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Comment: Re:Can't get good sound on RPi. Power problems. (Score 1) 202

by dannycim (#41121261) Attached to: Serious Problems With USB and Ethernet On the Raspberry Pi

Not "sound server" in the sense that you mean.

One of the boards is to be tasked with replacing an aging automatic player in a interactive information booth, the other would replace two loop players in localized FM broadcasts, for the visitors to a tourist centre.

They'd serve sound to the public, not to network clients. But that still makes them servers.

Comment: Can't get good sound on RPi. Power problems. (Score 4, Informative) 202

by dannycim (#41116889) Attached to: Serious Problems With USB and Ethernet On the Raspberry Pi

I bought two Raspberry Pi(es) to use as audio servers and have been disappointed by the sound quality. The on-board audio out's DSP has limited bandwidth so sound is down-sampled to 11 bits. Scratchy. It's not advertised so that was a let-down.

Using a USB AUDIO dongle is no-go either, because of the crappy USB drivers. Stutters non-stop. Here are oscilloscope grabs of two music samples and a 1Khz tone: The flat parts shouldn't be there. The only way to get good sound now is to use rather expensive USB soundboards or the HDMI output, but extracting line-level audio signals from that isn't a simple or cheap proposition.

The power design should be re-thought. If you power your Pi with exactly 5 volts, the voltage drop in the polyfuses causes early failures if you connect peripherals that have medium current demands. If you're lucky your power adapter might supply a bit more than 5 volts (5.25 is nice) and you might not experience too many problems. Me, I've soldered supply wires to test points T1(vcc) and T2(gnd) and bypassed the fuses completely.

I hope they come up with another revision, add a Low-drop-out regulator (+$2) and figure out the USB naggies.

Until then, caveat emptor.

Comment: Something strange in the article. (Score 2) 68

by dannycim (#37303106) Attached to: 18-Year-Old Student Discovers Comet Break-Up

FTA: Fragmentation in comets is rarely observed, but can occur when they are closest to the sun and develop spectacular tales of gas, dust and ice particles. The tale originates from the icy core (or nucleus), so when it heats up, vapor from sublimating ices are outgassed into space, dislodging dust and other material.

Shouldn't that be "tails" and "tail", or some different definition of the word "tale" I wasn't previously aware of?

Comment: 50 years later... This is humbling. (Score 1) 175

by dannycim (#35354482) Attached to: Futureproofing Artifacts: Spacewar! 1962 In HTML5

You know, after working on my own long term project (25 years between updates), which Spacewar over-shadows by a factor of two, I've realized that code I write now, no matter how trivial, may be read back a long time afterward. And since I'm a very sloppy programmer, this is is embarrassing on a large scale.

Oh well. if you're curious.


Model Says Religiosity Gene Will Dominate Society 729

Posted by timothy
from the getchyer-broad-brushes-n'-start-paintin' dept.
Hugh Pickens writes writes "PhysOrg reports on a study by Robert Rowthorn, emeritus professor at Cambridge University, that predicts that the genetic components that predispose a person toward religion are currently "hitchhiking" on the back of the religious cultural practice of high fertility rates and that provided the fertility of religious people remains on average higher than that of secular people, the genes that predispose people towards religion will spread. For example, in the past 20 years, the Amish population in the US has doubled, increasing from 123,000 in 1991 to 249,000 in 2010. The huge growth stems almost entirely from the religious culture's high fertility rate, which is about 6 children per woman, on average. Rowthorn says that while fertility is determined by culture, an individual's predisposition toward religion is likely to be influenced by genetics, in addition to their upbringing. In the model, Rowthorn uses a "religiosity gene" to represent the various genetic factors that combine to genetically predispose a person toward religion, whether remaining religious from youth or converting to religion from a secular upbringing. Rowthorn's model predicts that the religious fraction of the population will eventually stabilize at less than 100%, and there will remain a possibly large percentage of secular individuals. But nearly all of the secular population will still carry the religious allele, since high defection rates will spread the religious allele to secular society when defectors have children with a secular partner."

Fedora 15 Changes Network Device Naming Scheme 132

Posted by timothy
from the shock-horror-horror-shock dept.
dkd903 writes "Fedora developer Matt Domsch has announced that Fedora 15 is breaking the conventional ethX naming scheme used for Ethernet devices by adopting a new scheme called Consistent Network Device Naming. The ethX naming scheme works fine as long as the system has only one Ethernet port. However if there are more than one Ethernet ports, the actual problem starts."

Comment: Re:They Why ZFS? (Score 1) 235

by dannycim (#34311710) Attached to: Running ZFS Natively On Linux Slower Than Btrfs

XFS is extremely prone to data corruption if the system goes down uncleanly for any reason. We may strive for nine nines, but stuff still happens. A power failure on a large XFS volume is almost guaranteed to lead to truncated files and general lost data. Not so on ZFS.

[Citation Needed] as wikipedia would say. XFS is no more prone to data corruption than any other journalled filesystem in the event of unexpected halts.

You should see the fireworks I got on Solaris 10 while I was running a script that did a bunch of zpool commands just as the power went out. Borked everything.

I love ZFS, but I'm not deluded into thinking it's magic.

Comment: Luxury! (Score 1) 397

by dannycim (#34221484) Attached to: Auto Industry's Fastest Processor Is 128Mhz

Luxury. We used to have to get out of the lake at six o'clock in the morning, clean the lake, eat a handful of gravel, work twenty hour day at mill for tuppence a month, come home, and Dad would thrash us to sleep with a broken bottle, if we were lucky!

Meanwhile I'm working on a micro-controller project that runs at 500Hz (not kilo, just hertz).

If you keep the code tight and hand-craft it, 128Mhz is blindingly fast.

Comment: Here's how I'd do it. (Score 3, Insightful) 332

by dannycim (#34183628) Attached to: Sophos Researcher Suggests Password 'Free' to Spur Wi-Fi Encryption

1. Bring laptop with extra WiFi dongle into a public area.
2. Connect to Free WiFi spot using internal nic.
3. Act as an Access Point on second nic with a cooler sounding SSID.
4. NAT traffic to first WiFi net and grab everything of interest.
5. ???
6. Profit!!!1!!ONE!

Make it right before you make it faster.