On Tue, Jan 12, 2010 at 5:44 AM, Istvan Gabor
2010. január 12. 0:47 napon "Carlos E. R."
írta: On Monday, 2010-01-11 at 20:38 +0100, Istvan Gabor wrote:
What is the maximum number of partitions that can reside on a hard disk and/or can be handled by openSUSE?
[snip]
In 10.3 you have unlimited (meaning 63) number of partitions (only four primary), if you use the traditional library with IDE disks (PATA), which gives names like hda, hdb, hdc, etc. If you use the new library (sda, sdb, sdc...), which emulates scsi, you have partitions 1..15, that's all. For SATA drives you need the new library, no choice.
This means if I use SATA disk (no matter which driver I select at boot since for SATA the new driver is used),
False (see below)
I will not see more than 15 partitions on the SATA disk.
False, only true if you select libata and you use a 11.1 or older distribution (see below)
On parellel ATA disk I will see all the partitions (up to 63) if I use the old driver.
True as far as it goes (see below)
This applies to SUSE 10.3, 11.0 and 11.1 (kernel version < 2.28). Is this correct?
yes
What is the case with pre 10.3 systems? They use the old driver and see all IDE partitions, but how they handle SATA disks?
With the old ide you had to set the controller to :"legacy mode" even when talking to sata drives. == more detail The old ide driver basically supports everything it ever did. So if it supported your hardware in 10.2 or before, it probably still does. If not, it is a regression and the kernel team will likely work to fix it. ie. The old ide driver is still supported for regressions. The old ide driver supports the "legacy controller interface". The legacy interface can be used by the controller to talk to both IDE and SATA drives, thus the old driver can be used with SATA drives and it always could be. ie. In legacy mode the controller pretends to be a IDE controller, so the old ide driver just worked automatically. Thus if your brand new motherboard with sata only connectors offers a legacy mode in bios _and_ you have it selected, you can likely use the old ide driver even for brand new sata drives. I don't know if add-in controller cards tend to offer a legacy mode or not, but I assume they do. The new libata driver uniquely supports the newer controller interfaces. Specifically AHCI is very common and only the new libata driver supports it. So if you set your controller to AHCI mode you have to use the new libata driver. fyi: I'm pretty sure the AHCI is only used to talk to SATA drives.
From a performance perspective I believe AHCI is better than legacy, but I don't know any details.
Also in the last year or two (or three) the new libata driver has been growing "legacy controller" support. Thus for most legacy controllers you now have the option of using either the old ide or the new libata. (Some macintosh controllers are an exception. Only the old ide currently has support. Work is underway to resolve that.) I don't think libata with legacy controllers performs any better than the old ide driver. So if you only have legacy controllers, or controllers set in bios to act as legacy controllers, then you could flip a coin as to which driver to use. fyi: even now discussions of removing the old ide driver from the vanilla kernel make it sound years away. The issue is embedded computers. The old ide driver uses less resources than libata and embedded computers typically like to have as small a kernel as they can. fyi2: That does not mean the opensuse will continue to compile in the old ide driver for those same years. I know nothing about the plans for that. Greg -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org