Handle System Usage at Content Directions

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Handle System Usage atContent Directions

• Andy StevensContent Directions, Inc., Brooklyn,
  NY
• Handle Workshop
• CNRI, Reston, VASeptember 20, 2002

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Server Environment

• Red Hat Linux 7.0, 2.2.16 kernel
• JDK 1.3.1 (Blackdown distribution)
• Handle Server hsj-5.2.0
• One of many server programs running on a
  dual-processor 800MHz Compaq Proliant

Environment Issues

• Poor Linux threading Must run Handle Server in
  green thread mode to avoid running out of Unix
  processes
• Linux/JDK1.3 stacksize bug

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Installation Issues

• Easy to install if you know Java. YMMV.
• Wrote our own start/stop shell script (would be
  useful to include in distribution for Linux
  Solaris users)
• Our server configuration standalone (no
  mirroring)

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Software Development w/ Handle Client

• We use our locally installed Handle Server for
  software development and testing only. All
  production Handles are currently loaded into
  the CNRI-administered global server (DOI server)
• Occasionally have a software bug due to increased
  network latency and replication latency on remote
  production server.
• Development server usage currently loaded with
  20,000 Handles (wish there was an easy way to
  figure out this number!)

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Bugs discovered in Handle Server

• Corruption of large Handles (fixed)
• Cannot force-delete handles remotely
• Cache TTL is ignored (defaults to 24 hours)
• List Handles doesnt always work

Bugs discovered in Handle Client

• No way to turn off stderr in C client?

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Handle Server Wish List

• Include Javadoc with server distribution
• Would like method to automatically checkpoint
  server (would like ability to execute most
  administrative functions from a command line
  instead of GUI tool)
• Better reporting ability to list homed prefixes,
  list handles, etc.

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How Were Using Handles

• Ordinary URL redirects (unilinks)
• Multiple Resolution (MultiLinks)
• Store label/URL pairs as Handle values of type
  MULTIRES
• MultiLink choices are displayable by any
  knowledgeable client (CDI has written one)
• Use URL value as default for non-MultiLink
  clients.

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Example MultiLink Handle
INDEX TYPE VALUE
1000 MULTIRES Home Pagehttp//www.contentdirections.com
1001 MULTIRES Demoshttp//demo.contentdirections.com/
1 URL http//doi.contentdirections.com/mr/cdi.jsp?doi1715/3
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Example Implementation
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Example of embedded MultiLink using CDI software
library
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Hierarchical MultiLink
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Other RD

• Metadata Database Oracle database to hold
  metadata for each Handle.
• Pinger ping all URLs for a given Handle to
  check for bad links, etc.
• Autolinker Automatically generate MultiLinks
  based on metadata.