Shore - A High-Performance, Scalable, Persistent Object Repository
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The objective of the Shore project is to design, implement, and
evaluate a persistent object system that will serve the needs of a wide
variety of target applications including hardware and software CAD
systems, persistent programming languages, geographic information
systems, satellite data repositories, and multi-media applications.
Shore expands on the basic capabilities of the widely-used
EXODUS
Storage Manager (developed at Wisconsin, funded by
ARPA ) in a number of
ways including support for typed objects, multiple programming
languages, a ``Unix-like'' hierarchical name space for named objects, and
a Unix-compatible interface to objects with a ``text'' field. This
interface is intended to ease the transition of applications from the
Unix file system environment to Shore as existing Unix tools such as vi,
emacs, or cc will be able to store their data in Shore objects without
modification.
Shore has a layered architecture that allows users to choose the level of
support appropriate for a particular application.
We briefly overview this architecture here.
The paper
Shoring Up Persistent Applications
describes the design of Shore in much greater detail.
The
Shore Storage Manager
(SM) is a persistent object storage engine that supports creation of persistent
files of records. Each record can be any size, with
efficient storage of records from a few bytes to megabytes or larger. Records
may be retrieved by object identifier or by scanning files. The SM
provides full concurrency control and recovery (the so-called ACID properties)
with two-phase locking and write-ahead logging. It also provides robust
implementations of btrees and rtrees and record access through logical object
identifiers. The SM is designed to be used as a library to create
value-added servers tailored to specific applications.
The
Shore Value-Added Server
(SVAS) builds on the functionality of the SM
to provide typed objects, a Unix-like directory namespace, access control,
and a client-server architecture supporting object-level caching, transactional
semantics, and security at the server boundary. The NFS value-added server
fully implements the standard NFS (Network File Server) protocol, allowing
legacy applications to access Shore objects as if they were Unix files.
The Shore Data Language (SDL),
which is based on the Object Database Management
Group (ODMG) ODL language, supports language-independent description of
object-oriented data types. The SDL compiler compiles definitions into
type objects stored in the database and C++ language stubs. The
combination of the SDL compiler and an extensive run-time library allows
programmers to write applications that manipulate objects through type-safe
object references. The library takes care of fetching objects on
demand to an LRU client-level object cache, flushing changes to the server on
transaction commit, and swizzing and unswizzling references
as necessary.
Shore serves as the basis of other database projects, including
Paradise
at the University of Wisconsin and
PREDATOR
at Cornell University.
Paradise
is a scalable, parallel geographic
information system (GIS) that is capable of storing and manipulating massive
data sets. By applying object-oriented and parallel database technologies to
the problem of storing and manipulating geographic information, the Paradise
project hopes to significantly advance the size and complexity of GIS data sets
that can be successfully stored, browsed, and queried.
The
PREDATOR
object-relational database system from Cornell University
is freely available for
research and education purposes. PREDATOR is a multi-threaded client-server
system built on Shore. It supports standard relational query-processing with
SQL queries, extensibility with enhanced complex data types with user-defined
methods and aggregates, and WWW access through a Java applet client.
Beta Release (0.9)
On May 3, 1995 we had our first beta release.
Beta Release (0.9.3)
A second Beta-rlease of Shore (version 0.9.3)
was released on September 18, 1995.
It is now obsolete.
Version 1.0
On August 6, 1996 we released Shore, version 1.0.
Gzip'd tar files of the source, documentation and a binary release (sparc and
pentium solaris 2.5), can be found at
<ftp://ftp.cs.wisc.edu/shore/1.0/>
.
This release will be removed after release 1.1 is found to be stable.
Version 1.1
A updated release, with numerous bug fixes and performance enhancements
was announced August 9, 1997.
Gzip'd tar files of the source, documentation and a binary release (sparc and
pentium solaris 2.5), can be found at
<ftp://ftp.cs.wisc.edu/shore/1.1/>.
If you encounter any problems with it, please send mail to
shore_support@cs.wisc.edu.
Version 1.1.1
A minor bug-fix release relative to 1.1.
The most important change is that it has been patched to work under Linux.
There are two Shore-related mailing lists:
shore_support@cs.wisc.edu
and
shore_all@cs.wisc.edu.
shore_support@cs.wisc.edu
This mailing list reaches the Shore development team.
Use this address to submit questions, comments, and bug reports to us.
You cannot subscribe to this mailing list.
Note that the name is spelled with an underscore, not a hyphen.
shore_all@cs.wisc.edu
This is a mailing list for users of (and those interested in) Shore.
This list is managed by
Majordomo
software at the UW--Madison
CS department. It is currently unmoderated, but in the
event it gets cluttered with junk mail we will moderate it.
Use this list to discuss Shore with other users, ask for advice, exchange
tips, etc.
The list is also used by the maintainers to to notify interested
parties about new releases and other changes in the Shore ftp archive
By default, replies will be sent only to the sender, rather than being
posted to the entire list. If you want the entire list to see your
reply, just copy the reply to shore_all.
The shore_all list is a public mailing list, meaning that
anyone may subscribe to it. Only subscribers may post to the list.
Subscribing to shore_all
To subscribe or to change your subscription, send a message to
majordomo@cs.wisc.edu.
The Subject line of the message is ignored.
The body should contain one or more of the following commands.
- help
-
asks Majordomo to send you a brief summary of available commands.
- subscribe shore_all
-
asks that you be added to the mailing list.
Note that the list name is spelled with an underscore, not a hyphen.
- unsubscribe shore_all
-
asks that you be removed from the mailing list.
Archives
We keep an archive of past messages to the list.
Send a message containing
to
majordomo@cs.wisc.edu
to get a list of the archive files available.
The time period covered by each file should be obvious from the file name.
To have a copy of a particular archive file mailed to you, send a message
containing
to
majordomo@cs.wisc.edu.
For example,
get shore_all shore_all.archive.9704
will get an archive of
messages sent during April 1997.
Last Modified:
August 19, 1997
Marvin Solomon
/ solomon@cs.wisc.edu.