Communications Cross-connect Switch
Problem
The data storage module in the administration system for this carrier-class primary switching product had gone through a number of transitions due to reliability and data storage device end-of-life events. The devices (e.g., tape or magneto optical drives) were used to facilitate software updates and data backup and restoration. The company maintained a support staff and stockpile of spare modules to manage repair of field failures. The OEM was effectively providing clients technology upgrades as they suffered failures and was supporting a steadily increasing list of obsolete components. Additionally, engineering resources were consumed with constant qualification efforts, and corporate capital was tied up in last-time-buy procurements. Their engineers were tasked with finding or developing a module which increased overall reliability of the system and which would be available for an extended period of time as compared with the six month availability of traditional commercial data storage devices. Management wanted the solution available for three years to minimize qualification efforts, thereby freeing resources for development rather than sustaining engineering.
Application
Due to the application and duty cycles of the switch product, scheduled system downtime is virtually nonexistent, which translates to ignoring routine maintenance and cleaning of tape heads and/or magneto optical drives. This exaggerated the failure rate of this device, already the most failure prone component of the switch. A strong preference was expressed for a solution requiring no maintenance and no moving parts. The "wish list" of custom attributes for the application included a custom face plate and LED. The customer hoped to work with a vendor who would incorporate these attributes rather than leave the customization to the OEM as previous suppliers had done. The storage interface for this switch product is based on the 8-bit, SCSI-2 interface. The product will continue to be a major component of several carrier networks with a large installed base, so they insisted on maintaining the existing interface.
Solution
An Adtron removable media SCSI drive was tailored to include the custom attributes the OEM desired. The device is an internal 3.5" removable media SCSI flash drive which has a single PCMCIA slot and is rated for commercial temperature (0� to 60�C) operation.
Benefits
The solution as configured for the application provided solid state reliability and eliminated required maintenance and sustaining engineering efforts. No changes have been made since the Adtron SDDS was approved for use in the storage module in October 1999, and none are planned. The company achieved its goals for reliable storage with long-term availability.
Adtron Product
SDDS -- 3.5" SCSI removable flash drive
