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Hardware Headaches Inevitable?
JaneWalker6847 writes "Don Becker, co-founder of the Beowulf project, describes the inevitability of hardware administration headaches and warns users not to expect a silver bullet to solve these problems." From the article: "We're about to see another revolution, which is in network adapters -- that we [will] talk directly to [them] from application level. That's a massive change in how you interface with them. And that brings about a new round of device drivers completely unlike the device drivers we had 10 years ago. So, that part of the world isn't going to stabilize anytime soon."
What they're likely talking about is technology like Chimney, which, barring lawsuits, will be coming out in or around the time of Windows Vista. Effectively, instead of the TCP/IP stack coming from the OS and running on the main processor, the network card will have a processor and memory and run the TCP/IP stack there. This increases efficiency and reduces reduces latency because the main CPU doesn't have to get involved as much. In the future we will probably see things like SSL encryption being performed on the card as well.
What happens now (on windows) is that applications talk to winsock. Winsock sends the data to kernel mode code including tcpip.sys. From there, it ends up in ndis.sys and then the driver for your network card before being sent to the card.
What this new thing means is that applications send the data to winsock which hands it directly to a new kind of network card/driver which takes the data and header info and creates the TCP/UDP and IP packets on the card itself in card firmware. From there, the card wraps it up in the lower level protocols and then puts it out over the wire (or air if its wireless)
Individuals? Not many, at least not on a regular basis.
In a data center environment? Quite often.
The traditional problem with doing this is that when you put TCP/IP on the NIC, you still need a protocol for the operating system to communicate with the NIC, and the CPU on the NIC is much slower than the main CPU. I used to have a box full of smart NICs that people had discarded because they were more trouble than they were worth, even though they had paid premium prices for the onboard protocol processing features.
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The problem is that general-purpose cpus grow in power so quickly that the offload-engines get ever-larger problems beating them. And they get the aditional problem that they don't get packet-filtering or anything else that is not custom-written for that particular card (if it's even possible to convince the card to do it!)
It's also nothing new -- these cards have existed for literally decades, and haven't managed to make any kind of inroads, not even in specialized servers.
Have a look at this year-old Lwn-article for an example listing some disadvantages.
Hmm... Do I smell WinModem?
Except that WinModems are the exact OPPOSITE of the philosophy that's being espoused here with crypto offload engines, intelligent network cards, etc.
The WinModem was an attempt to take traditional modem functions and move them onto the CPU, in software. Rather than actually having a box full of circuitry that did the hardware handshaking, data compression, and all that good stuff, you just replace it with a simple device that barely connects the analog telephone line to the computer, and have the computer do all the heavy lifting.
I think the justification behind this approach is "software is cheap, hardware is expensive." Therefore, you put the 'brains' in software, and your dumb-hardware/smart-software combo is cheaper than the traditional combination of dumb-software/smart-hardware.
It's a pretty radical departure to essentially go in the opposite direction, from WinModems to these kind of "intelligent network cards," which seem more like a traditional serial modem in philosophy; they do all the work themselves and basically present the computer with a standardized data stream.
The only way that I could see this whole business being "WinModem-like" is in it being tremendously difficult to program for on non-Microsoft OSes. But that's not a consequence of the design per se, but of how I suspect MS will choose to implement it.
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