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{\bf
Hitachi S-810 and S-820
}

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{\bf
Vector Register Architecture
}

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{\bf Architecture:}
The S-810 comes in three models: the S-810/5, the S-810/10,
and S-810/20 (not available in the United States, only for
the Japanese market).
The S-820 comes
in two models: the S-820/60 and the S-820/80.
These may be available
outside Japan.

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Hitachi's approach has been to employ independent scalar and
vector processors. The S-810/20 relies on their current
top-of-the-line mainframe (the M280H) for their scalar
processor, with a cycle time of 28 nsec, and runs the
complete IBM 370 instruction set.  The vector unit was
designed with a cycle time of 14 nsec.  The main memory
capacity of the S-810/20 is 256 Mwords.

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\noindent
The model 20 has four floating-point add/logical units and
eight combination multiply/divide-add units.  In addition,
there are two load pipes and two load/store pipes to/from
memory, each capable of loads/stores at a rate of two words
(64 bits) per cycle.

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The vector register capacity is 32 registers, each with a
fixed length of 256 elements (64 bits). A unique feature of
the Hitachi design is that vectors greater than 256 elements
are managed automatically by the hardware.

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The more recent S-820 incorporates several enhancements to the
S-810 range.  Among these are a cycle time of 4 nsec, a change of
density from 2K to 5K gates/chip with the delay time reduced from
250 to 200 picoseconds. The PCBs now have 22 instead of 14 layers,
contain 100K rather than 50K gates, and have their cable delay
reduced from 5nsec/m to 3.8 nsec/m.
The number of pipes has been increased to 18 (4 add/logical, 4
multiply/add, 1 divide, 1 mask, 4 load, and 4 load/store) on the
model 80.
On the 60 all sets of 4 pipes are reduced to 2.
There are 512 32 (64-bit) word vector registers.

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{\bf Configuration:}
A memory of
512 Mbytes is available, and an expanded
memory of up to 12 Gbytes with a transfer rate of 2 Gbytes/sec can
be supplied. There are 64 I/O channels, rated at 6 Mbytes/sec for
an overall transfer rate of 288 Mbytes/sec.

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All machines are air cooled.

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{\bf Performance:}
The scalar speed of the Hitachi S-810 may be slower than
either the CRAY X-MP or Fujitsu VP-200.
A peak
performance of 3 Gflops is claimed for the model 80 and 1.5 Gflops
for the model 60.

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{\bf Software:}
Advanced Editor System for Programming
Environment (ASPEN) and interactive timing aids.

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{\bf Application:}
Application packages include the structural packages MATRIX/HAP
and ISAS II/HAP, GRADAS for graphics, HICAD3D for CAD. A partial
differential equation solver DEQSOL is integrated with the SGRAF
3-D graphics system.

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{\bf Status:}
The first installation of an S-810 was an S-810/20 at the University of Tokyo in November
1983. The S-820 range was announced in June 1987, with first
shipments in November 1987.

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\noindent
{\bf Contact:} 
\begin {flushleft}
Yoshihiro Koshimizu\\
Hitachi America Ltd.\\
Computer Division\\
950 Elm Ave.\\
Suite 100\\
San Bruno, CA 94066-3094\\
415-872-1902\\
\end {flushleft}
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