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0 pointsdublin7y ago0 comments

Back when I worked at Chevron in the early 90s, I noticed that new SGI workstations were way faster NFS servers than anything else, even the Suns. It took me a bit in those days (Ethernet network analyzers were over $50K then, so hard to borrow even in a big, rich company) to figure out why:

It took 6 Ethernet frames to send a single 8K NFS block, and regaining the carrier could be pretty time-consuming if there was other traffic. So SGI implemented a really elegant cheat that technically violated the Ethernet standards, but dramatically improved performance for the entire network, and especially their NFS servers: They simply never let anyone else get a chance to talk until they'd sent the entire block, "hogging" the carrier by going straight from the last bit of the previous frame to the preamble of the next one. It was a very clever way of more-or-less getting jumbo frames years before they became part of the standard!

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bogomipz7y ago

Interesting. I knew someone that worked for an ISP in 90's who had an odd SGI workstation amongst their standard SUN boxes for hosting customer sites. The SGI box was regarded to be faster than the newer SUN boxes. Eventually all customers were migrated off of the SGI box except one customer who refused and threatened to sue. I wonder if the reason for the performance gains of the SGI were the same as yours.

I believe 802.11n reduced the interframe gap down to a two microseconds for transmissions to the same receiver.

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bogomipz7y ago

I believe 802.11n reduced the interframe gap down to a two microseconds for transmissions to the same receiver.

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