D 2013-07-16T11:36:28.684
J comment WOLFRAM\sgives\sus\sreplicated\sfault-tolerance\sstorage,\swith\send-to-end\schecksums\shelping\sto\sprotect\sagainst\scorruption\sof\sdata\son\sdisk\sor\sin\stransit.\r\n\r\nHowever,\sCPU/RAM\serrors\sduring\sthe\sprocessing\sof\sa\sLITHIUM\shandler\sthat\supdates\sentity\sstate\svia\sWOLFRAM\swill\soften\sremain\sundetected.\sHardened\sprocessors\sand\sECC\sRAM\shelp\ssomewhat,\sbut\sit\swould\sbe\snice\sto\shave\sa\ssoftware\soffering.\r\n\r\nSee\sif\sit's\spractical\sto\smake\sit\spossible\sto\sexecute\shandlers\s<i>twice</i>\s(or\smore)\sin\sparallel.\sTo\smake\sthem\sabsolutely\sconsistent,\severy\saccess\sto\san\sAPI\sthat\sreads\sexternal\smutable\sstate\s(MERCURY,\sclocks,\setc)\sshould\sbe\s"cached"\sfor\sthe\sduration\sof\sthe\shandler\sso\sthat\sboth\sinstances\sof\sthe\shandler\sread\sexactly\sthe\ssame\svalue.\sWe\scan\sexecute\sthe\stwo\shandler\sinstances\sin\slock-step;\sthe\sfirst\sone\sto\scall\san\sAPI\sdoes\sso\sand\sthe\sarguments\sand\sresults\sof\sthe\sAPI\sstored\suntil\sthe\ssecond\sone\scalls\sto\sthe\sAPI,\swhich\sshould\sbe\sexactly\sthe\ssame\sone\s(or\swe\shave\sdetected\sa\sconsistency\sviolation),\sand\sit\sis\sthen\sprovided\swith\sthe\ssame\sresults.\sIf\sthe\sfirst\sinstance\stries\sto\scall\sanother\sAPI\sbefore\sthis,\sit\sshould\sblock\sto\slet\sthe\ssecond\sinstance\scatch\sup.\r\n\r\nIf\sthere\sis\sany\sdisparity\sin\sthe\ssequence\sof\sAPI\scalls\sperformed,\sthen\swe've\sdetected\san\sinconsistency,\sand\sshould\sabort\sthe\shandler\s(and\sretry\sit).\r\n\r\nConsistently\sfailing\shandlers\smay\sreveal\sa\sbug\sin\sour\sconsistent\sexecution\slogic,\sor\sa\sCPU/RAM\sso\sbroken\sthat\sthe\serror\srate\sis\sapproaching\s100%;\sso\sgive\sup\sand\sreject\sthe\shandler\soutright.
J private_contact edd852a1b86b4a3139e73d229e5a61a63d12b819
J severity Critical
J status Open
J title Consider\ssupport\sfor\sreplicated\sprocessing
J type Code_Defect
K 11776edc915f3dda05b476852bf1ddef5114de13
U alaric
Z d5c89f928fb9b9ab712ff9fbc4cf2686
