Risk Analysis for Event Builder and Level 3 Upgrade    23 Sept. 2002
 
The cost, schedule, and technical risks for the Event Builder and Level 3
upgrades are summarized here, along with steps already taken and further
plans to minimize or mitigate risk.
 
The proposal for the upgraded Event Builder (WBS 1.3.4)  is designed to
minimize risk.  The existing system based on ATM technology, which has
been very successfully used in Run 2A, will be upgraded to allow for
higher-bandwidth data transfer.  A new ATM switch, the ASX 4000,  will be
purchased as well as replacing the existing OC-3 connections with OC-12
connections.  This will give a factor of 3-4 increase in the
bandwidth. The project involves the purchase and construction of a
prototype system (WBS 1.3.4.4) and a production system (WBS 1.3.4.5).  It
should be noted that the presented plan is essentially identical to the
implementation of the Run 2a system which was completed within budget and
in a very timely fashion.
 
To evaluate the risk associated with the proposed Event Builder
system we consider the technical, schedule, and cost risks.  The ATM
technology has been used successfully at CDF for Run 2a and the ATM
upgrade is straight forward, an increase in bandwidth. ATM technology
is commonly used in telephony industry which guarantees its support
from the manufacturers for the lenght of Run 2b. Thus the technical
risk for this project is very low.  Additionally, alternate
technologies (Gigabit ethernet or MyriNet) are being evaluated so
that there is a fallback solution if one becomes necessary. There is
little cost risk that is not covered in the contingency because the
products which will be used in the system have well-defined
cost. Even if an alternate solution becomes necessary, the cost will
not be higher than the proposed system.
 
There is schedule risk in that the Linux/PCI and VxWorks PMC drivers must
be written, and it is possible that this could take longer than
foreseen.  The schedule estimates are based on Run 2a experience for
tasks which are very similar to what is required here. In addition,  extra
time has been built into the schedule, so it is unlikely that significant
schedule slippage will occur.  There is an additional schedule risk in
that the expertise in the MIT group is concentrated in one researcher,
and should this person leave, it would take time to train a  new
person.  To alleviate this potential problem, steps are being taken to
propagate expertise to other group members (post-docs and students).  In
addition, it is possible to add an external computer expert to the effort
if necessary.
 
To summarize, the cost, schedule and technical risks for the Event Builder
system are considered to be very low, and a formal plan of mitigation is
not necessary.

The upgrade to the Level 3 Farm / DAQ (WBS 1.3.5) consists of replacing
the existing PC's in a staged manner as they become obsolete and the need
for more computing power increases with increasing luminosities.  There is
insignificant schedule or technical risk as we are purchasing commodity
products that are easily available, and installing them within an existing
system.  The cost estimate also has little risk associated with it, as
purchasing power for processors continues to increase, and it is
not foreseen that there will be any difficulty in acquiring the needed
processing power within the proposed budget.