Bdtyktl

I have an HP Proliant N54L system that has an eSata port. I also have a spare USB3.0 3TB spinning disk external harddrive that I want to hook up to my proliant.

Is it possible to connect the drive to the port?

For the down voter .. cables like this exist to provide adaption in the opposite direction I require. Thus it seems technically possible.

Note that I know there are USB ports on the proliant that I can use, but I am running FreeNAS on the system and booting off a USB flash drive connected to an internal port. You can't control the USB boot order on the system and HP prioritized the external USB ports over the internal ones. So if I connect my external drive to a USB port then the damn machine can't re-boot. And under FreeNAS you just can't pull it out and then reconnect it - you have to do a bit of fiddling around. I am trying to avoid doing this.

SATA port and USB port use completely different protocols, and you can't connect one to the other.

However, nearly all USB harddrives are really SATA drives in an enclosure that has an USB-to-SATA bridge. Try to open your USB enclosre, take the harddisk out, get a SATA-to-eSATA adapter if necessary, and connect it to the eSATA port.

Edit Background:

The USB-to-eSATA "cable" contains the same kind of USB-to-SATA bridge as used in USB enclosures for harddisks. This bridge is a small computer on a single chip, with an USB port at one end and a SATA port at the other end, and software that translates from one to the other. The chip is small enough you can hide it in the cable, either in the plug at one end, or in a bulge in the middle.

Yes, in theory it would be possible to use a similar chip that translates in the other direction as well (restricted to USB storage devices), but nobody needs those (just use the driver directly, as I've described), so nobody makes those, so you can't buy them.

In theory you could, you would need a protocol converter cable so that your laptop's eSATA signals could be converted to USB3 and go to the external hard disk enclosure, where they would be converted back to SATA to "talk" to the disk.

Performance-wise, let's say it's not optimal.

There is also another problem: while USB3 provides a power supply, eSATA (natively) does not. So you would need an external power source, you couldn't just plug the cable and connect it to the enclosure.

The bundle you need to purchase, then, will of necessity be more expensive and less performant than an external eSATA enclosure; most of which enclosures additionally already have dual input (USB3 and eSATA), which makes the "cable" solution less flexible, too.

In other words, economically it would make little sense to build such a powered cable, because it would have next to no market; only people with a USB3 device they can't replace and can't open.

If you found such a cable, chances are that it was designed to work only with a very specific laptop.

I'm trying to think of an honest technical reason why it couldn't be done and I'm drawing a blank except that USB is a much more feature filled protocol than SATA, what with it being used from everything from mice to printer to hard disks.

Consider the cable you linked, it would have the following:

USB host (computer) => USB client (HDD profile) => SATA Host => SATA Disk

What you want is

eSATA host (computer) => SATA client => USB Host => USB Disk

The USB host side would potentially need a larger amount of logic than the SATA host side. De-packetizing USB and repackaging it as SATA would require a large amount of work, especially at USB3 speeds. The converse (first adaptor) will have been done in every USB based hard drive already, the silicon has already been made a thousand times over.

It is also probably also a lot easier using the computer-host USB, it was always intended to support hard drives and so almost certainly is intended to support disk commands with only minimal repackaging of data.