Original sentence: For small form-factor devices (such as external  disks), a PC-hosted USB or FireWire link supplies sufficient power to operate the device.Maximum cable length of  (USB and FireWire allow longer distances.Owners of desktop computers that lack a built-in eSATA interface can upgrade them with the installation of an eSATA host bus adapter (HBA), while notebooks can be upgraded with Cardbus or ExpressCard versions of an eSATA HBA.With passive adapters the maximum cable length is reduced to  due to the absence of compliant eSATA signal-levels
Edited sentence: For small form-factor devices (such as external 2.5 inch disks), a PC-hosted USB or FireWire link supplies sufficient power to operate the device.Maximum cable length of 6 ft (USB and FireWire allow longer distances.Owners of desktop computers that lack a built-in eSATA interface can upgrade them with the installation of an eSATA host bus adapter (HBA) on a PCI card, while laptops can be upgraded with Cardbus or ExpressCard versions of an eSATA HBA.Some manufacturers make PCI and PCI Express cards with two internal SATA and two external eSATA ports, when in fact the chip on the card only drives two ports.There are 3 Gbit/sec signals on those connectors, and "stubbing" off the signal lines on the interface can degrade their performance.There would be better performance and less market confusion if the card makers made an exclusively internal or external connector card instead.With passive adapters the maximum cable length is reduced to 3 feet due to the absence of compliant eSATA signal-levels