Thomas Schwarz, S.J. Technical Reports |

Witold Litwin, Thomas Schwarz: Algebraic Signatures

(Also at CERIA, U. Paris 9) (In Progress)

Signatures are short bit strings that (almost) uniquely identify objects. Algebraic signatures allow to calculate the signature of a changed object from the old object signature and the signature of the change. They also provably change if the object undergoes a slight or a typical change. Furthermore, the signature of a superobject can be calculated from the signatures of the subobjects. These valuable properties make algebraic signatures cryptographically insecure. Our version of algebraic signatures is based on Galois field calculations.

2002-
Thomas Schwarz, Jesse Steinberg and Walter Burkhard: Permutation Development Data Layout (PDDL) Disk Array Declustering, April 1998.

(UC San Diego, Dept. of Computer Science and Engineering Tech. Report CS98-584)

Design and performance measurement of a disk array declustering layout. Disk arrays (a.k.a. RAIDs) use redundant storage to survive failure of storage components such as disks or connections. Typically, the parity of a number of disk blocks is stored on another disk. If all but one of the blocks are available, then one can recalculate the missing block's content from all the other and the parity block. To achieve higher availability levels, an erasure correcting code can be used to generate more than one parity per group of blocks. Declustering arranges the grouping of the blocks. A good declustering scheme results in balanced loads before a failure, during the regeneration of data right after a failure, and after a failure. PDDL uses mathematical design theory for a very elegant and competitive declustering solutions. Parts of this work appeared at HPCA'98, Orlando.

1998 -
Thomas Schwarz, Walter Burkhard: "Multi-Dimensional Disk Array Reliability".

(UC San Diego, Dept. of Computer Science and Engineering Tech. Report CS93-324.)

1993

©2003 Thomas Schwarz, S.J., COEN, SCU | SCU | COEN | T. Schwarz |