On Wednesday 15 December 2010 12:41:51 Mark Knecht wrote: > On Wed, Dec 15, 2010 at 12:07 PM, Volker Armin Hemmann > <volkerar...@googlemail.com> wrote: > <SNIP> > > >> The logic and timing of the signals on SATA and eSATA cables is > >> (TTBOMK) intended to be identical. What those signals look like at > >> different places in the cable chain will be different. > >> > >> - Mark > > > > and you have sources to support that claims and did not just make it up. > > Ouch! Man, you like to put people in their place, don't you! :-) > > > How about: > > http://www.serialata.org/technology/why_sata.asp > http://www.serialata.org/technology/esata.asp > > Wikipedia is an interesting place to go for information but the > organization that is responsible for the spec itself is better. > > SATA is currently defined as supporting up to 6Gb/S (now Gen3) while > eSATA supports up to 1.5Gb/S (Gen1) or 3Gb/S (Gen2). Internal cables > have highly limited lengths. External cables can be much longer. (2 > meters) > > TTBOMK no one on this list is using a single drive that would exceed > 1.5Gb/S (roughly 187MB/S) so it's unlikely anyone would see a > difference in speed, but that doesn't mean the specs are the same. > > The 'logic' of what's on the cable during data transferred is > identical. The _rate_ at which it's transferred on eSATA is slower and > the electrical levels are modified to provide more reliability across > longer cables and reflections at cable/connector boundaries. > > I trust that you can read the Serial-ATA org web site yourself to get > properly educated on the matter. > > Cheers, > Mark
and where do you get that internal ports can't do hotplug? >From the site you just linked: Currently, most PC motherboards do not have an e-SATA connector. eSATA is readily enabled, however, through the addition of an eSATA HBA or bracket connector (as shown above) for desktop systems or with a Cardbus or Express Card for notebooks. New motherboards introduced in 2005 will start to incorporate e-SATA connectors directly, making the addition of external storage an easy option. Oh wow, all you have to do is to plug in the cable from the bracket... hmm... A little hint for you: all AHCI sata ports can do hotplugging. Every single one. The sockets are designed to allow hotplugging, so it is down to the controller and driver. And AHCI is completely fine in both regards. Some very early looks-like-ide controller chips could not do hotplugging but coldplugging (you had to tell the driver that you were offline the device), some could not do hotplugging at all - but not because of 'cheapness'. Again, all AHCI chips can do hotplugging. No matter where they are. And about esata: the only difference: cables are a bit fatter, connectors a little bit more robust. That is all. You can turn any ahci-sata port into an esata port without any problems. https://ata.wiki.kernel.org/index.php/SATA_hardware_features https://ata.wiki.kernel.org/index.php/AHCI
