Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?
DEAL: For $25 - Add A Second Phone Number To Your Smartphone for life! Use promo code SLASHDOT25. Also, Slashdot's Facebook page has a chat bot now. Message it for stories and more. Check out the new SourceForge HTML5 internet speed test! ×

Comment Re:Well if HP didn't already have a terrible rep.. (Score 1) 385

How would the switch know what is inside the ethernet frames?

By the time you get up to 48 ports, it's probably not a dumb switch. The layer 3 switches do look into them to do routing depending on how they are configured. IPv6 requires multicast support, and while dumb switch will send the packet out all ports, when you get up to 48 ports you only want to send it to the ports that are interested in it, and I've seen some switches that refuse to send any multicast unless there's a system sending out the IGPM query packets, or you specifically login to configure what ports to send it on. LAN switching - Layer 3 switching

Comment Re:We did it! (Score 1) 305

Before someone says "but OpenGL supports mutil-threading". No it doesn't. It supports multi-threaded worker threads for the drivers, but it does not support multiple threads communicating to the same context.

OpenGL supports multi-threading, just not when you give it that limitation. A context can only be active in one thread, so create multiple contexts, setup sharing so they can all use the same display lists, textures, and such, one thread draws to the frame buffer, the others upload textures, draw to frame buffer objects which becomes textures, whatever so all the data is ready for the drawing thread when it, you know, goes to draw. As far as I know modern graphics cards have lots of GPU cores, but they are all working on the same operation, so no matter how many threads you have feeding it draw commands, they are all getting serialized anyway.

Comment Re:I love Linux, I want Linux, but this isnt Linux (Score 1) 148

This is as Linux as Android is. Hell Android is probably more Linux this this.

I just dont understand why these mobile OS's keep wanting to force developers into a specific language. ... and now Ubuntu mobile OS is pushing QML/Javascript/HTML5.

I agree with your Android assessment, and even your JavaScript assessment for anything of a descent size complexity or efficiency demand, but I don't agree with your Ubuntu QML/Javascript/HTML5 assessment. QML is the 'new' (going on three maybe four years), GUI system for Qt. Qt is written in C++, you can write something only in QML, but I wouldn't and I haven't. The last large program I worked on from scratch was most all C++ using Qt, and used QML/JavaScript for the GUI. Even then for such as a QML button you use JavaScript for trivial stuff, because each QML property is assigned with a line of JavaScript such as the following.
width: height*3.0/4
color: global_background

So in those kinds of cases JavaScript is almost transparent, in other cases it is more of a glue between the C++ layer to modify properties or get feedback from the GUI by calling a routine in C++. QML isn't a programming language, it uses JavaScript for that, and the use of JavaScript can be kept to an absolute minimal assignments, so if you already know C/C++ then you wouldn't even have to know it was JavaScript.

In summary from my experience with C++/Qt/QML, it isn't going to be the pure C++ you are asking about, but if you are doing something with a GUI then this is going to let you do all the stuff you care about in C++ (and on Linux).

Comment Re:negative value comments Too Much Documentation (Score 1) 457

Putting in a code comment that documents why something is the way it is, when it is not obvious is good. Commenting what something does is good for an overview of a complicated routine. Then there's what I would term negative value comments. The ones that take up a line commenting the next line that was so obvious that anyone couldn't have gotten what the comment said by half looking at the code wouldn't have understood what the comment was trying to tell them either.

Actual comments from C++ code in production that I've seen.

// ladies and gents we have a textured quad
m_TexturedPolygon = true;

// construct the input string stream
std::istringstream iStream(buf);

// set color states

// includes
#include "...

If a comment doesn't add value it takes away value by taking up space, time to read it and try to ignore it, question the value of any comments by that person in the future, and such. That's why I can them negative value comments.

Comment Cubieboard? Re:Count me stunned (Score 1) 91

As far as I know, there is no Raspberry Pi equivalent using the A10.

This is the system I'm watching, http://cubieboard.org/ 1GHz ARM cortex-A8, Mali400, 1GB RAM, Ethernet, USB, SATA, $49. I would need to learn more about both to compare GPIO. From their web page (and links), they've shipped one batch, getting ready to ship another, and larger batch in about a month.

If Cubieboard was available now I would have picked one up, but with the Raspberry Pi upgraded to 512MB and this source code release it's going to be a much more difficult choice with that SATA weighing very much on the Cubieboard side.

Comment Re:"earlier Mars mission" == MER-A Spirit (Score 1) 87

It is worse if it must rearrange memory to accomodate the request.

You were going okay until here. You can't rearrange memory, malloc returns pointers, and there isn't any callback to ask for that pointer back to move it to another location.

Byte compiled languages like Java can rearrange memory but you call new not malloc so I know you weren't talking about them. Garbage collection is a much bigger problem especially if you think about mixing Java and real time operations. C/C++ in realtime means following the best practices, but for Java, get a different Java http://en.wikipedia.org/wiki/Real_time_Java.

Comment Re:Comparison (Score 1) 143

I guess we know what stuff matters. :/

Linux kernel mailing list, 774 today *
Guess we know where the Linux kernel activity is.

* and there's still 4 hours of today left for me

Comment N900 + bluetooth (Score 1) 158

I'm using my Nokia N900 for in car entertainment, aka podcasts while I drive. Since the radio uses bluetooth I'm using its buttons to control it, but I also used to use a bluetooth mouse I use while on a walk to control it. The mouse could be solder up someway to trigger the three mouse buttons and scroll wheel to send inputs over bluetooth. I don't use a display while driving, and the daylight readable would be a problem for most portable players and cell phone systems. Still since I have it working that's the route I would be taking.

Comment Re:single link dual link with a dual link single l (Score 1) 266

They didn't used to do that. My first APC UPS had a standard B USB port on it to take a standard cord.

If you are observant the cable is a keyed RJ-45, so you couldn't plug it into an ethernet port (an ethernet RJ-45 will plug into the UPS though), and if you are really observant it is a 10 conductor RJ-45 end where ethernet is 8. I haven't decided if they are trying to be extra cheap or make it so that one cable has a USB A port on the other end and a different one has a RS-232, with each uses different contacts on the UPS side. Then again if they were trying to support RS-232 and UPS then the older UPSes would be the ones that might need it not the newer ones.

The lame part is my second UPS came from the store as a bundle, the UPS, a separate power strip, and an extra long USB A to B cord which I was planning to use to put the UPS further away from the computer, imagine my surprise when I got the bundle and found there was no way that was going to plug in to the UPS.

Comment Re:Unfortunately, Nokia has no Steve Jobs (Score 1) 363

$70 doesn't sound like a bad price for the phone you posted, and running on a AA battery is a good idea. But for a car, why spend the money? Use an old cell phone. Back before I bought my first cell phone my mom gave me an old cell phone of hers for that purpose, I just checked and it is 2/3 bars of battery after probably having the last charge three years ago. The trick is to remove the battery before leaving it for emergencies. Being ready to respond to the on button really drains the battery (probably the real time clock), but whatever, the battery will last longer outside of a cell phone than in it even off.

Now that I've bought my first cell phone (Nokia N900 Maemo/Linux) and changing cars that spare phone hasn't made it back out to the car, but maybe it should, after a fresh charge.

Comment don't force 965 minimum width, ditch size bars (Score 1) 410

If my browser's width is less than 965 pixels it gives me a scroll bar preventing the browser from wrapping further even though the the main story is 478 pixels wide. That also means that portrait browsing my cell phone doesn't work because either the text is too small to read, or I zoom in and have to scroll side to side to see every line. Related to the above, give an option to ditch the side boxes completely. You go about an eighth of the way down one day's front page stories and both the left and right boxes run out and from then it it's white wasted space.

Comment hour training, both ways? (Score 1) 171

Aren't they completely missing the point when they list an hour of training? If it takes an hour to understand me enough to translate it into another language it's going to take another hour for them to train to be able to respond (either it requires training for a person or it doesn't). That makes it pointless, good luck finding a local to spend an hour talking to a computer so they can answer your simple question.

Comment Re:Linked story lacking in details (Score 1) 307

In the test vehicles (presumably the ones with red plates), there must be 2 people in the vehicle at all times, with one able to immediately take over control.

Anyone find it a bit strange that they would need a new law in Nevada to do what they've already been doing in California? Or is it intended to keep the home hobbyist out of the market? Why two people for a car that's supposed to be able to drive itself? They say what the one person is supposed to do, be ready to take over control, but the other?

Slashdot Top Deals

You have a massage (from the Swedish prime minister).