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hard drive size differences - same make/model
hard drive size differences - same make/model
- Let's say I buy two drives - same make model, same 'theoretical' size as per specifications of the drives. I format drive 1 with Windows 2003 let's say to create a C drive and get a certain size in properties of the drive. I then format drive 2 with the same Windows installation to create a D drive. Is it possible that the two drives could be slightly different as far as Windows is concerned after the formatting even though they were supposedly the same manufacturer raw size?
As far as the manufacturer raw size goes, regardless if they are exactly the same per manufacturer testing, is it possible that Windows might see two different raw sizes out of the box?
Finally as far as manufacturer raw size, is there a 'fudge' factor - e.g. same make/model drive but one has x bad blocks and the other has y bad blocks out of the box just because of the nature of manufacturing process so that they would report as different sizes with Windows?
답변
I am asking a general theoretical question.
In that case, all 3 of your questions can be answered with yes.
However, if you actually have this situation, post back (and run dispart "list disk" as well as the output of "dmdiag -v")
rgds,
Edwin.- 답변으로 제안됨David Shen - MSFTMSFT, 중재자2009년 11월 20일 금요일 오후 1:56
- 답변으로 표시됨David Shen - MSFTMSFT, 중재자2009년 11월 23일 월요일 오전 6:16
- ok, here is one explanation:
two identical drives, but one has a bad block due to manufacturing error.
the firmware of the drive with the bad block will remap the bad block, so no data can be written.
This would be a situation where the geometry of to identical drives is different as seen from the host, one drive has one block "missing" and will be "smaller"
does that answer your question ?
Also, you can check geometry of a drive using "dmdiag -v", in the output of a disk, it will list the geometry after the partition table, this is where you can compare if you run into this situation.
See example here:
---------- Partition Table Info Disk 2 ---------- 31,073 Cylinders 255 Tracks/Cylinder 63 Sectors/Track 512 Bytes/Sector 12 MediaType 499,187,745 Sectors (total) 255,584,125,440 Bytes (total) 249,593,873 KB 243,744 MB 238.0 GB 0 StartingOffset 255,590,400,000 PartitionLength 0 HiddenSectors 0 PartitionNumber 0 PartitionType 0 BootIndicator 0 RecognizedPartition 0 RewritePartition MBR PartitionStyle 4 PartitionCount 832c6776 Signature Starting Partition Hidden Total Partition Partition Boot Recognized Rewrite Offset (bytes) Length (bytes) Sectors Sectors Number Type (HEX) Indicator Partition Partition 65,536 255,584,059,904 128 499,187,617 0 0x07 1 1 0 0 0 0 0 1 0x00 0 0 0 0 0 0 0 2 0x00 0 0 0 0 0 0 0 3 0x00 0 0 0 255,584,125,440 Bytes (499187745 sectors) Geometric size 255,590,400,000 Bytes (499200000 sectors) True size (measured) 255,590,400,000 Bytes (499200000 sectors) Reported size (Partition0) 0 Bytes ( 0 sectors) missing/wasted- 답변으로 제안됨Edwin vMierloMVP, 중재자2009년 11월 22일 일요일 오후 3:38
- 답변으로 표시됨David Shen - MSFTMSFT, 중재자2009년 11월 23일 월요일 오전 6:16
- Yes, that is also true, but is completely dependend on the make/model.
If those blocks are sufficient to account for all damaged cylinders/tracks/sectors is hard to say without the actual drive to investigate further.
rgds,
Edwin.- 답변으로 표시됨David Shen - MSFTMSFT, 중재자2009년 11월 27일 금요일 오전 2:02
모든 응답
- Hello,
to see the Raw disk without install Windows, you may try use the OS with Windows installation disc to boot into Widnows PE. And then you can run with Diskpart command line to see the different raw size.
diskpart
list disk
A Description of the Diskpart Command-Line Utility
http://support.microsoft.com/kb/300415
Hope it helps.
This posting is provided "AS IS" with no warranties, and confers no rights. - I'm not asking for a specific situation. I am asking a general theoretical question.
- Hi,
Thanks for the reply.
What do you mean of the general theoretial question?
Can you please describe the demand?
Thanks.
This posting is provided "AS IS" with no warranties, and confers no rights. I am asking a general theoretical question.
In that case, all 3 of your questions can be answered with yes.
However, if you actually have this situation, post back (and run dispart "list disk" as well as the output of "dmdiag -v")
rgds,
Edwin.- 답변으로 제안됨David Shen - MSFTMSFT, 중재자2009년 11월 20일 금요일 오후 1:56
- 답변으로 표시됨David Shen - MSFTMSFT, 중재자2009년 11월 23일 월요일 오전 6:16
- I ran into a situation where I had two same make/model drives out of the box and went to software mirror them. The only way it worked was if I reduced the size of the source partition and given that nothing I could do would make the source drive 'bigger' than it came out of the box, my conclusion was that for some reason the 'target' was smaller. As well, I have had similar situations with Ghost - I have two identical drives per specification but when I go to Ghost one is smaller. So it was those types of situations that prompted me to wonder about the structure of hard drives in general and how this could come about 'theoretically' or be told that in theory it was impossible. So far I have asked in all kinds of places and not gotten a good theoretical explanation why these events take place. It has been suggested that drives with the same specs may have, due to the inherent variation in manufacturing processes, different numbers of bad blocks out of the starting gate which would explain why one of my drives would have been smaller than another. However others have countered that each drive comes with blocks to spare for that kind of situation and they would get swapped in so I would never see a difference based on bad blocks. So I still don't know. I was hoping to find somebody who has been involved intensely with hard drives - maybe somebody who creates partitioning/hard drive recovery/formatting software and thus would be able to say with experiential and theoretical authority - 'Yes, what you are saying is possible' or 'No, it's impossible' because ... It seems to me that there is a theoretical answer to this question - perhaps this is not the best place to post it but I have had very good luck here in the past so I thought I would ask. I didn't really think of this site as addressing only 'how do I fix it' problems. I fixed the problem - I'm curious what caused it.
- ok, here is one explanation:
two identical drives, but one has a bad block due to manufacturing error.
the firmware of the drive with the bad block will remap the bad block, so no data can be written.
This would be a situation where the geometry of to identical drives is different as seen from the host, one drive has one block "missing" and will be "smaller"
does that answer your question ?
Also, you can check geometry of a drive using "dmdiag -v", in the output of a disk, it will list the geometry after the partition table, this is where you can compare if you run into this situation.
See example here:
---------- Partition Table Info Disk 2 ---------- 31,073 Cylinders 255 Tracks/Cylinder 63 Sectors/Track 512 Bytes/Sector 12 MediaType 499,187,745 Sectors (total) 255,584,125,440 Bytes (total) 249,593,873 KB 243,744 MB 238.0 GB 0 StartingOffset 255,590,400,000 PartitionLength 0 HiddenSectors 0 PartitionNumber 0 PartitionType 0 BootIndicator 0 RecognizedPartition 0 RewritePartition MBR PartitionStyle 4 PartitionCount 832c6776 Signature Starting Partition Hidden Total Partition Partition Boot Recognized Rewrite Offset (bytes) Length (bytes) Sectors Sectors Number Type (HEX) Indicator Partition Partition 65,536 255,584,059,904 128 499,187,617 0 0x07 1 1 0 0 0 0 0 1 0x00 0 0 0 0 0 0 0 2 0x00 0 0 0 0 0 0 0 3 0x00 0 0 0 255,584,125,440 Bytes (499187745 sectors) Geometric size 255,590,400,000 Bytes (499200000 sectors) True size (measured) 255,590,400,000 Bytes (499200000 sectors) Reported size (Partition0) 0 Bytes ( 0 sectors) missing/wasted- 답변으로 제안됨Edwin vMierloMVP, 중재자2009년 11월 22일 일요일 오후 3:38
- 답변으로 표시됨David Shen - MSFTMSFT, 중재자2009년 11월 23일 월요일 오전 6:16
- Ok, thanks for all the detail -= I will definitely use it the next time I run into a similar situation. I understand about the bad block being marked 'out of bounds'. However, I have also been told that drives come with 'spare' blocks that get swapped in to make up for any' out of the box' bad blocks. Do you know if that's true?
- Yes, that is also true, but is completely dependend on the make/model.
If those blocks are sufficient to account for all damaged cylinders/tracks/sectors is hard to say without the actual drive to investigate further.
rgds,
Edwin.- 답변으로 표시됨David Shen - MSFTMSFT, 중재자2009년 11월 27일 금요일 오전 2:02
