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eSATA Connectors
buffalocheese writes "Since the introduction of the Serial ATA 1.0a specification in 2002, many manufacturers have introduced PCI and CardBus cards with both internal and external SATA connections.
At first these internal and external connectors were completely identical, but later, external connectors started to appear which were still fully compatible with the internal sockets but featured added extra screening for external use.
With the introduction of the SATA II specification in mid 2004 a new external SATA connector was defined. These new external (eSATA) connectors are not compatible with the original internal SATA connection.
Currently there are add-on cards and drive housings available which feature both types of SATA connection for external use. Gradually the older types will disappear and all new SATA cards will feature the eSATA connector for external drive connections."
While I'm not as certain when it comes to graphics cards, PCI-Express is/was sorely needed to replace PCI for general expansion cards. PCI had a limited amount of bandwidth available that was extremely easy to saturate (A single gigabit NIC would hit a bandwidth wall at something like 400mbit). The shared nature of the PCI bus was also an extremely frustrating limitation.
By contrast, PCI-Express 1x slightly increases the bandwidth from roughly 133MB/s to 150MB/s, but more importantly each device gets that, it's not shared anymore. And of course, 2x and higher slots provide more bandwidth.
But when it comes to graphics, AGP 8x was (at the time) providing more than enough bandwidth... as for the demands of modern monsterous graphics cards (such as the 8800 GTX), for all I know they might be able to saturate an AGP 8x bus.
As I understand it anyhow, the more tangible benefits from moving from AGP to PCI-Express were increase bi-directional bandwidth (AGP was great at Host->Card, but sucked at Card->Host), and increased ease with sticking multiple PCI-Express slots on the motherboard, making modern SLI possible.
well....... the SATA cable is kinda of a joke, (really easy to damage or knock loose)..... using a SATA cable for an external drive seems like a bad idea. But then again I'm not sure the eSATA are any more resilient
http://en.wikipedia.org/wiki/Serial_ATA
also it appears you can go to 2 meters in length with eSATA as opposed to maximum 1 meter with regular SATA cables
actually I am happy to see you, however that is in fact a banana in my pocket.
I have an eSATA external drive. My current mobo doesn't have eSATA built in, but I use it via a SATA to eSATA adapter card in my PC.
Well, it's definitely more snug than a regular SATA cable, but it isn't quite as snug as USB. Still, the speed is amazing, and the cables are better IMO. The speed is definitely faster than USB.
Only catch is if I hook up a drive while in Windows with that converter, it'll lockup. Has to be turned on before I boot the computer. This is a limitation of the adapter; from what I've read, you should be able to hot swap with a "real" eSATA port.
The official specs for eSATA essentially say the cable is better suited for external use. Here's what they have to say about it:
The external cable connector is a shielded version of the connector specificed in SATA 1.0a with these basic differences:
The External connector has no "L" shaped key, and the guide features are vertically offset and reduced in size. This prevents the use of unshielded internal cables in external applications.
To prevent ESD damage, the insertion depth is increased from 5mm to 6.6mm and the contacts are mounted further back in both the receptacle and plug.
To provide EMI protection and meet FCC and CE emission requirements, the cable has an extra layer of shielding, and the connectors have metal contact points.
There are springs as retention features built into the connector shield on both the top and bottom surfaces.
The external connector and cable are designed for over five thousand insertions and removals while the internal connector is only specified to withstand fifty.
They make it pretty clear exactly what's different. The biggest difference is the cable is shielded, while internal SATA is not (or less so?). And obviously the connector being rated for a hundred times more insertions is a pretty big difference.
I should note that in recent benchmarks done by MaximumPC, eSATA did not provide substantial performance benefits over Firewire800 drives. eSATA featured a higher burst speed, but more or less equivalent average transfer rates and seek times. Unless there were specific licensing issues with Firewire 800, I would rather have seen it become the preferred drive interface; I'll take a general purpose connector that I can use for other stuff over something as specific as eSATA any day, especially when eSATA provides little benefit.
It's funny about your USB/Ethernet example. A usb device will fit in an ethernet port quite easily. It will even be snug in one direction, although it will wobble the other way. On a lot of our Dells the Ethernet port is directly above a stack of 2-4 USB ports. A few times I've given one of the computers the reach-around and found i've plugged a mouse in the wrong port. Shorting all the pins on an ethernet card can't be a good thing, I think this is a bad design.
Do not meddle in the affairs of sysadmins, for they are subtle, and quick to anger.
Hold on. Many upgrades are not really necessary, but among the ones you missed were:
* PCI-Express: A true PCI successor at last. Back when the 3D accelerators were taking off, the PCI bus turned out to be not efficient enough, but a successor was not in sight. So, AGP was invented, which is essentially a PCI slot with accelerated CPU->GPU transfer (i.e. a hack).
* SATA: Longer, MUCH thinner cables, hotplugging functionality, lower power consumption, Native Command Queuing (the HD can rearrange requests for improved performance).
* Intel socket 775: The first socket where I found the CPU cooler installation to be easy. Previous sockets were a nightmare (478, or AMD's insane 462 socket). Oh, and no more pins means the CPU is no longer in danger of being useless because one pin got broken off.
* General trend towards mainboards with tons of integrated stuff: more space, less worries about compatibility.
* Core 2 duo: Finally the CPU manufacturers discover that wasting bazillions of watts is not a smart thing to do. I am still amazed by this CPU.
So not *all* upgrades are bad.
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It's your cables, and not necessarily because they're cheap. As the IT person for a 100% SATA shop I've had plenty of experience with this. Some SATA cables will fall off, sometimes without any provocation, others won't come off without significant provocation. Some SATA cables even have locking mechanisms to hold them to your drives. Asus for example ships motherboards with one of two different types of SATA cables. In my experience the red ones suck and the gray ones are excellent, but which you get seems to be luck of the draw (like when I order 40 motherboards, I get some with red and some with gray). Areca RAID controllers seem to come with great cables as well, I've got about 20 of them and they all came with the same cables.
Frag 'em all...
AGP was only fast one way pci-e is fast for bandwidth both ways.
You should be able to hot-swap with "real" SATA 2.0 as well. My guess is you've plugged you're adapter into a SATA 1.0/1.1 socket and that's why you have no hot-swap.
One correction, one addition:
I'm fairly positive that it's 250 MB/sec per lane, not 150 for PCI-E.
In addition, not only is that per-device, it is per-device, per-direction (full duplex, 250MB/sec to the device and 250MB/sec back at the same time)
As to why PCI-E couldn't have been developed back when PCI or AGP were available (rather than incremental steps) - Moore's law. It simply wasn't possible to make silicon capable of handling PCI Express data rates (each lane uses serial communications at 2.5 gbits/sec, which was definately NOT possible with the silicon available back when PCI or AGP were initially developed.)
For those that wonder why PCI-E uses 2.5 Gbit/sec signaling but only transfers 250MB/sec of data, it is because all data is encoded using either 4B5B or 8B10B encoding (I can't remember which of the two), which maps every 4 data bits to 5 signal bits for 4B5B or 8-to-10 for 8B10B. This is done to ensure a minimum number of bit transitions in a given period of time, and also ensure that the signaling has no DC bias. (i.e. equal number of 0s and 1s no matter what the input data is).
retrorocket.o not found, launch anyway?
SATA II is the old name of the organisation that created the SATA standard (although I can't find what the acronym used to stand for). It has since changed its name to SATA-IO ("International Organisation") because everyone mistook the two I's as Roman numerals and assumed the newly created SATA 3Gb/s standard was "version 2" of SATA. It's not. It's just a new signalling rate and other features like NCQ are separate.
You assume that the SATA protocol has equal or better efficiency than the firewire protocol.
For example, that latency sensitivity of SATA is less than or equal to that of firewire. You might be right, you might be wrong, I don't know. You might make the same assumption about USB, in which case you would definitely be wrong - the longer your USB cable, the slower your external hard disk because USB requires an ACK for every transmit with no windowing, while firewire can have multiple packets "in flight."
So, if your SATA drive has a similar limitation as USB, it is entirely possible that the SATA-to-FW bridge chip that would sit in the external drive case could buffer multiple data packets, taking advantage of the extremely short data-path between the drive and the bridge to produce a higher throughput over a long firewire cable than could be achieved over SATA cable of equal length.
Ignore the other responder to your question. Your cables suck. There's better ones available. I used to do embedded software development on a system that used 4 (or 8 or 16) SATA drives, and I've gone through a lot of different cables. Some don't attach very securely, and sound like the ones you have. Others were very secure; I could pick up the drive and move it around in operation and the connector didn't come loose. I believe some of the better cables had "Foxconn" connectors. We also found that newer cables seem to be better than the 1st-generation SATA cables.
In summary, try some different cables.
Yeah the cables make all the difference. Gigabyte generally ships their boards with the nice yellow SATA cables which have locking tabs on both sides of the connector. It just takes a light pinch to remove them from the SATA socket, but once they're in, they're not going anywhere.
.05 on two pieces of tin to make all cables lock like those. *sigh*
If only everyone spent
Only catch is if I hook up a drive while in Windows with that converter, it'll lockup. Has to be turned on before I boot the computer. This is a limitation of the adapter; from what I've read, you should be able to hot swap with a "real" eSATA port.
Another possible reason for your inability to hot-swap is that the SATA ports might be set to "IDE mode" in the motherboard's BIOS. This is a common setup on "home-built" computers since "IDE mode" allows pre-Vista Windows installation without the "F6 (floppy) installation method." To enable hot-swap, the SATA ports must be set to "SATA/AHCI mode" in the BIOS.
Here's some instructions from Intel's site on changing SATA modes on their motherboards:
- IDE mode - no AHCI, no RAID
- SATA mode (sometimes called AHCI mode) - AHCI enabled, no RAID
- RAID mode - AHCI enabled, RAID enabled
AHCI mode also allows for Hot Swapping drives.TO START
PRESS ANY KEY
Where's the 'ANY' key? I see Esk, Kitarl, and Pig-Up...