...

{+}\[RD01\]+

{+}\[RD01\]+

Introduction

...

Scope

This document describes the architecture for the ALMA Common Software (ACS), taking as applicable the requirements specified in the ALMA Common Software Technical Requirements document

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It will have to be possible to execute specific data reduction pipelines as a single executable and not load dynamically components.
This version of the ACS Architecture addresses many of these issues.
This document describes also some features that have not been implemented for ALMA until now and that possibly will not be implemented. It has been decided not to remove their description from the document for completeness and to make clear what is foreseen if any of these extensions needs to be implemented. These features are clearly identified in the text by the "Not implemented yet" or "Implementation not foreseen for ALMA" strings and by the usage of different fonts.

...

Overview

ACS is located in between the ALMA application software and other basic commercial or shared software on top of the operating systems and provides a generalized common interface between applications and the hardware in order to facilitate the implementation and the integration in the system of new hardware and software components.
ACS provides basic software services common to the various applications (like antenna control, correlator software, data pipelining)

...

etc. A lot of experience has been accumulated in the past years of ACS development, in particular for what concerns the application of these concepts to high level applications and in particular pipeline, offline data reduction and observation preparation. A lot of discussions with the AIPS++ team have helped shaping ACS based on the requirements in these application domains. It has been an initial and explicit decision of the ALMA project to use CORBA technology and at the same time to share software rather than to re-invent it. It is up to documents like this to provide elements to confirm the initial choice of CORBA as adequate.
The reasons for using CORBA are in short: Object Orientation, support for distributed systems, platform independence, it is a communication standard, it provides a variety of services.

...

Reference Architecture

A reference layout for the system is provided by the ALMA Software
Architecture

...

connected to various intelligent devices. The fact that the Antenna controller and all or part of these Devices is on Field-bus or LANs shall not make any difference in terms of the architecture proposed here.
Pipeline, offline data reduction and other high level applications are also assumed to be distributed over many hosts, with the need or deploying CPU intensive applications dynamically based on the available resources.

...

Reference Documents

The reference documents contain background information required to fully understand the structure of this document, the terminology used, the software environment in which ALMA shall be integrated and the interface characteristics to the external systems. 
The following documents are referenced in this document. 
*\[RD01\] ALMA Common Software Technical Requirements{*}, COMP-
70.25.00.00-003-A-SPE, G.Raffi, B.Glendenning, J.Schwarz ([<span style="color: #0000ff">{+}<a href="http://www.eso.org/+" class="external-link" rel="nofollow">http://www.eso.org/+</a></span>|http://www.eso.org/projects/alma/develop/acs/MilestoneReleases/Phase1/ACSTechReqs/Issue1.0/2000-06-05.pdf]
[<span style="color: #0000ff"><span style="text-decoration: underline; ">~almamgr/AlmaAcs/MilestoneReleases/Phase1/ACSTechReqs/Issue1.0/2000-06</span></span>|http://www.eso.org/projects/alma/develop/acs/MilestoneReleases/Phase1/ACSTechReqs/Issue1.0/2000-06-05.pdf][<span style="color: #0000ff"><span style="text-decoration: underline; ">05.pdf</span></span>|http://www.eso.org/projects/alma/develop/acs/MilestoneReleases/Phase1/ACSTechReqs/Issue1.0/2000-06-05.pdf][)|http://www.eso.org/projects/alma/develop/acs/MilestoneReleases/Phase1/ACSTechReqs/Issue1.0/2000-06-05.pdf] 
*\[RD02\] ALMA Construction Project Book{*}, Version 5.00, 2001-08-01 [(|http://www.mma.nrao.edu/projectbk/construction/][<span style="color: #0000ff">{+}<a href="http://www.mma.nrao.edu/projectbk/construction/+" class="external-link" rel="nofollow">http://www.mma.nrao.edu/projectbk/construction/+</a></span>|http://www.mma.nrao.edu/projectbk/construction/][)|http://www.mma.nrao.edu/projectbk/construction/] 
*\[RD03\]* *TANGO - an object oriented control system based on CORBA* 

• Wiki Markup

  J.M.Chaize et al., ICALEPCS'99 Conference, Trieste, IT, 1999 [(|http://www.elettra.trieste.it/ICALEPCS99/proceedings/papers/wa2i01.pdf][<span style="color: #0000ff">{+}<a href="http://www.elettra.trieste.it/ICALEPCS99/proceedings/papers/wa2i01.pdf+" class="external-link" rel="nofollow">http://www.elettra.trieste.it/ICALEPCS99/proceedings/papers/wa2i01.pdf+</a></span>|http://www.elettra.trieste.it/ICALEPCS99/proceedings/papers/wa2i01.pdf][)|http://www.elettra.trieste.it/ICALEPCS99/proceedings/papers/wa2i01.pdf] *\[RD04\]* *Implementing Distributed Controlled Objects with CORBA* - M.Plesko, PCs and Particle Accelerator Control Workshop, DESY, Hamburg, 1996 (See [<span style="color: #0000ff">{+}<a href="http://kgb.ijs.si/KGB/accomplishments_articles.php+" class="external-link" rel="nofollow">http://kgb.ijs.si/KGB/accomplishments_articles.php+</a></span>|http://kgb.ijs.si/KGB/accomplishments_articles.php][ |http://kgb.ijs.si/KGB/accomplishments_articles.php]for this and other related papers). *\[RD05\]* *SOSH Conventions for Control* - F.DiMajoC.Watson, Software Sharing (SOSH) for Accelerators & Physics Detectors ([<span style="color: #0000ff">{+}<a href="http://www.jlab.org/sosh/+" class="external-link" rel="nofollow">http://www.jlab.org/sosh/+</a></span>|http://www.jlab.org/sosh/][)|http://www.jlab.org/sosh/] *\[RD06\] Java Home Page* - ([<span style="color: #0000ff">{+}<a href="http://java.sun.com/+" class="external-link" rel="nofollow">http://java.sun.com/+</a></span>|http://java.sun.com/][)|http://java.sun.com/] *\[RD07\]* *Real-time CORBA with TAO (the ACE ORB)* - [(|http://www.cs.wustl.edu/~schmidt/TAO.html][<span style="color: #0000ff">{+}<a href="http://www.cs.wustl.edu/~schmidt/TAO.html+" class="external-link" rel="nofollow">http://www.cs.wustl.edu/~schmidt/TAO.html+</a></span>|http://www.cs.wustl.edu/~schmidt/TAO.html][)|http://www.cs.wustl.edu/~schmidt/TAO.html] *\[RD08\] ObjectStore home page* - ([<span style="color: #0000ff">{+}<a href="http://www.odi.com/objectstore/+" class="external-link" rel="nofollow">http://www.odi.com/objectstore/+</a></span>|http://www.odi.com/objectstore/][)|http://www.odi.com/objectstore/] *\[RD09\] MySQL home page* - ([<span style="color: #0000ff">{+}<a href="http://www.mysql.com+" class="external-link" rel="nofollow">http://www.mysql.com+</a></span>|http://www.mysql.com/][)|http://www.mysql.com/] *\[RD10\] SOFIA home page* - ([<span style="color: #0000ff">{+}<a href="http://sofia.arc.nasa.gov/+" class="external-link" rel="nofollow">http://sofia.arc.nasa.gov/+</a></span>|http://sofia.arc.nasa.gov/][)|http://sofia.arc.nasa.gov/] *\[RD11\]* *GTC home page* - ([<span style="color: #0000ff">{+}<a href="http://www.gtc.iac.es/+" class="external-link" rel="nofollow">http://www.gtc.iac.es/+</a></span>|http://www.gtc.iac.es/][)|http://www.gtc.iac.es/] *\[RD12\]* *ALMA Monitor and Control Bus, Interface* *Specification,* ALMAComputing Memo #7, M.Brooks, L.D'Addario,Rev.B 200102-05 *\[RD13\]* *National Instruments LabVIEW{*}- ([<span style="color: #0000ff">{+}<a href="http://www.ni.com/labview/+" class="external-link" rel="nofollow">http://www.ni.com/labview/+</a></span>|http://www.ni.com/labview/][)|http://www.ni.com/labview/] *\[RD14\] CORBA Telecom Log Service* - [(|http://www.omg.org/technology/documents/formal/telecom_log_service.htm][<span style="color: #0000ff">{+}<a href="http://www.omg.org/technology/documents/formal/telecom_log_service.htm+" class="external-link" rel="nofollow">http://www.omg.org/technology/documents/formal/telecom_log_service.htm+</a></span>|http://www.omg.org/technology/documents/formal/telecom_log_service.htm][)|http://www.omg.org/technology/documents/formal/telecom_log_service.htm] *\[RD15\] omniORB Home Page* - ([<span style="color: #0000ff">{+}<a href="http://www.uk.research.att.com/omniORB/+" class="external-link" rel="nofollow">http://www.uk.research.att.com/omniORB/+</a></span>|http://www.uk.research.att.com/omniORB/][)|http://www.uk.research.att.com/omniORB/] *\[RD16\]OpenOrb Home Page* - ([<span style="color: #0000ff">{+}<a href="http://openorb.sourceforge.net/+" class="external-link" rel="nofollow">http://openorb.sourceforge.net/+</a></span>|http://openorb.sourceforge.net/][)|http://openorb.sourceforge.net/] *\[RD17\]ALMA SE Practices - Software Development Process Methodology* *and Tools,* G.Chiozzi, R.Karban, P.Sivera - [(|http://www.mma.nrao.edu/development/computing/docs/joint/draft/SE-SwDev.pdf][<span style="color: #0000ff">{+}<a href="http://www.mma.nrao.edu/development/computing/docs/joint/draft/SE+" class="external-link" rel="nofollow">http://www.mma.nrao.edu/development/computing/docs/joint/draft/SE+</a></span>|http://www.mma.nrao.edu/development/computing/docs/joint/draft/SE-SwDev.pdf][<span style="color: #0000ff"><span style="text-decoration: underline; ">SwDev.pdf</span></span>|http://www.mma.nrao.edu/development/computing/docs/joint/draft/SE-SwDev.pdf][)|http://www.mma.nrao.edu/development/computing/docs/joint/draft/SE-SwDev.pdf] *\[RD18\] eXtensible Markup Language Home Page -* [(|http://www.w3.org/XML/][<span style="color: #0000ff">{+}<a href="http://www.w3.org/XML/+" class="external-link" rel="nofollow">http://www.w3.org/XML/+</a></span>|http://www.w3.org/XML/][)|http://www.w3.org/XML/] *\[RD19\] CERN Laser project home page* ([<span style="color: #0000ff">{+}<a href="http://proj-laser.web.cern.ch/proj+" class="external-link" rel="nofollow">http://proj-laser.web.cern.ch/proj+</a></span>|http://proj-laser.web.cern.ch/proj-laser/][<span style="color: #0000ff"><span style="text-decoration: underline; ">laser/</span></span>|http://proj-laser.web.cern.ch/proj-laser/][)|http://proj-laser.web.cern.ch/proj-laser/] *\[RD20\] IBM DB2 Home Page* - ([<span style="color: #0000ff">{+}<a href="http://www-4.ibm.com/software/data/db2/+" class="external-link" rel="nofollow">http://www-4.ibm.com/software/data/db2/+</a></span>|http://www-4.ibm.com/software/data/db2/][)|http://www-4.ibm.com/software/data/db2/] *\[RD21\] ALMA ACS and AMS Kitt Peak 2000 Test* ,G.Chiozzi et al. [(|http://www.mma.nrao.edu/development/computing/docs/joint/notes/2000-12-KP.pdf][<span style="color: #0000ff">{+}<a href="http://www.mma.nrao.edu/development/computing/docs/joint/notes/2000-12+" class="external-link" rel="nofollow">http://www.mma.nrao.edu/development/computing/docs/joint/notes/2000-12+</a></span>|http://www.mma.nrao.edu/development/computing/docs/joint/notes/2000-12-KP.pdf][<span style="color: #0000ff"><span style="text-decoration: underline; ">KP.pdf</span></span>|http://www.mma.nrao.edu/development/computing/docs/joint/notes/2000-12-KP.pdf][)|http://www.mma.nrao.edu/development/computing/docs/joint/notes/2000-12-KP.pdf] *\[RD22\]Design and Initial Implementation of Diagnostic and Error Reporting System of SMA{*}, SMA Technical Memo 132, Q.Zhang. *\[RD23\] The Adaptive Communication Environment (ACE) home page -* [(|http://www.cs.wustl.edu/~schmidt/ACE.html][<span style="color: #0000ff">{+}<a href="http://www.cs.wustl.edu/~schmidt/ACE.html+" class="external-link" rel="nofollow">http://www.cs.wustl.edu/~schmidt/ACE.html+</a></span>|http://www.cs.wustl.edu/~schmidt/ACE.html][)|http://www.cs.wustl.edu/~schmidt/ACE.html] *\[RD24\] Python language home page -* [(|http://www.python.org/][<span style="color: #0000ff">{+}<a href="http://www.python.org/+" class="external-link" rel="nofollow">http://www.python.org/+</a></span>|http://www.python.org/][)|http://www.python.org/] *\[RD25\] Home Page for the Official Tcl/Tk Contributed Sources Archive* - [(|http://www.neosoft.com/tcl/][<span style="color: #0000ff">{+}<a href="http://www.neosoft.com/tcl/+" class="external-link" rel="nofollow">http://www.neosoft.com/tcl/+</a></span>|http://www.neosoft.com/tcl/][)|http://www.neosoft.com/tcl/] *\[RD26\] Test Interferometer Control Software Design* *Concept{*}, B.Glendenning et al., DRAFT 2001-02-15 *\[RD27\] Advanced CORBA Programming with C++,{*}M.HenningS.Vinoski, Addison-Wesley, 1999 *\[RD28\] ALMA Software Glossary,* COMP-70.15.00.00-003-A-GEN [(|http://www.alma.nrao.edu/development/computing/docs/joint/draft/Glossary.htm][<span style="color: #0000ff">{+}<a href="http://www.alma.nrao.edu/development/computing/docs/joint/draft/Glossary.htm+" class="external-link" rel="nofollow">http://www.alma.nrao.edu/development/computing/docs/joint/draft/Glossary.htm+</a></span>|http://www.alma.nrao.edu/development/computing/docs/joint/draft/Glossary.htm] ) *\[RD29\] AMI/ACS Report{*}, R. Lemke, G. Chiozzi 2001-03-20 [(|http://www.eso.org./projects/alma/develop/acs/examples/amitest/AmiReport.pdf][<span style="color: #0000ff">{+}<a href="http://www.eso.org./projects/alma/develop/acs/examples/amitest/AmiReport.pdf+" class="external-link" rel="nofollow">http://www.eso.org./projects/alma/develop/acs/examples/amitest/AmiReport.pdf+</a></span>|http://www.eso.org./projects/alma/develop/acs/examples/amitest/AmiReport.pdf][)|http://www.eso.org./projects/alma/develop/acs/examples/amitest/AmiReport.pdf] *\[RD30\] ALMA Memo #298, Timing and Synchronization{*}, L. DÂ'Addario, 2000-03-09 ([<span style="color: #0000ff">{+}<a href="http://www.alma.nrao.edu/memos/html+" class="external-link" rel="nofollow">http://www.alma.nrao.edu/memos/html+</a></span>|http://www.alma.nrao.edu/memos/html-memos/alma298/memo298.pdf][<span style="color: #0000ff"><span style="text-decoration: underline; ">memos/alma298/memo298.pdf</span></span>|http://www.alma.nrao.edu/memos/html-memos/alma298/memo298.pdf][)|http://www.alma.nrao.edu/memos/html-memos/alma298/memo298.pdf] *\[RD31\] GNU Lesser General Public License (GPL)* [(|http://www.gnu.org/copyleft/lesser.html][<span style="color: #0000ff">{+}<a href="http://www.gnu.org/copyleft/lesser.html+" class="external-link" rel="nofollow">http://www.gnu.org/copyleft/lesser.html+</a></span>|http://www.gnu.org/copyleft/lesser.html][)|http://www.gnu.org/copyleft/lesser.html] *\[RD32\] ALMA Common Software Development Plan,* COMP-70.25.00.00001-C-PLA ([<span style="color: #0000ff">{+}<a href="http://www.eso.org/projects/alma/develop/acs/Plan/index.html+" class="external-link" rel="nofollow">http://www.eso.org/projects/alma/develop/acs/Plan/index.html+</a></span>|http://www.eso.org/projects/alma/develop/acs/Plan/index.html][)|http://www.eso.org/projects/alma/develop/acs/Plan/index.html] *\[RD33\] ALMA Software Architecture{*}, ALMA-70.15.00.00-001-I-GEN, J.Schwarz [(|http://almaedm.tuc.nrao.edu/forums/alma/dispatch.cgi/Architecture/docProfile/100017/d20021117183329/No/ALMASoftwareArchitecture.pdf][<span style="color: #0000ff">{+}<a href="http://almaedm.tuc.nrao.edu/forums/alma/dispatch.cgi/Architecture/docProfile/10+" class="external-link" rel="nofollow">http://almaedm.tuc.nrao.edu/forums/alma/dispatch.cgi/Architecture/docProfile/10+</a></span>|http://almaedm.tuc.nrao.edu/forums/alma/dispatch.cgi/Architecture/docProfile/100017/d20021117183329/No/ALMASoftwareArchitecture.pdf] [<span style="color: #0000ff"><span style="text-decoration: underline; ">0017/d20021117183329/No/ALMASoftwareArchitecture.pdf</span></span>|http://almaedm.tuc.nrao.edu/forums/alma/dispatch.cgi/Architecture/docProfile/100017/d20021117183329/No/ALMASoftwareArchitecture.pdf][)|http://almaedm.tuc.nrao.edu/forums/alma/dispatch.cgi/Architecture/docProfile/100017/d20021117183329/No/ALMASoftwareArchitecture.pdf] *\[RD34\]JacORB Home Page* ([<span style="color: #0000ff">{+}<a href="http://www.jacorb.org/+" class="external-link" rel="nofollow">http://www.jacorb.org/+</a></span>|http://www.jacorb.org/][)|http://www.jacorb.org/] *\[RD35\] Eclipse Home Page* ([<span style="color: #0000ff">{+}<a href="http://www.eclipse.org/+" class="external-link" rel="nofollow">http://www.eclipse.org/+</a></span>|http://www.eclipse.org/][)|http://www.eclipse.org/] *\[RD36\] Castor Home Page* ([<span style="color: #0000ff">{+}<a href="http://castor.codehaus.org/+" class="external-link" rel="nofollow">http://castor.codehaus.org/+</a></span>|http://castor.codehaus.org/][)|http://castor.codehaus.org/] *\[RD37\] OPUS Home Page* ([<span style="color: #0000ff">{+}<a href="http://www.stsci.edu/software/OPUS/bb.html+" class="external-link" rel="nofollow">http://www.stsci.edu/software/OPUS/bb.html+</a></span>|http://www.stsci.edu/software/OPUS/bb.html][)|http://www.stsci.edu/software/OPUS/bb.html] *\[RD38\] Rational Rose Home Page* ([<span style="color: #0000ff">{+}<a href="http://www.rational.com/+" class="external-link" rel="nofollow">http://www.rational.com/+</a></span>|http://www.rational.com/][)|http://www.rational.com/] *\[RD39\] Open ArchitectureWare project home page* [(|http://sourceforge.net/projects/architecturware/][<span style="color: #0000ff">{+}<a href="http://sourceforge.net/projects/architecturware/+" class="external-link" rel="nofollow">http://sourceforge.net/projects/architecturware/+</a></span>|http://sourceforge.net/projects/architecturware/][)|http://sourceforge.net/projects/architecturware/] *\[RD40\] Java Web Start home page* ([<span style="color: #0000ff">{+}<a href="http://java.sun.com/products/javawebstart/+" class="external-link" rel="nofollow">http://java.sun.com/products/javawebstart/+</a></span>|http://java.sun.com/products/javawebstart/][)|http://java.sun.com/products/javawebstart/] *\[RD41\] ALMA Common Software home page* [(|http://www.eso.org/projects/alma/develop/acs][<span style="color: #0000ff">{+}<a href="http://www.eso.org/projects/alma/develop/acs/+" class="external-link" rel="nofollow">http://www.eso.org/projects/alma/develop/acs/+</a></span>|http://www.eso.org/projects/alma/develop/acs][)|http://www.eso.org/projects/alma/develop/acs] *\[RD42\] CORBA Audio Video Streaming Service* [(|http://www.omg.org/technology/documents/formal/audio.htm][<span style="color: #0000ff">{+}<a href="http://www.omg.org/technology/documents/formal/audio.htm+" class="external-link" rel="nofollow">http://www.omg.org/technology/documents/formal/audio.htm+</a></span>|http://www.omg.org/technology/documents/formal/audio.htm][)|http://www.omg.org/technology/documents/formal/audio.htm] *\[RD43\] The design and performance of a CORBAAudio/Video Streaming* *ServiceCORBA Audio Video Streaming Service* *, D.C.Schmidt et al.,* [(|http://www.cs.wustl.edu/~schmidt/PDF/av.pdf][<span style="color: #0000ff">{+}<a href="http://www.cs.wustl.edu/~schmidt/PDF/av.pdf+" class="external-link" rel="nofollow">http://www.cs.wustl.edu/~schmidt/PDF/av.pdf+</a></span>|http://www.cs.wustl.edu/~schmidt/PDF/av.pdf][)|http://www.cs.wustl.edu/~schmidt/PDF/av.pdf] *\[RD44\] ARCUS Error Handling for Business Information Systems,* K.Renzel, sd&m Muenchen, 2003 [(|http://www.eso.org/projects/alma/develop/acs/OnlineDocs/ARCUSErrorHandling.pdf][<span style="color: #0000ff">{+}<a href="http://www.eso.org/~almamgr/AlmaAcs/OnlineDocs/ARCUSErrorHandling.pdf+" class="external-link" rel="nofollow">http://www.eso.org/~almamgr/AlmaAcs/OnlineDocs/ARCUSErrorHandling.pdf+</a></span>|http://www.eso.org/projects/alma/develop/acs/OnlineDocs/ARCUSErrorHandling.pdf][)|http://www.eso.org/projects/alma/develop/acs/OnlineDocs/ARCUSErrorHandling.pdf] *\[RD45\] EVLA Engineering Software Requirement,* B.Butler et. al. EVLA-SW004, Rev. 1.4, 2003 *\[RD46\] EVLA Array Operations Software Requirements,* J.Campbel et. al. EVLA-SW-003, Rev. 2.5, 2003 *\[RD47\] JFreeChart ({*}[<span style="color: #0000ff">{*}{+}<a href="http://www.jfree.org/jfreechart/+*" class="external-link" rel="nofollow">http://www.jfree.org/jfreechart/+*</a></span>|http://www.jfree.org/jfreechart/][{*})*|http://www.jfree.org/jfreechart/] *\[RD48\] MatplotlibJFreeChart* [{*}(*|http://matplotlib.sourceforge.net/installing.html][<span style="color: #0000ff">{*}{+}<a href="http://matplotlib.sourceforge.net/installing.html+*" class="external-link" rel="nofollow">http://matplotlib.sourceforge.net/installing.html+*</a></span>|http://matplotlib.sourceforge.net/installing.html][{*})*|http://matplotlib.sourceforge.net/installing.html]

  Anchor_Toc125024_Toc1250241.5Glossary

  Glossary

  An extended list of glossary definitions, abbreviations and acronyms is part of the main ALMA Software Glossary

  Wiki Markup
  +\[RD28\]{+}

  , available online at the following URL: {+}http://www.mma.nrao.edu/development/computing/docs/joint/draft/Glossary.htm+.
  The following list of abbreviations and acronyms is aimed to help the reader in recalling the extended meaning of the most important short expressions used in this document:

  ABM	Antenna Bus Master
  ACE	ADAPTIVE Communication Environment ({+}http://www.cs.wustl.edu/~schmidt/ACE.html+)
  ACS	ALMA Common Software
  ACU	Antenna Control Unit
  AIPS++	Astronomical Information Processing System ({+}http://aips2.nrao.edu/docs/aips++.html+)
  ALMA	Atacama Large Millimeter Array ({+}http://www.eso.org/projects/alma/+)
  AMB	ALMA Monitor and Control Bus
  ANKA	Synchrotron Radiation Source ANKA ({+}http://www.fzk.de/anka+)
  API	Application Programmatic Interface
  CAN	Controller Area Network
  CORBA	Common Object Request Broker Architecture
  COTS	Commercial Off The Shelf
  CPU	Central Processing Unit
  ESO	European Southern Observatory ({+}http://www.eso.org+)
  FITS	Flexible Image Transport Format
  GUI	Graphical User Interface
  GTC	Gran Telescopio CANARIAS ({+}http://www.gtc.iac.es/+)
  HW	Hardware
  IDL	CORBA Interface Definition Language
  IIOP	Internet Inter-ORB Protocol
  ISO	International Standardization Organisation
  JDBC	Java Database Connectivity
  LAN	Local Area Network
  LCU	Local Control Unit
  M&C	Monitor and Control
  N/A	Not Applicable
  NRAO	National Radio Astronomy Observatory ({+}http://www.nrao.edu/+)
  OMG	Object Management Group ({+}http://www.omg.org/+)
  ORB	Object Request Broker
  OSI	Open Systems Interconnection
  OVRO	Owens Valley Radio Observatory ({+}http://www.ovro.caltech.edu/+)
  RDBMS	Relational Data Base Management System
  RPC	Remote Procedure Call
  SLA	Subprogram Library A (Positional Astronomy Library)
  SW	Software
  TAO	The ACE ORB ({+}http://www.cs.wustl.edu/~schmidt/TAO.html+)
  TBC	To Be Confirmed
  TBD	To Be Defined
  TCL	Tool Command Language ({+}http://www.scriptics.com/resource/+)
  TCL (CORBA)	CORBA Trader Constraint Language
  TICS	ALMA Test Interferometer Control Software
  TPOINT	Telescope Pointing Analysis System
  UML	Unified Modeling Language
  URI	Uniform Resource Identifier ({+}http://www.w3.org/Addressing/+)
  URL	Uniform Resource Locator ({+}http://www.w3.org/Addressing/+)
  UTC	Universal Time Coordinated
  VME	Versa Module Eurocard
  VLT	Very Large Telescope
  WS	Workstation
  XML	eXtensible Markup Language ({+}http://www.w3.org/XML/+)

  Anchor_Toc125025_Toc1250252ACS

  ACS Basic Architecture

  Anchor_Toc125026_Toc1250262.1Overview

  Overview

  The ALMA Common Software (ACS) is located in between the ALMA application software (Applications) and other basic commercial or shared software on top of the operating systems. In particular, ACS is based on CORBA (CORBA Middleware), which provides the whole infrastructure for the exchange of messages between distributed objects. Whenever possible, ACS features will be provided using off the shelf components and ACS itself will provide the packaging and the glue between these components.
  The ACS is also based on an Object Oriented architecture

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  The following UML Package Diagram shows the main packages in which ACS has been subdivided.

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  Figure 2.1: ACS Packages

   
  Each package provides a basic set of services and tools that shall be used by all ALMA applications.
  Packages have been grouped in 4 layers. Packages are allowed to use services provided by other packages on the lower layers and on the same layer, but not on higher layers.
    Image Removed A 5^th group contains packages for software that is used by many ALMA Subsystems, but that is not used by other ACS packages. These packages are for convenience integrated and distributed together with ACS but are not integral parts of ACS.
  A brief description of the layers and the packages is provided hereafter, while the next chapter will contain a detailed description of the features included in the packages.

1. - Base Tools
   The bottom layer contains base tools that are distributed as part of ACS to provide a uniform development and run time environment on top of the operating system for all higher layers and applications. These are essentially off-the-shelf components and ACS itself just provides packaging and installation and distribution support. This ensures that all installations of ACS (development and run-time) will have the same basic set of tools with versions kept under configuration control.

The exact set of tools and versions are described in the documentation coming with each ACS release. Being these normally big packages the ACS installation procedures will have to offer the options of installing the tools in binary format, building them from sources or using an independent installation.
Three main packages have been identified in this layer:

• Development tools

Software development tools (compilers, configuration controls tools, languages, debuggers, documentation tools).

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