Transcript MDSplus Tom Fredian MIT Plasma Science and Fusion Center

MDSplus
Tom Fredian
MIT Plasma Science and Fusion Center
What is MDSplus?
• Data Acquisition System
• Remote Data Access System
• Data Visualization and Analysis System
– Data available via fortan, c, c++, java,
idl,matlab, visual basic, labview, php, python
• Data Archival System
History
• Designed and developed for use on Alcator CMod, RFX and ZTH between 1987-1991 to run
on OpenVMS platform
• Remote data access from wide variety of
platforms added 1994
• Ported to Unix/Windows 1999
• Added Globus Security Infrastructure 2002
– Based on X.509 identity certificates
MDSplus is Widely used in the
Fusion Community
MDSplus Worldwide
• MDSplus currently installed at over 30
experiments, fusion laboratories and
universities.
• Most widely used tool for accessing fusion
related data.
• Over 3000 downloads of the MDSplus
software.
MDSplus
• Data Acquisition
– MDSplus typically used in “pulse” mode
– DAQ Device support developed as needed
• Remote data access
– Simple efficient data access on the LAN
– Secure authenticated data access on the WAN
• Visualization Tools
– dwscope & jScope
– IDL, MATLAB, python, PHP interfaces (and more)
Data Storage
• The information about each pulse is stored in a hierarchical
structure.
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Diagnostic / Data analysis setup
Machine Control
Task scheduling
Raw and Analyzed results
Calibration information
• Data longevity
– All of the data from a diagnostic is stored in an organized way.
– This provides a mechanism for the data from a diagnostic to be self
descriptive.
• One set of tools can be used to operate on both data and setup
information.
• Concurrent multi-user read and write
Traverser
Icons for
Node usage
Expandable
Node
Right button
popup menu
Command
Window
Complex Data types
• In addition to a wide selection of primitive data types
(byte, word, long, float, double, complex, etc...)
MDSPlus supports data types to store commonly
used combinations of items.
– Signal (scaled data, raw data, dimension_0 [,dimension_1
…])
– Subscripting both arrays and signals
– With_units(item, units)
– Range - start : end : increment
– Action(dispatch, task)
– Dispatch(1, ident, phase, when, notify)
– etc…
Expressions
Homogeneous Data Access
Interface
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MdsConnect,host[:port]
MdsOpen, tree, shot
var = MdsValue(expression [,args…])
MdsPut, name, expression [,args…]
MdsClose [, tree, shot]
MdsDisconnect
Remote Access - details
• Types of client/server connections
– MdsConnect “thin client”
• One server process per client connection
• Server activated by inetd
• Expression evaluation done in server process ctx
– TreeOpen “thick client”
• One server process per client per tree host
• Server activated by inetd
• Expression evaluation done in client process ctx
MDSplus “Data Gateway”
• MDSplus is sometimes used as a gateway
to other data stores.
• Expression evaluation can call into local
shared libraries to retrieve or put data.
Secure WAN Access
• MDSplus network protocol (MDSIP)
layered on top of Globus GSI using XIO
• X509 Credentials used to authenticate
both client and server.
• Centralized management of access control
via ROAM (Resource Oriented
Authentication Manager)
ROAM used to solve authorization problem
• Resource Oriented Authorization Manager (ROAM) provides a central
location for authorization information
• Administrators & other stakeholders can control access
• Users can request access
ROAM data model is fundamental to a coherent
picture of authorization in the grid
• Oriented around resources: codes, databases, entire sites
• If you have to sign a paper
to get permission to use
something, then it’s
probably a resource
• Resources have associated
permissions
– e.g. “execute” for a
code, “access” for a site
People interact with ROAM through a web page
• An interactive web page allows users and resource owners to
request and grant permissions
• Less error-prone
than editing text
files
• No more gridmapfiles!
• Can take the place
of mdsip.hosts for
MDSplus
Potential use of MDSplus at FNAL
• Transfer of CERN control data to FNAL
– Push or pull data?
• Client application running at CERN gathering data and
writing it securely to MDSplus data storage at FNAL
• MDSplus data server running at CERN with access to control
data accessible securely via client at FNAL
– How much data? How often?
• MDSplus is currently “pulse” based. Not designed for
“trending” data (yet).
• Extensions for long pulse/continuous data to be explored
either via the “Collaborative Technology” SCIDAC proposal or
ITER projects.
– What type/structure of data? How will it be accessed?
Other topics (if time)
• Electronic Logbook (quick demo)
• MDSplus in action (C-Mod)
– ~2GB/shot (uncompressed) 15 minute reprate
– 82,000 tree nodes in each data set (“directories”
and “files”)
• Expressions examples for gateways
Summary
• MDSplus used at most fusion research
sites.
• Useful for handling some types of HEP
data?
• Next Steps?
– http://www.mdsplus.org/
– http://www.fusiongrid.org/
– [email protected]