Index: trunk/doc/release.2015/ps1.datasystem/datasystem.tex
===================================================================
--- trunk/doc/release.2015/ps1.datasystem/datasystem.tex	(revision 41206)
+++ trunk/doc/release.2015/ps1.datasystem/datasystem.tex	(revision 41207)
@@ -1056,9 +1056,50 @@
 \ippprog{psphotFullForce} program.
 
-The convolved galaxy models are also re-measured on the
-\ippstage{warp} images by the \ippstage{fullforce} stage analysis.  In
-this analysis, the galaxy models determined by the
+\textmod{The convolved galaxy models are also re-measured by the
+  \ippstage{fullforce} stage analysis using the \ippstage{warp}
+  images.}  In this analysis, the galaxy models determined by the
 \ippstage{staticsky} photometry analysis are used to seed the analysis
-in the individual \ippstage{warp} images.  The purpose of this
+in the individual \ippstage{warp} images.
+
+The analysis tests a grid of galaxy model parameters in the vicinity
+of the prior from the stack.  For each warp image, each parameter set
+is used to generate a model which is then convolved with the PSF for
+that warp image and then compared to the observed data.  The resulting
+grid of $\chi^2$ values can then be for the 
+
+For each object, a grid of galaxy model parameters is used compared tested on each
+warp image and
+
+** we calculate a normalization and chisq for each warp grid point.
+the chi square values can be summed across warps to give the solution
+chi square dist.  for a single warp, the error on Io goes like
+sqrt(Ncnts).  The average Io value is the weighted averages of the
+inputs.  The error on the weighted average is sqrt(1 / (sum(1/sigma^2))).  
+
+S_t^2 = 1 / (1 / S_0^2 + 1 / S_1^2 + 1 / S_2^2)
+
+S_0^2 = N0, S_1^2 = N1, etc
+
+S_t^2 = 1 / (1/N0 + 1/N1 + 1/N2 ...)
+
+ideal: S_t^2 = N0 + N1 + N2
+
+dI / Io = 1 / sqrt(No)
+
+The error on the 
+
+\textmod{For each warp
+  image, the galaxy model (convolved with the PSF) is compared to the
+  observed pixels to calculate an element of the total model $\chi^2$ value
+
+ a grid
+of the galaxy model parameters are  
+
+how does the error scale if I fit each Io for each warp vs a single
+value? (sounds like I do kill the S/N...)
+
+%%%%% fix all of this...
+
+The purpose of this
 analysis is the same as the \ippstage{fullforce} PSF photometry: the
 PSF of the \ippstage{stack} image is poorly determined due to the
@@ -1093,5 +1134,5 @@
 search for hazardous asteroids and the search for Type Ia supernovae to
 measure the history of the expansion of the universe.  Both of these
-projects require the discovery of faint, transient source in the
+projects require the discovery of faint, transient sources in the
 images.  For the hazardous asteroids, and solar system studies in
 general, the sources are transient because they are moving between
@@ -1261,5 +1302,8 @@
 metadata tables define general features of the database.
 Table~\ref{tab:DVO_schema} lists the full collection of database
-tables used by DVO.
+tables used by DVO.  \textadd{In the current implementation, as
+  described in more detail below, the database tables are stored on
+  disk using a distributed collection of FITS files, potentially
+  distributed across a large number of computers in the cluster.}
 
 In the most basic implementation, a collection of measurements for
@@ -1516,5 +1560,5 @@
 divides the sky in declination into bands 7.5\degree\ high, as defined
 by the HST Guide Star Catalog
-\citep[GSC][]{1988IAUS..133..239J,1990AJ.....99.2019L}.  Level 2
+\citep[GSC,][]{1988IAUS..133..239J,1990AJ.....99.2019L}.  Level 2
 subdivides these declination bands in the RA direction, with spacing
 related to the stellar density.  Level 3 divides these RA chunks into
@@ -1787,5 +1831,6 @@
 exposures which were believed to be obtained in photometric
 conditions.  This process, called ``\"ubercal'', is described in
-detail by \cite{2012ApJ...756..158S} for the first (PV1) version.  In
+detail by \cite{2012ApJ...756..158S} for the first (PV1) version
+\note{add SDSS ref mentioned in Schlafly, also in cal paper}.  In
 brief, photometric periods, with time-scales of a large fraction of a
 night, are identified by a combination of automatic analysis and