Re: [MLUG] Hard drive question

[McIntosh Jason <EMAIL:PROTECTED>]

Well, "linux" the kernel sees them as two different device types.  Interestingly enough, it also depends on the type of IDE drive, as newer Serial ATA drives use the SCSI subsystem rather than the IDE system.  This is due to SATA drives finally supporting things like Native Tagged Queuing that SCSI systems have supported for a long while.  Also, the communications protocols are moderately different, and include things like hot-swap support.

SCSI devices are usually of the format (for harddrives)

/dev/sdX with partitions of course being /dev/sdX1-7

IDE Drives are

/dev/hdX and partitions of /dev/hdaX1-7

SO, yes, they're very different according to the kernel.  Now, some other notes.  Previous Linux versions used SCSI emulation for some devices (i.e. CD burners) to enable more advanced communications, in order for things like burning support to work.  

SO, from the kernel's perspective, SCSI/IDE devices are very different.  NOW, utilities that work on harddrives, i.e. fdisk, don't see that much difference - they see a disk drive with a certain geometry and number of cylinders, etc.  At least, that's MY understanding.  I know the kernel sees the devices differently.  I'm not as sure about utilities like fdisk.

Jason

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On Jun 2, 2006, at 7:56 AM, Jennifer Dozar wrote:

I am curious, mainly cause i was intrigued by a Linux Admin test I took

for a job last night, and i didn't really know.  One question asked

about transferring data from an IDE drive to a SCSI drive. Can anyone

explain this to me?  I figured Linux just saw it as another hard drive,

not necessarily a "different type" of drive.  So, i'm just wondering if

anyone can help me out with that. I haven't ever come across this, but

doesn't mean i won't someday.  how many computers actually have both

types? don't mostly motherboards and such stick to one type of connect

for drives? 

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Jennifer Dozar

http://seul.org/~jennifer/osschools/

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