Month: February 2008

TCP Flow Bottleneck

The source of the throughput bottleneck is the mechanism TCP uses to regulate its data flow rate. The TCP sender requires an acknowledgement of every packet from the TCP receiver in order to inject more data into the network. When an acknowledgement is missed, TCP assumes that it is overdriving the network capacity and enters an aggressive congestion avoidance algorithm. This algorithm reduces the data flow rate severely, and recovers the rate too slowly to keep modern pipes full. Even small variation in round-trip latency or bit errors due to the network media can cause TCP to enter congestion avoidance. Standard TCP is not equipped to distinguish these sources of packet loss from true link congestion. The consequences to file transfer are dramatic

Library of Lost Dreams


This is a building where our deeply-troubled public school system once stored its supplies, and then one day apparently walked away from it all, allowing everything to go to waste. The interior has been ravaged by fires and the supplies that haven’t burned have been subjected to 20 years of Michigan weather. To walk around this building transcends the sort of typical ruin-fetishism and “sadness” some get from a beautiful abandoned building. This city’s school district is so impoverished that students are not allowed to take their textbooks home to do homework, and many of its administrators are so corrupt that every few months the newspapers have a field day with their scandals, sweetheart-deals, and expensive trips made at the expense of a population of children who can no longer rely on a public education to help lift them from the cycle of violence and poverty that has made Detroit the most dangerous city in America. To walk through this ruin, more than any other, I think, is to obliquely experience the real tragedy of this city; not some sentimental tragedy of brick and plaster, but one of people.
Pallet after pallet of mid-1980s Houghton-Mifflin textbooks, still unwrapped in their original packaging, seem more telling of our failures than any vacant edifice. The floor is littered with flash cards, workbooks, art paper, pencils, scissors, maps, deflated footballs and frozen tennis balls, reel-to-reel tapes. Almost anything you can think of used in the education of a child during the 1980s is there, much of it charred or rotted beyond recognition. Mushrooms thrive in the damp ashes of workbooks. Ailanthus altissima, the “ghetto palm” grows in a soil made by 1000s of books that have burned, and in the pulp of rotted English Textbooks. Everything of any real value has been looted. All that’s left is an overwhelming sense of knowledge unlearned and untapped potential.

that picture captures the state of american high school education perfectly

Superplonk

my favorite feature is superplonk. it remixes the environment and filters annoying persons, objects and sounds. that’s an augmented reality version of what i practice today with special earplugs. but soon that should be possible with modified hearing devices and slim head mounted displays. one experiment in my ongoing surveillance series simulates superplonk with images of network cameras. via motion detection i am reconstructing a place’s image without people and cars. all moving objects are becoming ghosts. only people and cars who are standing still are becoming visible.

Gates Envy

But just as huge, powerful countries can be awkward neighbors—a Canadian leader once likened his country’s relations with the United States to a mouse bedding down with an elephant—lavishly funded organisations can sometimes cause resentment among other outfits which are struggling to do a similar job. And whether because of jealousy or legitimate concerns, the Gates Foundation has not been having such an easy time of late with its public image.

Wherein the sleepy NGO world gets a rude awakening and a kick in the behind from the Gates foundation.

OpenOffice fails at life

if you ever tried to use OpenOffice or NeoOffice to create a presentation with images and timed animations (bare-bones, standard stuff, in other words), do yourself a favor and delete those useless applications from your machine. you’ll thank me. how those clowns can ship software that randomly replaces your images with the dreaded ‘broken image’ image, or that forgets about the animations it is supposed to show, and gives you a blank slide instead, is beyond me. with desktop “productivity” applications this bad, no wonder people are defecting to online.

Exaflop

Exaflop supercomputer. Petaflop machines don’t even ship yet.

Another problem for the institute is to reduce the amount of power needed to run a future exascale computer. “The electrical power needed with today’s technologies would be many 10s of megawatts — a significant fraction of a power plant. 1 megawatt can cost as much as $1m a year. We want to bring that down.”

2014-11-14: Towards the high petaflops

DOE has commissioned “Summit“, designed to peak at 150-300 petaFLOPS, 5x faster than the 54 petaFLOPS Tianhe-2.

2020-11-16: Fugaku has become the first 2 exaFLOPS system
2023-02-23: Zettaflop roadmap

AMD talked about getting to a Zettaflop in 2030-2035. It would need about 500 Megawatts of power. Exascale systems today consume 21MW of power.

Advice for real estate agents

I had the good fortune to speak to a large gathering of real estate agents last week. Here’s my best advice (everyone knows an agent or 2, so feel free to forward this along). Plan A: You should quit selling real estate. I’m serious. Quit being an agent. Get a job doing something else. Some of you have been waiting to hear that. My pleasure. … Now, if you’re still with me, you’ll be glad to know that the competition for attention just got smaller. The agents who built their business on low interest rates, easy money and speculation (the order takers) have left the building. The ones that are left, that’s you, can consider Plan B: If you’re not going to be able to make a living by taking orders, by selling houses the way everyone else does, by using the never-ending rise in real estate prices to make sales, then what are you going to do? Whining is not an option.

seth is trying too hard for plan b. there is no plan b, this is fundamentally a dumb occupation that needs to die