A Remote Collaboration Environment for Protein Crystallography HEPiX-HEPNT Conference, 8 Oct 1999 Nicholas Sauter, Stanford Synchrotron Radiation Laboratory General Goal: Allow a team of researchers distributed anywhere in the world to perform a complete crystallographic experiment, from data collection to structure publication. User at SSRL Team Member at Home Lab Remote Collaborator Collaboratory Manager Equipment Control DataCPU Internet Local Area Network

X-ray Diffraction Experiments Give the Detailed Atomic Structure of Protein Molecules Diffraction data Electron density Molecular model of Cholera toxin Protein crystal

Protein Diffraction Work Bears Several Similarities to the High Energy Physics Field Experiments performed at National facilities Large user base ~4 users per group ~90 groups per year at each beamline Big datasets Current detectors: ~0.6 Terabyte/year CCD next generation: ~20 Tb/year Acquisition software must perform well since each group has ~50 hours experimental time No downtime is possible Very little time for data backup Graphical user interface Users need shared access to data during an extended analysis period SSRL Synchrotron Source

Designing a Modern System from the Ground Up High Performance Computing Environment at the Beamline l Distributed Architecture l Cross Platform Compatibility l GUI’s Implemented in Tcl/Tk Extending this System for Remote Access l Viewing the Data from a Remote Platform l Live Video Feed from the Experimental Floor l Remote File Access and Data Archiving l General Security Considerations l Delivering X-window Legacy Applications with Terminal Server

The Problem of Multiple, Simultaneous User Interfaces

The Problem of Multiple Hardware Hosts

Solution: Distributed Control System (DCS)

A Peek Inside the DCS Server

Cross-Operating System Library (XOS) Features Supports portable, multithreaded, distributed programs Network communication using simplified socket objects. Thread creation and synchronization with mutexes and semaphores. Memory mapped files and hash tables. Inter-thread communication with message queues and Win32-style messages. Compile-time approach Header file xos.h loads appropriate, system-dependent include files. Advantages l Portability Compile code on Digital Unix, IRIX, OpenVMS, Windows NT/95. Easy to port to new platforms similar to any of the above. l Reliability Simpler APIs leads to more reliable code. Less need to study different platforms; easy for novice programmers. l Performance Native system calls on each platform for maximum performance No runtime overhead for platform independence. l Open Source

Tcl / Tk for GUI Development Source: John Ousterhoust, IEEE Computer, March 1998 Rapid Development l GUI needs only a fraction of the code necessary in C, C++ or Java. l Easy for the novice programmer! l Quick coding & easy maintenance is essential for rapidly changing beamline environment.

Other Advantages of Tcl /Tk Platform Independence Unix, VMS, Mac, and Win32. Scripts can be distributed without compilation and run on any computer Tcl/Tk has been installed on. Or…scripts can be bundled with Tcl/Tk binaries and distributed as a single executable file. Extensible in C/C++ Tcl was designed to be extended readily in C or C++. High performance code, multiple threads, etc., best implemented as extensions. XOS library is used for sockets. Object Orientation The [Incr Tcl] extension to Tcl provides object-oriented features such as classes. The [Incr Widgets] extension provides an object oriented framework for building complex widgets from built-in Tcl widgets.

Data Collection GUI written in Tcl/Tk

Adding a JPEG Compressor to the System

A Web-based Data Viewer at

Video Feeds from the Experimental Floor Sample Manipulation Beamline Instruments Videoconference

Architecture for Remote Video

Transparent File Access For Remote Collaborators

Metadata for Diffraction Images File Header Thumbnail View File Parameters Creation date Access control list Tape archive status User annotation Annotation by data processing software Move, rename, and copy tracking Larger JPEG View

Architecture for Remote Archiving

General Security Architecture

Legacy Applications Can Run Within X-window on Metaframe SGI Desktop at home lab Windows Terminal Server at SSRL Seen Through ICA Connection WRQ Reflection-X Showing SGI Desktop at SSRL Data Analysis Application Running at SSRL

Summary: Four Platforms for Remote Access