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How to know if a clean XP install is good?
Hi all,
We all know that CD/DVD drives, depending on their quality, can often mis-read occasionally, especially if the cd in question had surface marks say. So if I install XP from a cd which is not in 100% perfect condition, and the install completes without issue, can I really be sure that all is well? If my drive mis-read a few bits during the installation, how would I know? Would the XP installer be guaranteed to detect and flag such a fault? Or would it just proceed, allowing incorrect data into the install? Is there a way, post install, to determine the "goodness" of the installation? Many thanks for any thoughts! |
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#2
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How to know if a clean XP install is good?
When XP installs, it does a check on the files. If it installed correctly,
then all is well. -- Dustin Harper http://www.VistaRIP.com | Vista Resource & Information Page "shanex" wrote in message ... Hi all, We all know that CD/DVD drives, depending on their quality, can often mis-read occasionally, especially if the cd in question had surface marks say. So if I install XP from a cd which is not in 100% perfect condition, and the install completes without issue, can I really be sure that all is well? If my drive mis-read a few bits during the installation, how would I know? Would the XP installer be guaranteed to detect and flag such a fault? Or would it just proceed, allowing incorrect data into the install? Is there a way, post install, to determine the "goodness" of the installation? Many thanks for any thoughts! |
#3
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How to know if a clean XP install is good?
Hi Dustin,
Thanks for that. But how does this work? A file gets copied incorrectly from cd say, during install, because cd is bad, or drive is bad. If checksums are calculated before and after copy, presumably the 2 checksums could be wrong (but identical)... Unless checksums are stored on the cd seperately, and after copy you check copied checksum against checksum on cd? Or how does it work? Thanks! |
#4
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How to know if a clean XP install is good?
Let me describe my actual scenario:
I have a good cd drive (plextor premium), and about a year ago I used it to create an iso image (plextor have their own version of iso called .pxi file) of my xp cd, as a backup, to protect against cd damage. In fact I created 2 pxi images of the cd, binary compared them and they were identical. Call these 1.pxi and 2.pxi say. Yesterday, one year later, I did the same process. Same cd, same drive, same pxi creation tool. I created 3.pxi and 4.pxi and again they were binary identical. However if I binary compare 1.pxi and 3.pxi there are differences. My conclusions: 1) 1.pxi = 2.pxi and 3.pxi = 4.pxi implies drive is ok 2) 1.pxi not equal to 3.pxi implies cd is not ok. And indeed, there are some light marks on the cd which were not there when it was new. However I used this cd to install xp successfully, also yesterday. So my dilemma is: I know (almost 100%) that the cd has changed over time due to some very light marking, and yet I get no complaint from the xp installer if I use this cd to install xp. That's my real question ! |
#5
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How to know if a clean XP install is good?
shanex wrote:
Let me describe my actual scenario: I have a good cd drive (plextor premium), and about a year ago I used it to create an iso image (plextor have their own version of iso called .pxi file) of my xp cd, as a backup, to protect against cd damage. In fact I created 2 pxi images of the cd, binary compared them and they were identical. Call these 1.pxi and 2.pxi say. Yesterday, one year later, I did the same process. Same cd, same drive, same pxi creation tool. I created 3.pxi and 4.pxi and again they were binary identical. However if I binary compare 1.pxi and 3.pxi there are differences. My conclusions: 1) 1.pxi = 2.pxi and 3.pxi = 4.pxi implies drive is ok 2) 1.pxi not equal to 3.pxi implies cd is not ok. And indeed, there are some light marks on the cd which were not there when it was new. Duh! The creation dates differ. However I used this cd to install xp successfully, also yesterday. So my dilemma is: I know (almost 100%) that the cd has changed over time due to some very light marking, and yet I get no complaint from the xp installer if I use this cd to install xp. That's my real question ! Sort of related: The process used to create CDs on your home computer varies drastically from the method used to create CDs commercially. When Microsoft finishes development of a software package, including XP, they RTM. That's Release to MANUFACTURING, not "duplication." Commercial CD making involves "pressing" an image on an injection molding device, like chiseling a name on a granite tombstone. A CD-R uses a dye that simply changes color when subjected to a particular frequency of light, like printing the Sunday comics. The durability of a "pressed" CD is virtually infinite in that it is a physical construct. A CD-R, not nearly as long (about five years). CD-Rs degrade over time and use, eventually becoming unreadable. |
#6
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How to know if a clean XP install is good?
HeyBub,
I didn't know that creation dates are stored inside pxi files. Are you sure of this? I'm aware on the different processes btwn pressed cds and cdrs. My question really boils down to: if an xp install cd has a *known* error on it (even just 1 bit), and your cd drive doesn't flag it, will the installation process inform you of this error bit, or not. I suspect not. I can't see how every bit of the install is verified after installation. But I look forward to the counter argument. Thanks. |
#7
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How to know if a clean XP install is good?
Hi all,
We all know that CD/DVD drives, depending on their quality, can often mis-read occasionally, especially if the cd in question had surface marks say. So if I install XP from a cd which is not in 100% perfect condition, and the install completes without issue, can I really be sure that all is well? If my drive mis-read a few bits during the installation, how would I know? Would the XP installer be guaranteed to detect and flag such a fault? Or would it just proceed, allowing incorrect data into the install? Is there a way, post install, to determine the "goodness" of the installation? Many thanks for any thoughts! You could run sfc right after the install completes. That checks all the programs are there and working if you're in doubt. A clean install without errors though is higly likely to be OK; it has a lot of error checking built right into it. -- Regards, Twayne OO0 is a GREAT MS Office replacement www.openoffice.org Please respond to the newsgroup, not to my e-mail, so that all may benefit. I do not always respond to newsgroup e-mails. |
#8
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How to know if a clean XP install is good?
"shanex" wrote in message ... HeyBub, I didn't know that creation dates are stored inside pxi files. Are you sure of this? I'm aware on the different processes btwn pressed cds and cdrs. My question really boils down to: if an xp install cd has a *known* error on it (even just 1 bit), and your cd drive doesn't flag it, will the installation process inform you of this error bit, or not. I suspect not. I can't see how every bit of the install is verified after installation. But I look forward to the counter argument. Thanks. The installer checks for any errors (CRC or cyclic redundancy check) which will ensure that all the correct data has been sent to the computer. If there is any type of read error or the count in the CRC is incorrect the installation will fail..; |
#9
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How to know if a clean XP install is good?
shanex wrote:
Thanks for that. But how does this work? You asked how you would know if it worked. He answered your question. |
#10
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How to know if a clean XP install is good?
My conclusions:
1) 1.pxi = 2.pxi and 3.pxi = 4.pxi implies drive is ok 2) 1.pxi not equal to 3.pxi implies cd is not ok. And indeed, there are some light marks on the cd which were not there when it was new. Here's my shot in the dark. What other info is in the .pxi files, besides the .iso data read from the CD? If were to contain sommething like say the date of creation, then 1.pxi, and 2.pxi created the same day would indeed be binary equal, and 3.pxi and 4.pxi created the same day again, binary equal, but different from 1 or 2.pxi Maybe you need to make a "real" iso image of your disk. http://isorecorder.alexfeinman.com/isorecorder.htm However I used this cd to install xp successfully, also yesterday. So my dilemma is: I know (almost 100%) that the cd has changed over time due to some very light marking, and yet I get no complaint from the xp installer if I use this cd to install xp. That's my real question ! As the data is being read from the cd it is checked with a CRC (Cyclic Redundancy Check) code. It's like knowing how many 1's and 0's there should be. If the count's wrong, then depending on how many errors there are, they can be fixed as they are read. If there's too many to fix, then the faulty block is read again. It's VERY clever how it works. Good luck. |
#11
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How to know if a clean XP install is good?
shanex wrote:
HeyBub, I didn't know that creation dates are stored inside pxi files. Are you sure of this? Yes. |
#12
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How to know if a clean XP install is good?
Hmmm, I'm not convinced. I just ran the same pxi extraction now as I did
yesterday. Binary identical. So unless it only stores the month and year ...! |
#13
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How to know if a clean XP install is good?
"shanex" wrote in message ... Hi all, We all know that CD/DVD drives, depending on their quality, can often mis-read occasionally, especially if the cd in question had surface marks say. So if I install XP from a cd which is not in 100% perfect condition, and the install completes without issue, can I really be sure that all is well? If my drive mis-read a few bits during the installation, how would I know? Would the XP installer be guaranteed to detect and flag such a fault? Or would it just proceed, allowing incorrect data into the install? Is there a way, post install, to determine the "goodness" of the installation? The data structure on a CD or DVD has inbuilt error detection and correction. Most people are singularly unaware of how many read errors actually occur when reading CDs or DVDs because this all happens transparently. The error detection is able to detect the error and (if it is not too serious) correct it. If it can't be corrected, an error message will tell you. If your XP installation has proceeded to its conclusion, then no unrecoverable errors have occured. |
#14
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How to know if a clean XP install is good?
"M.I.5¾" wrote in message ... "shanex" wrote in message ... Hi all, We all know that CD/DVD drives, depending on their quality, can often mis-read occasionally, especially if the cd in question had surface marks say. So if I install XP from a cd which is not in 100% perfect condition, and the install completes without issue, can I really be sure that all is well? If my drive mis-read a few bits during the installation, how would I know? Would the XP installer be guaranteed to detect and flag such a fault? Or would it just proceed, allowing incorrect data into the install? Is there a way, post install, to determine the "goodness" of the installation? The data structure on a CD or DVD has inbuilt error detection and correction. Most people are singularly unaware of how many read errors actually occur when reading CDs or DVDs because this all happens transparently. The error detection is able to detect the error and (if it is not too serious) correct it. If it can't be corrected, an error message will tell you. If your XP installation has proceeded to its conclusion, then no unrecoverable errors have occured. Yes. If setup can't read a file from the disk during install you will get an error message to that effect - (not that that means the disk is FUBAR). I doubt any OS install would let you continue without a critical component. |
#15
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How to know if a clean XP install is good?
Hi,
Copy your #1 and also your #3 to your hard drive. Open them both in seperate file explorers and see where they differ, folder by folder. ---==X={}=X==--- Jim Self AVIATION ANIMATION, the internet's largest depository. http://avanimation.avsupport.com Your only internet source for spiral staircase plans. http://jself.com/stair/Stair.htm Experimental Aircraft Association #140897 EAA Technical Counselor #4562 |
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