MESSAGE
| DATE | 2014-12-06 |
| FROM | Ruben Safir
|
| SUBJECT | Re: [LIU Comp Sci] Parity Bit Algebra
|
From owner-learn-outgoing-at-mrbrklyn.com Sat Dec 6 23:27:23 2014
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Date: Sat, 6 Dec 2014 23:27:21 -0500
From: Ruben Safir
To: Maneesh Kongara
Cc: learn-at-mrbrklyn.com
Subject: Re: [LIU Comp Sci] Parity Bit Algebra
Message-ID: <20141207042721.GA25628-at-panix.com>
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Your not going to send a copy of what you have?
On Sat, Dec 06, 2014 at 10:02:24PM -0500, Maneesh Kongara wrote:
> Damn! I get it now!!!
> On Dec 6, 2014 10:00 PM, "Maneesh Kongara" wrote:
>
> > It gives us the desired answer?
> > On Dec 6, 2014 9:58 PM, "Ruben Safir" wrote:
> >
> >> On 12/07/2014 02:50 AM, Maneesh Kongara wrote:
> >> > Have you seen the review questions?
> >>
> >>
> >> What happens when you subtract a comp 2 number again and again
> >>
> >>
> >> >
> >> > On Sat, Dec 6, 2014, 9:49 PM Ruben Safir wrote:
> >> >
> >> >>
> >> >> I can't even read the question
> >> >>
> >> >>
> >> >>
> >> >> On 12/07/2014 02:38 AM, Maneesh Kongara wrote:
> >> >>> I've finished all other questions... I'm breaking my head with the
> >> last
> >> >>> question.
> >> >>> On Dec 6, 2014 9:36 PM, "Ruben Safir" wrote:
> >> >>>
> >> >>>> On 12/06/2014 11:09 PM, Maneesh Kongara wrote:
> >> >>>>> Preliminary work as in answers to the other questions of the
> >> >> assignment?
> >> >>>>> On Dec 6, 2014 6:08 PM, "Ruben Safir" wrote:
> >> >>>> I'm going to crash, how far did you get in the assingment.
> >> >>>>
> >> >>>> Call me is 20 minutes. I have one hour to do it :)
> >> >>>>
> >> >>>>
> >> >>>>>> On 12/06/2014 10:52 PM, Maneesh Kongara wrote:
> >> >>>>>>> Thanks so much for sharing Mr Rubin. Have you completed the
> >> >> assignment?
> >> >>>>>>> On Dec 6, 2014 5:49 PM, "Ruben Safir" wrote:
> >> >>>>>> Not even looked at it outside of the library. I'm burning up
> >> trying
> >> >> to
> >> >>>>>> catch up. Do you have some preliminary work?
> >> >>>>>>
> >> >>>>>> I did give it throught. Part of the solution must have to do with
> >> the
> >> >>>>>> Comp + 2 binary
> >> >>>>>>
> >> >>>>>> I can't even find my notes...
> >> >>>>>>
> >> >>>>>>>> This is from theidiscussion of Raid 3 Stallings Text which the
> >> slide
> >> >>>>>>>> come from. It is related to the problem you asked about the
> >> parity
> >> >>>> bit
> >> >>>>>>>> calculation for the Hamming Code
> >> >>>>>>>>
> >> >>>>>>>> Not the methodology for logical calculation, it is straight math
> >> >>>>>>>>
> >> >>>>>>>> Note that X is XOR for whatever UFT reason
> >> >>>>>>>>
> >> >>>>>>>>
> >> >>>>>>>> REDUNDANCY In the event of a drive failure, the parity drive is
> >> >>>> accessed
> >> >>>>>>>> and data is reconstructed from the remaining devices. Once the
> >> >> failed
> >> >>>>>>>> drive is replaced, the missing data can be restored on the new
> >> drive
> >> >>>> and
> >> >>>>>>>> operation resumed.
> >> >>>>>>>>
> >> >>>>>>>> Data reconstruction is simple. Consider an array of five drives
> >> in
> >> >>>> which
> >> >>>>>>>> X0 through X3 contain data and X4 is the parity disk.The parity
> >> for
> >> >>>> the
> >> >>>>>>>> ith bit is calculated as follows:
> >> >>>>>>>>
> >> >>>>>>>> X4(i) = X3(i) { X2(i) { X1(i) { X0(i)
> >> >>>>>>>>
> >> >>>>>>>> where { is exclusive-OR function.
> >> >>>>>>>>
> >> >>>>>>>> Suppose that drive X1 has failed. If we add X4(i) { X1(i) to both
> >> >>>> sides
> >> >>>>>>>> of the preceding equation, we get
> >> >>>>>>>>
> >> >>>>>>>> X1(i) = X4(i) { X3(i) { X2(i) { X0(i)
> >> >>>>>>>>
> >> >>>>>>>>
> >> >>>>>>>> file:///home/ruben/william stallings - computer organization and
> >> >>>>>>>> architecture designing for performance (8th edition).pdf
> >> >>>>>>>>
> >> >>>>>>>> Page 202
> >> >>>>>>>>
> >> >>>>>>>>
> >> >>>>>>>>
> >> >>>>>>>> http://www.nylxs.com/images/raid3_parity_math.png
> >> >>>>>>>>
> >> >>>>>>>> Ruben
> >> >>>>>>>>
> >> >>
> >>
> >>
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