Hard drive partition strategy

Question

As a new user, I like to feel that I have made good progress since posting my first question a week or so ago, having rebuilt my old computer from scratch (first time effort) and successfully installed Ubuntu. Of course, I now have another question.

My "new" computer (planned to be part of a MythTV system, if anyone knows about that) contains a 250GB SSD, a 3TB HD and a 500GB HD (which was in the original computer running on Windows). I have configured the computer to boot first from the SSD, then the 3TB and finally, the old HD. However, I wanted to "reformat" the 500GB HD to remove Windows, since from now on, the system will be running only on Ubuntu. When I tried to work this out using the Ubuntu settings, I was confronted by a lot of new terminology and concepts, not to mention the fact that even the brand new HDs show nominal volumes much less than their supposed capacity. I gather that this all is to do with partitioning.

I've read several of the past threads about partitioning in Ubuntu on this site, but can't really make sense of the comments, in the context of my own situation. Partitioning in any language is still something I'm rather unclear about.

Is is possible that Elder Geek, or some similar font of knowledge, could direct me to a clear source of information about partitioning, intelligible to a newbie, from which I might be able to learn how to manage my drives appropriately, and remove Windows from the old one? Apart from booting the computer, the ultimate function of these drives will be to store and process television programmes.

Thanks for your patient assistance, Peter

Answer 1

you ask a wide question. Hopefully I understood your point correctly and my few hints are useful.

Maybe first a bit of info about partitioning. Basically you could think of a fresh new disk like a excel table without lines. Basically a blank screen. When you partition a disk you put on the disk a structure. The analogy in Excel would be the grid lines that make an empty table. Obviously, there are many variable like how wide and high the cells are, how many cells in a row etc. A disk would be like an excel file. The term 'partitioning' means to put a structure in. Unfortunately there is another meaning of the term 'partition', a noun. In the excel analogy that is a sheet. You divide up the whole excel file into individual sheets. Each sheet is a partition. What the Excel analogy does not have is a kind of Table of Contents. That in fact are several tables. Each disk has a table that lists all partitions (i.e. sheets) on the disk. Then each partition also has a kind of table to tell it where which file can be found. The matter gets complicated, because disks have been growing larger so much, that the first way of partitioning disks used numbers that were not large enough to be able to cover todays large drives, e.g. your 3TB drive. The borderline was 2GB maximum. So since 2006 there has been a new "partitioning scheme" introduces that is called 'GPT' GUID Partition Table. The concept is pretty simple, its a list with starting and end addresses of each partition. The old concept was the so called "Partition Table" in the "Master Boot record (MBR)", terms you might have come across. Thats basically the same. A table at the very first begin of the disk. The difference to GPT is that it uses smaller numbers and that it only has 4 table lines. That means you only can make 4 partitions. Thats actually not very much and has lead to the invention of an "Extended Partition". They are used until today in all computers that doe not run an "UEFI" BIOS. Its a pretty crude workaround where one of the 4 partitions is not really a partition but just a container for partitions inside. Since a container is not formally a partition, you can not boot from such a partition (at least not from windows). Linux is a lot smarter and has no problems doing that. So partitioning itself is not really very complex. Complex it gets, because the two ways of partitioning are paired with a certain way to boot a computer. That differs very much between the "MBR scheme" and the "GPT scheme". The GPT scheme is used my modern computers with UEFI BIOS. The old bios is a pretty dump piece of code and quite linear. UEFI is more an operating system on its own and can have all sorts of modules. Its not easy to understand what it exactly does and how it works. It get worse, because the UEFI GPT scheme is downward compatible, that means it has a certain mode, so called "legacy mode" that should behave like the MBR scheme.

I am sure I totally lost you by now. Thats a good point to go into Wikipedia and read up about MBR and GPT. Also you should look into BIOS and UEFI. You'll get a good feeling about the complexity there and you will meet many terms from above again. I'd recommend to get through that a bit, because some basic understanding can help you a lot as background knowledge when working with Linux in the long run. The major thing you should remember is that whatever you do, you need to decide between UEFI/GPT and BIOS/MBR/'Uefi Legacy', because you can not mix those groups. That is disk wise. If you have installed on OS, say windows in UEFI mode, installing linux in BIOS/MBR mode is gonna make your disk inconsistent. Its extremly hard to correct that, sometime not possible and you may loose all data. Personally I struggle a lot with UEFI, because it behaves not exactly the same between all boards and is IMHO a lot more difficult to fix. All computers I maintain will use the old scheme. If the boards have UEFI bios I will use the UEFI legacy mode. Exception is only when a system disk is larger than 2GB, because then the old mode can not work any more. I can not see any disadvantage to use the older scheme. On the contrary, if you will meet some trouble, you can be sure there is not problem that someone did not have before your and fixed it with a description in the net. Thats quite different with UEFI. In your case I would install Linux on the SSD because its really large and linux does not require many resources.

I would start the live CD, run gparted, the partition editor, select the ssd and create 2 partitions. 1. a partition with the type "Linux swap" with 4GB (if you have 2 GB main memory) 2. a partition to have linux on it with 60GB, type "ext4" and in the box "mount point" select "/". The "/" just means that the whole Linux installation goes into that partition. When you entered those in gparted you need to check the green check mark button, because it did not yet execute any of the changes you made.

Then I would run Install Linux, and in the selection where you want to install it you can select "other" and actually see the list of partitions you created and double check you are on the right disk. Then you select the linux disk with the "ext4" type and continue the dialog.

A final note to the very confusing way linux names its drives. You will see things like "sda", "sda1", "sdb1", "sdc". Linux has nothing like C: or D:. It takes quite a while to get used to that and its quite hard because you feel totally lost in the beginning. But you need to go through that. After a while you will get used to it because you are continually stumbling across those terms and grasp them. Its not too bad, because the system is very logic and actually predictable. That means you could often tell what the name a certain setup will have. The system is actually extremely helpful because it names disks and partitions even when they are not formatted. In Windows only a formatted disk has a name. Sometimes the C:, D: etc. get lost or mixed and your are in deep trouble. There are numbers but there is not deeper logic.

Right. Thats a long text. I apologies for all the typos. And I am really sorry to say that this is only a fraction of what you need to know about this "partitioning" to really get going. Hopefully it provides a tiny little bit of orientation.

Cheers CatMan