Re: AW: [HACKERS] beta testing version

2000-12-08 Thread Daniele Orlandi
Bruce Guenter wrote: > > CRCs are designed to catch N-bit errors (ie N bits in a row with their > values flipped). N is (IIRC) the number of bits in the CRC minus one. > So, a 32-bit CRC can catch all 31-bit errors. That's the only guarantee > a CRC gives. Everything else has a 1 in 2^32-1 cha

RE: AW: [HACKERS] beta testing version

2000-12-06 Thread Christopher Kings-Lynne
> CRCs are designed to catch N-bit errors (ie N bits in a row with their > values flipped). N is (IIRC) the number of bits in the CRC minus one. > So, a 32-bit CRC can catch all 31-bit errors. That's the only guarantee > a CRC gives. Everything else has a 1 in 2^32-1 chance of producing the >

Re: AW: [HACKERS] beta testing version

2000-12-06 Thread Bruce Guenter
On Wed, Dec 06, 2000 at 11:13:33PM +, Daniele Orlandi wrote: > Bruce Guenter wrote: > > - Assume that a CRC is a guarantee. A CRC would be a good addition to > > help ensure the data wasn't broken by flakey drive firmware, but > > doesn't guarantee consistency. > Even a CRC per transactio

Re: AW: [HACKERS] beta testing version

2000-12-06 Thread Daniele Orlandi
Bruce Guenter wrote: > > - Assume that a CRC is a guarantee. A CRC would be a good addition to > help ensure the data wasn't broken by flakey drive firmware, but > doesn't guarantee consistency. Even a CRC per transaction (it could be a nice END record) ? Bye! -- Daniele --

Re: AW: [HACKERS] beta testing version

2000-12-06 Thread Bruce Guenter
On Wed, Dec 06, 2000 at 11:15:26AM -0500, Tom Lane wrote: > Zeugswetter Andreas SB <[EMAIL PROTECTED]> writes: > > Yes, but there would need to be a way to verify the last page or > > record from txlog when running on crap hardware. > How exactly *do* we determine where the end of the valid log da

Re: AW: [HACKERS] beta testing version

2000-12-06 Thread Daniele Orlandi
Tom Lane wrote: > > Zeugswetter Andreas SB <[EMAIL PROTECTED]> writes: > > Yes, but there would need to be a way to verify the last page or > > record from txlog when running on crap hardware. > > How exactly *do* we determine where the end of the valid log data is, > anyway? Couldn't you use a

Re: AW: [HACKERS] beta testing version

2000-12-06 Thread Tom Lane
Zeugswetter Andreas SB <[EMAIL PROTECTED]> writes: > Yes, but there would need to be a way to verify the last page or > record from txlog when running on crap hardware. How exactly *do* we determine where the end of the valid log data is, anyway? regards, tom lane