diff --git a/src/server/client.ts b/src/server/client.ts
index c8e7f2fdcb1..07c742db4f8 100644
--- a/src/server/client.ts
+++ b/src/server/client.ts
@@ -46,21 +46,21 @@ module ts.server {
             return lineMap;
         }
 
-        private lineColToPosition(fileName: string, lineCol: protocol.Location): number {
-            return ts.computePositionOfLineAndCharacter(this.getLineMap(fileName), lineCol.line - 1, lineCol.col - 1);
+        private lineOffsetToPosition(fileName: string, lineOffset: protocol.Location): number {
+            return ts.computePositionOfLineAndCharacter(this.getLineMap(fileName), lineOffset.line - 1, lineOffset.offset - 1);
         }
 
-        private positionToOneBasedLineCol(fileName: string, position: number): protocol.Location {
-            var lineCol = ts.computeLineAndCharacterOfPosition(this.getLineMap(fileName), position);
+        private positionToOneBasedLineOffset(fileName: string, position: number): protocol.Location {
+            var lineOffset = ts.computeLineAndCharacterOfPosition(this.getLineMap(fileName), position);
             return {
-                line: lineCol.line + 1,
-                col: lineCol.character + 1
+                line: lineOffset.line + 1,
+                offset: lineOffset.character + 1
             };
         }
 
         private convertCodeEditsToTextChange(fileName: string, codeEdit: protocol.CodeEdit): ts.TextChange {
-            var start = this.lineColToPosition(fileName, codeEdit.start);
-            var end = this.lineColToPosition(fileName, codeEdit.end);
+            var start = this.lineOffsetToPosition(fileName, codeEdit.start);
+            var end = this.lineOffsetToPosition(fileName, codeEdit.end);
 
             return {
                 span: ts.createTextSpanFromBounds(start, end),
@@ -134,15 +134,15 @@ module ts.server {
             // clear the line map after an edit
             this.lineMaps[fileName] = undefined;
 
-            var lineCol = this.positionToOneBasedLineCol(fileName, start);
-            var endLineCol = this.positionToOneBasedLineCol(fileName, end);
+            var lineOffset = this.positionToOneBasedLineOffset(fileName, start);
+            var endLineOffset = this.positionToOneBasedLineOffset(fileName, end);
 
             var args: protocol.ChangeRequestArgs = {
                 file: fileName,
-                line: lineCol.line,
-                col: lineCol.col,
-                endLine: endLineCol.line,
-                endCol: endLineCol.col,
+                line: lineOffset.line,
+                offset: lineOffset.offset,
+                endLine: endLineOffset.line,
+                endOffset: endLineOffset.offset,
                 insertString: newText
             };
 
@@ -150,18 +150,18 @@ module ts.server {
         }
 
         getQuickInfoAtPosition(fileName: string, position: number): QuickInfo {
-            var lineCol = this.positionToOneBasedLineCol(fileName, position);
+            var lineOffset = this.positionToOneBasedLineOffset(fileName, position);
             var args: protocol.FileLocationRequestArgs = {
                 file: fileName,
-                line: lineCol.line,
-                col: lineCol.col
+                line: lineOffset.line,
+                offset: lineOffset.offset
             };
 
             var request = this.processRequest<protocol.QuickInfoRequest>(CommandNames.Quickinfo, args);
             var response = this.processResponse<protocol.QuickInfoResponse>(request);
 
-            var start = this.lineColToPosition(fileName, response.body.start);
-            var end = this.lineColToPosition(fileName, response.body.end);
+            var start = this.lineOffsetToPosition(fileName, response.body.start);
+            var end = this.lineOffsetToPosition(fileName, response.body.end);
 
             return {
                 kind: response.body.kind,
@@ -173,11 +173,11 @@ module ts.server {
         }
         
         getCompletionsAtPosition(fileName: string, position: number): CompletionInfo {
-            var lineCol = this.positionToOneBasedLineCol(fileName, position);
+            var lineOffset = this.positionToOneBasedLineOffset(fileName, position);
             var args: protocol.CompletionsRequestArgs = {
                 file: fileName,
-                line: lineCol.line,
-                col: lineCol.col,
+                line: lineOffset.line,
+                offset: lineOffset.offset,
                 prefix: undefined
             };
 
@@ -194,11 +194,11 @@ module ts.server {
         }
      
         getCompletionEntryDetails(fileName: string, position: number, entryName: string): CompletionEntryDetails {
-            var lineCol = this.positionToOneBasedLineCol(fileName, position);
+            var lineOffset = this.positionToOneBasedLineOffset(fileName, position);
             var args: protocol.CompletionDetailsRequestArgs = {
                 file: fileName,
-                line: lineCol.line,
-                col: lineCol.col,
+                line: lineOffset.line,
+                offset: lineOffset.offset,
                 entryNames: [entryName]
             };
 
@@ -219,8 +219,8 @@ module ts.server {
 
             return response.body.map(entry => {
                 var fileName = entry.file;
-                var start = this.lineColToPosition(fileName, entry.start);
-                var end = this.lineColToPosition(fileName, entry.end);
+                var start = this.lineOffsetToPosition(fileName, entry.start);
+                var end = this.lineOffsetToPosition(fileName, entry.end);
                 
                 return {
                     name: entry.name,
@@ -237,14 +237,14 @@ module ts.server {
         }
 
         getFormattingEditsForRange(fileName: string, start: number, end: number, options: ts.FormatCodeOptions): ts.TextChange[] {
-            var startLineCol = this.positionToOneBasedLineCol(fileName, start);
-            var endLineCol = this.positionToOneBasedLineCol(fileName, end);
+            var startLineOffset = this.positionToOneBasedLineOffset(fileName, start);
+            var endLineOffset = this.positionToOneBasedLineOffset(fileName, end);
             var args: protocol.FormatRequestArgs = {
                 file: fileName,
-                line: startLineCol.line,
-                col: startLineCol.col,
-                endLine: endLineCol.line,
-                endCol: endLineCol.col,
+                line: startLineOffset.line,
+                offset: startLineOffset.offset,
+                endLine: endLineOffset.line,
+                endOffset: endLineOffset.offset,
             };
 
             // TODO: handle FormatCodeOptions
@@ -259,11 +259,11 @@ module ts.server {
         }
 
         getFormattingEditsAfterKeystroke(fileName: string, position: number, key: string, options: FormatCodeOptions): ts.TextChange[] {
-            var lineCol = this.positionToOneBasedLineCol(fileName, position);
+            var lineOffset = this.positionToOneBasedLineOffset(fileName, position);
             var args: protocol.FormatOnKeyRequestArgs = {
                 file: fileName,
-                line: lineCol.line,
-                col: lineCol.col,
+                line: lineOffset.line,
+                offset: lineOffset.offset,
                 key: key
             };
 
@@ -275,11 +275,11 @@ module ts.server {
         }
 
         getDefinitionAtPosition(fileName: string, position: number): DefinitionInfo[] {
-            var lineCol = this.positionToOneBasedLineCol(fileName, position);
+            var lineOffset = this.positionToOneBasedLineOffset(fileName, position);
             var args: protocol.FileLocationRequestArgs = {
                 file: fileName,
-                line: lineCol.line,
-                col: lineCol.col,
+                line: lineOffset.line,
+                offset: lineOffset.offset,
             };
 
             var request = this.processRequest<protocol.DefinitionRequest>(CommandNames.Definition, args);
@@ -287,8 +287,8 @@ module ts.server {
 
             return response.body.map(entry => {
                 var fileName = entry.file;
-                var start = this.lineColToPosition(fileName, entry.start);
-                var end = this.lineColToPosition(fileName, entry.end);
+                var start = this.lineOffsetToPosition(fileName, entry.start);
+                var end = this.lineOffsetToPosition(fileName, entry.end);
                 return {
                     containerKind: "",
                     containerName: "",
@@ -301,11 +301,11 @@ module ts.server {
         }
 
         getReferencesAtPosition(fileName: string, position: number): ReferenceEntry[] {
-            var lineCol = this.positionToOneBasedLineCol(fileName, position);
+            var lineOffset = this.positionToOneBasedLineOffset(fileName, position);
             var args: protocol.FileLocationRequestArgs = {
                 file: fileName,
-                line: lineCol.line,
-                col: lineCol.col,
+                line: lineOffset.line,
+                offset: lineOffset.offset,
             };
 
             var request = this.processRequest<protocol.ReferencesRequest>(CommandNames.References, args);
@@ -313,8 +313,8 @@ module ts.server {
 
             return response.body.refs.map(entry => {
                 var fileName = entry.file;
-                var start = this.lineColToPosition(fileName, entry.start);
-                var end = this.lineColToPosition(fileName, entry.end);
+                var start = this.lineOffsetToPosition(fileName, entry.start);
+                var end = this.lineOffsetToPosition(fileName, entry.end);
                 return {
                     fileName: fileName,
                     textSpan: ts.createTextSpanFromBounds(start, end),
@@ -340,11 +340,11 @@ module ts.server {
         }
 
         getRenameInfo(fileName: string, position: number, findInStrings?: boolean, findInComments?: boolean): RenameInfo {
-            var lineCol = this.positionToOneBasedLineCol(fileName, position);
+            var lineOffset = this.positionToOneBasedLineOffset(fileName, position);
             var args: protocol.RenameRequestArgs = {
                 file: fileName,
-                line: lineCol.line,
-                col: lineCol.col,
+                line: lineOffset.line,
+                offset: lineOffset.offset,
                 findInStrings,
                 findInComments
             };
@@ -355,8 +355,8 @@ module ts.server {
             response.body.locs.map((entry: protocol.SpanGroup) => {
                 var fileName = entry.file;
                 entry.locs.map((loc: protocol.TextSpan) => {
-                    var start = this.lineColToPosition(fileName, loc.start);
-                    var end = this.lineColToPosition(fileName, loc.end);
+                    var start = this.lineOffsetToPosition(fileName, loc.start);
+                    var end = this.lineOffsetToPosition(fileName, loc.end);
                     locations.push({
                         textSpan: ts.createTextSpanFromBounds(start, end),
                         fileName: fileName
@@ -400,7 +400,7 @@ module ts.server {
                 text: item.text,
                 kind: item.kind,
                 kindModifiers: item.kindModifiers || "",
-                spans: item.spans.map(span=> createTextSpanFromBounds(this.lineColToPosition(fileName, span.start), this.lineColToPosition(fileName, span.end))),
+                spans: item.spans.map(span=> createTextSpanFromBounds(this.lineOffsetToPosition(fileName, span.start), this.lineOffsetToPosition(fileName, span.end))),
                 childItems: this.decodeNavigationBarItems(item.childItems, fileName),
                 indent: 0,
                 bolded: false,
@@ -444,19 +444,19 @@ module ts.server {
         }
 
         getBraceMatchingAtPosition(fileName: string, position: number): TextSpan[] {
-            var lineCol = this.positionToOneBasedLineCol(fileName, position);
+            var lineOffset = this.positionToOneBasedLineOffset(fileName, position);
             var args: protocol.FileLocationRequestArgs = {
                 file: fileName,
-                line: lineCol.line,
-                col: lineCol.col,
+                line: lineOffset.line,
+                offset: lineOffset.offset,
             };
 
             var request = this.processRequest<protocol.BraceRequest>(CommandNames.Brace, args);
             var response = this.processResponse<protocol.BraceResponse>(request);
 
             return response.body.map(entry => {
-                var start = this.lineColToPosition(fileName, entry.start);
-                var end = this.lineColToPosition(fileName, entry.end);
+                var start = this.lineOffsetToPosition(fileName, entry.start);
+                var end = this.lineOffsetToPosition(fileName, entry.end);
                 return {
                     start: start,
                     length: end - start,
diff --git a/src/server/editorServices.ts b/src/server/editorServices.ts
index 4861c2cdfd3..1f9df9b46f0 100644
--- a/src/server/editorServices.ts
+++ b/src/server/editorServices.ts
@@ -27,9 +27,13 @@ module ts.server {
             this.svc = ScriptVersionCache.fromString(content);
         }
 
-        setFormatOptions(tabSize: number, indentSize: number) {
-            this.formatCodeOptions.TabSize = tabSize;
-            this.formatCodeOptions.IndentSize = indentSize;
+        setFormatOptions(tabSize?: number, indentSize?: number) {
+            if (tabSize) {
+                this.formatCodeOptions.TabSize = tabSize;
+            }
+            if (indentSize) {
+                this.formatCodeOptions.IndentSize = indentSize;
+            }
         }
 
         close() {
@@ -160,15 +164,12 @@ module ts.server {
         reloadScript(filename: string, tmpfilename: string, cb: () => any) {
             var script = this.getScriptInfo(filename);
             if (script) {
-                script.svc.reloadFromFile(tmpfilename, script.formatCodeOptions.TabSize, cb);
+                script.svc.reloadFromFile(tmpfilename, cb);
             }
         }
 
         editScript(filename: string, start: number, end: number, newText: string) {
             var script = this.getScriptInfo(filename);
-            if (newText && (newText.length > 0)) {
-                newText = expandTabs(newText, script.formatCodeOptions.TabSize);
-            }
             if (script) {
                 script.editContent(start, end, newText);
                 return;
@@ -207,33 +208,33 @@ module ts.server {
             }
             else {
                 var nextLineInfo = index.lineNumberToInfo(line + 2);
-                len = nextLineInfo.col - lineInfo.col;
+                len = nextLineInfo.offset - lineInfo.offset;
             }
-            return ts.createTextSpan(lineInfo.col, len);
+            return ts.createTextSpan(lineInfo.offset, len);
         }
 
         /**
          * @param line 1 based index
-         * @param col 1 based index
+         * @param offset 1 based index
          */
-        lineColToPosition(filename: string, line: number, col: number): number {
+        lineOffsetToPosition(filename: string, line: number, offset: number): number {
             var script: ScriptInfo = this.filenameToScript[filename];
             var index = script.snap().index;
 
             var lineInfo = index.lineNumberToInfo(line);
-            // TODO: assert this column is actually on the line
-            return (lineInfo.col + col - 1);
+            // TODO: assert this offset is actually on the line
+            return (lineInfo.offset + offset - 1);
         }
 
         /**
          * @param line 1-based index
-         * @param col 1-based index
+         * @param offset 1-based index
          */
-        positionToLineCol(filename: string, position: number): ILineInfo {
+        positionToLineOffset(filename: string, position: number): ILineInfo {
             var script: ScriptInfo = this.filenameToScript[filename];
             var index = script.snap().index;
-            var lineCol = index.charOffsetToLineNumberAndPos(position);
-            return { line: lineCol.line, col: lineCol.col + 1 };
+            var lineOffset = index.charOffsetToLineNumberAndPos(position);
+            return { line: lineOffset.line, offset: lineOffset.offset + 1 };
         }
     }
 
@@ -372,12 +373,6 @@ module ts.server {
         hostInfo: string;
     }
 
-    export function expandTabs(text: string, tabSize: number) {
-        var spaces = generateSpaces(tabSize);
-        return text.replace(/\t/g, spaces);
-    }
-
-
     export class ProjectService {
         filenameToScriptInfo: ts.Map<ScriptInfo> = {};
         // open, non-configured files in two lists
@@ -421,7 +416,7 @@ module ts.server {
             }
             else {
                 if (info && (!info.isOpen)) {
-                    info.svc.reloadFromFile(info.fileName, info.formatCodeOptions.TabSize);
+                    info.svc.reloadFromFile(info.fileName);
                 }
             }
         }
@@ -646,7 +641,7 @@ module ts.server {
         /**
          * @param filename is absolute pathname
          */
-        openFile(fileName: string, openedByClient: boolean, tabSize?: number) {
+        openFile(fileName: string, openedByClient: boolean) {
             fileName = ts.normalizePath(fileName);
             var info = ts.lookUp(this.filenameToScriptInfo, fileName);
             if (!info) {
@@ -661,25 +656,11 @@ module ts.server {
                 }
                 if (content !== undefined) {
                     var indentSize: number;
-                    if (!tabSize) {
-                        tabSize = this.hostConfiguration.formatCodeOptions.TabSize;
-                        indentSize = this.hostConfiguration.formatCodeOptions.IndentSize;
-                    }
-                    else {
-                        indentSize = tabSize;
-                    }
-                    if (openedByClient) {
-                        this.log("Expanding tabs for file " + fileName + " with tab size " + tabSize.toString());
-                        content = expandTabs(content, tabSize);
-                    }
                     info = new ScriptInfo(this.host, fileName, content, openedByClient);
                     this.filenameToScriptInfo[fileName] = info;
                     if (!info.isOpen) {
                         info.fileWatcher = this.host.watchFile(fileName, _ => { this.watchedFileChanged(fileName); });
                     }
-                    else {
-                        info.setFormatOptions(tabSize, indentSize);
-                    }
                 }
             }
             if (info) {
@@ -695,9 +676,9 @@ module ts.server {
          * @param filename is absolute pathname
          */
 
-        openClientFile(filename: string, tabSize?: number) {
+        openClientFile(filename: string) {
             // TODO: tsconfig check
-            var info = this.openFile(filename, true, tabSize);
+            var info = this.openFile(filename, true);
             this.addOpenFile(info);
             this.printProjects();
             return info;
@@ -878,7 +859,7 @@ module ts.server {
 
     export interface ILineInfo {
         line: number;
-        col: number;
+        offset: number;
         text?: string;
         leaf?: LineLeaf;
     }
@@ -1159,9 +1140,8 @@ module ts.server {
             return this.currentVersion;
         }
 
-        reloadFromFile(filename: string, tabSize: number, cb?: () => any) {
+        reloadFromFile(filename: string, cb?: () => any) {
             var content = ts.sys.readFile(filename);
-            content = expandTabs(content, tabSize);
             this.reload(content);
             if (cb)
                 cb();
@@ -1272,7 +1252,7 @@ module ts.server {
 
         getLineMapper() {
             return ((line: number) => {
-                return this.index.lineNumberToInfo(line).col;
+                return this.index.lineNumberToInfo(line).offset;
             });
         }
 
@@ -1309,7 +1289,7 @@ module ts.server {
             else {
                 return {
                     line: lineNumber,
-                    col: this.root.charCount()
+                    offset: this.root.charCount()
                 }
             }
         }
@@ -1395,7 +1375,7 @@ module ts.server {
                     // check whether last characters deleted are line break
                     var e = pos + deleteLength;
                     var lineInfo = this.charOffsetToLineNumberAndPos(e);
-                    if ((lineInfo && (lineInfo.col == 0))) {
+                    if ((lineInfo && (lineInfo.offset == 0))) {
                         // move range end just past line that will merge with previous line
                         deleteLength += lineInfo.text.length;
                         // store text by appending to end of insertedText
@@ -1571,14 +1551,14 @@ module ts.server {
             if (!childInfo.child) {
                 return {
                     line: lineNumber,
-                    col: charOffset,
+                    offset: charOffset,
                 }
             }
             else if (childInfo.childIndex < this.children.length) {
                 if (childInfo.child.isLeaf()) {
                     return {
                         line: childInfo.lineNumber,
-                        col: childInfo.charOffset,
+                        offset: childInfo.charOffset,
                         text: (<LineLeaf>(childInfo.child)).text,
                         leaf: (<LineLeaf>(childInfo.child))
                     };
@@ -1590,7 +1570,7 @@ module ts.server {
             }
             else {
                 var lineInfo = this.lineNumberToInfo(this.lineCount(), 0);
-                return { line: this.lineCount(), col: lineInfo.leaf.charCount() };
+                return { line: this.lineCount(), offset: lineInfo.leaf.charCount() };
             }
         }
 
@@ -1599,13 +1579,13 @@ module ts.server {
             if (!childInfo.child) {
                 return {
                     line: lineNumber,
-                    col: charOffset
+                    offset: charOffset
                 }
-            }
+            } 
             else if (childInfo.child.isLeaf()) {
                 return {
                     line: lineNumber,
-                    col: childInfo.charOffset,
+                    offset: childInfo.charOffset,
                     text: (<LineLeaf>(childInfo.child)).text,
                     leaf: (<LineLeaf>(childInfo.child))
                 }
diff --git a/src/server/protocol.d.ts b/src/server/protocol.d.ts
index a7a0642de2e..d63aa53ba12 100644
--- a/src/server/protocol.d.ts
+++ b/src/server/protocol.d.ts
@@ -96,7 +96,7 @@ declare module ts.server.protocol {
 
     /**
       * Instances of this interface specify a location in a source file:
-      * (file, line, col), where line and column are 1-based.
+      * (file, line, character offset), where line and character offset are 1-based.
       */
     export interface FileLocationRequestArgs extends FileRequestArgs {
         /** 
@@ -105,9 +105,9 @@ declare module ts.server.protocol {
         line: number;
 
         /** 
-          * The column for the request (1-based).
+          * The character offset (on the line) for the request (1-based).
           */
-        col: number;
+        offset: number;
     }
 
     /**
@@ -126,11 +126,11 @@ declare module ts.server.protocol {
     }
 
     /**
-      * Location in source code expressed as (one-based) line and column.
+      * Location in source code expressed as (one-based) line and character offset.
       */
     export interface Location {
         line: number;
-        col: number;
+        offset: number;
     }
 
     /**
@@ -202,9 +202,9 @@ declare module ts.server.protocol {
         symbolName: string;
 
         /**
-          * The start column of the symbol (on the line provided by the references request).
+          * The start character offset of the symbol (on the line provided by the references request).
           */
-        symbolStartCol: number;
+        symbolStartOffset: number;
 
         /** 
           * The full display name of the symbol.
@@ -339,6 +339,8 @@ declare module ts.server.protocol {
     export interface OpenRequestArgs extends FileRequestArgs {
         /** Initial tab size of file. */
         tabSize?: number;
+        /** Number of spaces to indent during formatting */
+        indentSize?: number;
     }
 
     /**
@@ -424,9 +426,9 @@ declare module ts.server.protocol {
         endLine: number;
         
         /**
-          * Last column of range for which to format text in file.
+          * Character offset on last line of range for which to format text in file.
           */
-        endCol: number;
+        endOffset: number;
     }
 
     /**
@@ -805,7 +807,7 @@ declare module ts.server.protocol {
       */
     export interface ChangeRequestArgs extends FormatRequestArgs {
         /**
-          * Optional string to insert at location (file, line, col).
+          * Optional string to insert at location (file, line, offset).
           */
         insertString?: string;
     }
@@ -829,7 +831,7 @@ declare module ts.server.protocol {
     /**
       * Brace matching request; value of command field is "brace".
       * Return response giving the file locations of matching braces
-      * found in file at location line, col.
+      * found in file at location line, offset.
       */
     export interface BraceRequest extends FileLocationRequest {
     }
diff --git a/src/server/session.ts b/src/server/session.ts
index d6243e4b7a7..79eefb879da 100644
--- a/src/server/session.ts
+++ b/src/server/session.ts
@@ -44,7 +44,7 @@ module ts.server {
         else if (a.file == b.file) {
             var n = compareNumber(a.start.line, b.start.line);
             if (n == 0) {
-                return compareNumber(a.start.col, b.start.col);
+                return compareNumber(a.start.offset, b.start.offset);
             }
             else return n;
         }
@@ -55,8 +55,8 @@ module ts.server {
        
     function formatDiag(fileName: string, project: Project, diag: ts.Diagnostic) {
         return {
-            start: project.compilerService.host.positionToLineCol(fileName, diag.start),
-            end: project.compilerService.host.positionToLineCol(fileName, diag.start + diag.length),
+            start: project.compilerService.host.positionToLineOffset(fileName, diag.start),
+            end: project.compilerService.host.positionToLineOffset(fileName, diag.start + diag.length),
             text: ts.flattenDiagnosticMessageText(diag.messageText, "\n")
         };
     }
@@ -260,7 +260,7 @@ module ts.server {
             }
         }
 
-        getDefinition(line: number, col: number, fileName: string): protocol.FileSpan[] {
+        getDefinition(line: number, offset: number, fileName: string): protocol.FileSpan[] {
             var file = ts.normalizePath(fileName);
             var project = this.projectService.getProjectForFile(file);
             if (!project) {
@@ -268,7 +268,7 @@ module ts.server {
             }
 
             var compilerService = project.compilerService;
-            var position = compilerService.host.lineColToPosition(file, line, col);
+            var position = compilerService.host.lineOffsetToPosition(file, line, offset);
 
             var definitions = compilerService.languageService.getDefinitionAtPosition(file, position);
             if (!definitions) {
@@ -277,12 +277,12 @@ module ts.server {
 
             return definitions.map(def => ({
                 file: def.fileName,
-                start: compilerService.host.positionToLineCol(def.fileName, def.textSpan.start),
-                end: compilerService.host.positionToLineCol(def.fileName, ts.textSpanEnd(def.textSpan))
+                start: compilerService.host.positionToLineOffset(def.fileName, def.textSpan.start),
+                end: compilerService.host.positionToLineOffset(def.fileName, ts.textSpanEnd(def.textSpan))
             }));
         }
 
-        getRenameLocations(line: number, col: number, fileName: string,findInComments: boolean, findInStrings: boolean): protocol.RenameResponseBody {
+        getRenameLocations(line: number, offset: number, fileName: string,findInComments: boolean, findInStrings: boolean): protocol.RenameResponseBody {
             var file = ts.normalizePath(fileName);
             var project = this.projectService.getProjectForFile(file);
             if (!project) {
@@ -290,7 +290,7 @@ module ts.server {
             }
 
             var compilerService = project.compilerService;
-            var position = compilerService.host.lineColToPosition(file, line, col);
+            var position = compilerService.host.lineOffsetToPosition(file, line, offset);
             var renameInfo = compilerService.languageService.getRenameInfo(file, position);
             if (!renameInfo) {
                 return undefined;
@@ -310,8 +310,8 @@ module ts.server {
 
             var bakedRenameLocs = renameLocations.map(location => (<protocol.FileSpan>{
                 file: location.fileName,
-                start: compilerService.host.positionToLineCol(location.fileName, location.textSpan.start),
-                end: compilerService.host.positionToLineCol(location.fileName, ts.textSpanEnd(location.textSpan)),
+                start: compilerService.host.positionToLineOffset(location.fileName, location.textSpan.start),
+                end: compilerService.host.positionToLineOffset(location.fileName, ts.textSpanEnd(location.textSpan)),
             })).sort((a, b) => {
                 if (a.file < b.file) {
                     return -1;
@@ -328,7 +328,7 @@ module ts.server {
                         return -1;
                     }
                     else {
-                        return b.start.col - a.start.col;
+                        return b.start.offset - a.start.offset;
                     }
                 }
             }).reduce<protocol.SpanGroup[]>((accum: protocol.SpanGroup[], cur: protocol.FileSpan) => {
@@ -350,7 +350,7 @@ module ts.server {
             return { info: renameInfo, locs: bakedRenameLocs };
         }
 
-        getReferences(line: number, col: number, fileName: string): protocol.ReferencesResponseBody {
+        getReferences(line: number, offset: number, fileName: string): protocol.ReferencesResponseBody {
             // TODO: get all projects for this file; report refs for all projects deleting duplicates
             // can avoid duplicates by eliminating same ref file from subsequent projects
             var file = ts.normalizePath(fileName);
@@ -360,7 +360,7 @@ module ts.server {
             }
 
             var compilerService = project.compilerService;
-            var position = compilerService.host.lineColToPosition(file, line, col);
+            var position = compilerService.host.lineOffsetToPosition(file, line, offset);
 
             var references = compilerService.languageService.getReferencesAtPosition(file, position);
             if (!references) {
@@ -374,10 +374,10 @@ module ts.server {
 
             var displayString = ts.displayPartsToString(nameInfo.displayParts);
             var nameSpan = nameInfo.textSpan;
-            var nameColStart = compilerService.host.positionToLineCol(file, nameSpan.start).col;
+            var nameColStart = compilerService.host.positionToLineOffset(file, nameSpan.start).offset;
             var nameText = compilerService.host.getScriptSnapshot(file).getText(nameSpan.start, ts.textSpanEnd(nameSpan));
             var bakedRefs: protocol.ReferencesResponseItem[] = references.map((ref) => {
-                var start = compilerService.host.positionToLineCol(ref.fileName, ref.textSpan.start);
+                var start = compilerService.host.positionToLineOffset(ref.fileName, ref.textSpan.start);
                 var refLineSpan = compilerService.host.lineToTextSpan(ref.fileName, start.line - 1);
                 var snap = compilerService.host.getScriptSnapshot(ref.fileName);
                 var lineText = snap.getText(refLineSpan.start, ts.textSpanEnd(refLineSpan)).replace(/\r|\n/g, "");
@@ -385,24 +385,27 @@ module ts.server {
                     file: ref.fileName,
                     start: start,
                     lineText: lineText,
-                    end: compilerService.host.positionToLineCol(ref.fileName, ts.textSpanEnd(ref.textSpan)),
+                    end: compilerService.host.positionToLineOffset(ref.fileName, ts.textSpanEnd(ref.textSpan)),
                     isWriteAccess: ref.isWriteAccess
                 };
             }).sort(compareFileStart);
             return {
                 refs: bakedRefs,
                 symbolName: nameText,
-                symbolStartCol: nameColStart,
+                symbolStartOffset: nameColStart,
                 symbolDisplayString: displayString
             };
         }
 
-        openClientFile(fileName: string, tabSize?: number) {
+        openClientFile(fileName: string, tabSize?: number, indentSize?: number) {
             var file = ts.normalizePath(fileName);
-            this.projectService.openClientFile(file, tabSize);
+            var info = this.projectService.openClientFile(file);
+            if (info) {
+                info.setFormatOptions(tabSize, indentSize);
+            }
         }
 
-        getQuickInfo(line: number, col: number, fileName: string): protocol.QuickInfoResponseBody {
+        getQuickInfo(line: number, offset: number, fileName: string): protocol.QuickInfoResponseBody {
             var file = ts.normalizePath(fileName);
             var project = this.projectService.getProjectForFile(file);
             if (!project) {
@@ -410,7 +413,7 @@ module ts.server {
             }
 
             var compilerService = project.compilerService;
-            var position = compilerService.host.lineColToPosition(file, line, col);
+            var position = compilerService.host.lineOffsetToPosition(file, line, offset);
             var quickInfo = compilerService.languageService.getQuickInfoAtPosition(file, position);
             if (!quickInfo) {
                 return undefined;
@@ -421,14 +424,14 @@ module ts.server {
             return {
                 kind: quickInfo.kind,
                 kindModifiers: quickInfo.kindModifiers,
-                start: compilerService.host.positionToLineCol(file, quickInfo.textSpan.start),
-                end: compilerService.host.positionToLineCol(file, ts.textSpanEnd(quickInfo.textSpan)),
+                start: compilerService.host.positionToLineOffset(file, quickInfo.textSpan.start),
+                end: compilerService.host.positionToLineOffset(file, ts.textSpanEnd(quickInfo.textSpan)),
                 displayString: displayString,
                 documentation: docString,
             };
         }
 
-        getFormattingEditsForRange(line: number, col: number, endLine: number, endCol: number, fileName: string): protocol.CodeEdit[] {
+        getFormattingEditsForRange(line: number, offset: number, endLine: number, endOffset: number, fileName: string): protocol.CodeEdit[] {
             var file = ts.normalizePath(fileName);
             var project = this.projectService.getProjectForFile(file);
             if (!project) {
@@ -436,8 +439,8 @@ module ts.server {
             }
 
             var compilerService = project.compilerService;
-            var startPosition = compilerService.host.lineColToPosition(file, line, col);
-            var endPosition = compilerService.host.lineColToPosition(file, endLine, endCol);
+            var startPosition = compilerService.host.lineOffsetToPosition(file, line, offset);
+            var endPosition = compilerService.host.lineOffsetToPosition(file, endLine, endOffset);
             
             // TODO: avoid duplicate code (with formatonkey)
             var edits = compilerService.languageService.getFormattingEditsForRange(file, startPosition, endPosition,
@@ -448,14 +451,14 @@ module ts.server {
 
             return edits.map((edit) => {
                 return {
-                    start: compilerService.host.positionToLineCol(file, edit.span.start),
-                    end: compilerService.host.positionToLineCol(file, ts.textSpanEnd(edit.span)),
+                    start: compilerService.host.positionToLineOffset(file, edit.span.start),
+                    end: compilerService.host.positionToLineOffset(file, ts.textSpanEnd(edit.span)),
                     newText: edit.newText ? edit.newText : ""
                 };
             });
         }
 
-        getFormattingEditsAfterKeystroke(line: number, col: number, key: string, fileName: string): protocol.CodeEdit[] {
+        getFormattingEditsAfterKeystroke(line: number, offset: number, key: string, fileName: string): protocol.CodeEdit[] {
             var file = ts.normalizePath(fileName);
 
             var project = this.projectService.getProjectForFile(file);
@@ -464,7 +467,7 @@ module ts.server {
             }
 
             var compilerService = project.compilerService;
-            var position = compilerService.host.lineColToPosition(file, line, col);
+            var position = compilerService.host.lineOffsetToPosition(file, line, offset);
             var formatOptions = this.projectService.getFormatCodeOptions(file);
             var edits = compilerService.languageService.getFormattingEditsAfterKeystroke(file, position, key,
                 formatOptions);
@@ -519,16 +522,16 @@ module ts.server {
 
             return edits.map((edit) => {
                 return {
-                    start: compilerService.host.positionToLineCol(file,
+                    start: compilerService.host.positionToLineOffset(file,
                         edit.span.start),
-                    end: compilerService.host.positionToLineCol(file,
+                    end: compilerService.host.positionToLineOffset(file,
                         ts.textSpanEnd(edit.span)),
                     newText: edit.newText ? edit.newText : ""
                 };
             });
         }
 
-        getCompletions(line: number, col: number, prefix: string, fileName: string): protocol.CompletionEntry[] {
+        getCompletions(line: number, offset: number, prefix: string, fileName: string): protocol.CompletionEntry[] {
             if (!prefix) {
                 prefix = "";
             }
@@ -539,7 +542,7 @@ module ts.server {
             }
 
             var compilerService = project.compilerService;
-            var position = compilerService.host.lineColToPosition(file, line, col);
+            var position = compilerService.host.lineOffsetToPosition(file, line, offset);
 
             var completions = compilerService.languageService.getCompletionsAtPosition(file, position);
             if (!completions) {
@@ -554,7 +557,7 @@ module ts.server {
             }, []);
         }
 
-        getCompletionEntryDetails(line: number, col: number,
+        getCompletionEntryDetails(line: number, offset: number,
             entryNames: string[], fileName: string): protocol.CompletionEntryDetails[] {
             var file = ts.normalizePath(fileName);
             var project = this.projectService.getProjectForFile(file);
@@ -563,7 +566,7 @@ module ts.server {
             }
 
             var compilerService = project.compilerService;
-            var position = compilerService.host.lineColToPosition(file, line, col);
+            var position = compilerService.host.lineOffsetToPosition(file, line, offset);
 
             return entryNames.reduce((accum: protocol.CompletionEntryDetails[], entryName: string) => {
                 var details = compilerService.languageService.getCompletionEntryDetails(file, position, entryName);
@@ -589,13 +592,13 @@ module ts.server {
             }
         }
 
-        change(line: number, col: number, endLine: number, endCol: number, insertString: string, fileName: string) {
+        change(line: number, offset: number, endLine: number, endOffset: number, insertString: string, fileName: string) {
             var file = ts.normalizePath(fileName);
             var project = this.projectService.getProjectForFile(file);
             if (project) {
                 var compilerService = project.compilerService;
-                var start = compilerService.host.lineColToPosition(file, line, col);
-                var end = compilerService.host.lineColToPosition(file, endLine, endCol);
+                var start = compilerService.host.lineOffsetToPosition(file, line, offset);
+                var end = compilerService.host.lineOffsetToPosition(file, endLine, endOffset);
                 if (start >= 0) {
                     compilerService.host.editScript(file, start, end, insertString);
                     this.changeSeq++;
@@ -644,8 +647,8 @@ module ts.server {
                 kind: item.kind,
                 kindModifiers: item.kindModifiers,
                 spans: item.spans.map(span => ({
-                    start: compilerService.host.positionToLineCol(fileName, span.start),
-                    end: compilerService.host.positionToLineCol(fileName, ts.textSpanEnd(span))
+                    start: compilerService.host.positionToLineOffset(fileName, span.start),
+                    end: compilerService.host.positionToLineOffset(fileName, ts.textSpanEnd(span))
                 })),
                 childItems: this.decorateNavigationBarItem(project, fileName, item.childItems)
             }));
@@ -681,8 +684,8 @@ module ts.server {
             }
 
             return navItems.map((navItem) => {
-                var start = compilerService.host.positionToLineCol(navItem.fileName, navItem.textSpan.start);
-                var end = compilerService.host.positionToLineCol(navItem.fileName, ts.textSpanEnd(navItem.textSpan));
+                var start = compilerService.host.positionToLineOffset(navItem.fileName, navItem.textSpan.start);
+                var end = compilerService.host.positionToLineOffset(navItem.fileName, ts.textSpanEnd(navItem.textSpan));
                 var bakedItem: protocol.NavtoItem = {
                     name: navItem.name,
                     kind: navItem.kind,
@@ -706,7 +709,7 @@ module ts.server {
             });
         }
 
-        getBraceMatching(line: number, col: number, fileName: string): protocol.TextSpan[] {
+        getBraceMatching(line: number, offset: number, fileName: string): protocol.TextSpan[] {
             var file = ts.normalizePath(fileName);
             
             var project = this.projectService.getProjectForFile(file);
@@ -715,7 +718,7 @@ module ts.server {
             }
             
             var compilerService = project.compilerService;
-            var position = compilerService.host.lineColToPosition(file, line, col);
+            var position = compilerService.host.lineOffsetToPosition(file, line, offset);
             
             var spans = compilerService.languageService.getBraceMatchingAtPosition(file, position);
             if (!spans) {
@@ -723,8 +726,8 @@ module ts.server {
             }
             
             return spans.map(span => ({
-                start: compilerService.host.positionToLineCol(file, span.start),
-                end: compilerService.host.positionToLineCol(file, span.start + span.length)
+                start: compilerService.host.positionToLineOffset(file, span.start),
+                end: compilerService.host.positionToLineOffset(file, span.start + span.length)
             }));
         }
 
@@ -741,49 +744,50 @@ module ts.server {
                 switch (request.command) {
                     case CommandNames.Definition: { 
                         var defArgs = <protocol.FileLocationRequestArgs>request.arguments;
-                        response = this.getDefinition(defArgs.line, defArgs.col, defArgs.file);
+                        response = this.getDefinition(defArgs.line, defArgs.offset, defArgs.file);
                         break;
                     }
                     case CommandNames.References: { 
                         var refArgs = <protocol.FileLocationRequestArgs>request.arguments;
-                        response = this.getReferences(refArgs.line, refArgs.col, refArgs.file);
+                        response = this.getReferences(refArgs.line, refArgs.offset, refArgs.file);
                         break;
                     }
                     case CommandNames.Rename: {
                         var renameArgs = <protocol.RenameRequestArgs>request.arguments;
-                        response = this.getRenameLocations(renameArgs.line, renameArgs.col, renameArgs.file, renameArgs.findInComments, renameArgs.findInStrings);
+                        response = this.getRenameLocations(renameArgs.line, renameArgs.offset, renameArgs.file, renameArgs.findInComments, renameArgs.findInStrings);
                         break;
                     }
                     case CommandNames.Open: {
                         var openArgs = <protocol.OpenRequestArgs>request.arguments;
-                        this.openClientFile(openArgs.file,openArgs.tabSize);
+                        this.openClientFile(openArgs.file,openArgs.tabSize, openArgs.indentSize);
                         responseRequired = false;
                         break;
                     }
                     case CommandNames.Quickinfo: {
                         var quickinfoArgs = <protocol.FileLocationRequestArgs>request.arguments;
-                        response = this.getQuickInfo(quickinfoArgs.line, quickinfoArgs.col, quickinfoArgs.file);
+                        response = this.getQuickInfo(quickinfoArgs.line, quickinfoArgs.offset, quickinfoArgs.file);
                         break;
                     }
                     case CommandNames.Format: {
                         var formatArgs = <protocol.FormatRequestArgs>request.arguments;
-                        response = this.getFormattingEditsForRange(formatArgs.line, formatArgs.col, formatArgs.endLine, formatArgs.endCol, formatArgs.file);
+                        response = this.getFormattingEditsForRange(formatArgs.line, formatArgs.offset, formatArgs.endLine, formatArgs.endOffset, formatArgs.file);
                         break;
                     }
                     case CommandNames.Formatonkey: {
                         var formatOnKeyArgs = <protocol.FormatOnKeyRequestArgs>request.arguments;
-                        response = this.getFormattingEditsAfterKeystroke(formatOnKeyArgs.line, formatOnKeyArgs.col, formatOnKeyArgs.key, formatOnKeyArgs.file);
+                        response = this.getFormattingEditsAfterKeystroke(formatOnKeyArgs.line, formatOnKeyArgs.offset, formatOnKeyArgs.key, formatOnKeyArgs.file);
                         break;
                     }
                     case CommandNames.Completions: {
                         var completionsArgs = <protocol.CompletionsRequestArgs>request.arguments;
-                        response = this.getCompletions(request.arguments.line, request.arguments.col, completionsArgs.prefix, request.arguments.file);
+                        response = this.getCompletions(completionsArgs.line, completionsArgs.offset, completionsArgs.prefix, completionsArgs.file);
                         break;
                     }
                     case CommandNames.CompletionDetails: {
                         var completionDetailsArgs = <protocol.CompletionDetailsRequestArgs>request.arguments;
-                        response = this.getCompletionEntryDetails(request.arguments.line, request.arguments.col, completionDetailsArgs.entryNames,
-                                                                  request.arguments.file);
+                        response =
+                            this.getCompletionEntryDetails(completionDetailsArgs.line,completionDetailsArgs.offset,
+                                                           completionDetailsArgs.entryNames,completionDetailsArgs.file);
                         break;
                     }
                     case CommandNames.Geterr: {
@@ -794,7 +798,7 @@ module ts.server {
                     }
                     case CommandNames.Change: {
                         var changeArgs = <protocol.ChangeRequestArgs>request.arguments;
-                        this.change(changeArgs.line, changeArgs.col, changeArgs.endLine, changeArgs.endCol,
+                        this.change(changeArgs.line, changeArgs.offset, changeArgs.endLine, changeArgs.endOffset,
                                     changeArgs.insertString, changeArgs.file);
                         responseRequired = false;
                         break;
@@ -831,7 +835,7 @@ module ts.server {
                     }
                     case CommandNames.Brace: {
                         var braceArguments = <protocol.FileLocationRequestArgs>request.arguments;
-                        response = this.getBraceMatching(braceArguments.line, braceArguments.col, braceArguments.file);
+                        response = this.getBraceMatching(braceArguments.line, braceArguments.offset, braceArguments.file);
                         break;
                     }
                     case CommandNames.NavBar: {