On Thursday 10 January 2008 09:37:08 pm Robert LeBlanc wrote: > As Michael said, SCSI has supported hot-swap for year, so has fibre > channel. SATA gets sticky because some manufactures use ATA type > commands and controller technologies and some use SCSI. A few years > ago, some SATA drives showed up as /dev/hd* and some showed up as > /dev/sd*. I found this out the hard way when we went to install ESX > Server on a SATA drive and it did not show up as /dev/sd*. ESX > requires SCSI or FC drives (version 2.5). I think for the most part > they show up as SCSI now for both types of implementations.
This really depends the BIOS settings, the kernel, and therefore the distribution. Let me explain. Some older BIOSes allowed for the IDE emulation of SATA. That means the SATA controller and the drives would appear from a system standpoint as IDE drives for compatibility with non-SATA-enabled OS's. In the Linux kernel, SATA was built upon the SCSI framework because of its many similarities. Hence, any SATA drives that used the correct SATA driver (rather than IDE) would show up as /dev/sd*. In the last little while (and I'm too lazy to look it up), the SATA subsystem in the kernel was expanded to deal with PATA (parallel ATA or IDE) as well as SATA, often in the same driver (as is the case with several Intel chipsets). What that translates to is having *all* hard drives and CD drives appear as SCSI devices, even old IDE drives. This is where distributions come in. Distributions have the choice of using the old legacy IDE subsystem (/dev/hd*) or selecting the newer SATA/PATA subsystem (/dev/sd*). Anyway, sorry for the history lesson, but I think sometimes it is good to know what is going on and the context on which it goes on. :-) -- Alberto Treviño [EMAIL PROTECTED] Testing Center Brigham Young University -------------------- BYU Unix Users Group http://uug.byu.edu/ The opinions expressed in this message are the responsibility of their author. They are not endorsed by BYU, the BYU CS Department or BYU-UUG. ___________________________________________________________________ List Info: http://uug.byu.edu/mailman/listinfo/uug-list
