A 3-tier RAID storage system with RAID1, RAID5 and compressed RAID5 for Linux

Presents the design and implementation of a host-based driver (a “volume manager") for a RAID storage system, currently with three tiers: a small RAID1 tier and larger RAID5 and compressed RAID5 (cRAID5) tiers. Based on access patterns (“temperature"), the driver automatically migrates frequently accessed data to RAID1, while demoting less frequently accessed data to RAID5/cRAID5. The prototype system, called “Temperature-Sensitive Storage" (TSS), provides reliable persistence semantics for data migration between the tiers using ordered updates or logging. Mechanisms are separated from policies through an API so that any desired policy can be implemented in trusted user processes. We also discuss the problems faced while moving from the original implementation on the Solaris platform to Linux. Finally, we present comparison of the performance of our design with comparable systems using striping or RAID

Dynamic characterization of machining systems

In the working space model of machining, an experimental procedure is implemented to determine the elastic behaviour of the machining system. In this paper, a dynamic characterization and vibration analysis has long been used for the detection and identification of the machine tool condition. The natural frequencies of the lathe machining system are required (Ernault HN400 - France) according to three different situations with no cutting process are acquired. The system modal analysis is used to identify the natural frequencies. These frequencies are then compared to the ones obtained on the spindle numerical model by Finite Element Method. This work is validated by experimental tests based on measures of the lathe machine tool frequencies domain. The main objective is to identify a procedure giving the natural frequencies values for the machine tool components, in order to establish a better condition in the cutting process of the machine tool