\ 
.nr PS 10
.nr VS 12
.nr LL 6.25i
.nr PD 0.18i
.nr PO 1.0i
.fi
.LP
.DS I 4.5i
December 14, 1987
.DE
.PP
.LP
Dear X3D Member:
.LP
Attached is Version 3.00 of the PEX protocol specification document.
With this version,
the PEX Architecture Team feels that all major architectural issues
have been resolved and an implementation effort may now begin.
Even though we believe the architectural issues are well in hand,
we are always interested in receiving specific comments about the
specification.  It is almost assured that the specification will change
somewhat during the implementation stage, and we are interested in rectifying
any and all typos, contradictions, and errors in the PEX documents.
The PEX specification documents will continue to be updated in conjunction
with the implementation effort.
The final version of the specification will be released
in conjunction with the release of the public implementation software.
.LP
An attached document describes in more detail
the changes that were made to go from PEX V2.00 to PEX V3.00.
There are four major reasons for the changes that were made:
.DS
\(bu Changes to improve support for PHIGS
\(bu Changes to be more compatible with the spirit and philosophy of X
\(bu Addition of PHIGS and PHIGS+ functionality that was not yet in PEX
\(bu Incorporation of October PHIGS and PHIGS+ changes
.DE
The first three cover the majority of the changes that were made and
were largely responsible for the length of time it has taken to produce
PEX V3.00.
The Architecture Team is currently working on revising the \fIPEX
Introduction and Overview\fP document.  Since this effort might take
several more weeks, and since the Architecture Team
felt it was important to send out the protocol document as soon as possible,
the introduction/overview document
will be mailed out separately when it is ready.
.LP
Merry "X"mas to everyone!
.sp 2
.ti 4.0i
PEX Architecture Team
