[comp.sys.sgi] Big SMD disks

mmcneill@ncsa.uiuc.edu (Michael Mcneill -Visualization) (12/14/90)

We've encountered two problems while trying to put some large SMD disks 
CDC 9720-2500, 2.5 GB) onto our 4D/240GTX.  First, the disk controller
appears to be capable of addressing only 2048 cylinders.  Strangely enough,
this limitation seems to be limited to the SGI revision of this controller.
The SMD controllers Xylogics makes for other machines have the extended
addressing to accomodate the new larger disks.  

Second, according to information obtained via the SGI Hotline, the current 
implementation of the disk volume header only allows for 597 defects per disk.
We were able to eventually find two of these 2.5 GB disks with around 400 
errors, even though the manufacturers spec is 1 error/MB.  Does anyone know if 
and when SGI plans to support these larger disks?

In a related question, does anyone know why a bad sector on an SMD disk causes
the entire track to be mapped out versus just mapping out the bad sector?  

advTHANKSance............................................Mike


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mmcneill@ncsa.uiuc.edu