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Mini Cray

Case CPU RAM HD Video Drives OS Sound Monitor Modem Network
Mid Tower 2xPIII 
1gb 80gb
CDRom, 3.5", Unix sb live 17" none 10/100


    Back when I was a teen ager, and into my twenties, The Cray was the finest, fastest, most powerful, and most exotic computer in the world. These machines cost millions of dollars, and were, virtually, custom built, and installed. Adding to their mystique, were the uses to which they were put. There were Cray computers at the super secret NSA, advanced labs like Sandia, and Los Alamos, and places like the National Center for Atmospheric Research, NASA, and Caltech/JPL. The computers themselves were somewhat of a secret, and were little known, or known only by reputation. These computers were so secret, that upon their retirement, they generally had to be dismantled, and destroyed. These super secret, super powerful computers were not made in Silicon Valley, or even in Los Angeles, or New York. They were made in Chipewa Falls, Wisconsin. This added to the romance of these limited production machines. I.B.M. DEC, Data General, and other companies, would make large numbers of computers like the Ford or GM of the computer industry. In contrast, the small number of craftsmen at Cray would only make a limited run of high quality, specialized machines in their little shop in northern Wisconsin, in the manner of Rolls Royce. Unfortunately, it is rather difficult to get exact specs on the Crays, other than their performance in gigaflops. This is in part due to the custom nature of the machines, but is reminiscent of the Rolls Royce policy of not disclosing engine horsepower ratings for their cars.
    The Cray Operating System (COS), and latter Unicos, are both variants of Unix. The native programing environment is C, though there is also FORTRAN available. Cray went out of business for a while (1995), but was eventually resurrected, and is now associated with Silicon Graphics. There is little hope for the non-millionare to produce a computer which will rival the contemporary Cray, but it is possible to set up a machine which can mimic the old Cray-1, Cray-XMP/YMP, and possibly the Cray-2 or Cray-3 machines. I have gleaned some information on the specs of the machines, and have entered it in the table below. The problem with setting up a table like this for a custom machine, is that the specs do not cover the whole series produced. In particular, it is difficult to get exact data on the mass storage systems used. Often, these storage systems were not even built by Cray, but were ordered from other sources by the purchaser. Cray machines use a variant of Unix, and will often use resources located on other machines. This is particularly true of hard drives, and other mass storage systems. In many cases, other computer systems would function as file servers. The Cray would load needed data into it's silicon disk (ssdisk), as needed, and use this as a virtual hard drive. The table is primarily based on information from NCAR, which has been using Crays from the earliest models, and continues to use them today.
    As can be seen from the table, incomplete though it may be, it is well within the capabilities (and budget) of the average enthusiast to put together a machine to roughly equal some of the earlier Crays. The main problem is with the CPU. Cray rates their processor speed in nanoseconds, rather than the more familiar Megahertz. It is easy enough to convert, and I have done so in the table, giving both numbers. It can be seen that current processors from AMD, and Intel easily match, and exceed the speeds of the early Crays, but there is more to processing power than clock speed. Crays used 64 bit processors, while the Intel/AMD units use 32 bit processors with 64 bit data paths. Some Cray processors have two math units. There are other architectural differences as well. Cray machiens were also the earliest to use what we now call RISC processing. There can thus be no direct comparison, at least not on the basis of speed alone. There is also the fact that, except for the Cray 1, Crays used more than one CPU. There are, in addition, some features that have never been implemented on standard PC's. One of these is the solid state disk, which can greatly speed up data intensive calculations.
    My initial Cray wanabee was a poor excuse for a Cray, and I would put it at a level between the Cray-1, and the XMP, without the speed offered by the solid state disk. Varmint Al, who used to work at the Lawrence Livermore Labs, and used Cray computers, puts his Pentium 200 (64mb/2.7gb) machine at about a fifth of a Cray-1. I will take his word for it, as he claims to be able to run the same modeling software on it that he ran on the old Cray, years ago. It is a credit to the architecture of these machines that a Cray using an 80mhz cpu, and 4mb of ram can be considered 5 times the machine as one using a 200mhz cpu, with 64mb of ram.
    My machine is presently configured, as shown above. It runs the Sun version of Unix, and I have linked resources with my Solaris machine, in the manner that was common in multi computing environments of a decade or two ago. I would stack my Cray emulator up against a Cray-3. Like the Cray-3, my Sun e450 has quad 64 bit RISC processors, running at a speed of 480mhz. It has 4 gb of RAM, which is more than the machine I used to set up my table had, but which was not unusual in other examples of the Cray-3. I also took some liberties with the amount of hard drive space. My Sun machine has a pair of 16gb SCSI drives, installed by Sun. These hold the OS, and some other files, as well as most of the working directories. This is already more than was common, even on supercomputers, ten years ago. In addition, I added a raid controller, which controls 8 hard drives of 300gb each. Using RAID 5, this gives a capacity of 2.1 TB, with redundancy. Amazing!!
    I am getting to be a big believer in RAID, particularly modes 10, and 5. Mode 10 gives great speed, as well as redundancy, while mode 5 gives great capacity, and redundancy. Take your pick.
Unit Clock Ram HD Registers Megaflops vintage
Cray 1 12.5ns 
4mb (64x1mb)
64 80+ 1976
Cray XMP 8.5ns (x4cpu) 
32mb (64x8mb) 2gb ssdisk 64 220 1985
Cray YMP 6ns (x8cpu) 
512mb (64x64mb) 2gb ssdisk 64 1000 1990
Cray 2 4.1ns (x4cpu) 1gb 

Cray 3 2.08ns (x4cpu) 
1gb (128x512mb) 20gb 64
Cray YMP8I 2.08ns (x8cpu) 
2gb ssd 
79gb drive
This table is based on actual machines used by NCAR over the years. The Cray 2, and 3 could have as much as 4gb of ram. The Cray 3 could have as many as 16 processors, while the 2 can have as many as 8. Mass storage was added according to the needs of the customer. many of the Crays of this era were capable of 3 or 4 megaflops.
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