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#1
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GPT partition only?
This is not a big deal but I decided to put a 750 gig drive from a dead
laptop and put it in an external USB enclosure to use as a backup drive. I connected it to my Linux machine and deleted the partitions, then recreated a single primary NTFS partition. I was able to copy date to it and use it with my Linux machine and also my Win7 and Win10 machines. Next I decided to back up a few files from some older Win2k and XP machines...but Windows Explorer did not recognize the drive. Disk management sees it as a GPT partition. From XP or Win2k there was no option to delete the partition so I attached it to my Linux machine and just deleted the drive and did not recreate a partition. Back in the XP or Win2k machine Disk Management still sees it as GPT I'm now puzzled. At any rate, Since I can easily back up those old machine with other drives, I'm going to just leave that one as GPT...but still I'm curious as to what might have happened. |
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#2
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GPT partition only?
philo wrote:
This is not a big deal but I decided to put a 750 gig drive from a dead laptop and put it in an external USB enclosure to use as a backup drive. I connected it to my Linux machine and deleted the partitions, then recreated a single primary NTFS partition. I was able to copy date to it and use it with my Linux machine and also my Win7 and Win10 machines. Next I decided to back up a few files from some older Win2k and XP machines...but Windows Explorer did not recognize the drive. Disk management sees it as a GPT partition. From XP or Win2k there was no option to delete the partition so I attached it to my Linux machine and just deleted the drive and did not recreate a partition. Back in the XP or Win2k machine Disk Management still sees it as GPT I'm now puzzled. At any rate, Since I can easily back up those old machine with other drives, I'm going to just leave that one as GPT...but still I'm curious as to what might have happened. In diskpart, do a Clean All on the selected drive, and it'll stop complaining about everything. Clean All zeros the entire drive, and no 128MB GPT partition tables will be discovered by accident. The "Clean" option just zeros the MBR itself and takes a microsecond. Whereas Clean All will take a couple hours. On your Linux machine, you can try disktype /dev/sda and have it analyze what it sees. Or try gparted and see if it noticed any traces of GPT. I think I've had TestDisk jump to conclusions about what is on a drive too. I don't really know what a good amount of zeroing is for such a drive. Would just zeroing the first 1GB of the drive stop this behavior ? It seems that removing the 0xEE partition from the partition table, is not sufficient to prevent GPT detection by all tools. There is a protective partition entry in the MBR. It's a single entry. The size of the entry spans the entire drive. The partition type is 0xEE. That indicates a GPT table is present. A 128MB GPT table presumably is big enough to define 128 partitions. For some reason, the GPT partition table might still be recognized once that is removed or replaced with real MBR partition info. And what I usually do to stop such behavior, is just Clean All and walk away. If you're in a rush, you can dab at it with dd if=/dev/zero of=/dev/sdX bs=1048576 count=1024 and see if the obnoxious detections stop. Since that also clears the MBR on that drive, no partitions will be defined right after that. And then Disk Management is going to ask you to pick a partition scheme (MBR or GPT). The only reason I'm not recommending the usage of GPT, is because of the state of free tools available to work on hard drives. It's just "cheaper" to leave drives smaller than 2.2TB in MBR partition mode. For example, TestDisk will probably work better, or that free NTFS recovery utility only knows about MBR, and it's probably easier to get a fix for a situation like that later (legacy MBR). Paul |
#3
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GPT partition only?
On 02/05/2018 07:18 PM, Paul wrote:
and have it analyze what it sees. Or try gparted and see if it noticed any traces of GPT. I think I've had TestDisk jump to conclusions about what is on a drive too. I don't really know what a good amount of zeroing is for such a drive. Would just zeroing the first 1GB of the drive stop this behavior ? It seems that removing the 0xEE partition from the partition table, is not sufficient to prevent GPT detection by all tools. There is a protective partition entry in the MBR. It's a single entry. The size of the entry spans the entire drive. The partition type is 0xEE. That indicates a GPT table is present. A 128MB GPT table presumably is big enough to define 128 partitions. For some reason, the GPT partition table might still be recognized once that is removed or replaced with real MBR partition info. And what I usually do to stop such behavior, is just Clean All and walk away. If you're in a rush, you can dab at it with Â*Â* dd if=/dev/zero of=/dev/sdX bs=1048576 count=1024 and see if the obnoxious detections stop. Since that also clears the MBR on that drive, no partitions will be defined right after that. And then Disk Management is going to ask you to pick a partition scheme (MBR or GPT). The only reason I'm not recommending the usage of GPT, is because of the state of free tools available to work on hard drives. It's just "cheaper" to leave drives smaller than 2.2TB in MBR partition mode. For example, TestDisk will probably work better, or that free NTFS recovery utility only knows about MBR, and it's probably easier to get a fix for a situation like that later (legacy MBR). Â*Â* Paul Thank you very much Paul. Since I'm now copying data to the drive I guess I will just leave it but now I will know the next time anything like this happens. You really know your stuff! |
#4
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GPT partition only?
philo wrote:
On 02/05/2018 07:18 PM, Paul wrote: and have it analyze what it sees. Or try gparted and see if it noticed any traces of GPT. I think I've had TestDisk jump to conclusions about what is on a drive too. I don't really know what a good amount of zeroing is for such a drive. Would just zeroing the first 1GB of the drive stop this behavior ? It seems that removing the 0xEE partition from the partition table, is not sufficient to prevent GPT detection by all tools. There is a protective partition entry in the MBR. It's a single entry. The size of the entry spans the entire drive. The partition type is 0xEE. That indicates a GPT table is present. A 128MB GPT table presumably is big enough to define 128 partitions. For some reason, the GPT partition table might still be recognized once that is removed or replaced with real MBR partition info. And what I usually do to stop such behavior, is just Clean All and walk away. If you're in a rush, you can dab at it with dd if=/dev/zero of=/dev/sdX bs=1048576 count=1024 and see if the obnoxious detections stop. Since that also clears the MBR on that drive, no partitions will be defined right after that. And then Disk Management is going to ask you to pick a partition scheme (MBR or GPT). The only reason I'm not recommending the usage of GPT, is because of the state of free tools available to work on hard drives. It's just "cheaper" to leave drives smaller than 2.2TB in MBR partition mode. For example, TestDisk will probably work better, or that free NTFS recovery utility only knows about MBR, and it's probably easier to get a fix for a situation like that later (legacy MBR). Paul Thank you very much Paul. Since I'm now copying data to the drive I guess I will just leave it but now I will know the next time anything like this happens. You really know your stuff! In this case, all I'm doing is relaying the weirdness I've seen. For whatever reason, just zeroing the MBR isn't enough for GPT drives, when it really should be. It suggests the MBR is protective and not descriptive (it's there to make legacy OSes go away, not to actual dictate what kind of partitioning scheme it is). It suggests an OS may be looking for the partition table GPT uses in any case. That's the only explanation that fits the symptoms. ******* One other tidbit for your trivial collection - *don't* make NTFS partitions in Windows 10 at the current time. Use your Windows 7 OS to make an NTFS partition. Since 16299, I've noticed that $MFTMIRR is not being made properly by Windows 10. This is not an MBR versus GPT issue, and it could happen any time you make a fresh NTFS partition under Windows 10. The problem can be fixed by TestDisk. It has an MFTMIRR repair facility. Windows doesn't seem to care, and CHKDSK won't fix it. If you don't fix it, the partition won't mount in Linux. That's how I detected there was a problem, and TestDisk verified it. Paul Paul |
#5
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GPT partition only?
On 02/05/2018 09:06 PM, Paul wrote:
philo wrote: On 02/05/2018 07:18 PM, Paul wrote: and have it analyze what it sees. Or try gparted and see if it noticed any traces of GPT. I think I've had TestDisk jump to conclusions about what is on a drive too. I don't really know what a good amount of zeroing is for such a drive. Would just zeroing the first 1GB of the drive stop this behavior ? It seems that removing the 0xEE partition from the partition table, is not sufficient to prevent GPT detection by all tools. There is a protective partition entry in the MBR. It's a single entry. The size of the entry spans the entire drive. The partition type is 0xEE. That indicates a GPT table is present. A 128MB GPT table presumably is big enough to define 128 partitions. For some reason, the GPT partition table might still be recognized once that is removed or replaced with real MBR partition info. And what I usually do to stop such behavior, is just Clean All and walk away. If you're in a rush, you can dab at it with Â*Â*Â* dd if=/dev/zero of=/dev/sdX bs=1048576 count=1024 and see if the obnoxious detections stop. Since that also clears the MBR on that drive, no partitions will be defined right after that. And then Disk Management is going to ask you to pick a partition scheme (MBR or GPT). The only reason I'm not recommending the usage of GPT, is because of the state of free tools available to work on hard drives. It's just "cheaper" to leave drives smaller than 2.2TB in MBR partition mode. For example, TestDisk will probably work better, or that free NTFS recovery utility only knows about MBR, and it's probably easier to get a fix for a situation like that later (legacy MBR). Â*Â*Â* Paul Thank you very much Paul. Since I'm now copying data to the drive I guess I will just leave it but now I will know the next time anything like this happens. You really know your stuff! In this case, all I'm doing is relaying the weirdness I've seen. For whatever reason, just zeroing the MBR isn't enough for GPT drives, when it really should be. It suggests the MBR is protective and not descriptive (it's there to make legacy OSes go away, not to actual dictate what kind of partitioning scheme it is). It suggests an OS may be looking for the partition table GPT uses in any case. That's the only explanation that fits the symptoms. ******* One other tidbit for your trivial collection - *don't* make NTFS partitions in Windows 10 at the current time. Use your Windows 7 OS to make an NTFS partition. Since 16299, I've noticed that $MFTMIRR is not being made properly by Windows 10. This is not an MBR versus GPT issue, and it could happen any time you make a fresh NTFS partition under Windows 10. The problem can be fixed by TestDisk. It has an MFTMIRR repair facility. Windows doesn't seem to care, and CHKDSK won't fix it. If you don't fix it, the partition won't mount in Linux. That's how I detected there was a problem, and TestDisk verified it. Â*Â* Paul Â*Â* Paul As it turned out, the data copy was going abnormally slow ...so I ran the WD diagnostic and got: Data Address Mark (DAM) Error. There may be media errors present on this drive. Test was early aborted due to too many errors So the drive is junk. But just the same thank you for the valuable info |
#6
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GPT partition only?
philo wrote:
This is not a big deal but I decided to put a 750 gig drive from a dead laptop and put it in an external USB enclosure to use as a backup drive. I connected it to my Linux machine and deleted the partitions, then recreated a single primary NTFS partition. I was able to copy date to it and use it with my Linux machine and also my Win7 and Win10 machines. Next I decided to back up a few files from some older Win2k and XP machines...but Windows Explorer did not recognize the drive. Disk management sees it as a GPT partition. GPT is not a type of partition, it's a type of partition table, which describes the partitions on the disk. So it sounds like you have a GPT partition table, that points to a single NTFS partition. Is it possible that when you worked the disk over with Linux you wiped out and recreated the partition table in the GPT format? It's certainly possible that an older OS - like Win2K or XP - wouldn't know how to read a GPT table. From XP or Win2k there was no option to delete the partition If it can't read the table, it can't even tell that there is a partition, much less give you an option to delete it. so I attached it to my Linux machine and just deleted the drive and did not recreate a partition. Deleted the drive? I assume you mean you deleted the partition. Back in the XP or Win2k machine Disk Management still sees it as GPT Of course, because you didn't delete the partition table, just the partition. -- Tim Slattery tim at risingdove dot com |
#7
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GPT partition only?
On 02/06/2018 09:52 AM, Tim Slattery wrote:
philo wrote: This is not a big deal but I decided to put a 750 gig drive from a dead laptop and put it in an external USB enclosure to use as a backup drive. I connected it to my Linux machine and deleted the partitions, then recreated a single primary NTFS partition. I was able to copy date to it and use it with my Linux machine and also my Win7 and Win10 machines. Next I decided to back up a few files from some older Win2k and XP machines...but Windows Explorer did not recognize the drive. Disk management sees it as a GPT partition. GPT is not a type of partition, it's a type of partition table, which describes the partitions on the disk. So it sounds like you have a GPT partition table, that points to a single NTFS partition. Is it possible that when you worked the disk over with Linux you wiped out and recreated the partition table in the GPT format? It's certainly possible that an older OS - like Win2K or XP - wouldn't know how to read a GPT table. From XP or Win2k there was no option to delete the partition If it can't read the table, it can't even tell that there is a partition, much less give you an option to delete it. so I attached it to my Linux machine and just deleted the drive and did not recreate a partition. Deleted the drive? I assume you mean you deleted the partition. Back in the XP or Win2k machine Disk Management still sees it as GPT Of course, because you didn't delete the partition table, just the partition. Thanks for the info... I am pretty sure my problem was due to the drive itself being defective. |
#8
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GPT partition only? Follow up
On 02/06/2018 08:43 AM, philo wrote:
snip (legacy MBR). Â*Â*Â* Paul Thank you very much Paul. Since I'm now copying data to the drive I guess I will just leave it but now I will know the next time anything like this happens. You really know your stuff! In this case, all I'm doing is relaying the weirdness I've seen. For whatever reason, just zeroing the MBR isn't enough for GPT drives, when it really should be. It suggests the MBR is protective and not descriptive (it's there to make legacy OSes go away, not to actual dictate what kind of partitioning scheme it is). It suggests an OS may be looking for the partition table GPT uses in any case. That's the only explanation that fits the symptoms. ******* One other tidbit for your trivial collection - *don't* make NTFS partitions in Windows 10 at the current time. Use your Windows 7 OS to make an NTFS partition. Since 16299, I've noticed that $MFTMIRR is not being made properly by Windows 10. This is not an MBR versus GPT issue, and it could happen any time you make a fresh NTFS partition under Windows 10. The problem can be fixed by TestDisk. It has an MFTMIRR repair facility. Windows doesn't seem to care, and CHKDSK won't fix it. If you don't fix it, the partition won't mount in Linux. That's how I detected there was a problem, and TestDisk verified it. Â*Â*Â* Paul Â*Â*Â* Paul As it turned out, the data copy was going abnormally slow ...so I ran the WD diagnostic and got: Data Address Mark (DAM) Error. There may be media errors present on this drive. Test was early aborted due to too many errors So the drive is junk. But just the same thank you for the valuable info Because I have no other major projects going , I decided to try a newer WD utility and it disagreed with the results of the other one. It has a "fast" zero wipe utility where it simply zeros out the beginning and end of the drive...so I tried that and put it back in an XP machine and now Disk Management sees it as blank. I am now giving it a long format and when done will see how it performs. |
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