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Whats going on with Windows partitioning?


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28 replies to this topic

#1 NickAu

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Posted 13 September 2015 - 10:40 PM

As most of you know I got a HP laptop a few weeks ago and it had Windows 8.1 on it, as it was 8.1 and the new 10 being all the rage I decided to upgrade 8.1 to 10. Everything went fine, I did all the updates installed ESET Endpoint Security then took out the HDD and put it in a safe place. I figure it cant hurt to have a activated Windows as a backup. Then I put a new HDD in the laptop and put Ubuntu on it.

 

Anyway.

 

Something was bugging me last night about all this 4 primary partitions with Windows 7 and 8, so this morning I put the HDD with Windows 10 on it back into the laptop then booted it using Live Linux, and ran Gparted.

 

 

This is what I found. Remember Windows 8.1 was pre-installed and all I did was upgrade it to Windows 10 via Windows Update,

I wonder whats on sda3

jj.png


Edited by NickAu, 13 September 2015 - 10:44 PM.


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#2 Guest_hollowface_*

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Posted 13 September 2015 - 11:28 PM

Based on the size, position, and flag I believe it's an M.S.R. (Microsoft Reserved Partition). You drive appears to be setup as described in the "Partition Configurations" section of https://technet.microsoft.com/en-us/library/hh824839.aspx

I have not attempted the Windows 10 upgrade yet. My experience with previous editions of Windows was that if there was any free space on the drive during an install it would automatically create an M.S.R., I guess the Windows 10 upgrade does the same thing?

 

EDIT: My theory is moot, according to https://msdn.microsoft.com/en-us/library/windows/hardware/dn898510%28v=vs.85%29.aspx on Windows 10 the MSR should be 16MB not 128MB. Are you sure Windows 8.1 didn't already have that partition?


Edited by hollowface, 13 September 2015 - 11:33 PM.


#3 yu gnomi

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Posted 13 September 2015 - 11:51 PM

Assuming your drive is GPT - the 300 MB partition is RE tools, the 100 MB partition is EFI boot, the 128 MB partition is (I think) your protective MBR - so if some program needs to see an MBR on your drive to recognize it, it will see one.

 

I am running Win 8.1, my system drive has those plus a 9GB partition which I think is for the 'System Refresh' feature- to contain a system image.



#4 NickAu

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Posted 13 September 2015 - 11:55 PM

 

Are you sure Windows 8.1 didn't already have that partition?

No idea.



#5 Guest_hollowface_*

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Posted 14 September 2015 - 01:07 AM

 

 

Are you sure Windows 8.1 didn't already have that partition?

No idea.

 

Then I suspect it did. Both of my computers came with an MSR, as that's the default when Windows installs on a blank drive.

 

The protective MBR is a block in the table itself that comes before the GPT header. For those interested, the layout of a GPT disk is discussed in the notes section of SHA-512: 6d8f6926eb98dbd0ffb5c1b4a37bb76cc7d5908d92a58f7944e51be9db6ecaf99df4965608c0948df2e011c7ce4aac9cc98bed7ed550816ef6b254e501388e80  (If link is dead, there is an index of checksums at (http://f286bc32.permalink.per.red), alternatively try googling.)



#6 yu gnomi

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Posted 14 September 2015 - 02:15 PM

MSR is specified as being 128 MB in size for drives over a certain size, so I am pretty sure Hollowface is right about that being sda3. Honestly don't know what, if anything, the MSR gets used for.

 

I know one of the regular posters at 8forums deleted all the extra partitions on his system drive and was running Windows 8.1 that way with no issues, but he probably had a MBR partition system drive.



#7 Guest_hollowface_*

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Posted 14 September 2015 - 02:59 PM

The MSR is used on UEFI/GPT systems, to support software components that formerly used hidden sectors.
- REF: https://technet.microsoft.com/en-us/library/dd799232%28v=ws.10%29.aspx

 

The MSR is not a requirement to run Windows 8 and earlier (not sure about Windows 10). For example if you install WIndows on a drive that has no unformatted space, Windows won't create an MSR. I think Bitlocker encryption requires an MSR, but don't quote me on that, as I don't use Bitlocker. My main computer came with an MSR, but I got rid of it when I re-deployed Windows. I'm not sure if it's safe to flat-out delete an MSR; I've never attempted it, but I'd love to know.



#8 yu gnomi

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Posted 14 September 2015 - 03:07 PM

If/when I decide to do a clean install of 8.1 or 10 (when I upgrade), I will first try blowing up my MSR partition to see what happens.



#9 wizardfromoz

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Posted 14 September 2015 - 03:45 PM

If it's of any assistance as a comparison, below is from Elaine's new laptop. Shipped with Win 8.1, 1TB HDD. I was able to resize the drive by half and installed Linux Mint 17.2 Cinnamon 64-bit.

 

4m2cTZ3.png

 

You can see the similarities and differences, especially with sda3.

 

:wizardball: Wizard

BTW - unit is a Toshiba Satellite

Edit - added BTW


Edited by wizardfromoz, 14 September 2015 - 03:46 PM.


#10 JohnC_21

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Posted 14 September 2015 - 04:46 PM

On a UEFI/GPT disk computer Microsoft requires a EFI system partition formatted FAT32 and a Microsoft System Reserved Partition that is 128MB on any disk larger than 16GB. See What is the MSR here. Edit: As hollowface posted MSR is 16MB in Windows 10.

 

What disks require an MSR?

Every GPT disk must contain an MSR. The order of partitions on the disk should be ESP (if any), OEM (if any) and MSR followed by primary data partition(s). It is particularly important that the MSR be created before other primary data partitions.

Who creates the MSR?

The MSR must be created when disk-partitioning information is first written to the drive. If the manufacturer partitions the disk, the manufacturer must create the MSR at the same time. If Windows partitions the disk during setup, Windows creates the MSR.

Why must the MSR be created when the disk is first partitioned?

After the disk is partitioned, there will be no free space left to create an MSR.

How big is the MSR?

When initially created, the size of the MSR depends on the size of the disk drive:

  • On drives less than 16GB in size, the MSR is 32MB.
  • On drives greater than or equal two 16GB, the MSR is 128 MB.  

As the MSR is divided into other partitions, it becomes smaller.

What partitions are required by Windows?

For UEFI systems, the boot drive must contain an ESP, an MSR, and at least one basic data partition that contains the operating system. Only one ESP should exist on a system even if multiple operating systems are installed on that system. In a mirrored boot configuration there may actually be two drives with an ESP but they are considered to be a redundant copy of the same ESP. Each data drive must contain at least an MSR and one basic data partition.

 

 

Hard to believe but I have seen up to 7 partitions on an upgraded Windows 8 to 8.1 or 10 computer, a total freaking mess.

 

http://www.bleepingcomputer.com/forums/t/584864/what-are-all-these-partitions/


Edited by JohnC_21, 14 September 2015 - 04:59 PM.


#11 NickAu

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Posted 14 September 2015 - 05:00 PM

 

If/when I decide to do a clean install of 8.1 or 10 (when I upgrade), I will first try blowing up my MSR partition to see what happens.

I will be doing a clean install of Windows 10 to SSD tomorrow or the day after ( Got it on Ebay new ). See what happens.



#12 yu gnomi

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Posted 14 September 2015 - 11:16 PM

interested to find out- please report results.



#13 NickAu

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Posted 21 September 2015 - 02:48 AM

My new Sandisk  SSDplus 120 GiB arrived today, I now own 4 Sandisk SSD's and am happy with them.

 

I installed the SSD to my laptop, And booted a Windows 10 ISO, ( I downloaded the ISO, not the media creation tool, and burned it in Linux with Brasero )

 

I did the default install thing when it came to partitioning, I just hit next, I did NOT manually create any partitions, Windows 10 did it all.

 

And here is the result. This is going to cause issues for novices when trying to dual boot Linux, Mark my words.

 

partition.png


Edited by NickAu, 21 September 2015 - 02:52 AM.


#14 wizardfromoz

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Posted 21 September 2015 - 03:32 AM

It's GPT though, no 4 (or 3+) partition limit.

 

:wizardball:



#15 NickAu

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Posted 21 September 2015 - 04:44 AM

And that's the end of that exercise, I just nuked Windows and installed Ubuntu 15.

 

I’m sorry Microsoft I tried I truly did, For about a month, I have nothing good to say about it, I can do it faster,easier, more secure in Linux, and the best thing You Microsoft have no idea what I am doing on my PC, See that bit My PC. When you give me a PC free then you can spy on me.


Edited by NickAu, 21 September 2015 - 04:47 AM.





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