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Comment: Other QRSS modulation projects (Score 3, Informative) 82

by leighklotz (#45082035) Attached to: Juno Needs Radio Amateurs!

This modulation scheme is called QRSS and can also be used to send very low power (milliwatt and microwatt) signals around the world ionospherically, and on bands such as VLF (very low frequency). Here the open source from a couple of projects by Hans Summers from a book I edited for the ARRL on the Arduino: and plenty of links about QRSS from there.

Comment: Re:Smart move (Score 2) 457

by leighklotz (#44383257) Attached to: After a User Dies, Apple Warns Against Counterfeit Chargers

Voltage? Not 5V? I took a quick look through the USB Power Delivery docs and didn't see that.
Wikipedia doesn't mention it either, though it does discuss the raising of the pre-negotiation current limit from 0.5A to 1.5A, and the max negotiated limit at 5A, which would be 25W.

Do you have any links on the higher voltages?

You probably already understand, but many do not, that you cannot push or provide current at 5V that the device doesn't want. If your device will draw only 500mA due to its internal design, attaching it to a 2A or 5A port won't do anything.

Comment: Re:Symbolics, Lisp Machines, RMS, GNU EMACS (Score 1) 201

by leighklotz (#43264849) Attached to: A Glimpse of a Truly Elastic Cloud

Carl Hewitt's "Actor" model, which is the basis for Erlang, was first implemented on multi-server systems on Symbolics Lisp Machines at the MIT-AI lab. The CADR machines could not be produced fast enough to dedicate enough to the project but when commercial ones were available Carl got a grant and bought 6 of them and they called it the Apiary. They didn't use it all the time so i thought of it mostly as a source of free machines, and we are now only just getting to the point where the multi-CPU network based shared nothing architecture begins to be a mainstream approach.

Comment: Careful setting dates (Score 1) 169

by leighklotz (#42471001) Attached to: Adobe and Apple Didn't Unit Test For "Forward Date" Bugs. Do You?

In late 1999, we tested a product by rolling the date forward to 2000-01-01 and it worked fine. Then we rolled the date back to the normal date, and files that got touched during the test period caused trouble, because their modification date was "IN THE FUTURE!?!?!?" as one piece of code put it. The most broken was the timestamp data for a time-based UID generator, which flat out refused to run, saying that it was in danger of generating collisions.

Comment: Re:The Internet Archive already has a good design (Score 1) 69

by leighklotz (#41994925) Attached to: Google Engineers Open Source Book Scanner Design


Yes, that's in the original submission, as you see above. For the record, Brewster Kahle (who founded, Jeff and Danny (who did this project), and I are all MIT alums, and the "Internet Archive scanning robot" is from a company called Kirtas, which also has ties to Xerox.

Comment: Re:Having looked at the design... (Score 1) 69

by leighklotz (#41994833) Attached to: Google Engineers Open Source Book Scanner Design

In point of fact, for individual scanning, the video even mentions that this linear scanner is SLOWER than a manual scanner such as the diybookscanner. The gains come in that since its automatic, a single person could keep 8 or 10 of them running at at time.

Yup. Progress in clock speeds has pretty much slowed down, and Google appears to expect future performance enhancements to come in the form of parallelism


+ - Google open non-destructive book scanner; books and libraries rejoice->

Submitted by
leighklotz writes "Google released open hardware designs for a book scanner that "sucks" pages to turn them, using a vacuum cleaner. The Google Tech Talk Video starts with Jeff Breidenbach of the Google Books team, and moves on to Dany Qumsiyeh showing how simple his design is to build. Could it be that the Google Books team has had enough of destroying the library in order to save it? Or maybe the just want to up-stage the Internet Archive's Scanning Robot.

Disclaimer: I worked with Jeff when we were at Xerox (where he did the awesome hack Gnu Chess on your Scanner), but this is more awesome because it saves books."

Link to Original Source

Comment: Email theft (Score 2) 148

by leighklotz (#41835597) Attached to: Court Rules Website Terms of Service Agreement Completely Invalid

Email lists are regularly stolen from ecommerce and info sites, as anybody who owns their own domain for email and can give out single-use email addresses knows. I report it every time it happens, and I've only gotten a positive response once, from Walgreen's Photo. Everybody else either fails to answer or points me to their privacy policy (as if that somehow prevented them from having data stolen). My suspicion is that there is a back-door or two in popular mailing-list software that ecommerce sites use; it can't be *that* many corrupt insiders stealing and selling email addresses to have actual human inside involvement.

Comment: Re:Enlighten me please (Score 1) 203

by leighklotz (#41388203) Attached to: UK's 'Unallocated' IPv4 Block Actually In Use, Not For Sale

How many bits for a IPv6 IP vs a IPv4 IP?

Yes of course they should of thought about this before designing the hardware with a maximum ability to comprehend a ipv4 IP...

I remember having this discussion with people close to the principles about the NCP to TCP/IP transition when the 32-bit (four octet) address size was picked.
The sound bite was that it's bigger than the biggest European phone number, so they planned ahead for a time when there would be as many computers as phones, which seemed way enough. (Remember, NCP had a hosts.txt file that listed all the hosts.)

For DNS, they designed an hierarchical system, but events overtook the hierarchy and people got fetishistic about names, leading to most names being in ".com" and being public-facing. The original theory was that the hierarchy would be more important, with more hosts in organizations and so on.

But on the IP side, the segmentation with subnetting (and later, classless subnetting) made things more complicated, so it became possible to run out of IP addresses even though there were still plenty available, but fragmented. Along the way with all the subnetting routing got more complicated and there were a few routing table crises that required new algorithms and lots of new designs, and that pretty much works miraculously now, but doesn't solve the walled-off inaccessible IP address problems.

If you can figure out a way to transparently change who firewalled-off Class A subnet over to a non-routable private net and then release the class A net, you could reset the clock back to the problem IPv4 thought it was solving and become a zillionaire in the process.

The sooner you fall behind, the more time you have to catch up.