries = 0
 
 [GridInfo]
     ;