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Serial ATA Technology Explained
Mike Parsons writes "Explosive Labs has an interesting article on Serial ATA . Here is a quote: 'In the rapidly moving computer industry, there are rarely the kinds of revolutionary changes like what is about to take place in secondary storage segment. Soon the hard drives and configuration methods that have existed since the origins of the personal computer will change forever. The basic IDE technology has been around for nearly twenty years. When the lifetimes of other computer components like CPUs and video are measured in months, twenty years ago seems like prehistory.'"
Um, no. Gen 1 SATA is 1.5 Gb/s. Firewire is not faster.
"The defense of freedom requires the advance of freedom" - George W Bush
Since the site is slashdotted, here are further links about Serial ATA:
Cnet
SATA and ISCSI
Intel Dev Paper
Maxtor White Paper
The battle between serial and parallel communications is neverending. Show me a Serial WAN connection like a DS3, and I can say "Well, since you never send partial bytes, we could strap 8 of these side by side, send one byte at a time with the bits split up over the 8 DS3s in parallel frames, and we get an 8x speed improvement that's usable by a single connection and no additional latency".
Or show me a parallel bus like IDE, and I can say "Look, having all those data lines next to each other causes additional interference we have to account for, and they're bulky, cost more, overly complex, blah blah. If we just put a serial bitstream on a pair of wires, it would be so much simpler that for the same cost we can turn up the bitrate more than enough to make up for the lost parallelism."
It's all the same. Various communication technologies tend to rise and fall, serial replacing parallel replacing serial replacing parallel ad infinitum. In some cases (like PCI busses) parallel just makes a lot more sense, but in a lot of cases (network stuff, storage stuff especially) there's a tradeoff where both are better and worse than the other in different ways. You could just pick one and stick with it and do you incremental improvements, but the occasional switcheroo provides upgrade revenues and more user "wow" factor and buzzwords.
11*43+456^2
- The PC parallel port was defined, in a very loose manner, by IBM when the IBM-PC was introduced in the early 1980s. The original PC parallel port was unidirectional and good for little else than driving a printer. While a number of manufacturers offered bi-directional versions of the PC parallel port (including IBM, in the late 1980s, with the IBM-PS/2) no actual standard existed until the release of IEEE-1284, in the mid-1990s, which gives us the modern ECP/EPP option.
- The VGA pin-out dates from the introduction of the IBM-PS/2 in 1988/1989.
- The PC keyboard pin-out and protocol have only been around since the introduction of the IBM-PC, and have undergone at least two revisions, first for the IBM-AT keyboard, and second for the IBM-PS/2.
The reference to IDE having been around for 20 years is a pretty dubious one, unless you count IDE as just a variation on the vernerable IBM-PC expansion bus. (commonly known as the ISA bus) Still, 20 years ago, there was no such thing as IDE, even as a glimmer of a hope in anyone's eye.All data goes through the PCI bus
No it doesnt. Data goes through the PCI bus if the address is not claimed by something else along the way. That means that everything from the southbridge up is not limited by the PCI bus bandwidth. That means that integrated SATA controllers (not available until next year) are only limited by the bandwidth between the northbridge and southbridge.
Ever read the actual throughput specs on a drive?
Drive throughput has been steadily increasing, and it is predicted to pass up PATA within a few years, and that is not counting RAID striping or the 8 MB drive caches. Its always desirable for the bottleneck to be the drive rather than the controller.
"The defense of freedom requires the advance of freedom" - George W Bush