jpt@uf.msc.umn.edu (Joseph Thomas) (05/19/89)
>>#1: You cannot use the SUN XD7053, you need a Xylogics 753 certified for >>the 3.0 transfer rate. The SUN controllers don't always have drivers >>which are fast enough for the 3.0 rate. > >I'm using a SUN SMD-4 (the 7053) with a CDC 9720-1230 drive and I've never >had any problems, so the SMD-4 does handle 3 MB/s transfer rates. I know >the documentation for the SMD-4 says that it will only support up to 2.4 >transfer rates, but I called SUN technical support and they said it really >does support 3.0 transfer rates.... Actually, Xylogics ( who designed the board for Sun ) was here talking with us just at the time the 7053 first became available. Their story is that the first 7053's shipped/manufactured, only used driver chips which were rated for the 2.4 rate. The current boards use parts rated for the full 3.0. What this really means is that if you got one of the first few 7053's, your best bet is to try it. It may or may not work at the 3.0 rate. Anything you get today should be just fine. (BTW: None of this was give to me in writing, so the truth lies ??? ) Joseph Thomas Minnesota Supercomputer Center 1200 Washington Ave So. Minneapolis, MN 55415 (612) 626-1888 jpt@msc.umn.edu
henry@zoo.toronto.edu (Henry Spencer) (05/27/89)
>What this really means is that if you got one of the first few 7053's, >your best bet is to try it. It may or may not work at the 3.0 rate. Do remember that just because it works once doesn't mean it will work consistently and reliably. Things like temperature changes and component aging can turn a very small positive margin into a very small negative one, or no margin at all (which means unreproducible intermittent failures). It is not uncommon for chips and boards rated for a given speed to work at higher speeds when the phase of the Moon is right; the problem is that the phase of the Moon changes. Henry Spencer at U of Toronto Zoology uunet!attcan!utzoo!henry henry@zoo.toronto.edu