Should prove extremely useful to underground mining practitioners, everywhere. The overall focus is directed towards more productive, safer and environmentally sound mining operations. The book ‘Support of Underground Excavations in Hard Rock’ testi-fies to the willingness of Canadian industries and universities to col.
The Electric Power Research Institute has updated its reference book for power system operators, EPRI Power System Dynamics Tutorial, and is now making the electronic version of this tutorial available.
This tutorial reference book is now being used as one of the official reference books for power system operator training and certification at the North American Electric Reliability Corporation (NERC).
“Several generations of transmission control room operators in the power system community have benefited from earlier editions of this reference source,” said Arshad Mansoor, vice president for Power Delivery and Utilization at EPRI. “For more than 20 years, this tutorial has provided a comprehensive overview of the expertise that operators need in understanding power system dynamics. By offering this book, EPRI's goal is to give even more system operators the chance to acquire the necessary knowledge to use critical judgment in emergency situations that fall outside the scope of step-by-step utility procedures.”
In the updated book, a new section has been added to introduce the basic concepts of Wide Area Measurement System (WAMS) and Wide Area Control System (WACS). This edition has been expanded to explain the causes of wide area power outages and puts the emphasis on power system restoration, methods used and lessons learned for restoring power on the North American power systems. Use of the tutorial increases operator proficiency, while supporting economic and reliable power system operation.
“NERC uses the EPRI tutorial reference book for our certification examinations,” said John Theotonio, manager of personnel certification at NERC. “It is used to validate and create exam questions. Our subject matter experts rely on several books and each book is listed in a reference document for system operators to study in preparation of sitting for one of four different exams.”
The EPRI Light Blue Book is one of a series of industry reference books developed and published by EPRI. These comprehensive reference books — each with a distinctive colored cover— document and distill the knowledge and experience of the world’s top power delivery experts. As utilities cope with issues related to aging workforces and the loss of expertise, these industry-standard references preserve institutional knowledge while presenting the latest advances in technology, tools, and practices.
The Network File System (NFS) is a standardized, well-proven and widely supported network protocol that allows files to be shared between separate hosts.
The Network Information Service (NIS) can be used to have a centralized user management in the network. Combining NFS and NIS allows using file and directory permissions for access control in the network. NFS with NIS makes a network transparent to the user.
In the default configuration, NFS completely trusts the network and thus any machine that is connected to a trusted network. Any user with administrator privileges on any computer with physical access to any network the NFS server trusts can access any files that the server makes available.
Often, this level of security is perfectly satisfactory, such as when the network that is trusted is truly private, often localized to a single cabinet or machine room, and no unauthorized access is possible. In other cases the need to trust a whole subnet as a unit is restrictive and there is a need for more fine-grained trust. To meet the need in these cases, NFS supports various security levels using the Kerberos infrastructure. Kerberos requires NFSv4, which is used by default. For details, see Book “Security Guide”, Chapter 6 “Network Authentication with Kerberos”.
The following are terms used in the YaST module.
A directory exported by an NFS server, which clients can integrate into their systems.
The NFS client is a system that uses NFS services from an NFS server over the Network File System protocol. The TCP/IP protocol is already integrated into the Linux kernel; there is no need to install any additional software.
The NFS server provides NFS services to clients. A running server depends on the following daemons:
nfsd
(worker), idmapd
(ID-to-name mapping for NFSv4, needed for certain scenarios only), statd
(file locking), and mountd
(mount requests). NFSv3 is the version 3 implementation, the “old” stateless NFS that supports client authentication.
NFSv4 is the new version 4 implementation that supports secure user authentication via Kerberos. NFSv4 requires one single port only and thus is better suited for environments behind a firewall than NFSv3.
The protocol is specified as http://tools.ietf.org/html/rfc3530.
Parallel NFS, a protocol extension of NFSv4. Any pNFS clients can directly access the data on an NFS server.
![Underground Underground](/uploads/1/2/6/3/126315861/366346090.png)
Important: Need for DNS
In principle, all exports can be made using IP addresses only. To avoid time-outs, you need a working DNS system. DNS is necessary at least for logging purposes, because the
mountd
daemon does reverse lookups.