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 18:08:13 2014
Return-Path:
X-Original-To: archive-at-mrbrklyn.com
Delivered-To: archive-at-mrbrklyn.com
Received: by mrbrklyn.com (Postfix)
id 2B31916007B; Sat, 6 Dec 2014 18:08:13 -0500 (EST)
Delivered-To: learn-outgoing-at-mrbrklyn.com
Received: by mrbrklyn.com (Postfix, from userid 28)
id 1436F16112F; Sat, 6 Dec 2014 18:08:13 -0500 (EST)
Delivered-To: learn-at-mrbrklyn.com
Received: from mailbackend.panix.com (mailbackend.panix.com [166.84.1.89])
by mrbrklyn.com (Postfix) with ESMTP id 021D116007B
for ; Sat, 6 Dec 2014 18:08:11 -0500 (EST)
Received: from [10.0.0.42] (unknown [96.57.23.82])
by mailbackend.panix.com (Postfix) with ESMTPSA id B9DE813961
for ; Sat, 6 Dec 2014 18:08:10 -0500 (EST)
Message-ID: <54838C85.60705-at-panix.com>
Date: Sat, 06 Dec 2014 23:08:53 +0000
From: Ruben Safir
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0
MIME-Version: 1.0
To: learn-at-mrbrklyn.com
Subject: Re: [LIU Comp Sci] Parity Bit Algebra
References: <54838832.6010205-at-panix.com>
In-Reply-To:
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Sender: owner-learn-at-mrbrklyn.com
Precedence: bulk
Reply-To: learn-at-mrbrklyn.com
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
>>
|
|
