1. Links and more … D. Breton
ETD/online session - Frascati Meeting
December 3rd 2009

2. Number of links We held the front-end dedicated session yesterday:
Each sub-detector was able to present an estimation of its number of links
It was mostly targetting the readout links
The numbers are very reasonable for the triggered systems:
SVT : 58
DCH : 30 (35 for the trigger primitives)
PID : 12
IFR : 40
They are less reasonable for an untriggered calorimeter:
Barrel : 160 (200 ?)
Forward : 450 (560 ?)
=> shouldn’t we find another solution ? (see talk about L1 trigger)
We commonly estimated that for all the triggered sytems, the numbers of ECS and FCTS links could be the same as that of the readout links
For the calorimeter, we agreed to have 80 links for the barrel and 80 for the forward.
We would like to get the safety factors for each subsystem and to understand what they are based on.

3. ROMs and event size
These numbers allowed us to produce the first estimation of the ETD cost.
We had to make a guess about the number of ROMs.
We assumed that:
1 crate per sub-detector would be necessary
This would allow to ensure an easy partitionning of the system
8 links per ROM would be very conservative
This number mainly depends on the smaller data compression ratio
This leads us to the following request, in junction with the event size estimation:
We would like all subdetector to estimate:
The event size at the input of the ROM
What type of event processing (zero suppression, data compression, digital filtering, feature extraction, …) you feel like performing inside the ROM
The event size after said processing
These numbers are necessary in order to scale the load on the network and the PC farm

4. Option 1: untriggered EMC

5. Option 2: triggered EMC