johng@uniwa.uwa.oz.au (John Gibbins) (05/10/91)
A neighbouring site has a Cipher 990M front loading 1/2" tape drive which has been running on a Xylogics 772 controller. As Sun does not support the 772, they are trying to downgrade the controller to a Xylogics 472 controller so as to be able to use the drive at 4.1. They had a third party device driver for the 772 at 4.0.3, but this is not available for 4.1[.1]. When they replaced the controller, any dump tapes they wrote were unreadable. Any tapes written on the 772 controller could be read fine. After playing around for a while I discovered that if you write to a tape with a small block size eg 32 (ie 16kb) and then write with a large block size (64+), it was possible to write/read dump tapes (dump was used with block size of 126). This method was not always reliable. We tried swapping the 472 with another one: same problem. We found another site that also was running SunOS 4.0.3 on a Sun 3/160 with a 472 and Cipher (although it was a Cipher F880 not 990) drive. Our tests showed that they had the same problem. Is anyone else running a Cipher drive on a 472 controller? Have you seen this problem and know anything about? If so please HELP!!!! If we don't find a solution, we will have to put back the 772 and never advance beyond 4.0.3! Please mail as I am a slow news reader. John Gibbins GPO Box D184 Internet: johng@uniwa.uwa.oz.au PERTH W.A. 6001 Phone: 61-9-3408547 AUSTRALIA Fax: 61-9-3883414