3 ms·

> While Rosenthal was visiting the International Space Station headquarters in Montgomery, Ala., in 2013, a top scientist said, “‘The data stored on the station

> While Rosenthal was visiting the International Space Station headquarters in Montgomery, Ala., in 2013, a top scientist said, “‘The data stored on the station gets erased every 24 hours by cosmic rays,’” Rosenthal recalls. “‘And we have to keep rewriting the data over and over and over again.’” This doesn't seem right to me, considering the amount and age of COTS hardware with a variety of flash-storage in them (Thinkpads, Nikon DSLRs etc.)

pcl 2y ago
Perhaps the more precise phrasing would be that the data is corrupted within a short enough period of time that they need to rewrite every 24 hours to ensure validity. IIRC the shuttle’s magnetic-coil memory was hardened explicitly to defend against this sort of corruption, with additional windings to maintain a stronger charge state than would be used within the shield of the atmosphere.
- simne 2y ago
  It all depends on used technology. DRAM/SRAM really have problems with cosmic rays, but on LEO enough to use ECC, as DRAM refresh it's contents every few milliseconds. In Deep space missions (on Mars and beyond), even hardened electronics hangs, as I could remember, approximately every year. Magnetic-core memory is not affected by cosmic rays (only support circuits affected), but unfortunately it is not dense enough for current storage demands (exists micro-electronics magnetic-core technology, but even it cannot compete with CMOS). Unfortunately, ECC notebook (mobile) platforms are not produced anymore (yes, tens years ago exists Sun notebooks, built on server platform, but they not produced for long time), and on ISS used off-the-shelf technologies, that's why they have troubles with cosmic rays. Because of this, Shuttle flight control computers was special radiation hardened but with DRAM. Magnetic-core storage is just don't used in modern spacecrafts, but used radiation hardened CMOS and for storage used cylindrical magnetic domains technology (you could buy it on free market easy, but it is still magnitudes less dense than single layer flash). PS to be strict, Shuttle flight computers was upgraded at least once, but from beginning was hardened semiconductor.
  - adrian_b 2y ago
    There still are mobile workstation laptops with ECC memory, e.g. the Dell Precision 5000/7000 series and some similar series at HP and Lenovo. My own laptop is such a Dell Precision model. EDIT: Looking now at the Dell site, I see that buying a laptop with ECC memory has become much more difficult than a few years ago. For many of the "mobile workstations" ECC memory is not offered at this time, while for those where you can customize the laptop and choose ECC, the price is absolutely outrageous, e.g. $850 for 64 GB of ECC memory. Of course, anyone sensible would buy the "mobile workstation" with the smallest and cheapest memory option, then they would buy separately 64 GB of ECC SODIMM memory at a price 4 times lower than demanded by Dell.
    - simne 2y ago
      Thank you for info! I most time avoid to read about top ultrabooks, because mostly this info useless for me, but now I first time hear about notebook with server processor (xeon 5xxx).
jazzyjackson 2y ago
Maybe a bit gets flipped every 24 hours but yeah cosmic rays don't just erase a whole drive... bit of a case of telephone here tho, just relaying a moment of inspiration.
- simne 2y ago
  DRAM/SRAM/Flash bits and CMOS triggers flipped (not all at once, random). Magnetic media is much more resistant, but in almost all HDDs using classic CPU (and DRAM cache), which are affected by cosmic rays, so info corrupted when travel from HDD surface to computer motherboard.

pcl 2y ago

Perhaps the more precise phrasing would be that the data is corrupted within a short enough period of time that they need to rewrite every 24 hours to ensure validity. IIRC the shuttle’s magnetic-coil memory was hardened explicitly to defend against this sort of corruption, with additional windings to maintain a stronger charge state than would be used within the shield of the atmosphere.

simne 2y ago
It all depends on used technology. DRAM/SRAM really have problems with cosmic rays, but on LEO enough to use ECC, as DRAM refresh it's contents every few milliseconds. In Deep space missions (on Mars and beyond), even hardened electronics hangs, as I could remember, approximately every year. Magnetic-core memory is not affected by cosmic rays (only support circuits affected), but unfortunately it is not dense enough for current storage demands (exists micro-electronics magnetic-core technology, but even it cannot compete with CMOS). Unfortunately, ECC notebook (mobile) platforms are not produced anymore (yes, tens years ago exists Sun notebooks, built on server platform, but they not produced for long time), and on ISS used off-the-shelf technologies, that's why they have troubles with cosmic rays. Because of this, Shuttle flight control computers was special radiation hardened but with DRAM. Magnetic-core storage is just don't used in modern spacecrafts, but used radiation hardened CMOS and for storage used cylindrical magnetic domains technology (you could buy it on free market easy, but it is still magnitudes less dense than single layer flash). PS to be strict, Shuttle flight computers was upgraded at least once, but from beginning was hardened semiconductor.
- adrian_b 2y ago
  There still are mobile workstation laptops with ECC memory, e.g. the Dell Precision 5000/7000 series and some similar series at HP and Lenovo. My own laptop is such a Dell Precision model. EDIT: Looking now at the Dell site, I see that buying a laptop with ECC memory has become much more difficult than a few years ago. For many of the "mobile workstations" ECC memory is not offered at this time, while for those where you can customize the laptop and choose ECC, the price is absolutely outrageous, e.g. $850 for 64 GB of ECC memory. Of course, anyone sensible would buy the "mobile workstation" with the smallest and cheapest memory option, then they would buy separately 64 GB of ECC SODIMM memory at a price 4 times lower than demanded by Dell.
  - simne 2y ago
    Thank you for info! I most time avoid to read about top ultrabooks, because mostly this info useless for me, but now I first time hear about notebook with server processor (xeon 5xxx).

jazzyjackson 2y ago

Maybe a bit gets flipped every 24 hours but yeah cosmic rays don't just erase a whole drive... bit of a case of telephone here tho, just relaying a moment of inspiration.

simne 2y ago
DRAM/SRAM/Flash bits and CMOS triggers flipped (not all at once, random). Magnetic media is much more resistant, but in almost all HDDs using classic CPU (and DRAM cache), which are affected by cosmic rays, so info corrupted when travel from HDD surface to computer motherboard.