What Causes a Switch to Crash?

[shortstop20]

are you sure it was a bit flip or was that a random guess by a TAC guy wanting to close it out?

I still have the SP and RP crashfiles... here are the relevant bits from the SP crashfile:

Code Select Expand

Cache error detected!
  CPO_ECC     (reg 26/0): 0x00000089
  CPO_CACHERI (reg 27/0): 0xA0000000
  CP0_CAUSE   (reg 13/0): 0x00001C00

Real cache error detected.  System will be halted.

Error: Primary data cache, fields: data,
Actual physical addr 0x00000000,
virtual address is imprecise.

Imprecise Data Parity Error

Imprecise Data Parity Error

08:58:20 PDT Wed Jul 13 2011: Interrupt exception, CPU signal 20, PC = 0x40FEA860



--------------------------------------------------------------------
   Possible software fault. Upon reccurence, please collect
   crashinfo, "show tech" and contact Cisco Technical Support.
--------------------------------------------------------------------


-Traceback= 417BEE50
$0 : 00000000, AT : 42640000, v0 : 52D11A90, v1 : 45BF04F8
a0 : 52D11AC4, a1 : 52D44E3C, a2 : 40FEA848, a3 : 52D44E3C
t0 : 408B5698, t1 : 3400FF01, t2 : 3400F100, t3 : FFFF00FF
t4 : 417B13A8, t5 : 0000FFFF, t6 : 00000004, t7 : 0000030D
s0 : 52D44E3C, s1 : 00000002, s2 : 40FEA848, s3 : 52D44E3C
s4 : 43ECEF90, s5 : 00000004, s6 : 00000000, s7 : EFFFFFFA
t8 : 55BB5088, t9 : 00000000, k0 : 55B8DC94, k1 : 408EAE50
gp : 42647238, sp : 52D44D90, s8 : 9FBF04BE, ra : 40FEA860
EPC  : 417BEE50, ErrorEPC : 40FEA860, SREG     : 3400FF05
MDLO : 3B13B68E, MDHI     : 00000719, BadVaddr : 00000000
DATA_START : 0x42322420
Cause 00000000 (Code 0x0): Interrupt exception



The SP crash forced the RP to reload and then all hell broke loose....   more info

How is it possible when Cisco equipment uses ECC memory?

I can't answer that question but we have seen the parity errors on a Catalyst 6807, twice.