This message announces the availability of wb-2a3.

"WB" is a disk based (sorted) associative-array package with C, SCM,
Java, and C# libraries.  These associative arrays consist of variable
length (0.B to 255.B) keys and values.  Functions are provided to:

   * create, destroy, open and close disk-files and associative arrays;

   * insert, delete, retrieve, find next, and find previous (with
     respect to dictionary order of keys); and

   * The atomic `put' and `rem' operations allow associations to be
     used for process mutexs.

   * apply functions, delete, or modify values over a range of
     consecutive key values.

The (database) disk files interoperate between the various language
libraries.  The interface to the SCM Scheme implementation supports
longer data values and SLIB relational databases.

The WB implementation has a file size limit of 2^32 * block size
(default 2048.B) = 2^43 bytes (8796.GB).  WB routinely runs with
databases of several hundred Megabytes.  WB does its own memory and
disk management and maintains a RAM cache of recently used blocks.

Multiple associative arrays can reside in one disk file.  Simultaneous
access to multiple disk files is supported.  A structure checking and
garbage collecting program and a viewer are provided.  Compiled, WB
occupies approximately 66 kilobytes.

WB is implemented using a variant of B-tree structure.  B-trees give
slower access than hashing but are dynamic and provide an efficient
determination of successor and predecessor keys.  All operations are
O(log(n)) in the size of the database.  B-trees are commonly used by
database systems for implementing index structures.  B-trees are
optimized for using the minimum number of disk operations for large data
structures.  Prefix and suffix key compression are used for storage
efficiency in WB.

WB is free software and part of the GNU project.  It is released under
the GNU Lesser General Public License (LGPL).

Documentation and distributions in several formats are linked from
WB's home page:

	     http://people.csail.mit.edu/jaffer/WB.html

Links to distributions of WB and related softwares are at the end of
this message.

				-=-=-
wb-2a3 news:

* now operates with any number of open database files (segs).
* now uses native mutexes: pthread_mutex on unix; Windows mutex in MSVC.
* init-wb can now be called multiple times.
* moved C source, objects, and programs into c subdirectory.
* URLs updated.
* bugs fixed.

				-=-=-

  * c: Moved C source, objects, and programs into c subdirectory.

  * scm2cs (schlep-let): Named let becomes just label; not while(true).
  * schlep (schlep1): Take optional destination directory as last arg.
  * schlep, scm2cs, scm2java: Using 'schlep' for all internal names
  eases porting improvements between compilers.
  * schlep: Removed 1st line "%0 %*" for MS-DOS scripting.
  * scm2java, java/*.java: Wrapped java '?' ifs with ().
  * scm2cs.typ (namespace): is now "wb".
  * scm2cs.typ, scm2java.typ (blkio:*): Corrected return types to
  boolean.

  * wbview (wbview): Fixed (had gone stale).
  * csharp/Test.cs, csharp/TestA.cs: Fixed test files.
  * benchmark.scm: Updated; changed to test creating 100 segs.
  * Makefile (scheck): Separated Scheme-check from check target.
  * test.scm, example.scm, csharp/Test.cs, java/Example.java: Don't
  close and reopen new segment.

  * c/wbsys.c, c/wbsys.h (_MSC_VER): Made 'lck's block own thread.
  * java/Lck.java, csharp/Cssys.cs: Made 'lck's self-blocking.
  * ents.scm (init-wb): Added check that 'lck's are self-blocking.
  * ents.c, segs.c, wbsys.c, wbsys.h: Locks are pthread_mutex on
  unix; Windows mutex in MSVC.
  * java/Lck.java: Supplied missing '\n's in error messages.
  * ents.scm, segs.scm: Reorganized lck numbering.
  * ents.scm (empty-blk, empty-blk-lck): Removed.

  * ents.scm (final-wb): Close segs before freeing ents.

  * segs.scm (make-seg): Fail if bt-open-new fails.
  (bt-open-new): Make repeated calls to try-get-free-ent rather than
  one call to get-free-free-ent.  Fixes bug opening many segments.
  * c/db.c, c/segs.c, java/Segs.java, segs.scm (open-seg): Don't
  leave uninitialized seg in seg-chain when open-seg fails.

  * java/Ents.java, ents.c, ents.scm (init-wb): Return NOTPRES (-1)
  if already initialized.
  * ents.c, ents.scm, java/Ents.java, java/Segs.java, segs.c,
  segs.h, segs.scm, wb.info, wb.texi (init-wb): Don't err if called
  multiple times.

  * (segtab): Eliminated; segs are now allocated objects.

  * rwb-isam.scm (make-base): Don't reopen new segment.
  (open-base, write-base): Open-seg takes boolean third argument.

  * java/Blkio.java, blkio.c, blkio.scm (blkio:file-extend): Don't
  need to write block.

				-=-=-

WB source is available from:
 http://swissnet.ai.mit.edu/ftpdir/wb-2a3.tar.gz

WB source is available from:
 http://swissnet.ai.mit.edu/ftpdir/scm/wb-2a3.zip
 http://swissnet.ai.mit.edu/ftpdir/scm/wb-2a3-1.src.rpm
Also available as i386 binary RPM:
 http://swissnet.ai.mit.edu/ftpdir/scm/wb-2a3-1.i386.rpm

WB comes with an interface to the Scheme implementation SCM; and
contains "wbtab.scm", SCM code allowing WB to implement SLIB
relational databases.

SCM source is available from:
 http://swissnet.ai.mit.edu/ftpdir/scm/scm-5e6.zip
 http://swissnet.ai.mit.edu/ftpdir/scm/scm-5e6-1.src.rpm
Also available as i386 binary RPM:
 http://swissnet.ai.mit.edu/ftpdir/scm/scm-5e6-1.i386.rpm

SLIB is a portable Scheme library which SCM uses:
 http://swissnet.ai.mit.edu/ftpdir/scm/slib-3b2.zip
Also available as RPM:
 http://swissnet.ai.mit.edu/ftpdir/scm/slib-3b2-1.noarch.rpm