Spectre GCR Manual Manuals - Atari Documentation Archive

InterCude Tour
just to /(g.ep its mar6Ces.
'J{ow cuid tlie inj{uence of
cosmic rays to alI this. 7{p, I'm not
into 'UTO s or ShirCey :Mae-faine;
it s for rea£. 'Wlien a cosmic ray,
which you and I and 60th of our
computers are constantCy 6eing
60m6arded with, hits a dy namic
'1\..:4!M 6it, tlie 6it goes IItwallf(,
and sometimes fCips. Some
computer designers put in parity
6its " to de tect this; if a memory 6it
magicalIy changes (Ci/(g. due to a
cosmic ray), tlie computer I(nows
it s a Cost cause, and gives up. %is
is tlie drecuie£f Parity Cliecl(fa uCt
on tlie FE:M Pc. On tlie sr;
trwugh, we £On 't fiave "parity
6its ", and if tlie computer hits one
of tlie 6cui data 6its, tftere s no
way to teCL
Jtnd wlien your CP'U tries to
e;l(ecute that ins truction, that s tlie
6alIgame.
%inl(of it as '1\..ussian
1\puCette Computing. If you Cive at
70
'tb'
'lJenvers aCtitude, as I £0, you can
e:rpect one cosmic ray "memory hit "
per day; Cower aCtitudes have
somewhat 6etter shieUing, 6ecause
of tlie atmospliere.
%us, wlien your computer
ffa/(g.s out, Cases your wort or
whatever, it might not even 6e
your computers fa uCt - might just
6e a cosmic ray.
'In) to thinl(of that cosmic
ray, traveCing for possi6Cy mifIions
of years, and mimons of miCes, alI
to end up zapping some 6its in
your computer. %e phiCasophicaC
impCications are staggering, tlie
sort of thing I consider at three in
tlie morning, whiCe writing
computer manuafs.
Or ...
Just thin/(. .. tlie ne;l(t time
your system inei(JJCica6Cy craslies ...
trw.t you just might have caught a.
cosmic ray from 'lJarth o/cuier s
sfiip.