Background

This document provides some background on the process by which the DEIMOS interacts with the Sybase database servers.

Relevant Machines

waiaha is the Keck Sybase server which contains the Keck copy of the database. The machine is a Linux host running CentOS which lives at Keck HQ.
spgcvs is the Lick Sybase server which contains the master copy of the database.
slitmaskpc is the primary PC used for slitmask milling. It is a Linux PC that lives in the summit instrument lab.
slitmaskpc2 is a clone of slitmaskpc and is used in case the latter fails.

Information Flow

DREMEL Process

The diagram below illustrates the flow of information between keamano and waiaha during the reconfiguration process on DEIMOS.

Click to enlarge.

The following processes make direct connections to the Sybase server:

Process	Host	Path	Function
GenMaskData	keamano	/local/kroot/bin/mask/GenMaskData	Generate FITS chunks for inclusion into image headers.
dremel	keamano	/local/kroot/bin/dremel	Read current configuration information
CodeGen	keamano	/usr/local/ucolick/share/tcl/memes/CodeGen	Read database and write config file for dispatchers
confio	keamano	/local/kroot/bin/confio	Upload configuration info to database
dashboard	polo	/local/kroot/bin/obsr	DEIMOS observer interface

Slitmask Design & Milling

Click to enlarge.

Database Syncing

The image below, extracted from Managing DEIMOS removable elements and instrument configuration a 2002 SPIE poster by De Clarke, provides an overview of the process of maintaining sychronization between the operational version of the database at Keck and the master version at Lick.

Click to enlarge.

To summarize this diagram:

Daily at 0600 HST the contents of the Keck database on waiaha are wiped ("stomped") and the contents of the Lick database are transferred to Keck.
Hourly from 0800 to 1700 HST new slitmask information is transferred from slitmaskpc to waiaha.
On the half hour from 0830 to 1930 HST the new slitmask information is transferred to Lick.
Twice daily at 05:00 PT and 18:00 PT the MaskKeeper process runs at Lick and sends updates to mask maintainers and observers on the status of slitmasks.

Information

The following information relevant to DEIMOS is stored in the database tables: (TBD)

Background

Relevant Machines

Information Flow

DREMEL Process

Slitmask Design & Milling

Database Syncing

Information

See Also