[Leaplist] Partitioning Gurus?

["pberry2" at cfl.rr.com]

John Simpson wrote:
> On 2007-02-10, at 1004, Chris wrote:
>>
>> I'm probably confused, but i thought that the gods of rotating
>> media had decreed that hard drives could have only four
>> primary partitions - and that only one of those could be
>> an extended partition. Dell seems to have chewed that up.
>>
>> I'd love to hear otherwise?
>
> otherwise.
>
> when IBM designed the partition table format for the first IBM PC 
> BIOS, they made room for four partitions. microsoft later added the 
> idea of an "extended partition", which itself contains a four-entry 
> partition table, as part of MS-DOS version 2.25 (for government users) 
> or version 3 (for the unwashed masses.)
>
> other hardware platforms (mac, sun, alpha, amiga, etc.) have other 
> partition table formats, usually with higher limits on the number of 
> partitions. the mac partition table format, for example, has all kinds 
> of room- i have personally set up mac partition tables with up to 15 
> partitions in them, for example. the linux kernel has always had 
> options to include support for all of these other partition table 
> types, so that if you pulled a disk out of (for example) a sun 
> machine, and plugged it into a PC, linux would be able to decode the 
> partition table and find each filesystem on the disk... and as long as 
> the filesystem was one which linux understood, you could read and 
> possibly write files.
>
> then there's microsoft's "dynamic disk", which is their own 
> proprietary format, usually stored in such a way that any process 
> (including the machine's BIOS) which looks at the "real" partition 
> table (the old MS-DOS format partition table, courtesy of IBM) sees 
> one partition which takes up the entire disk, and a boot loader within 
> that partition which knows how to decode their proprietary partition 
> table (which is also stored inside that partition), find the "C drive" 
> partition, and load the NT kernel from within that partition. think of 
> it as an "extended partition" which doesn't have the same format as a 
> normal "extended partition".
>
> and of course there's LVM, which is similar to microsoft's "dynamic 
> disk", but it's a lot more flexible and it's open source. each 
> physical partition becomes part of a "volume group", basically a pool 
> of disk blocks which serve the same basic funcion as a physical disk. 
> each volume group can have up to 255 "logical volumes" in it, where a 
> "logical volume" is roughly the same thing as a partition. the nice 
> thing there is that new LVs (partitions) can be created, resized, 
> and/or destroyed without having to reboot... and if the filesystem 
> contained within an LV is capable of being resized, this can also be 
> done without rebooting (unless the filesystem is your "/", of course.)
>
> so it wasn't the "gods of rotating media", it was IBM... and the 
> four-partition limit only applies to disks which need to be bootable 
> on hardware which runs a BIOS where this is the only partition table 
> format which can be read, or used with operating systems which only 
> understand this partition table format. if you aren't in this 
> situation (i.e. if you're on non-PC hardware, or if you're using linux 
> and you're not talking about the disk that your machine boots from) 
> then you can use any kind of partition table supported by your kernel.
>
> ----------------------------------------------------------------
> | John M. Simpson    ---   KG4ZOW   ---    Programmer At Large |
> | http://www.jms1.net/                         <jms1 at jms1.net> |
> ----------------------------------------------------------------
> | http://video.google.com/videoplay?docid=-4312730277175242198 |
> ----------------------------------------------------------------
>
>
> ------------------------------------------------------------------------
More, as I try to assist poor Microsoft users, in any way, especially to 
convert to Linux, I find troubles on Compaq/HP, (who both now seem to 
have a strange drive partitioning system), and Dell systems "Media 
Direct" 'feature',  with their new, proprietary weirdness, that is their 
implementation of the space permitted by the "Host Protected Area" (HPA) 
concepts.

In the midst of struggling, and have tried out QTparted, Gparted,  Ark 
Linux, PCLinuxOS, and a few other great Distros. 

This instant, am on the Compaq desktop that had the total failure of 
HAL.DLL but, the drive is there, just that the partition table is 
totally screwed, and so, it won't take an install of GNU/Linux, nor,  
even accept any of the partitioning.   


And the fun or the Mac ELI system of the 4 partition limit will not be 
challenged, here, though I would love to.