GPT disk vs MSDOS disk - HDD/SSD/USB/SD/microSD

[gcmartin]

This thread is to provide members some understanding of the 2 types of disks.

Simple understanding is this:
MSDOS disks

• allows the user to have up to 4 Primary partitions with one of the Primary partitions capable of being an extended partition. An extended partition allow ANY number of additional individual partitions to be defined within the extened partition's area. Use of the extended partition definition extend the drive's use beyond 4 partitions.
  
  Note: An extended partition COULD be the ONLY partition a system's drive. In this case, the user is free to create as many partitions in the extended area as one chooses. Thus one could define many many partitions within this type of Primary Partition (area) without the existence of any other Primary partition.

Fig. 1 - above shows the type of disk in use on this PC

GPT disks

• every partition is a Primary partition with no regard for an extended partition in its concept.
  
  Note: GPTs have been around for awhile and are prevalent in modern PCs and the drives that come with them; no matter the OS that is present on the drive. It is a modern technology approach getting beyond the 4 Primary partition limit while doing away with use of Extended partition definition or need. Thus, the user just defines all of the partitions desired without regard of Primary/Extended.

Additional comments or insights about the technology are invited

[Burn_IT]

Note: An extended partition COULD be the ONLY partition a system's drive

Not true!
A drive can only have one extended partition, but can also have three other primary ones as well.
An Extended partition is just another partition as far as the disk is concerned. The logical drives inside it are the responsibility of the OS to recognise although some boot managers do as well.
I have disks that have four primary partitions, one of which is an extended one.

[gcmartin]

That is a misunderstood interpretation of that statement.

Correct interpretation is that a single drive could (a user choice) have a single "Extended". Within the extended, there can be as many additional partitions as anyone desires. This is true for MSDOS drives only.

Hope this clarifies.

[Burn_IT]

I am not going to argue with you!!

[bark_bark_bark]

That is a misunderstood interpretation of that statement.

Correct interpretation is that a single drive could (a user choice) have a single "Extended". Within the extended, there can be as many additional partitions as anyone desires. This is true for MSDOS drives only.

Hope this clarifies.

Brun_IT got it right.

With MBR drives you can have upto 4 primary partitons, one of those can be an extended partition. Within that extended partition, you can have several logical partitions.

Example you can have a partition table like this:
sda1 - primary partition
sda2 - primary partition
sda3 - primary partition
(N/A?) - extended partition

Within the extended partition you can have have:
-sda5 - logical partition
-sda6 - logical partition
-sda7 - logical partition
....
and so on and so on....

[gcmartin]

The intent of this thread is to present a clear understanding for any user wanting to modify a disk for use on his PC. So let STOP trying to point fingers and try to clarify the idea. This is not a battle of who is right, its about how to create a disk using the ideas presented so that anyone understands disks and structures allowed.

Here in this post, I want to clarify the item that @Burn_IT is addressing.

See if this makes sense to you. Forget any grammar and try again to understand what is offered. Merely that comment he references is about one type of disk option a user can employ. 1 extended area with as many partitions as the user desires within

Picture is worth a thousand words. But, my explanation, whether you agree with its format or not, is accurate. If you have a manner you want to express it to other users so that they understand the option, be my guest (there is no need to accept my way of explaining it).

Picture below: The picture depict what that statement addresses. The picture is accurate and the disk works for any use anyone would have on a Linux system or on a Windows which has ext support. Partitions can be ANY filesystem format users select.

Hope this clarifies.

[bark_bark_bark]

Hope this clarifies.

What you are saying is clear, but not 100% accurate. You forget to make the distinction between primary partitions vs extended partitions vs logical partition. You keep ignoring the fact that extended partitions on MBR disks can co-exist along side 3 other primary partitions. you also forget that the partitions inside the extended partition are logical partitions.

With the MBR partition table below we have:
3 primary partitions
1 extended partition, which contains:
-several logical partitions

EDIT: the original post in thread was changed for improved accuracy.

[gcmartin]

...

[bark_bark_bark]

EDIT: Well, you changed the opening post to make it more accurate.

EDIT2:

You are splitting hairs as its not addressed your way. Try rewording your post to present clarity in your explanation And, please, address it to users who would be viewing this thread for their understanding. OK?

Actually What I said is very clear, and I have a screenshot for those that need it.

[gcmartin]

What??? Where are you coming from on this. You ignore that appeal to address your position of clarity so that users know what steps you want them to know and instead are trying attack which misses the thread's mission.

Again, for clarity on what my discussions try to clarify:
Prior posts I have made are about the single sentence that @Burn_IT is referencing. Those posts intend to provide clarity of that sentence. There is NO attacking in clarifying things.

Hope that single sentence is clear for new user use. The opening post is accurate. And, of course, there are other ways to express anything. The other ways, often more complex, are found all over the internet. If you have a preference, post them here for users to follow as well so that they achieve proper understandings.

[bark_bark_bark]

When I saw your posts initially they weren't clear and accurate, but then you fixed them and I stopped the criticism.

As of this post, the OP you posted is correct and on track; I have no issues at this point with your OP.

[Burn_IT]

And since my original post applies to the now non-existent wording........???

[bark_bark_bark]

And since my original post applies to the now non-existent wording........???

Is that question to me or gcmartin? I was responding to gcmartin and my first post in this thread was me agreeing with you. I'm confused.

[Burn_IT]

It was not a question or anything - just an observation.
I could not remember exactly whether my comment still applies without looking back and I am in the middle of eating.

[gcmartin]

The opening post is not fixed as you claim??? Again what are you referring to. Any changes to a forum post after the original post has a comment is posted. So again, the statements about opening post changes, is not correct. There is NO indication of a correction or edit of the Opening Post. NO CHANGE is noted! That is an inaccurate accusation.

The opening post (which is the original, and the referenced sentence) is an accurate depiction, in words, what the picture, seen and explained here, clarifies regarding that single sentence.

For the final time, this thread is not about whose right or wrong. It should be addressing useful information so that users can navigate properly to setup disks with good understandings.

Hope this helps

[ASD]

Most importantly, does the distinction matter; meaning:

given size compatibility, can all the partitions (with their various formats and contents) be easily cloned from either type of disk to the other type of disk?

Also, since huge numbers of partitions are available on both types of disk, a pros and cons discussion might be more informative.

[gcmartin]

I will offer couple of ideas. In reverse order:

GPT is suppose to do all that MSDOS disk do in providing access to the data in partitions it contains. Further, it is applicable for all newer UEFI systems (tablets/laptops/PC/etc) as well as understandable by the older non-UEFI systems. And, most notably, GPT does away with the concept of Primary and Primary-Extended partitions flattening understanding to just primary partitions (or as I call them on GPT ... just "partitions" since there is only 1 type). This is some of the most obvious things discussed, generally. There are other advantages that exist.

There are several ideas and approaches on converting from one disk type to another. Here is one that is found where a Linux user shows how they was able to successfully convert from MSDOS to GPT with no data loss. (I strongly encourage backup as a precautionary step before any conversion attempt is made, if there is treasured data on the disk)

There is much other information on both items scattered over the Internet.

Hope this is helpful

[ASD]

gcmartin et al,

Thank you, gcmartin, for your research and both references in your last post. However, my unanswered question sought an easy solution to events such as:
(1) Joe has an 8-year-old computer with an MSDOS disk and 12 data partitions. His modern extra-super-duper high tech replacement is expected to be delivered tomorrow and he wants to transfer everything from his old box to his new box.
(2) Jen, his sister, has a modern computer with a GTP disk and 10 partitions, but it’s low spec and Joe has offered to give her his 8-year-old box which is faster, bigger and better than hers. Jen will want to transfer everything to the old box.

[jamesbond]

Thank you, gcmartin, for your research and both references in your last post. However, my unanswered question sought an easy solution to events such as:
(1) Joe has an 8-year-old computer with an MSDOS disk and 12 data partitions. His modern extra-super-duper high tech replacement is expected to be delivered tomorrow and he wants to transfer everything from his old box to his new box.
(2) Jen, his sister, has a modern computer with a GTP disk and 10 partitions, but it’s low spec and Joe has offered to give her his 8-year-old box which is faster, bigger and better than hers. Jen will want to transfer everything to the old box.

If Joe and Jen only run Windows, then they are both screwed. If the computers are laptops, they are doubly screwed.

If they run Linux (any flavours) however, then all they need to do is to get an external enclosure, connect it to their machines through USB, issue dd if=/dev/original-disk of=/dev/usb-disk-enclosure bs=4M, and wait patiently until its done. When done, replace the old disk with the new one. Then boot the new disk, and use gparted to resize the partitions as they wish, to fill the entire disk. While resizing partition, depending on how you do it, expect a few hours too. Oh, and do it sequentially - Joe should run the process until completion first and verify the new enlarged partition works okay, before giving his disk to Jen - so that they always have a backup (the original disk) while the new one is being processed. And make sure you don't swap "if=" and "of=" parameter or you'll end up with empty disks.

This isn't a general answer, it's the easiest one for the particular question that you're asking.

[Burn_IT]

If Joe and Jen only run Windows, then they are both screwed. If the computers are laptops, they are doubly screwed.

Why? to both parts.

Your comment is less than worthless without reasons!