DEC-RA-FamilyOfWinchesterDiskDrives

This document describes Digital's RA Family of Winchester Disk Drives (RA70, RA82, RA81, RA60), designed to provide high-capacity, high-performance, and reliable mass storage for medium and large systems, while minimizing disruptions.

Key features and benefits include:

• Digital Storage Architecture (DSA) and Standard Disk Interface (SDI): These foundational technologies enable investment protection, easy maintenance, data integrity, high availability, and performance.
• Data Integrity: Utilizes the Reed-Solomon Code, an advanced error-correction system capable of fixing up to 80 bits of error per sector, and can make media defects invisible to applications.
• High Performance: Features multiple data paths to avoid I/O bottlenecks, sophisticated algorithms for seek ordering and bad block replacement, and dual-positioning systems (for RA70, RA82, RA81) for faster, more accurate data access. Rotational latency is minimized by intelligent data channel allocation.
• High Availability: Supports radial connections and dual access, allowing drives to be plugged/unplugged without downtime and providing redundant paths to data. Modular sub-assemblies ensure easy maintenance and minimal repair times.

• Models:

  • RA70: A 5.25-inch, 280 MB (formatted) drive, notable for being the first of its size to offer full DSA/SDI functions and dual access, with a design that separates the Head Disk Assembly (HDA) from the electronics for enhanced data availability.
  • RA82: A 14-inch, 622 MB (formatted) drive, representing Digital's highest capacity offering with proven reliability and the lowest service cost in its class.
  • RA81: A 14-inch, 456 MB (formatted) drive, sharing design and architectural features with the RA82.
  • RA60: A 14-inch, 205 MB (formatted) removable-media drive, ideal for high security and data interchange, engineered for high reliability through precision-mounted components and a direct-drive spindle.

• Service and Support: Digital offers a one-year, onsite hardware warranty, comprehensive DECservice options including predictive maintenance, remote diagnosis, and committed response times (e.g., two-hour response for VAX 8000 systems).

Overall, the RA Family drives are positioned as a robust and flexible storage solution, prioritizing data integrity, performance, and uptime for demanding computing environments.