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Windows 7: Benefits of GPT vs MBR Primary and MBR Logical Partitions ?

10 Feb 2014   #11
mjf

Windows 7x64 Home Premium SP1
 
 

@Alan10
I think your original question is a good one that I raised in the VIP area. I didn't get any feedback but I personally tend to agree with the views of TVeblen. I run a UEFI BIOS and recognize its significant benefits over the older BIOS. However, I choose to retain an MBR boot drive at the moment. Why - I boot to an SSD 128GB (well under 2.2TB!). My internal data HDDs are 1TB and I only require 2-3 partitions. I am uncertain about the compatibility of some of my software with GPT formatted drives.


My System SpecsSystem Spec
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11 Feb 2014   #12
milindsmart

Windows 7 Home Premium x64
 
 

What kind of software is this that worries about your partition type? Partitioning software? If you aren't using paid software then refresh your software collection.

Also, "UEFI BIOS" is better expressed as "UEFI firmware".
My System SpecsSystem Spec
11 Feb 2014   #13
mjf

Windows 7x64 Home Premium SP1
 
 

Quote   Quote: Originally Posted by milindsmart View Post
What kind of software is this that worries about your partition type? Partitioning software? If you aren't using paid software then refresh your software collection.

Also, "UEFI BIOS" is better expressed as "UEFI firmware".
Not so long ago free Macrium Reflect would not work on a GPT partitioned drive - that's one example.
MS state:
" Legacy software that does not know about GPT interprets only the Protected MBR when it accesses a GPT disk. These tools will view a GPT disk as having a single encompassing (possibly unrecognized) partition by interpreting the Protected MBR, rather than mistaking the disk for one that is unpartitioned." Source.
I guess this is not much of an issue for many people and you could argue stop using legacy software that wants to access an MBR partition table.
The reference describes the benefits of GPT but they don't have an impact on me at the moment so I decided to stay with MBR for the time being. If I wanted a > 2.2TB internal data drive then it would be GPT but I can never see myself wanting to boot to one.

On my ASUS Motherboard box it has blazon in bold UEFI BIOS as opposed to Legacy BIOS. Of course the BIOS is firmware so by all means refer to it as UEFI firmware if you like
My System SpecsSystem Spec
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13 Feb 2014   #14
milindsmart

Windows 7 Home Premium x64
 
 

It's not an economically justifiable shift, from MBR to GPT, right now, but you'll want to consider just how many different implementation quirks have been shoved into a "specification" for MBR to work. It's stable and working to the extent it is because of a large number of workarounds implemented in every little low level program that accesses disks. Not robust by design.

Why would you want to use MBR for the sole purpose of using an old tool? What if I told you 1 bit unexpected corruption could potentially cause your entire partition to become useless? Does MBR still seem like a great default system?

It's the equivalent of your surgeon being a decrepit old man/woman with shaking hands and stinking white(?) coat. Sure xe may be more familiar. But do you think xe's reliable? No problems till you need a surgery, but what might happen during one?
My System SpecsSystem Spec
13 Feb 2014   #15
Computer0304

Windows 7 Professional 32-bit/Windows 8 64-bit/Win7 Pro64-bit
 
 

Quote   Quote: Originally Posted by alan10 View Post
Thanks.

My MoBo can only boot MBR but can access both programs and data partitions on my GPT HDD.
My largest existing HDD is 1 GB.
Is it probable that my existing 4 year old MoBo and BIOS would fail to deal with a 3 GB partition or even a 3 GB HDD,
regardless of whether it was MBR or GPT style ?

Supplementary Question on (Extended) Partition Tables :-
Are all such tables read from all HDDs upon start-up and the Partition Letters and MFT/Directory etc. locations copied to RAM,
or does the Operating System trawl through these tables on each HDD each time I try to access an item in partition F:\ ?

Regards
Alan
You meant 1tb right?
My System SpecsSystem Spec
13 Feb 2014   #16
mjf

Windows 7x64 Home Premium SP1
 
 

Quote   Quote: Originally Posted by milindsmart View Post
What if I told you 1 bit unexpected corruption could potentially cause your entire partition to become useless?
You wouldn't be telling me anything I didn't know. It applies to lots of things.
I'm quite familiar with the MBR and the partition table structure. Besides I back up the MBR, mainly because of the partition table, and can restore it whenever I like. I also keep numerous system images.
When you can say a GPT is going to make my system work better then I may bother to convert. This would involve a clean install and I have a lot of paid software that would need reactivating. Reactivating the software may involve headaches.
My System SpecsSystem Spec
17 Feb 2014   #17
milindsmart

Windows 7 Home Premium x64
 
 

Like I said, it's not something you can justify for an audit. It just vastly decreases the probability of ambiguity when modifying partition tables.
My System SpecsSystem Spec
17 Feb 2014   #18
alan10

Windows 7 Ultimate 64 bit SP1 x64
 
 

In my opinion it can be dangerous for a Partition Manager to modify the partitions of the drive that holds the live Windows C:\ partition which it is running under.
Safer to use a Boot CD.

Question :-
Is it safer to use a Boot CD from a third party that has :-
a newly developed (i.e. Beta release) GPT capability on a drive with an allegedly "less ambiguous" Fake MBR plus GPT partitions;
or well established and finely honed capability on a drive with MBR partitions ?

There are tools that can make and restore image backups of "Track Zero",
which I believe holds the MBR and the primary and extended partition tables,
so hopefully it is possible to promptly correct any sort of disaster when altering MBR partitions.

Is it possible to promptly correct any sort of disaster when altering GPT partitions ?

Regards
Alan
My System SpecsSystem Spec
17 Feb 2014   #19
milindsmart

Windows 7 Home Premium x64
 
 

It's not "beta" at all. It's been around for about ten years now and defined before 2000s.

What do you have against the "fake" MBR? It's a partition covering the entire interior of the disk, and ANY TOOL that does not understand GPT will refuse to work with it. 0xEE is unknown for all pure-MBR tools. It's not fake except in a VERY narrow sense.

Besides, I have had serious problems on computers of 2009-10 with MBR partitions with tools like diskpart AND gparted. Five partitions had been created somehow, and I have no idea which other partition got sacrificed. No more "finely-tuned" than GPT tools. Other than that, witness the steady stream of problems people have even today with partitioning : a direct consequence of how badly MBR was designed and how precariously it has been made to work today.

Again, Track 0 DOES NOT hold EBR and logical partition table. They start from the beginning of the Extended Partition and CHAIN each logical partition to the next in LINKED-LIST style. So no, Track 0 backup CANNOT restore any of your logical partitions.

Yes you CAN take Backups of GPT. It's just as simple as that of MBR, take 1st 34 sectors backup. One such backup is stored at the end of the disk, COMPULSORILY. Only thing to be careful about is to not use sector by sector copies of GPT disks, the partition GUIDs must be set to zero.
My System SpecsSystem Spec
17 Feb 2014   #20
alan10

Windows 7 Ultimate 64 bit SP1 x64
 
 

"Beta Release" refers to the first generation/issue/release of a Partition MANAGER.
I was not applying the term "Beta Release" to the definition of GPT Partitions.


I have nothing against the "Fake MBR" other than it is an extra detail to understand.
Please note that I was not being derogatory by calling it a "Fake MBR",
I was just using the term which I once saw in a technical article.


You might have experienced a loss of an MBR partition when using Diskpart and Gparted.

I have lost ALL GPT PARTITIONS on a complete W.D.C. drive due to Windows 7 incompatibility with GPT drives connected via SATA.

Microsoft have published a "USER BEWARE AND DEAL WITH IT" type a KB????,
warning that they are NOT going to deal with their own stupid mistakes.
When physical drives are connected via SATA,
Windows Disk Management allocates drive numbers from 0 to (number of physical drives-1)
in "order of enumeration", and NOT in a sensible fixed basis of physical port numbers etc.

The consequence is that my physical drives are numbered after a cold start-up as
W.D.C. GPT HDD = 0
Samsung MBR HDD = 1
OCZ MBR SSD = 2
That numbering is changed by a RESTART when Windows starts up and finds the HDD's are running at speed.

Windows is full of race hazards.
I guess that when I did a cold start-up and BRIEFLY examined a BIOS setting before allowing the boot-up to continue into Windows,
the drives were at partial speed and as a result of some race hazard,
Windows REPLACED the W.D.C. GUID with an exact duplicate of the Samsung 8_Hex_Digit Disk Identity,
and then complained about having two disks with the same Identity,
and then put the Samsung OFFLINE.

The W.D.C. GPT Disk was seen as MBR style with a couple of RAW partitions and everything else was alleged to be "Unalllocated Space".

I was able to put the W.D.C. OFFLINE and then make the Samsung ONLINE and the Samsung has not lost any data.
There seems to be no way that I can replace the incorrect 8_Hex_Digit Disk Identity with an appropriate GUID,
and no partition manager is able to deal with this horrendous situation because Windows insists it is an MBR drive.

Freeware LAZESOFT has rescued all the files that were ever on the W.D.C. when it had been seen as a GPT style.
Unfortunately this also includes files which I had recently deleted but which had NOT been over-written with more recent files.
Lazesoft Recovery Suite Home Free Download

LAZESOFT has also shown there seem to be 3 MByte partitions between the partitions that I knew were on the drive before the catastrophe.
I had assumed that each of these 3 MB partitions held another link in the link-list of GPT partitions.
Whatever they are - they are another mystery.

Summary of my experience :-
MBR partitions all immune to catastrophic disaster,
GPT partitions very susceptible and NOT easily repairable.

My decision :-
Never again have a mixture of GPT and MBR drives connected via SATA.

Regards
Alan
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 Benefits of GPT vs MBR Primary and MBR Logical Partitions ?




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