diff --git a/ArcFormats/ArcFormats.csproj b/ArcFormats/ArcFormats.csproj
index e123709c..b97c8754 100644
--- a/ArcFormats/ArcFormats.csproj
+++ b/ArcFormats/ArcFormats.csproj
@@ -63,6 +63,9 @@
     <Compile Include="ArcXP3.cs" />
     <Compile Include="ArcYPF.cs" />
     <Compile Include="Blowfish.cs" />
+    <Compile Include="CreateONSWidget.xaml.cs">
+      <DependentUpon>CreateONSWidget.xaml</DependentUpon>
+    </Compile>
     <Compile Include="CreateSGWidget.xaml.cs">
       <DependentUpon>CreateSGWidget.xaml</DependentUpon>
     </Compile>
@@ -122,6 +125,10 @@
     </None>
   </ItemGroup>
   <ItemGroup>
+    <Page Include="CreateONSWidget.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:Compile</Generator>
+    </Page>
     <Page Include="CreateSGWidget.xaml">
       <SubType>Designer</SubType>
       <Generator>MSBuild:Compile</Generator>
diff --git a/ArcFormats/ArcNSA.cs b/ArcFormats/ArcNSA.cs
index 045d1fef..976ea0db 100644
--- a/ArcFormats/ArcNSA.cs
+++ b/ArcFormats/ArcNSA.cs
@@ -29,6 +29,8 @@ using System.Collections.Generic;
 using System.ComponentModel.Composition;
 using GameRes.Formats.Strings;
 using GameRes.Utility;
+using GameRes.Formats.Properties;
+using System.Text;
 
 namespace GameRes.Formats.ONScripter
 {
@@ -37,22 +39,174 @@ namespace GameRes.Formats.ONScripter
         public Compression CompressionType { get; set; }
     }
 
+    public class NsaOptions : ResourceOptions
+    {
+        public Compression CompressionType { get; set; }
+    }
+
     public enum Compression
     {
         Unknown = 256,
         None    = 0,
-        Spb     = 1,
-        Lzss    = 2,
-        Nbz     = 4,
+        SPB     = 1,
+        LZSS    = 2,
+        NBZ     = 4,
     }
 
     [Export(typeof(ArchiveFormat))]
-    public class NsaOpener : ArchiveFormat
+    public class SarOpener : ArchiveFormat
     {
-        public override string Tag { get { return "NSA"; } }
+        public override string Tag { get { return "SAR"; } }
         public override string Description { get { return arcStrings.NSADescription; } }
         public override uint Signature { get { return 0; } }
         public override bool IsHierarchic { get { return true; } }
+        public override bool CanCreate { get { return true; } }
+
+        public override ArcFile TryOpen (ArcView file)
+        {
+            int num_of_files = Binary.BigEndian (file.View.ReadInt16 (0));
+            if (num_of_files <= 0)
+                return null;
+            uint base_offset = Binary.BigEndian (file.View.ReadUInt32 (2));
+            if (base_offset >= file.MaxOffset || base_offset < 10 * (uint)num_of_files)
+                return null;
+
+            uint cur_offset = 6;
+            var dir = new List<Entry>();
+            for (int i = 0; i < num_of_files; ++i)
+            {
+                if (base_offset - cur_offset < 10)
+                    return null;
+                int name_len;
+                byte[] name_buffer = ReadName (file, cur_offset, base_offset-cur_offset, out name_len);
+                if (0 == name_len || base_offset-cur_offset == name_len)
+                    return null;
+                cur_offset += (uint)(name_len + 1);
+                if (base_offset - cur_offset < 8)
+                    return null;
+
+                var entry = new Entry
+                {
+                    Name = Encodings.cp932.GetString (name_buffer, 0, name_len),
+                };
+                entry.Type   = FormatCatalog.Instance.GetTypeFromName (entry.Name);
+                entry.Offset = Binary.BigEndian (file.View.ReadUInt32 (cur_offset)) + (long)base_offset;
+                entry.Size   = Binary.BigEndian (file.View.ReadUInt32 (cur_offset+4));
+
+                cur_offset += 8;
+                dir.Add (entry);
+            }
+            return new ArcFile (file, this, dir);
+        }
+
+        public override Stream OpenEntry (ArcFile arc, Entry entry)
+        {
+            var nsa_entry = entry as NsaEntry;
+            if (null != nsa_entry &&
+                (Compression.LZSS == nsa_entry.CompressionType ||
+                 Compression.SPB  == nsa_entry.CompressionType))
+            {
+                using (var input = arc.File.CreateStream (nsa_entry.Offset, nsa_entry.Size))
+                {
+                    var decoder = new Unpacker (input, nsa_entry.UnpackedSize);
+                    switch (nsa_entry.CompressionType)
+                    {
+                    case Compression.LZSS:  return decoder.LzssDecodedStream();
+                    case Compression.SPB:   return decoder.SpbDecodedStream();
+                    }
+                }
+            }
+            return arc.File.CreateStream (entry.Offset, entry.Size);
+        }
+
+        public override void Create (Stream output, IEnumerable<Entry> list, ResourceOptions options,
+                                     EntryCallback callback)
+        {
+            var encoding = Encodings.cp932.WithFatalFallback();
+            int callback_count = 0;
+
+            var real_entry_list = new List<Entry>();
+            var used_names = new HashSet<string>();
+            int index_size = 0;
+            foreach (var entry in list)
+            {
+                if (!used_names.Add (entry.Name)) // duplicate name
+                    continue;
+                try
+                {
+                    index_size += encoding.GetByteCount (entry.Name) + 1;
+                }
+                catch (EncoderFallbackException X)
+                {
+                    throw new InvalidFileName (entry.Name, arcStrings.MsgIllegalCharacters, X);
+                }
+                index_size += 8;
+                real_entry_list.Add (entry);
+            }
+
+            long start_offset = output.Position;
+            long base_offset = 6+index_size;
+            output.Seek (base_offset, SeekOrigin.Current);
+            foreach (var entry in real_entry_list)
+            {
+                using (var input = File.OpenRead (entry.Name))
+                {
+                    var file_size = input.Length;
+                    if (file_size > uint.MaxValue)
+                        throw new FileSizeException();
+                    long file_offset = output.Position - base_offset;
+                    if (file_offset+file_size > uint.MaxValue)
+                        throw new FileSizeException();
+                    entry.Offset = file_offset;
+                    entry.Size   = (uint)file_size;
+                    if (null != callback)
+                        callback (callback_count++, entry, arcStrings.MsgAddingFile);
+
+                    input.CopyTo (output);
+                }
+            }
+
+            if (null != callback)
+                callback (callback_count++, null, arcStrings.MsgWritingIndex);
+            output.Position = start_offset;
+            using (var writer = new BinaryWriter (output, encoding, true))
+            {
+                writer.Write (Binary.BigEndian ((short)real_entry_list.Count));
+                writer.Write (Binary.BigEndian ((uint)base_offset));
+                foreach (var entry in real_entry_list)
+                {
+                    writer.Write (encoding.GetBytes (entry.Name));
+                    writer.Write ((byte)0);
+                    writer.Write (Binary.BigEndian ((uint)entry.Offset));
+                    writer.Write (Binary.BigEndian ((uint)entry.Size));
+                }
+            }
+        }
+
+        protected static byte[] ReadName (ArcView file, uint offset, uint limit, out int name_len)
+        {
+            byte[] name_buffer = new byte[40];
+            for (name_len = 0; name_len < limit; ++name_len)
+            {
+                byte b = file.View.ReadByte (offset+name_len);
+                if (0 == b)
+                    break;
+                if (name_buffer.Length == name_len)
+                {
+                    byte[] new_buffer = new byte[checked(name_len/2*3)];
+                    Array.Copy (name_buffer, new_buffer, name_len);
+                    name_buffer = new_buffer;
+                }
+                name_buffer[name_len] = b;
+            }
+            return name_buffer;
+        }
+    }
+
+    [Export(typeof(ArchiveFormat))]
+    public class NsaOpener : SarOpener
+    {
+        public override string Tag { get { return "NSA"; } }
 
         public override ArcFile TryOpen (ArcView file)
         {
@@ -90,9 +244,9 @@ namespace GameRes.Formats.ONScripter
                 switch (compression_type)
                 {
                 case 0:  entry.CompressionType = Compression.None; break;
-                case 1:  entry.CompressionType = Compression.Spb; break;
-                case 2:  entry.CompressionType = Compression.Lzss; break;
-                case 4:  entry.CompressionType = Compression.Nbz; break;
+                case 1:  entry.CompressionType = Compression.SPB; break;
+                case 2:  entry.CompressionType = Compression.LZSS; break;
+                case 4:  entry.CompressionType = Compression.NBZ; break;
                 default: entry.CompressionType = Compression.Unknown; break;
                 }
                 cur_offset += 13;
@@ -101,88 +255,86 @@ namespace GameRes.Formats.ONScripter
             return new ArcFile (file, this, dir);
         }
 
-        public override Stream OpenEntry (ArcFile arc, Entry entry)
+        public override ResourceOptions GetDefaultOptions ()
         {
-            var nsa_entry = entry as NsaEntry;
-            if (null != nsa_entry &&
-                (Compression.Lzss == nsa_entry.CompressionType ||
-                 Compression.Spb  == nsa_entry.CompressionType))
-            {
-                using (var input = arc.File.CreateStream (nsa_entry.Offset, nsa_entry.Size))
-                {
-                    var decoder = new Unpacker (input, nsa_entry.UnpackedSize);
-                    switch (nsa_entry.CompressionType)
-                    {
-                    case Compression.Lzss:  return decoder.LzssDecodedStream();
-                    case Compression.Spb:   return decoder.SpbDecodedStream();
-                    }
-                }
-            }
-            return arc.File.CreateStream (entry.Offset, entry.Size);
+            return new NsaOptions {
+                CompressionType     = Settings.Default.ONSCompression,
+            };
         }
 
-        protected static byte[] ReadName (ArcView file, uint offset, uint limit, out int name_len)
+        public override object GetCreationWidget ()
         {
-            byte[] name_buffer = new byte[40];
-            for (name_len = 0; name_len < limit; ++name_len)
-            {
-                byte b = file.View.ReadByte (offset+name_len);
-                if (0 == b)
-                    break;
-                if (name_buffer.Length == name_len)
-                {
-                    byte[] new_buffer = new byte[checked(name_len/2*3)];
-                    Array.Copy (name_buffer, new_buffer, name_len);
-                    name_buffer = new_buffer;
-                }
-                name_buffer[name_len] = b;
-            }
-            return name_buffer;
+            return new GUI.CreateONSWidget();
         }
-    }
 
-    [Export(typeof(ArchiveFormat))]
-    public class SarOpener : NsaOpener
-    {
-        public override string Tag { get { return "SAR"; } }
-
-        public override ArcFile TryOpen (ArcView file)
+        public override void Create (Stream output, IEnumerable<Entry> list, ResourceOptions options,
+                                     EntryCallback callback)
         {
-            int num_of_files = Binary.BigEndian (file.View.ReadInt16 (0));
-            if (num_of_files <= 0)
-                return null;
-            uint base_offset = Binary.BigEndian (file.View.ReadUInt32 (2));
-            if (base_offset >= file.MaxOffset || base_offset < 10 * (uint)num_of_files)
-                return null;
+            var ons_options = GetOptions<NsaOptions> (options);
+            var encoding = Encodings.cp932.WithFatalFallback();
+            int callback_count = 0;
 
-            uint cur_offset = 6;
-            var dir = new List<Entry>();
-            for (int i = 0; i < num_of_files; ++i)
+            var real_entry_list = new List<NsaEntry>();
+            var used_names = new HashSet<string>();
+            int index_size = 0;
+            foreach (var entry in list)
             {
-                if (base_offset - cur_offset < 10)
-                    return null;
-                int name_len;
-                byte[] name_buffer = ReadName (file, cur_offset, base_offset-cur_offset, out name_len);
-                if (0 == name_len || base_offset-cur_offset == name_len)
-                    return null;
-                cur_offset += (uint)(name_len + 1);
-                if (base_offset - cur_offset < 8)
-                    return null;
-
-                var entry = new NsaEntry
+                if (!used_names.Add (entry.Name)) // duplicate name
+                    continue;
+                try
                 {
-                    Name = Encodings.cp932.GetString (name_buffer, 0, name_len),
-                };
-                entry.Type   = FormatCatalog.Instance.GetTypeFromName (entry.Name);
-                entry.Offset = Binary.BigEndian (file.View.ReadUInt32 (cur_offset)) + (long)base_offset;
-                entry.Size   = Binary.BigEndian (file.View.ReadUInt32 (cur_offset+4));
-                entry.UnpackedSize = entry.Size;
-                entry.CompressionType = Compression.None;
-
-                cur_offset += 8;
-                dir.Add (entry);
+                    index_size += encoding.GetByteCount (entry.Name) + 1;
+                }
+                catch (EncoderFallbackException X)
+                {
+                    throw new InvalidFileName (entry.Name, arcStrings.MsgIllegalCharacters, X);
+                }
+                var header_entry = new NsaEntry { Name = entry.Name };
+                index_size += 13;
+                real_entry_list.Add (header_entry);
+            }
+
+            long start_offset = output.Position;
+            long base_offset = 6+index_size;
+            output.Seek (base_offset, SeekOrigin.Current);
+            foreach (var entry in real_entry_list)
+            {
+                using (var input = File.OpenRead (entry.Name))
+                {
+                    var file_size = input.Length;
+                    if (file_size > uint.MaxValue)
+                        throw new FileSizeException();
+                    long file_offset = output.Position - base_offset;
+                    if (file_offset+file_size > uint.MaxValue)
+                        throw new FileSizeException();
+                    entry.Offset = file_offset;
+                    entry.Size   = (uint)file_size;
+                    entry.UnpackedSize    = entry.Size;
+                    entry.CompressionType = Compression.None;
+                    if (null != callback)
+                        callback (callback_count++, entry, arcStrings.MsgAddingFile);
+
+                    input.CopyTo (output);
+                }
+            }
+
+            if (null != callback)
+                callback (callback_count++, null, arcStrings.MsgWritingIndex);
+            output.Position = start_offset;
+            using (var writer = new BinaryWriter (output, encoding, true))
+            {
+                writer.Write (Binary.BigEndian ((short)real_entry_list.Count));
+                writer.Write (Binary.BigEndian ((uint)base_offset));
+                foreach (var entry in real_entry_list)
+                {
+                    writer.Write (encoding.GetBytes (entry.Name));
+                    writer.Write ((byte)0);
+                    writer.Write ((byte)entry.CompressionType);
+                    writer.Write (Binary.BigEndian ((uint)entry.Offset));
+                    writer.Write (Binary.BigEndian ((uint)entry.Size));
+                    writer.Write (Binary.BigEndian ((uint)entry.UnpackedSize));
+                }
             }
-            return new ArcFile (file, this, dir);
         }
     }
 
diff --git a/ArcFormats/CreateONSWidget.xaml b/ArcFormats/CreateONSWidget.xaml
new file mode 100644
index 00000000..5fa3cab0
--- /dev/null
+++ b/ArcFormats/CreateONSWidget.xaml
@@ -0,0 +1,21 @@
+<Grid x:Class="GameRes.Formats.GUI.CreateONSWidget"
+      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+      xmlns:s="clr-namespace:GameRes.Formats.Strings"
+      xmlns:p="clr-namespace:GameRes.Formats.Properties"
+      xmlns:gui="clr-namespace:GameRes.Formats.GUI">
+    <Grid.Resources>
+        <gui:CompressionToStringConverter x:Key="guiCompressionConverter" />
+    </Grid.Resources>
+    <StackPanel Orientation="Vertical">
+        <Label Content="{x:Static s:arcStrings.ONSCompression}" Target="{Binding ElementName=Compression}" Padding="4,0,0,5"/>
+        <ComboBox Name="Compression" Width="120" HorizontalAlignment="Left" SelectedValuePath="Content"
+                  SelectedValue="{Binding Source={x:Static p:Settings.Default}, Path=ONSCompression, Mode=TwoWay, Converter={StaticResource guiCompressionConverter}}">
+            <ComboBoxItem Content="{x:Static s:arcStrings.ONSCompressionNone}"/>
+            <ComboBoxItem Content="SPB"/>
+            <ComboBoxItem Content="LZSS"/>
+<!--not implemented
+            <ComboBoxItem Content="NBZ" Tag="NBZ"/>-->
+        </ComboBox>
+    </StackPanel>
+</Grid>
diff --git a/ArcFormats/CreateONSWidget.xaml.cs b/ArcFormats/CreateONSWidget.xaml.cs
new file mode 100644
index 00000000..148f119d
--- /dev/null
+++ b/ArcFormats/CreateONSWidget.xaml.cs
@@ -0,0 +1,51 @@
+using System;
+using System.Globalization;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Data;
+using GameRes.Formats.ONScripter;
+using GameRes.Formats.Strings;
+
+namespace GameRes.Formats.GUI
+{
+    /// <summary>
+    /// Interaction logic for CreateONSWidget.xaml
+    /// </summary>
+    public partial class CreateONSWidget : Grid
+    {
+        public CreateONSWidget ()
+        {
+            InitializeComponent ();
+        }
+    }
+
+    [ValueConversion (typeof (Compression), typeof (string))]
+    class CompressionToStringConverter : IValueConverter
+    {
+        public object Convert (object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            switch ((Compression)value)
+            {
+            case Compression.SPB:   return "SPB";
+            case Compression.LZSS:  return "LZSS";
+            case Compression.NBZ:   return "NBZ";
+            default:                return arcStrings.ONSCompressionNone;
+            }
+        }
+
+        public object ConvertBack (object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            string s = value as string;
+            if (!string.IsNullOrEmpty (s))
+            {
+                if ("SPB" == s)
+                    return Compression.SPB;
+                else if ("LZSS" == s)
+                    return Compression.LZSS;
+                else if ("NBZ" == s)
+                    return Compression.NBZ;
+            }
+            return Compression.None;
+        }
+    }
+}
diff --git a/ArcFormats/Properties/Settings.Designer.cs b/ArcFormats/Properties/Settings.Designer.cs
index a9445ed2..2b0369eb 100644
--- a/ArcFormats/Properties/Settings.Designer.cs
+++ b/ArcFormats/Properties/Settings.Designer.cs
@@ -129,5 +129,17 @@ namespace GameRes.Formats.Properties {
                 this["SGFileNameEncoding"] = value;
             }
         }
+        
+        [global::System.Configuration.UserScopedSettingAttribute()]
+        [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+        [global::System.Configuration.DefaultSettingValueAttribute("None")]
+        public global::GameRes.Formats.ONScripter.Compression ONSCompression {
+            get {
+                return ((global::GameRes.Formats.ONScripter.Compression)(this["ONSCompression"]));
+            }
+            set {
+                this["ONSCompression"] = value;
+            }
+        }
     }
 }
diff --git a/ArcFormats/Properties/Settings.settings b/ArcFormats/Properties/Settings.settings
index ed32b483..09655123 100644
--- a/ArcFormats/Properties/Settings.settings
+++ b/ArcFormats/Properties/Settings.settings
@@ -29,5 +29,8 @@
     <Setting Name="SGFileNameEncoding" Type="System.String" Scope="User">
       <Value Profile="(Default)">shift-jis</Value>
     </Setting>
+    <Setting Name="ONSCompression" Type="GameRes.Formats.ONScripter.Compression" Scope="User">
+      <Value Profile="(Default)">None</Value>
+    </Setting>
   </Settings>
 </SettingsFile>
\ No newline at end of file
diff --git a/ArcFormats/Strings/arcStrings.Designer.cs b/ArcFormats/Strings/arcStrings.Designer.cs
index 03932d18..a0052e8c 100644
--- a/ArcFormats/Strings/arcStrings.Designer.cs
+++ b/ArcFormats/Strings/arcStrings.Designer.cs
@@ -216,6 +216,15 @@ namespace GameRes.Formats.Strings {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Updating index....
+        /// </summary>
+        public static string MsgUpdatingIndex {
+            get {
+                return ResourceManager.GetString("MsgUpdatingIndex", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Writing index....
         /// </summary>
@@ -252,6 +261,33 @@ namespace GameRes.Formats.Strings {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Archive type.
+        /// </summary>
+        public static string ONSArchiveType {
+            get {
+                return ResourceManager.GetString("ONSArchiveType", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Compression.
+        /// </summary>
+        public static string ONSCompression {
+            get {
+                return ResourceManager.GetString("ONSCompression", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to None.
+        /// </summary>
+        public static string ONSCompressionNone {
+            get {
+                return ResourceManager.GetString("ONSCompressionNone", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Amaterasu Translations Muv-Luv script file.
         /// </summary>
diff --git a/ArcFormats/Strings/arcStrings.resx b/ArcFormats/Strings/arcStrings.resx
index 2c752c56..e2109835 100644
--- a/ArcFormats/Strings/arcStrings.resx
+++ b/ArcFormats/Strings/arcStrings.resx
@@ -171,6 +171,9 @@ predefined encryption scheme.</value>
   <data name="MsgIllegalCharacters" xml:space="preserve">
     <value>File name contains illegal characters</value>
   </data>
+  <data name="MsgUpdatingIndex" xml:space="preserve">
+    <value>Updating index...</value>
+  </data>
   <data name="MsgWritingIndex" xml:space="preserve">
     <value>Writing index...</value>
   </data>
@@ -183,6 +186,15 @@ predefined encryption scheme.</value>
   <data name="NSADescription" xml:space="preserve">
     <value>ONScripter game engine resource archive</value>
   </data>
+  <data name="ONSArchiveType" xml:space="preserve">
+    <value>Archive type</value>
+  </data>
+  <data name="ONSCompression" xml:space="preserve">
+    <value>Compression</value>
+  </data>
+  <data name="ONSCompressionNone" xml:space="preserve">
+    <value>None</value>
+  </data>
   <data name="SCRDescription" xml:space="preserve">
     <value>Amaterasu Translations Muv-Luv script file</value>
   </data>
diff --git a/ArcFormats/Strings/arcStrings.ru-RU.resx b/ArcFormats/Strings/arcStrings.ru-RU.resx
index 9b1a589e..63e095a8 100644
--- a/ArcFormats/Strings/arcStrings.ru-RU.resx
+++ b/ArcFormats/Strings/arcStrings.ru-RU.resx
@@ -156,9 +156,21 @@
   <data name="MsgIllegalCharacters" xml:space="preserve">
     <value>Имя файла содержит недопустимые символы</value>
   </data>
+  <data name="MsgUpdatingIndex" xml:space="preserve">
+    <value>Обновляется оглавление...</value>
+  </data>
   <data name="MsgWritingIndex" xml:space="preserve">
     <value>Записывается оглавление...</value>
   </data>
+  <data name="ONSArchiveType" xml:space="preserve">
+    <value>Тип архива</value>
+  </data>
+  <data name="ONSCompression" xml:space="preserve">
+    <value>Компрессия</value>
+  </data>
+  <data name="ONSCompressionNone" xml:space="preserve">
+    <value>Без компрессии</value>
+  </data>
   <data name="SGLabelEncoding" xml:space="preserve">
     <value>Кодировка имён файлов</value>
   </data>
diff --git a/ArcFormats/app.config b/ArcFormats/app.config
index 7f2bf1c5..ed747043 100644
--- a/ArcFormats/app.config
+++ b/ArcFormats/app.config
@@ -31,6 +31,9 @@
             <setting name="SGFileNameEncoding" serializeAs="String">
                 <value>shift-jis</value>
             </setting>
+            <setting name="ONSCompression" serializeAs="String">
+                <value>None</value>
+            </setting>
         </GameRes.Formats.Properties.Settings>
     </userSettings>
 </configuration>
\ No newline at end of file