diff --git a/src/vs/vscode.proposed.d.ts b/src/vs/vscode.proposed.d.ts
index 48cff5d1f66ca..b4ee0962bd6ff 100644
--- a/src/vs/vscode.proposed.d.ts
+++ b/src/vs/vscode.proposed.d.ts
@@ -19,6 +19,17 @@ declare module 'vscode' {
 		export function changeLanguage(document: TextDocument, languageId: string): Thenable<void>;
 	}
 
+	//#region Joh - read/write in chunks
+
+	export interface FileSystemProvider {
+		open?(resource: Uri): number | Thenable<number>;
+		close?(fd: number): void | Thenable<void>;
+		read?(fd: number, pos: number, data: Uint8Array, offset: number, length: number): number | Thenable<number>;
+		write?(fd: number, pos: number, data: Uint8Array, offset: number, length: number): number | Thenable<number>;
+	}
+
+	//#endregion
+
 	//#region Rob: search provider
 
 	/**
diff --git a/src/vs/workbench/api/electron-browser/mainThreadFileSystem.ts b/src/vs/workbench/api/electron-browser/mainThreadFileSystem.ts
index a1005d30a80d9..60985bd290202 100644
--- a/src/vs/workbench/api/electron-browser/mainThreadFileSystem.ts
+++ b/src/vs/workbench/api/electron-browser/mainThreadFileSystem.ts
@@ -92,6 +92,10 @@ class RemoteFileSystemProvider implements IFileSystemProvider {
 
 	// --- forwarding calls
 
+	private static _asBuffer(data: Uint8Array): Buffer {
+		return Buffer.isBuffer(data) ? data : Buffer.from(data.buffer, data.byteOffset, data.byteLength);
+	}
+
 	stat(resource: URI): TPromise<IStat> {
 		return this._proxy.$stat(this._handle, resource).then(undefined, err => {
 			throw err;
@@ -103,10 +107,7 @@ class RemoteFileSystemProvider implements IFileSystemProvider {
 	}
 
 	writeFile(resource: URI, content: Uint8Array, opts: FileWriteOptions): TPromise<void> {
-		let encoded = Buffer.isBuffer(content)
-			? content
-			: Buffer.from(content.buffer, content.byteOffset, content.byteLength);
-		return this._proxy.$writeFile(this._handle, resource, encoded, opts);
+		return this._proxy.$writeFile(this._handle, resource, RemoteFileSystemProvider._asBuffer(content), opts);
 	}
 
 	delete(resource: URI, opts: FileDeleteOptions): TPromise<void> {
@@ -128,4 +129,20 @@ class RemoteFileSystemProvider implements IFileSystemProvider {
 	copy(resource: URI, target: URI, opts: FileOverwriteOptions): TPromise<void> {
 		return this._proxy.$copy(this._handle, resource, target, opts);
 	}
+
+	open(resource: URI): TPromise<number> {
+		return this._proxy.$open(this._handle, resource);
+	}
+
+	close(fd: number): TPromise<void> {
+		return this._proxy.$close(this._handle, fd);
+	}
+
+	read(fd: number, pos: number, data: Uint8Array, offset: number, length: number): TPromise<number> {
+		return this._proxy.$read(this._handle, fd, pos, RemoteFileSystemProvider._asBuffer(data), offset, length);
+	}
+
+	write(fd: number, pos: number, data: Uint8Array, offset: number, length: number): TPromise<number> {
+		return this._proxy.$write(this._handle, fd, pos, RemoteFileSystemProvider._asBuffer(data), offset, length);
+	}
 }
diff --git a/src/vs/workbench/api/node/extHost.protocol.ts b/src/vs/workbench/api/node/extHost.protocol.ts
index 49421a3b34131..bc70721284e3e 100644
--- a/src/vs/workbench/api/node/extHost.protocol.ts
+++ b/src/vs/workbench/api/node/extHost.protocol.ts
@@ -691,6 +691,10 @@ export interface ExtHostFileSystemShape {
 	$delete(handle: number, resource: UriComponents, opts: FileDeleteOptions): TPromise<void>;
 	$watch(handle: number, session: number, resource: UriComponents, opts: IWatchOptions): void;
 	$unwatch(handle: number, session: number): void;
+	$open(handle: number, resource: UriComponents): TPromise<number>;
+	$close(handle: number, fd: number): TPromise<void>;
+	$read(handle: number, fd: number, pos: number, data: Buffer, offset: number, length: number): TPromise<number>;
+	$write(handle: number, fd: number, pos: number, data: Buffer, offset: number, length: number): TPromise<number>;
 }
 
 export interface ExtHostSearchShape {
diff --git a/src/vs/workbench/api/node/extHostFileSystem.ts b/src/vs/workbench/api/node/extHostFileSystem.ts
index 1b4e15972f086..6faf26d9b3d7d 100644
--- a/src/vs/workbench/api/node/extHostFileSystem.ts
+++ b/src/vs/workbench/api/node/extHostFileSystem.ts
@@ -105,6 +105,11 @@ export class ExtHostFileSystem implements ExtHostFileSystemShape {
 		if (typeof provider.copy === 'function') {
 			capabilites += files.FileSystemProviderCapabilities.FileFolderCopy;
 		}
+		if (typeof provider.open === 'function' && typeof provider.close === 'function'
+			&& typeof provider.read === 'function' && typeof provider.write === 'function'
+		) {
+			capabilites += files.FileSystemProviderCapabilities.FileOpenReadWriteClose;
+		}
 
 		this._proxy.$registerFileSystemProvider(handle, scheme, capabilites);
 
@@ -201,4 +206,21 @@ export class ExtHostFileSystem implements ExtHostFileSystemShape {
 			this._watches.delete(session);
 		}
 	}
+
+	$open(handle: number, resource: UriComponents): TPromise<number> {
+		return asWinJsPromise(() => this._fsProvider.get(handle).open(URI.revive(resource)));
+	}
+
+	$close(handle: number, fd: number): TPromise<void> {
+		return asWinJsPromise(() => this._fsProvider.get(handle).close(fd));
+	}
+
+	$read(handle: number, fd: number, pos: number, data: Buffer, offset: number, length: number): TPromise<number> {
+		return asWinJsPromise(() => this._fsProvider.get(handle).read(fd, pos, data, offset, length));
+	}
+
+	$write(handle: number, fd: number, pos: number, data: Buffer, offset: number, length: number): TPromise<number> {
+		return asWinJsPromise(() => this._fsProvider.get(handle).write(fd, pos, data, offset, length));
+	}
+
 }