• BIT FLIPS are a COMMON thing in the universe 😀 so EEC RAM ACTUALLY MAKES SENSE 😀
  • “Studies by IBM in the 1990s suggest that computers typically experience about one cosmic-ray-induced error per 256 megabytes of RAM per month”[15]
  • As chip (CPU transistors and RAM) density increases, the likelyhood goes up: ” 1 to 5 bit errors per hour for 8GB of RAM” (src)
  • “So, if the program has large dataset (several GB), or has high memory reading or writing rate (GB/s or more), and it runs for several hours, then we can expect up to several silent bit flips on desktop hardware” (src)
  • The sun is ONE source of cosmic radiation but also a SHIELD against other cosmic radiation (Heliosphere)
  • especially problematic if it’s a computer that life directly depends on like: pacemakers
    • “the prime suspect that she says most likely sparked this unsettling episode was a cosmic ray from outer space” (src)

Veritasium: https://www.youtube.com/watch?v=AaZ_RSt0KP8

“The Space Shuttle’s fly-by-wire control system was entirely reliant on its main computer, the Data Processing System (DPS).”

NASA Space Shuttle General Purpose Computers (GPC) AP-101S (left) and AP-101B general purpose computers consolidated into one box in 1991

NASA Space Shuttle General Purpose Computers (GPC) AP-101S (left) and AP-101B general purpose computers consolidated into one box in 1991 (src)

“Space Shuttle used five AP-101 computers as general-purpose computers (GPCs)” (src)

It is assumed, that 4x computers were doing the same work, and if calculations results were not the same, a majority vote of the computers would decide which result to trust.

“space shuttle Columbia will be ruled by majority vote” (src)

“The DPS controlled the flight controls and thrusters on the orbiter, as well as the ET and SRBs during launch. The DPS consisted of five general-purpose computers (GPC), two magnetic tape mass memory units (MMUs)”

Mass memory unit (MMU) built by Odetics, Inc., the manufacturer of the Space Shuttle Mass Memory Units that used magnetic tape. This MMU uses solid-state memory instead. It has the same form factor and connectors as the Shuttle MMU but does not bear a NASA contract number. The item was contracted by McDonnell-Douglas and has an MDSSC label on the front. The unit measures 11.5″ x 15.5″x 7.5″.
It was purchased by the consignor at a NASA sale in the same lot as an Odetics Space Shuttle magnetic tape MMU. While the consignor believes this to be a developmental prototype of a solid-state replacement for the magnetic tape MMU, it may also be a corporate (and not NASA) funded development by McDonnell-Douglas and proposed to NASA as a replacement. Unfortunately, the writing on the adhesive tape on the top of the unit is no longer readable. (src)

“and the associated sensors to monitor the Space Shuttle components.[2]: 232–233  The original GPC used was the IBM AP-101B, which used a separate central processing unit (CPU) and input/output processor (IOP), and non-volatile solid-state memory.” (src)



liked this article?

  • only together we can create a truly free world
  • plz support dwaves to keep it up & running!
  • (yes the info on the internet is (mostly) free but beer is still not free (still have to work on that))
  • really really hate advertisement
  • contribute: whenever a solution was found, blog about it for others to find!
  • talk about, recommend & link to this blog and articles
  • thanks to all who contribute!