tcas

14 ms·

91.
by tcas 12y ago
I still have a copy of a TI TTL Data Book, completely useless these days with the internet, LVCMOS everywhere, all in one microcontrollers and FPGAs, but it's still cool to flip through every so often.
92.
by tcas 12y ago
That is a great link. Also USB Made Simple is good addition to that. It's pretty amazing that the protocol works in the first place. It's a multi-driver, differential bus with 3 valid states (not including bus arbitration). It doe
93.
by tcas 12y ago
In 1956 AT&T opened all of it's patents to everyone without royalties to settle an antitrust suit, including the transistor. http://explodingthephone.com/docs/dbx1036.pdf
94.
by tcas 12y ago
NYC does this right now on high traffic routes with their select bus system. You pay at the stop which then prints out a receipt that is valid on that route for 1 hour. Every so often inspectors board the bus and look at the tickets.
95.
by tcas 12y ago
The 8b10b encoding mostly helps with clock recovery and preventing a DC bias (+/- charge) build up in the cable, which helps with error detection (I think it can detect only single bit) and recovery from, but can't correct.
96.
by tcas 12y ago
At Netflix's scale I'm almost certain that paying for the space and power would still be much cheaper than having to pay direct bandwidth costs / external CDN costs. I wonder how they decide who gets to put a server in there
97.
by tcas 12y ago
It's explained pretty well in the article. Basically with CTR using the block # as the nonce you break the security assumptions of a nonce (use only once). If the cryptofunc is static, and you are editing a document in place, an attack
98.
by tcas 12y ago
Another good source is: http://www.damninteresting.com/a-potentially-disastrous-desi... Apparently it costed $8 million to repair.
99.
by tcas 13y ago
I've clocked Acela at just below 150mph on my GPS in between Providence and Boston. As I understand it, they would like to go faster in other sections, but the track / catenary isn't able to sustain that speed on most of the
100.
by tcas 13y ago
Are you guys planning on doing custom cables as well (at least on the other sites)? I imagine the molding tooling makes this a no-go for anything but larger orders.
101.
by tcas 13y ago
There are, but they aren't close in specs and price to this one. The AT91 series are completely different in terms of functionality vs the Broadcom. The AT91SAM9 series don't even have a floating point unit last time I checked. Th
102.
by tcas 13y ago
This is very interesting in regards to a having cheap Linux SoM (system on module) for businesses to use in their products as well, by far the cheapest I know of with these specs. Doing routing and verification for a chip like that is no ea
103.
by tcas 13y ago
Additionally, device tree support in the Linux kernel allows many board specific ports to be packaged onto a single kernel, and the bootloader specify which peripherals and their addresses and features are there. Still nowhere near as power
104.
by tcas 13y ago
I believe that. Even for 0.5mm QFPs, trying to do a stencil at home controlling the amount of solder paste is very difficult. Almost every attempt I've tried leads to at least a few bridges (easy to fix, but still annoying). With the p
105.
by tcas 13y ago
Depends on a lot of factors: how big (reputable) the company doing the testing is, how big your device is, what voltages your devices runs on, what frequencies are on the board, number of I/O, number of configurations to test (to expla
106.
by tcas 13y ago
BTLE and WiFi are getting a bit easier thankfully. I know the TI CC3000 doesn't require intentional emitter testing if the recommended design is followed which saves a _lot_ of money and time. [0] Agreed that FCC unintentional emitter
107.
by tcas 13y ago
QFNs and most reflows are tricky as well, since it requires you to also design the board properly to reflow correctly. For example, if the QFN has a large ground pad in the middle, putting unmasked vias in the middle can cause solder to get
108.
by tcas 13y ago
Profitability seems very very very far away Just to add, right on their S1 risk factors: We have incurred significant losses in each period since our inception in 2005. We incurred net losses of $50.3 million in our fiscal year ende
109.
by tcas 13y ago
In addition, part of a private pilot license training is stall recovery, and engine loss scenarios. I remember sitting in on a lesson while my brother was getting his private pilot's license. The instructor would randomly idle the engi
110.
by tcas 13y ago
One more that I like is: http://www.mothersruin.com/software/SuspiciousPackage/ Shows the contents of any pkg file including scripts
111.
by tcas 13y ago
The air pollution levels are similar to living an airport smoking lounge. http://www.bloomberg.com/news/2013-01-30/beijing-air-akin-to...
112.
by tcas 13y ago
Inertial navigation systems[1] have been used for more years than GPS has existed. Even now almost all military drones / rockets / ICBMs use very precise inertial systems. [1] http://en.wikipedia.org/wiki/Iner
113.
by tcas 13y ago
Pretty cool, but I think the PCB design will need a bit more work before it can be assembly house produced. There seems to be a lot of pointless via in pads that are not plated over (plated over costs $). From most assembly houses I've
114.
by tcas 13y ago
Haven't used sidestep, but sshuttle [1] is a nice command line utility that does the same, just not automatically. Much easier than setting up a VPN server. [1] https://github.com/apenwarr/sshuttle
115.
by tcas 13y ago
That's true of stream ciphers, and if they reuse a nonce. It looks like they used 3DES which is for all intents and purposes here, immune to a this kind of attack. EDIT: If they use 3DES in a CTR mode then it could be vulnerable to thi
116.
by tcas 13y ago
I just tried this -- you don't know _which_ combination is missing unfortunately in the case of a 2 or 3 digit number. With 3 you might be able to figure it out by using the limit of 250 (e.g. if 2 4 and 7 are missing there is only 1 t
117.
by tcas 13y ago
True, but if I recall correctly spatial multiplexing can be used to increase channel capacity. Using the same 50db SNR for WiFi at 40Mhz we get: ((40000000)*(log(1+100000)/log(2))) ans = 6.6439e+08 or 664Mbit/s, however,
118.
by tcas 13y ago
If you're curious how subways signaling/safety mechanisms operate, the nycsubway site[1] has a pretty good rundown on NYC's procedures, and its original language is English as well. It basically is a large ad-hoc system (+ so
119.
by tcas 13y ago
So, essentially feeding it into something like BUF? I thought those were optimized out on modern FPGAs. I can see the sourcing issue when trying to fan out too much from a single module, but I don't see any issue doing a high speed int
120.
by tcas 13y ago
"In high speed designs, it’s an error to use a signal that’s sourced from another module" How else are you supposed to get I/O from one module to another, say a 32bit data bus? Also, what's the definition of high speed h

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