Readers Drives

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JJW009
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Post by JJW009 » Sat Jul 30, 2005 4:34 pm

I was just wondering, how big is yours?



I have 3 main PCs I use every day... and they are very dull and boring. Here is the 1st one:



<img src='http://www.yourwired.co.uk/photo/Robo-chan.jpg' border='0' alt='user posted image'>



It's a K6-2-450 with 256MB ram, FSB is 100MHz, and it was loaded with 5 large hard disks from 120 - 200 Gigs. It has been in constant service since 22nd December 1999 when I bought the processor for ?43 and 128MB of memory for ?130 !!!



That was my Y2K bonus (and then some) all spent in one very small package!!!



The power supply died a few weeks ago... so it is currently resting for the 1st time in 5 years!!!




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KindaWobbly
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Post by KindaWobbly » Sun Jul 31, 2005 7:58 pm

Here's mine:

<img src='http://img258.imageshack.us/img258/4095 ... 6jj.th.jpg' border='0' alt='user posted image'>

It's the first computer I've built myself, and I'm still slighty surprised that it all works each time I press the 'on' button!
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Post by JJW009 » Sun Jul 31, 2005 8:09 pm

Without getting too technical, how many drives does it have and where are they? It looks a bit strange if you see where the molex pugs are going. It looks like one mounted transversly at the back, and ??? at the front ?



The dual processors look very business like with those coolers on!




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Post by KindaWobbly » Sun Jul 31, 2005 8:23 pm

Molex pugs? I suppose I could have included more info!



It's got three 200GB Maxtor Diamondthingy 10 drives in the front, inside one of these:

http://www.evermax.co.uk/mb235.htm

And another one in the back, all in a raid 5 array.



The processors are AMD Opteron 250s, and the Motherboard is a Tyan K8WE.
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Post by JJW009 » Mon Aug 01, 2005 1:22 pm

I've now read several lengthy descriptions of how RAID 5 works... and I still don't get it!



They say that, for 4 drives you get the storage of capacity of 3, but it can survive a disk failure. I can't make that add up <!--emo&:(--><img src='http://i6.ifrm.com/html/emoticons/sad.gif' border='0' style='vertical-align:middle' alt='sad.gif' /><!--endemo-->



If you've got say 4 x 200GB drives, with the how can 200GB of parity give redundancy for 600GB of data?!



I understand raid 0 and 1 ... but this is doing my noodle in :blink:




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Post by KindaWobbly » Mon Aug 01, 2005 5:50 pm

This is straying quite far from the silly! It all done with exclusive OR logical operations, the best example I have read is this one:
Let's take an example to show how this works; you can do this yourself easily on a sheet of paper. Suppose we have the following four bytes of data: D1=10100101, D2=11110000, D3=00111100, and D4=10111001. We can "XOR" them together as follows, one step at a time:



&nbsp; &nbsp; D1 XOR D2 XOR D3 XOR D4

&nbsp; &nbsp; = ( (D1 XOR D2) XOR D3) XOR D4

&nbsp; &nbsp; = ( (10100101 XOR 11110000) XOR 00111100) XOR 10111001

&nbsp; &nbsp; = (01010101.XOR 00111100) XOR 10111001

&nbsp; &nbsp; = 01101001 XOR 10111001

&nbsp; &nbsp; = 11010000



So "11010000" becomes the parity byte, DP. Now let's say we store these five values on five hard disks, and hard disk #3, containing value "00111100", goes el-muncho. We can retrieve the missing byte simply by XOR'ing together the other three original data pieces, and the parity byte we calculated earlier, as so:



&nbsp; &nbsp; D1 XOR D2 XOR D4 XOR DP

&nbsp; &nbsp; = ( (D1 XOR D2) XOR D4) XOR DP

&nbsp; &nbsp; = ( (10100101 XOR 11110000) XOR 10111001) XOR 11010000

&nbsp; &nbsp; = (01010101 XOR 10111001) XOR 11010000

&nbsp; &nbsp; = 11101100 XOR 11010000

&nbsp; &nbsp; = 00111100



Which is D3, the missing value. Pretty neat, huh? :^) This operation can be done on any number of bits, incidentally; I just used eight bits for simplicity. It's also a very simple binary calculation--which is a good thing, because it has to be done for every bit stored in a parity-enabled RAID array.
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Post by JJW009 » Mon Aug 01, 2005 6:44 pm

Now THAT is absolute genious!!! Thanks, I get it now :P



Other explanations just talked of Parity, which is exactly what it is I guess, but it didn't make sense without the detail. Parity is just "Odd or Even", normally applied to a Byte - but here it is applied across the bytes. Lovely <!--emo&:)--><img src='http://i6.ifrm.com/html/emoticons/smile.gif' border='0' style='vertical-align:middle' alt='smile.gif' /><!--endemo-->




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Post by KindaWobbly » Mon Aug 01, 2005 9:42 pm

<!--emo&:)--><img src='http://i6.ifrm.com/html/emoticons/smile.gif' border='0' style='vertical-align:middle' alt='smile.gif' /><!--endemo-->
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Post by JJW009 » Tue Aug 02, 2005 11:22 pm

KindaWobbly wrote:This is straying quite far from the silly!
What is ironic; this forum was suposed to releave the PCpro forum of sillyness; and I've just come back from a "Who's the sexiest Alien" thread :blink:




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Post by RedeyesUK » Tue Aug 02, 2005 11:28 pm

now that is silly; everyone knows it's seven of nine. :rolleyes:
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Post by JJW009 » Tue Aug 02, 2005 11:38 pm

RedeyesUK wrote:now that is silly; everyone knows it's seven of nine. :rolleyes:


Ahhh no! See, she was born Human !! :P




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Post by RedeyesUK » Tue Aug 02, 2005 11:48 pm

*sheesh*



pedant.



:rolleyes: :D



can't think of any others right now, 'cos i'm seriously exhausted and my brain is slowly turning into boiled cabbage.



i also can't post any piccies of my rigs, 'cos i don't have any pics, and i'm at work. i'll try to get some sorted tomorrow <!--emo&:)--><img src='http://i6.ifrm.com/html/emoticons/smile.gif' border='0' style='vertical-align:middle' alt='smile.gif' /><!--endemo-->
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