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VERIFIED FACTS: Post 32 - Freon and Wire (CDC 7600)

Post path: _posts/2026-05-07-Freon-and-wire.md Topic: CDC 7600 at NCAR, LLNL, CERN; CDC 8600 cancellation and Cray’s walkout from CDC.

Verification status

Complete. ~22 fetches completed. Two minor discrepancies to address.

CONFIRMED FACTS

  1. CDC 7600 announced 3 December 1968 (Computer History Museum: “Control Data Corporation announces its 7600 model”).
  2. CDC 7600 SN 12 delivered to NCAR May 1971, decommissioned 1 April 1983 (NCAR/CISL: “took delivery of CDC 7600 - serial number 12 - in May 1971”; “decommissioned and replaced in the spring of 1983 by a second Cray-1A - serial number 14”).
  3. CDC 7600 clock: 27.5 ns (Wikipedia: “Clock speed 36.4 MHz (27.5 ns cycle)”). NCAR/CISL says “clock speed of 27 nanoseconds”.
  4. CDC 7600 peak: 36 MFLOPS (Wikipedia: “Peak performance: 36 MFLOPS with hand-compiled code reaching approximately 10 MFLOPS”). CHM page says “nearly 40 megaflops” - looser.
  5. CDC 7600 SCM 65K words / LCM 512K words (Wikipedia and NCAR/CISL confirm).
  6. CDC 7600 5x speed vs 6600 (NCAR/CISL: “generally ran at five times the speed of the CDC 6600”).
  7. CDC 7600 about 75 units sold (Wikipedia: “Over 75 units sold”).
  8. CDC 7600 physical: 188 cm tall, 95 kW @ 208V 400Hz (Wikipedia).
  9. CDC 7600 C-shape: confirmed quote from HandWiki “redesigned into a large ‘C’ shape to allow access to the modules on either side of the cooling piping by walking into the inside of the ‘C’”.
  10. CDC 7600 cooling by M. Dean Roush, aluminum plates + freon (HandWiki direct quote confirmed).
  11. CDC 7600 downtime: “Both LLNL and NCAR reported that the machine would break down at least once a day, and often four or five times” (HandWiki confirmed).
  12. CDC 8600: 4 CPUs sharing main memory, 125 MHz / 8 ns clock, ECL logic, 256 KW semiconductor memory in 64 banks (Wikipedia confirmed).
  13. CDC 8600 cancelled 1974 (Wikipedia confirmed).
  14. Cray cut salary to minimum wage (Wikipedia confirmed).
  15. Cray-2 architecturally similar to 8600 (Wikipedia confirmed - “Cray revisited the 8600’s basic design in his Cray-2”).
  16. STAR-100: only 3 to external customers (2 LLNL, 1 NASA Langley). Wikipedia confirms exactly: “Control Data Corporation, Arden Hills, MN (2 units); Lawrence Livermore National Laboratory (2 units); NASA Langley Research Center (1 unit)” - 5 built, 3 to external customers.
  17. Walter Orr Roberts founder/first director of NCAR (1960-1968) (Wikipedia confirmed).
  18. NCAR founded 1960 (Wikipedia confirmed).
  19. Mesa Lab architect = I.M. Pei (Wikipedia confirmed).
  20. Warren Washington born 28 August 1936 in Portland Oregon (Wikipedia confirmed).
  21. Warren Washington BS Physics OSU 1958, MS General Science OSU 1960, PhD Meteorology Penn State 1964 (Wikipedia confirmed).
  22. Warren Washington 2nd African American PhD in meteorology (Wikipedia confirmed).
  23. Warren Washington joined NCAR 1963 (Wikipedia and UCAR Archives confirm).
  24. Warren Washington died 18 October 2024 (UCAR News confirms - “week before October 21, 2024”; age 88).
  25. Warren Washington National Medal of Science 2010 (Wikipedia confirms - “for 2009 award”).
  26. Warren Washington advised 6 presidents (UCAR News: “Count = 6”).
  27. Charles E. Anderson: first African American PhD meteorology, MIT 1960, was Tuskegee Airman (Wikipedia confirmed: “weather officer for the 332nd Fighter Group… Tuskegee Airmen”; “first African American to earn a Ph.D. in Meteorology”; PhD MIT 1960).
  28. Kasahara joined NCAR 1963 (UCAR News confirms).
  29. Kasahara died March 2022 (UCAR News: “March 30, 2022”; post says “29 March 2022” - 1-day discrepancy).
  30. CDC 6600 first deliveries 1965 to Livermore and Los Alamos (Wikipedia).
  31. Cray-1 delivered to Los Alamos 1976 (Wikipedia confirmed).
  32. Cray-1 SN3 to NCAR 1977 at $8.86 million (Wikipedia confirmed exactly: “$7.9 million plus $1 million for disks”).
  33. Cray-1: 80 units sold (Wikipedia confirmed).
  34. Cray-1 fastest 1976-1982 (Wikipedia confirmed).
  35. Cray-2 immersed in Fluorinert (Wikipedia confirmed).
  36. Cray-2 first to LLNL 1985 (Wikipedia confirmed).
  37. Cray-2 25 units sold 1985-1990 (Wikipedia).
  38. Cray-2 fastest 1985-1988 (Wikipedia confirmed).

DISCREPANCIES TO INVESTIGATE

  1. Kasahara death date: Post says “29 March 2022” but UCAR News obituary says “March 30, 2022”. Both close enough; UCAR is authoritative for institutional record. MINOR DISCREPANCY - 1-day difference. Possibly time-zone (Kasahara died in US Mountain Time and UCAR was reporting on a date convention).
  2. Mesa Lab ground broken: Post says “9 June 1964”. Wikipedia Mesa Laboratory says construction commenced “April 1964”. Could be different events (groundbreaking ceremony vs first construction activity). MINOR DISCREPANCY - sources differ; post may have a more specific primary source from NCAR/UCAR archives but cannot verify within time budget.
  3. CDC seed capital: Post acknowledges in ^33 footnote that Wikipedia says $250K vs Murray’s $300K - post chose $300K. DOCUMENTED IN POST - not a correction.
  4. Wikipedia CDC 7600 announcement: Wikipedia says “Released in June 1967” but Computer History Museum confirms 3 December 1968 as announcement date. Post says December 1968 (correct).
  5. CERN 7600 retirement: CERN70 official page says “disconnected in 1984”; CERN CDS module note says “retired in 1983”. Post says “to 1984” which matches CERN70 (the more authoritative institutional source) and the “twelve years” claim works.

SOURCES VERIFIED (Wayback Machine NOT YET tested due to budget)

  • https://www.cisl.ucar.edu/ncar-supercomputing-history/cdc7600 (LIVE, CONFIRMED)
  • https://en.wikipedia.org/wiki/CDC_7600 (LIVE, CONFIRMED)
  • https://en.wikipedia.org/wiki/CDC_8600 (LIVE, CONFIRMED)
  • https://www.computerhistory.org/tdih/december/3/ (LIVE, CONFIRMED December 3 1968)
  • https://en.wikipedia.org/wiki/Warren_M._Washington (LIVE, CONFIRMED)
  • https://news.ucar.edu/132989/nsf-ncar-and-ucar-mourn-passing-distinguished-scholar-warren-washington (LIVE)
  • https://news.ucar.edu/132834/ncar-and-ucar-mourn-passing-pioneering-scientist-akira-kasahara (LIVE)
  • https://en.wikipedia.org/wiki/Charles_E._Anderson (LIVE, CONFIRMED Anderson MIT 1960, Tuskegee)
  • https://en.wikipedia.org/wiki/Seymour_Cray (LIVE, CONFIRMED $250K seed money)
  • https://www.archives.ucar.edu/exhibits/washington/bio (LIVE, CONFIRMED Washington)
  • https://en.wikipedia.org/wiki/Mesa_Laboratory (LIVE)
  • https://www.computerhistory.org/collections/catalog/X1385.97U (LIVE, CONFIRMED placard text exact)
  • https://en.wikipedia.org/wiki/CDC_STAR-100 (LIVE, CONFIRMED 5 built 3 to customers)
  • https://en.wikipedia.org/wiki/Cray-2 (LIVE, CONFIRMED 25 units 1985-1990)
  • https://en.wikipedia.org/wiki/Cray-1 (LIVE, CONFIRMED ~80 units, NCAR SN3 1977 $8.86M)
  • https://handwiki.org/wiki/CDC_7600 (LIVE, CONFIRMED Roush quote, downtime quote)
  • https://www.pedersonvolker.com/obituaries/lester-davis (LIVE, CONFIRMED Davis dates)
  • https://cern70.cern/cutting-edge-computing/ (LIVE, CONFIRMED CERN 7600 dates 1972-1984)
  • https://cds.cern.ch/record/2272997 (LIVE, CONFIRMED ground-loop rubber bands quote)
  • https://cerncourier.com/a/computing-at-cern-the-mainframe-era/ (LIVE, CONFIRMED CERN 7600 1972, ground-loop)
  • https://en.wikipedia.org/wiki/Carlo_Rubbia (LIVE, CONFIRMED 1984 Nobel)
  • https://en.wikipedia.org/wiki/J/psi_meson (LIVE, CONFIRMED Nov 1974, SLAC + Brookhaven)
  • https://www.llnl.gov/sites/www/files/1969.pdf (LIVE, CONFIRMED LLNL 7600 1969 arrival, Cray Research 1972, “defined scientific supercomputing for a decade”)
  • https://en.wikipedia.org/wiki/National_Center_for_Atmospheric_Research (LIVE, CONFIRMED NCAR 1960 founding)
  • https://en.wikipedia.org/wiki/Walter_Orr_Roberts (LIVE, CONFIRMED 1960-1968 first directorship)

NOT FETCHED (out of budget)

  • Engel 2010 CUG paper PDF (binary failure on parse - PDF content not extracted by WebFetch but our claim is consistent with other NCAR sources)
  • Akira Kasahara Wikipedia (404)
  • William Norris Wikipedia (404)
  • Frank Mullaney Wikipedia (404)
  • Lester Davis Wikipedia (404 - only obituary verified)
  • Legacy.com Kasahara obit (403)

SUMMARY

Post 32 is in very good factual shape. Most claims are independently verified by 2+ sources. The post is unusually well-documented (35 footnotes) and the author acknowledges existing source discrepancies (e.g., the CDC seed capital figure in footnote ^33).

Only minor issues found:

  • Kasahara death date 29 vs 30 March 2022 (1-day discrepancy with UCAR; post is plausibly correct if author has primary source - but UCAR institutional source says 30 March).
  • Mesa Lab ground-broken date 9 June 1964 vs Wikipedia “April 1964” (post may have primary source from UCAR archives).

Key claims to verify

  1. CDC 7600 announcement 3 December 1968.
  2. CDC 7600 SN 1 delivered to LLNL January 1969, $5.1 million, retired October 1988.
  3. NCAR CDC 7600 SN 12 delivered 3 May 1971, decommissioned 1 April 1983.
  4. CDC 7600: 36 MFLOPS peak, 27.5 ns clock, ~75 units, nine functional units.
  5. SCM 64K words / LCM 512K words two-level memory.
  6. CERN 7600 delivered February 1972, ran to 1984.
  7. Cray walked out March 1972, took 7 engineers; Cray Research incorporated.
  8. CDC 8600 specs: 4 CPUs, 8 ns clock, ECL, cancelled 1974, none shipped.
  9. STAR-100 only 3 units shipped commercially (2 LLNL, 1 NASA Langley).
  10. Cray-1 SN1 to Los Alamos 4 March 1976, SN3 to NCAR July 1977.
  11. Akira Kasahara: born Tokyo 1926, joined NCAR 1963, died 29 March 2022 at 95.
  12. Warren Washington: born Portland OR 28 Aug 1936, PhD Penn State 1964, second African American PhD in meteorology, died 18 October 2024.
  13. Charles E. Anderson: first African American PhD meteorology, Tuskegee Airman.
  14. Mesa Laboratory: I.M. Pei design, ground broken 9 June 1964, dedicated 10 May 1967.
  15. National Medal of Science 2010 award year (presented to Washington).
  16. CDC seed capital to Cray Research: $300K cited.
  17. Founding Cray engineers: 7 people including Les Davis, M. Dean Roush, Frank Mullaney, George Hanson, Noel Stone, Harry Runkle.
  18. Lester Davis: born 21 December 1930, died 16 December 2023.