\noindent
{\bf
CRAY-1
}
\noindent
Company no longer marketed this machine.
\noindent
{\bf
Vector Register Architecture
}
\noindent
This machine is no longer being produced, although when
first introduced in 1976 (Los Alamos), it was without doubt
the fastest processor in the world and is still used as a
benchmark for high-speed computing. Since many CRAY
customers are currently upgrading their systems to an X-MP,
there are opportunities to buy a second-hand CRAY-1S at
knockdown prices.
\begin{tabbing}
aaa\=bbb\= \kill
{\bf Architecture:}\\
\vspace{.1in}
\> A uniprocessor.\\
\> Vector processor, uses pipelining and chaining to gain speed.\\
\> 12.5-nsec clock. Fast scalar.\\
\> Uses only four chip types with 2 gates per chip.\\
\> 64-bit word size up to 4 Mwords of storage.\\
\vspace{.25in}
\> The CRAY 1-S has bipolar (in units of 4K RAM), and the newer (1982)\\
\>\> CRAY 1-M has MOS memory (in units of 16K RAM).\\
\vspace{.25in}
\> Logic chips - ECL with a gate delay of .7 nsec.\\
\> Main memory banked up to 16 ways. The bank busy time is 50 nsec (70\\
\>\> nsec on the 1-M) and the memory access time (latency) is 12 clocks\\
\>\> (150 nsec).\\
\> No virtual memory\\
\> Register-to-register machine\\
\> 8 registers of length 64 (64-bit) words each\\
\> Word addressable (64-bits).\\
\> No half precision.\\
\> Double precision (128 bits) is through software and is extremely slow (factors of\\
\>\> about fifty times single precision (64 bits) are common).
\end{tabbing}
\noindent
There is only one pipe from memory-to-vector registers,
resulting in a major bottleneck with loads and stores to
memory from registers. Loads can be chained with arithmetic
operations; stores cannot.
\vspace {.1in}
\noindent
{\bf Software:}
An extensive range of software exists for this machine.
Since the instruction set is compatible with the X-MP range,
this software will also run on that range.
\vspace {.1in}
\noindent
{\bf Performance:}
Low vector start-up times and fast scalar performance make
this a very general-purpose machine. Max. performance 160
Mflops; 64-bit arithmetic; max. attainable sustained
performance 150 Mflops. There are codes for matrix
multiplication and the solution of equations which get close
to this. Maximum scalar rate is 80 mips. It is easy to
attain over 100 Mflops for certain problems, even using
Fortran.
\vspace {.1in}
\noindent
{\bf Contact:}
\vspace{.1in}
\begin{flushleft}
Cray Research Inc.\\
1440 Northland Drive\\
Mendota Heights, MN 55120\\
612-452-6650\\
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