MESSAGE
DATE | 2014-12-06 |
FROM | Maneesh Kongara
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SUBJECT | Re: [LIU Comp Sci] Parity Bit Algebra
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From owner-learn-outgoing-at-mrbrklyn.com Sat Dec 6 21:38:07 2014 Return-Path: X-Original-To: archive-at-mrbrklyn.com Delivered-To: archive-at-mrbrklyn.com Received: by mrbrklyn.com (Postfix) id 6C55516007B; Sat, 6 Dec 2014 21:38:07 -0500 (EST) Delivered-To: learn-outgoing-at-mrbrklyn.com Received: by mrbrklyn.com (Postfix, from userid 28) id 374C116112F; Sat, 6 Dec 2014 21:38:07 -0500 (EST) Delivered-To: learn-at-mrbrklyn.com Received: from mail-qc0-f179.google.com (mail-qc0-f179.google.com [209.85.216.179]) by mrbrklyn.com (Postfix) with ESMTP id F22FD16007B for ; Sat, 6 Dec 2014 21:38:05 -0500 (EST) Received: by mail-qc0-f179.google.com with SMTP id c9so2169466qcz.24 for ; Sat, 06 Dec 2014 18:38:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=v7LBGLfvDbicY8iVeCqXm7sTNITMmWIme7+R3XJR6ZU=; b=XkwgpiS9ExDvWHDILCFEVHAvWJo2pRvx93BPTQ/YUN9Bc8QwZfDXz9XCclIhAeISsd hvADBJKm0tm7dHl6SiqrujsK19MtWuVp5Hu1A6WktK55aUafGzMZMZs+IN0ufGk8SVyC M0D48t+7al5CoZDYci1DJ3LdHYbsHRGF83JpHAvfKnqh9+vDz8AZTi/pAlD02rHTlVvJ utqzcwDXswZOLpl99piqgqfnFgqDnoaf83wzbALfJr+2Fgn4o8vcLVe2o6Nggdbqbjq+ xhZNKMqyB8rZvEF+B6S3O62H9gK5T1hL4etpm9fWN6AarsV//F8moPaJ9B5WfijbbOEW AhvQ== MIME-Version: 1.0 X-Received: by 10.224.74.132 with SMTP id u4mr40075940qaj.61.1417919884403; Sat, 06 Dec 2014 18:38:04 -0800 (PST) Received: by 10.141.1.136 with HTTP; Sat, 6 Dec 2014 18:38:04 -0800 (PST) Received: by 10.141.1.136 with HTTP; Sat, 6 Dec 2014 18:38:04 -0800 (PST) In-Reply-To: <5483BD3C.9020609-at-panix.com> References: <54838832.6010205-at-panix.com> <54838C85.60705-at-panix.com> <5483BD3C.9020609-at-panix.com> Date: Sat, 6 Dec 2014 21:38:04 -0500 Message-ID: Subject: Re: [LIU Comp Sci] Parity Bit Algebra From: Maneesh Kongara To: learn-at-mrbrklyn.com Content-Type: multipart/alternative; boundary=089e0129503e07aca50509973362 Sender: owner-learn-at-mrbrklyn.com Precedence: bulk Reply-To: learn-at-mrbrklyn.com
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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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I've finished all other questions... I'm breaking my= head with the last question.
On Dec 6, 2014 9:36 PM, "Ruben Safir" = < mrbrklyn-at-panix.com> wrote:= 0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On 12/06/2014 11:09= PM, Maneesh Kongara wrote:
> Preliminary work as in answers to the other questions of the assignmen= t?
> On Dec 6, 2014 6:08 PM, "Ruben Safir" <mrbrklyn-at-panix.com">mrbrklyn-at-panix.com> wrote:
I'm going to crash, how far did you get in the assingment.
Call me is 20 minutes.=C2=A0 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 as= signment?
>>> On Dec 6, 2014 5:49 PM, "Ruben Safir" <"mailto:mrbrklyn-at-panix.com">mrbrklyn-at-panix.com> wrote:
>> Not even looked at it outside of the library.=C2=A0 I'm burnin= g up trying to
>> catch up.=C2=A0 Do you have some preliminary work?
>>
>> I did give it throught.=C2=A0 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.=C2=A0 It is related to the problem you asked ab= out the parity bit
>>>> calculation for the Hamming Code
>>>>
>>>> Not the methodology for logical calculation, it is straigh= t math
>>>>
>>>> Note that X is XOR for whatever UFT reason
>>>>
>>>>
>>>> REDUNDANCY In the event of a drive failure, the parity dri= ve 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 d= rives in which
>>>> X0 through X3 contain data and X4 is the parity disk.The p= arity for the
>>>> ith bit is calculated as follows:
>>>>
>>>> X4(i) =3D 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) =3D X4(i) { X3(i) { X2(i) { X0(i)
>>>>
>>>>
>>>> file:///home/ruben/william stallings - computer organizati= on and
>>>> architecture designing for performance (8th edition).pdfr> >>>>
>>>> Page 202
>>>>
>>>>
>>>>
>>>> ng" target=3D"_blank">http://www.nylxs.com/images/raid3_parity_math.png=
>>>>
>>>> Ruben
>>>>
>>
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