DELPHI User Guide

For

Computing and Analysis

User Registration

To be able to access DELPHI data, you have to have a CERN account which is registered in group XX. Get in touch with the former management to request this access. You will then be added to the e-group xx, after which you can change the GID on the accounts page to the Unix group XX. Going through the Delphi Information on the Web, the user will find restricted Delphi pages. To be able to read such information, a user identification and password is needed. This is NOT the normal afs password for general computing, but a special Delphi WWW password.

Back from Surfing ? Real work should now start

Before publishing Physics results, the need for analysis arises.

The user should first look in the General Offline page. In there, a lot of information is being linked to and give guidance to Newcomers and experienced users.

On top of the General Offline page are links to General User Support, Meetings and Tutorials. The Tutorials represented information on the current computing in Delphi and Software in use to start Analysis. Analysis must be done within Physics Teams and the appropriate convenors.

The Software for Analysis is organized within the Delphi Software Tasks. For each defined task are one or more people responsible and are the reference persons to be contacted for any questions.

All about Delphi Data

First, learning the Data Structure of the Delphi DST's (Data Summary Tapes).

After the Event re-constructions (done at the local Delphi Computer Farm) the DST's are saved on the General Delphi diskspace and on Magnetic Tapes (DLT or Robotics). The Analyst may find particular data sets with search tools, like SCANFAT. SCANFAT is a composition of Scan the FATMEN Database of Delphi which contains the catalogue of Delphi Data for the entire LEP era.

Global data information is given with the link to Physics Data Sets. This is for fast look-up when users need to know the current status of re-processings.

Getting closer to Analysis and Results

By now, the User is eager to start working, but he should know more about how to produce a working script for execution. A userfriendly Web template will be of help. Make your own script, using information below:

Analysis Tools, like SKELANA (see the Analysis sections in Tutorials), and Physics Data sets.

But which computer IS the Delphi platform ?
Well, several Unix platforms are used by Delphi. For Unix introductions, have a look in the Delphi unix help.

Batch and Interactive Services (for Public Login Unix Servers) are the interactive and batch platforms for code testing, Internet, etc. And, very important, for physics analysis using PAW with Ntuple files. Such interactive Analysis can be done on dxplus, hpplus, lxplus or your linux machine.

An alternative physics analysis program is ROOT which may be executed on a PC or on any PLUS machine. The Batch only platform for Analysis jobs is DELSHIFT. Now is the time to introduce the User to Frequently Asked Questions (FAQ) and to the Delphi Support group concerning problems with software and computing. The FAQ pages contain a compilation of questions asked by Users and general hints on how to go on, like Job-submitting, Example Jobs, Delphi-WWW, Use of Printers,User Tapes to store results, etc.

Where to store Programs or Data files

To start with a new user receives afs home-directory space allocation of 50Mb by default. This is enough to house lots of program files and scripts for some time. If the user is a hard worker, more space could be needed. A request for more afs diskspace by e-mail should then be sent to one of the Delphi administrators.

Data files cannot be kept in a Home Directory because the file size is too important. Scratch areas should be used for intermediate files created by batch jobs or interactive work. For details, see Delphi Diskspace.

If a user would like to save files somewhere in order to offload the home directory space, then the archive features should be used. Program pubarch archives your files to a tape, for usage, see man pages.

Software Support Group , General Offline Page

Delphi General Home Page, Cern Home Page

Comments and questions send to delphi-core@cern.ch

Created by Hansjoerg Klein, Jiri Chudoba.
Last modification: November 25, 1999