Term Definition
extents Objects are stored on the disk in one or more extents, which can be files in the file system, data in raw partitions, or a mixture. An extent is divided up into a number of pages and disk i/o is performed in units of a page.
DPNSUnion Data Pages Needs Scavenging Union, the set of data pages that have shadowed objects on them.
gcgem A specialized gem that performs garbage collection tasks.
GCI GemBuilder for C Interface. The GCI library is used for communication between client Smalltalk images and gems.
gem A GemStone VM.
Maintenance VM A GemStone VM that is intended to be run in parallel with your Seaside Gems whether they be running Hyper or FastCGI. The standard Maintenance VM unregisters expired Seaside sessions and runs a markForCollection once an hour.
netldi The GemStone network server process is called NetLDI (Network Long Distance Information). Each NetLDI reports the location of GemStone services on its node to remote processes that must connect to those services. It also spawns other GemStone processes on request.
Object Table A Btree-based data structures that maintains a mapping between the OOP of an object and the page that the object is located on.
OOP A unique object id.
page A page is approximately 16K bytes. Pages are loaded directly into the Shared Page Cache, providing access to objects, and other system data structures.
pagemanager A process that coordinates the management of pages on the Stone‘s Shared Page Cache as well as remote Shared Page Caches.
pgsvrmain A process that is attached to the Shared Page Cache that performs one of a number of maintenance tasks: free frame management (Free Frame Page Servers), page management (AIO Page Servers), and local communication on behalf of remote gems.
Repository The GemStone database.
Seaside Gems A set of one or more GemStone VMs that are running as web servers running either Hyper or FastCGI.
Session A Session is created when a User is authenticated in a gem process. All GemStone activity is carried out in the context of a Session. Not to be confused with a web session (WASession).
shadowed object When an object has been changed by a session the new version of the object is written to a new data page, the old object on the old data page is said to be shadowed.
Shared Page Cache A segment of the operating system’s virtual memory where objects are cached and are accessible to all gems running as Sessions in the same Stone.
shrpcmonitor A process that creates and maintains a shared page cache for the GemStone server. The size of the shared page cache is configurable and should be scaled to match the size of the repository and the number of concurrent sessions.
Stone The collection of processes (gem, pgsvrmain, stoned, shrpcMonitor, topaz), Extents, Transaction Logs and Shared Page Cache that work together to serve up the objects stored in the extents.
stoned A process that acts as a resource coordinator. It synchronizes critical repository activities and ensures repository consistency.
transaction logs Transaction logs permit recovery of committed data if a system crash occurs. They also reduce disk activity by eliminating the need to flush to the extents all data pages written by each transaction.
topaz A program that provides command line access to GemStone. Allows one to build Smalltalk scripts that get executed by a gem
User A GemStone User has an ID, password, priviliges for executing certain functionality (i.e., Garbage Collection, or Code Modification), and permissions for accessing objects in the Repository. Not to be confused with the web user associated with a web session.