Killer Micro Question vs. mainframes

[Tim Sesow SSDS Rocky Mntn]

Neil Rickert writes: 
>Suppose you wanted a system to manage huge databases.  You needed strong
>integrity controls for concurrent database updates.  You needed to access the
>data in a huge room packed to the gills with disk drives.  You needed to be
>able to access the same data from any CPU in the system.  You couldn't
>tolerate the performance hit of the bottleneck caused by pumping all the data
>down an ethernet.
>
> You just might find the mainframes a better solution than the workstations.
>
Mainframes do not really solve the stated problem either.  My
understanding is that DB2 (IBM's mainframe database star) is
limited in database size to something less than 32 gigabytes
(which is a real problem for databases in credit card companies,
the Social Security Admin, etc)).
Also, the channel speeds (FIPS60, etc) don't really match the
performance of IPI-3 drives (not to mention PTDs and RAIDs).
FDDI, not Ethernet,  would be a preferred networking interface to get
up to 24 Mbps effective throughput.
It is practical with current products to build distributed 
processing systems with over 100 gigabytes of disk space
using SYBASE or ORACLE and to provide the level of concurrency
and integrity control necessary for thousands of users.  However,
cost is probably not the biggest advantage (big, fast disks
are expensive everywhere) as is the increased reliability
of loosely coupled (networked) multi-processors.

Tim Sesow
SSDS,Inc.
Littleton, CO