Path: utzoo!attcan!uunet!deimos.cis.ksu.edu!atanasoff!hascall
From: hascall@atanasoff.cs.iastate.edu (John Hascall)
Newsgroups: comp.arch
Subject: Re: SCSI on steroids, mainframes move over
Message-ID: <1383@atanasoff.cs.iastate.edu>
Date: 26 Aug 89 14:14:11 GMT
References: <5932@pt.cs.cmu.edu> <3238@scolex.sco.COM> <26970@amdcad.AMD.COM>
Reply-To: hascall@atanasoff.cs.iastate.edu.UUCP (John Hascall)
Organization: Iowa State Univ. Computation Center
Lines: 26

In article <26970> davec@cayman.amd.com (Dave Christie) writes:
 
}In article <5932> butcher@g.gp.cs.cmu.edu (Lawrence Butcher) writes:

   ...

}and wonderful data structures out on disk?  For the latter, the 180
}architecture, along with the NOS/VE OS, provides what I think is the
}ultimate(*) in user-level i/o: none!  What I really mean is: implicit i/o
}via memory mapped files.  Simply associate a file(s) with a data
}structure(s) in the virtual address space of your software, and 
}access it anyway you like.  Actual physical i/o occurs simply as
}part of normal paging.  No fuss, no muss.


      But since you can also do this in VMS, it is by definition bad. ;-)

      I find it a very useful feature, too bad hardly anyone ever takes
      advantage of it (and its so easy, just two system calls: open and
      crmpsc).

      Almost makes you appreciate the AS/400 architecture (*almost*!).


John Hascall
ISU Comp Center