This paper considers the problem of dynamically establishing dependable connections (D-connections) with specified failure restoration guarantees in wavelength-routed wavelength-division multiplexed (WDM) networks. We call a connection with fault tolerant requirements as a D-connection. We recommend using a pro-active approach to fault tolerance wherein a D-connection is identified with the est...

The data transmission potential inherent in optical networks is enormous, and because of this great potential, optical networks are in dire need of fault toleration. Recently, various fault toleration techniques exploiting the special properties of optical data transmission have been presented, one of the most interesting being backup-multiplexing. Backup multiplexing comes in a couple of diffe...

In distributed data base systems (DDBSs), a transaction blocks during two-phase commit (2PC) processing if the coordinator site fails and at the same time some participant site has declared itself ready to commit the transaction. The blocking phenomena reduces availability of the system since the blocked transactions keep all the resources until they receive the final command from the coordinat...

Storage capacity, like computing power, follows its Moore’s law and grows dramatically. Consequently, the need for data backup services increases. The domain of data backup was recently hit by the peer-to-peer wave: several projects propose to use a cooperative approach to the backup problem. In this paper we survey these projects, the various problems they face and the techniques they propose ...

We present a trace-driven simulator that evaluates the performance of backup algorithms. We use this simulator to compare the performance of the commonly-used level scheme (our name for the algorithm used by the UNIX dump utility) with that of a new algorithm called the Z scheme. We show that the Z scheme has better backup performance than the level scheme and slightly worse restore performance...

Disk drives are now available with capacity and price per capacity comparable to (and in some cases better than) nearline tape systems. Given disks' superior performance , density and maintainability characteristics, it seems likely that disks will soon overtake tapes as the backup medium of choice. In this paper, we outline the potential advantages of a backup system composed of high-capacity ...

We present a novel peer-to-peer backup technique that allows computers connected to the Internet to back up their data cooperatively: Each computer has a set of partner computers, which collectively hold its backup data. In return, it holds a part of each partner’s backup data. By adding redundancy and distributing the backup data across many partners, a highly-reliable backup can be obtained i...

Since first introduced by Satoshi Nakamoto in 2008, Bitcoin has become the biggest and most well-known decentralized digital currency. Its anonymity allows users all over the world to make transactions with each other and keep their identities hidden. However, protecting private key becomes a very important issue because it is the only access to a unique account and can hardly be recovered if m...