Catch up on stories from the past week (and beyond) at the Slashdot story archive


Forgot your password?

Comment Re:hyperloop without the hyper or loop (Score 1) 166

Once the vacuum has been created, the amount of energy required to maintain it is not significant assuming that there are no major leaks. I imagine that at the stations that the pod would enter a chamber where the air is removed before entering the main tube. Since most of the volume would be from the pod the amount of air needing to be removed would not be all that great. It also isn't a high vacuum, so it takes much less energy to obtain.

Comment Re:Density is nice, but what about longevity? (Score 1) 156

I imagine that in a DVR a decent SSD should do just fine. Each NAND block is good for several thousand write cycles. If you completely overwrote the SSD every 24 hours that would give you years of service, though even a DVR rarely overwrites the entire hard drive in 24 hours.

Comment Re:I don't blame FTDI, fake chips hurt them (Score 2) 268

Just using a counterfeit chip could potentially introduce unintended behavior. I've dealt with a number of USB to serial chips and many of them are crap. I have cables that will just suddenly stop working, or the baudrates that suddenly change. I wouldn't be surprised if the counterfeit chips have similar problems. FTDI should be able to program their chip and expect it to work as designed. If it's counterfeit and it doesn't, then it's not their fault. They shouldn't have to debug problems in counterfeit chips. On top of that, the counterfeit chips eat into their bottom line. FTDI chips tend to be more expensive and for good reason. They're better chips. On top of that they have excellent documentation as well as library support for doing all sorts of things. Want to do i2c or JTAG with their USB to serial chips? It's fully documented with a library to support it.

I can tell you as someone who writes device drivers that trying to debug problems caused by some unknown counterfeit chip is a nightmare. After all, it's not your job to Q/A not only your own hardware, but cheap Chinese counterfeit chips as well.

As far as I can tell, sending an ASCII string is probably the best thing they could have done given that they're screwed no matter what they do.

Comment Re:How can FTDI not figure out how to do it? (Score 1) 268

No, their drivers belong to them and are designed to work with USB devices that have the FTDI vendor ID and FTDI product ID, which FTDI paid for. If the devices fail it is because they are counterfeit. With this change, nobody in their right mind will use counterfeit chips and distributors will be more careful about their supply chain. No matter what FTDI does people will complain. If their drivers just don't work at all it's basically the same as bricking the device. At least this way the device will continue to work. FTDI are in no way responsible for transmitting reliable data over counterfeit chips. If those manufacturers want reliable data then they should write their own damned drivers.

Comment Re:How can FTDI not figure out how to do it? (Score 1) 268

Probably because nobody would want to use a non-FTDI chip. I've worked on products where we specifically chose FTDI due to the features of the chip as well as the reliability. I have used a number of other non-FTDI USB to serial chips and had a lot of problems with them. In our case, we use the quad FTDI USB to serial chips and make use of features like i2c and JTAG support.

I really can't blame FTDI. After all, if the fake chips are causing a lot of support issues, that affects their bottom line as well as their reputation. Why should FTDI need to provide a bunch of support to customers who keep having problems with fake chips? By doing this they will drive the counterfeit chip manufacturers away since any product based on these chips will be rendered unusable from the start. The supply chain will also be more careful to prevent the fake chips from entering it.

A serial driver cannot just pop up a message and say that a fake device was detected. The next best thing is to do what they are doing.

Comment I don't blame FTDI, fake chips hurt them (Score 4, Informative) 268

One problem these counterfeit chips pose is that all the sudden companies like FTDI end up with a lot of support costs for people who bought shoddy products with the fake chips, which often don't work nearly as well as the real thing. This is a way for FTDI to crack down on the counterfeit chips. While it sucks for the consumers that end up with the fake chips, it will also help put a stop to the counterfeit chips since any product that uses them will not work.

At my company we make a number of development boards using the quad FTDI chips for the serial interface. We use them because in addition to RS232 they also can talk I2C and JTAG, among other things. I can reliably run the FTDI chips at 10Mbps. I've used other USB to serial devices in the past but I've had lots of problems with them. Some cables I bought, for example, will just suddenly stop working and I have to periodically reset the baud rates.

Why should FTDI have to bear the burden and support costs of counterfeit chips? If somebody else slaps the FTDI manufacturer ID and product ID onto their USB device then they deserve whatever happens. Why should FTDI have to spend resources supporting fake chips? By doing what they are doing, it will drive the fake chips out of the system and prevent future ones.

I work for a chip manufacturer and while there's a very low risk that someone will make fake chips like ours (very complex network processors), we have had to add features to our chips so that our end customers can prevent counterfeit equipment which just copies their software. We have some large customers who have been battling Chinese made counterfeit equipment.

Comment Re:Remember the NASA Wind Turbines? (Score 1) 179

Current blades are trucked in one piece (per blade) which is impressive to see. Three of them were parked on I-5 outside of Patterson, California a few months ago. There are a lot of net videos and photos which convey the scale.

Even at the current size they can't get through many highway interchanges and local intersections. The larger ones won't be able to ship in one piece at all.

Comment Remember the NASA Wind Turbines? (Score 4, Interesting) 179

NASA Wind Turbines approached this scale in the '80's. Unfortunately, this was a previously-unexplored area of aerodynamics for NASA, and they had mechanical stress and noise problems (including subsonics) and were all demolished. I think there was one near Vallejo, CA being taken down when I got to Pixar in '87, and one in Boone, NC, which famously rattled windows and doors.

The art has since improved. I took a ride to the top of the turbine at Grouse Mountain, that was fun! That's the only one I have heard of where you can actually get to see it from the top.

Comment Starting out with the wrong assumptions (Score 2) 165

This is starting out with the wrong assumptions.

Design a brick system that can be produced with 3-D printers, and will hold together when fabricated within the tolerances of an SLA printer. Forget FDM, it's too low precision and SLA is already achieving an equal or lower cost of manufacture compared with FDM.

LEGO is manufactured to astonishingly high precision, but I am not convinced that this is the only way to make a brick system.

Slashdot Top Deals

Money cannot buy love, nor even friendship.