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Hi Volodymyr , Hmmm, seems that when I go down this path, there appears to be a disconnect between the SRM and a data access system concepts. What xrootd provides to clients is low latency high performance random access on par with the best commercial systems out there. That can't be done with the SRM protocol (i.e., delivering random access data to client analysis jobs). On the other hand, xrootd relies on some other entity to manage the disk cache. All that xrootd requires is physical access to that cache and some amount of predictability in its management (though it's reselient to crazed management). To date, xrootd interfaces to the mps system which can be customized to talk to a general purpose MSS (it can actually talk to an SRM/DRM combination as well if you don't mind double caching). The general integration of SRM calls for using SRM facilities to bring files into some disk cache when needed. Access to data in those files uses either the root framework or the Posix calls (which in turn use the xrootd). Where that fits in depends on what whether the SRM implementation provides some disk cache management features or not. So, from an SE perspective, the SE provides an SRM interface to the outside world but internally provides xrootd access to applications. Andy ----- Original Message ----- From: "Volodymyr Kapchynskyy" <[log in to unmask]> To: "Andy Hanushevsky" <[log in to unmask]>; <[log in to unmask]>; "Patrick Fuhrmann" <[log in to unmask]> Sent: Monday, September 19, 2005 1:28 AM Subject: Re: dCache wants to communicate with XRootd > > Hi Andy, > > Thanks for the detailed reply. > We will make ourselves familiar with the descriped > mechanisms. > There is just some question left about integrating > SRM into the xrootd service. > Did I understand correctly that > "to integrate xrootd with a generalized SRM" means that > instead of having oss/ofs and/or MPS you would prefer to talk > SRM client protocol and with that have a general interface > to mass storage systems (disk/tape) ? > BTW: are there any plans to let xrootd talk the SRM > server protocol so that it can serve as a Storage Element ? > > dCache Team >