Go to advanced search

by AlanCox
Thu Jan 26, 2012 11:22 am
Forum: General discussion
Topic: USB Output, simulate HID ,removable storage similar to teensy?
Replies: 3
Views: 3036

Re: USB Output, simulate HID ,removable storage similar to teensy?

The Linux input layer has a loopback facility so you can write an app on a Linux box to take input from anything including over the network, so while HID might be neat it's not essential.

Alan
by AlanCox
Thu Jan 26, 2012 11:18 am
Forum: General discussion
Topic: Downloadable SD Card Images
Replies: 51
Views: 9248

Re: Downloadable SD Card Images

<r>Pedantically speaking the dd default is for hard disk media – which is 512 byte sector until recently. When you are using it for things like rescuing material the fact it uses the real block size is important.<br/> <br/> For more normal use dd bs=1M will be better.<br/> <br/> SD is slow though, a...
by AlanCox
Tue Jan 24, 2012 11:40 pm
Forum: General discussion
Topic: Kernel Patches
Replies: 13
Views: 2863

Re: Kernel Patches

Not sure that'll work too well - there are rather a lot of "issues".

No offence intended to the developers btw - its in a lot better nick than some of the stuff people actually try submitting.

Can do though if that's the official preferred way to do it.

Alan
by AlanCox
Tue Jan 24, 2012 10:40 pm
Forum: General discussion
Topic: Kernel Patches
Replies: 13
Views: 2863

Re: Kernel Patches

Where should I start sending review comments and bug reports from code review ?

Alan
by AlanCox
Tue Dec 06, 2011 3:55 pm
Forum: General discussion
Topic: Raspberry Pi: Hi-Res audio over USB?
Replies: 12
Views: 4042

Re: Raspberry Pi: Hi-Res audio over USB?

<t>Carlos, it\'s completely irrelevant how noisy the Pi power supply is. USB audio is a digital signal an you convert it onto S/PDIF digital signals. You can run digital audio over pieces of old coathanger without audio lossage. It\'s a problem if you use stuff like analogue \'CD quality\' outputs b...
by AlanCox
Tue Nov 29, 2011 10:32 pm
Forum: General discussion
Topic: Preinstalled kernel modules
Replies: 16
Views: 3831

Re: Preinstalled kernel modules

<t>Given almost all the stacks and other bits are modular you can build an 'everything USB' kernel and then just put some of the drivers (the ones you want) plus their dependancies on the SD card.<br/> <br/> It's something the bigger distros like Fedora simply assume isn't worth bothering with but i...
by AlanCox
Wed Nov 23, 2011 10:18 pm
Forum: General discussion
Topic: data memory barriers (technical)
Replies: 3
Views: 2542

Re: data memory barriers (technical)

<t>The former is a memory barrier at the CPU level, the latter is a compiler memory barrier. It tells gcc not to cache anything in registers or temporaries across the boundary. We use it extensively in Linux and it's also implied by the various locking operators. The basic problem is that the C lang...
by AlanCox
Wed Nov 16, 2011 7:40 pm
Forum: Other projects
Topic: Might I suggest...
Replies: 8
Views: 1884

Re: Might I suggest...

<t>Quote from NRoach44 on November 16, 2011, 08:44<br/> That instead of creating an Image for each distribution to boot from, create an image of the first stage of grub, and that boots into the OS, after finding the files on the SD card.k; That would mean I could install any distro I want to (that s...
by AlanCox
Wed Nov 16, 2011 7:14 pm
Forum: Other projects
Topic: Blue ray
Replies: 7
Views: 2884

Re: Blue ray

<t>HDMI itself is no great secret. HDMI devices that support things like blu-ray negotiate with each other using an encryption scheme and key system called HDCP. HDCP was also cracked in 2010 and HDCP strippers are not exactly hard to obtain.<br/> <br/> HDMI capture won't reasonably fit down a USB l...
by AlanCox
Wed Nov 16, 2011 10:43 am
Forum: Other projects
Topic: Blue ray
Replies: 7
Views: 2884

Re: Blue ray

<t>It depends on your hardware. Getting permission to do blu-ray requires jumping through all sorts of hoops. However the crypto was broken long ago (it didn't in fact take very long) so its basically all symbolic. It's not about stopping piracy so much as controlling users.<br/> <br/> Whether you a...
by AlanCox
Wed Nov 16, 2011 10:25 am
Forum: Off topic discussion
Topic: The Slashdot Attitude
Replies: 19
Views: 3785

Re: The Slashdot Attitude

I really don't think thats fair. If you take the slashdot users of any country they don't seem to be anything but trolls and haven't been for years. It's like wearing an "I ? The Dail Mail" T shirt.

I really wouldn't worry what either of the two think !
by AlanCox
Mon Nov 14, 2011 11:53 pm
Forum: General discussion
Topic: How do you program a Raspberry Pi
Replies: 7
Views: 2269

Re: How do you program a Raspberry Pi

<r>[quote]<B><s>[b]</s>Quote from Hammond7372 on November 14, 2011, 22:48<e>[/b]</e></B><br/> So can you get programs to run at startup and use the Rpi solely to run one program. My Dad would like to make use it to program the boiler ( not entirely sure what he has in mind but there you go <E>:)</E>...
by AlanCox
Mon Nov 14, 2011 11:45 pm
Forum: General discussion
Topic: Just short of being great?
Replies: 10
Views: 1861

Re: Just short of being great?

<t>Terminology Guide:<br/> <br/> Dumb framebuffer: The processor does all the display work - each pixel is written by, copied by and updated by the processor. This is how you are seeing Quake running (akin to how it ran on DOS with SVGA cards)<br/> <br/> X (X11): A protocol and extensions for graphi...
by AlanCox
Mon Nov 14, 2011 4:49 pm
Forum: Other projects
Topic: Lack of Broadcom documentation
Replies: 32
Views: 7895

Re: Lack of Broadcom documentation

<t>Quote from jamesh on November 14, 2011, 16:12<br/> Well, I disagree. For the target audience of the Pi, as long as it works, it's fine. And it will work out of the box.<br/> <br/> <br/> Well time will tell that. I think until then we can but disagree 8)<br/> <br/> <br/> kernel is already supporte...
by AlanCox
Mon Nov 14, 2011 3:48 pm
Forum: Staffroom, classroom and projects
Topic: Teaching Youngsters Programming
Replies: 131
Views: 34139

Re: Teaching Youngsters Programming

<t>The PI ought to be able to run things like sugar which may also be quite interesting as an experiment, and as an environment now getting a lot of exposure on OLPC. The OLPC runs a sugar based environment in 256MB combined with a gecko derived browser and abiword rather than libreoffice. The latte...
by AlanCox
Mon Nov 14, 2011 3:42 pm
Forum: General discussion
Topic: Version C?
Replies: 32
Views: 6374

Re: Version C?

<t>Well the sources and config for the NAS kernel will have been supplied by the vendor as it's GPL licensed.<br/> <br/> The serial port management is not even Linux specific, its documented in the standards documents and is POSIX/SuS standards compliant (ie its the same as most things except Window...
by AlanCox
Mon Nov 14, 2011 3:37 pm
Forum: Other projects
Topic: FreeBSD on Raspberry Pi
Replies: 22
Views: 9733

Re: FreeBSD on Raspberry Pi

<t>Quote from tufty on November 13, 2011, 10:48<br/> Converting the Linux drivers for the Broadcom-specific stuff shouldn't be /too/ onerous<br/> Simon<br/> <br/> You cannot simply "convert" a GPL licensed driver and stick it under a BSD license. One thing that is probably worth doing is asking the ...
by AlanCox
Mon Nov 14, 2011 3:33 pm
Forum: Other projects
Topic: Lack of Broadcom documentation
Replies: 32
Views: 7895

Re: Lack of Broadcom documentation

<r>Quote from abishur on November 14, 2011, 14:32<br/> I mean why should we sacrifice a superior option just because it's more complicated? Well, we say more complicated, but the complication exists at a level we don't and can't access. All access we need to the device is still available via open so...
by AlanCox
Sat Nov 12, 2011 10:12 pm
Forum: Staffroom, classroom and projects
Topic: Inspirational people in Computer Science
Replies: 99
Views: 18323

Re: Inspirational people in Computer Science

I'd have gone with Sir Uncle Clive personally, the ZX81 and ZX80 are the historic ancestors to this kind of "minimal component count, make it cheap, make it available" thinking. I just hope the PI is better assembled (ducks)
by AlanCox
Sat Nov 12, 2011 6:30 pm
Forum: General discussion
Topic: VGA
Replies: 126
Views: 27751

Re: VGA

<r>Yeah my monitors are all without HDMI, ditto my TV and I don't think its atypical right now. But in 2 years time ?<br/> <br/> PAL I think is best avoided - its a nightmare getting all the TV frequency stuff screened even in a boxed product and the regulations and testing for radio emissions are r...
by AlanCox
Sat Nov 12, 2011 6:24 pm
Forum: General discussion
Topic: Virtualized Desktop
Replies: 5
Views: 1638

Re: Virtualized Desktop

<r>[quote]<B><s>[b]</s>Quote from kme on November 12, 2011, 15:03<e>[/b]</e></B><br/> The problem with remote X is that it is horrible slow.<br/> [/quote]<br/> <br/> Generally no. The problem with remote X is that most of the modern applications and toolkits are very sloppy about avoiding latency. T...
by AlanCox
Fri Nov 11, 2011 7:46 pm
Forum: General discussion
Topic: Really dumb question about power.
Replies: 30
Views: 5793

Re: Really dumb question about power.

<r>[quote]<B><s>[b]</s>Quote from hippy on November 11, 2011, 15:49<e>[/b]</e></B><br/> But nor is it a high cost even at 30p per kWh; less than £6 per year, and that\'s accepting it will always draw 2W minimum.<br/> [/quote]<br/> <br/> And assuming a 100% conversion efficiency on the wall-wart, whi...
by AlanCox
Fri Nov 11, 2011 7:41 pm
Forum: General discussion
Topic: Confused about GPU
Replies: 21
Views: 4802

Re: Confused about GPU

Youtube also supports standards based video (Vorbis,H.264)
by AlanCox
Fri Nov 11, 2011 11:18 am
Forum: General discussion
Topic: Really dumb question about power.
Replies: 30
Views: 5793

Re: Really dumb question about power.

<t>\"Non commercial\" is not defined anywhere useful. See the Creative Commons research on this. It\'s a bit of a problem because everyone thinks they know what it means, everyone wants it and everyone has a different definition of non-commercial. Probably safer to use a CC0, CC-BY or similar image ...
by AlanCox
Thu Nov 10, 2011 8:28 pm
Forum: General discussion
Topic: Smallest Linux Install
Replies: 47
Views: 15642

Re: Smallest Linux Install

<t>About the absolute minimum is busybox + kernel + ucLibc Pre-seed the kernel with device nodes or include devtmpfs. That will get you enough to actually bootstrap a lot of projects and stuff. It'll also build with a full glibc if you want to be able to drop on fullblown apps without mucking about....

Go to advanced search