On 6/9/2011 20:27, Darren New wrote:
> The main difference between mainframes and smaller systems is that
> mainframes are optimized for I/O. Even the mainframe I used 30 years ago

Another example: The mainframe knew which disks were fast (having multiple 
heads per platter, for example) and which were slower, and it put the 
indexes of databases and directories and such (etc) on the fast disk and the 
bulk data and actual file contents on the slow disks.  It also allocated 
random-access files on cylinder boundaries.

Nowadays, the blades and desktop machines don't even know what the cylinder 
boundaries of their disks are.

-- 
Darren New, San Diego CA, USA (PST)
   "Coding without comments is like
    driving without turn signals."

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