READ ME FIRST

            4615 Unsuitable for Use in Systems with High SBus Traffic

                           Read This Before You Begin!


DESCRIPTION

  Use of 4615 in newer, faster systems under conditions of intensive SBus
  activity may permit undetected data corruption of ATM traffic.

  Affected adapter part numbers include:
  * 4615-155-MM
  * 4615-155-SM
  * 4615-155-UTP

  Not affected:
  * 4625-UTP-128-I


TECHNICAL DETAILS

  Recommended uses for 4615 are single SBus-adapter per SBus applications in
  Sun SPARCStation 2, 5, 10, 20, IPC, IPX, Classic, LX and SPARCServer 600MP.

  In applications with intensive, multiple adapter, SBus I/O traffic, an
  onboard memory-to-ATM front-end transfer cycle can be aborted and not
  retried. This allows an incorrect data transfer without a status or error
  indication from the adapter. Further, use of the built-in TCP/IP (UDP)
  checksum method is insufficient to guarantee detection of this corruption
  for ATM frames longer than 1470 bytes (ATM frames are generally optimized
  to 9 KBytes).

  While currently only observed in a Sun Ultra-2 (E3000) system and one other
  high-speed proprietary design, the company believes that this problem could
  occur in systems other than those recommended, above.

  We apologize for any inconvenience this may cause our customers and stand
  ready to assist with any technical issues which may arise.


CHANGES FROM UGR0138-000,REVA 1/13/98

  Previous version:

  * Indicated 4625 had the same problem. This is incorrect. 4625 employs a
    different onboard memory-to-ATM front-end design. 4625 does not exhibit
    this problem.

  * Attempted to relate system CPU speed to potential for high traffic on SBus.
    The problem scenario is not clearly defined using this method.








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Read Me First 4615 Unsuitable for Use in Systems with High SBus Traffic
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