catting weird things to /dev/audio

1. The concept of devices as files
2. Standard input/output redirection to/from files (implemented with > and < in Bash)
3. /dev/audio

The trick is finding ways to get interesting patterns out of the speakers. One way to do this is to write simple programs:

int n=0, i=1;
for(;;) {
     cout << char(n+=i);
     if (n>255 || i<=0) {i++; n = n % 255;}
} 

If this particularly interests you, you may download a sampling of crud i have created (mostly with this method) at http://charon.sjs.org/~mcc/awk

mcc's mention of catting your hard drive to /dev/audio has made me notice a peculiar thing; different filesystems sound noticeably different. Specifically:

• ext2 sounds like a deep, mostly monotonous buzzing
• reiserfs sounds like static (or modem noises) overlaid with a startlingly regular repeating tone
• FAT32 sounds like a high-frequency triangle wave (much more jarring than ext2 or reiserfs)
• NTFS sounds almost like machine-gun fire, or a badly skipping audio CD
• BeFS sounds like radio static with arhythmic beeps.

These measurements were made under Linux 2.4, with the ALSA sound drivers version 0.9.0beta6, and a SoundBlaster Live! sound card.

Data     :ADRGESHTFDZDRSRGSEWERT00000000000000000000
Waveform :/\/\/\\\\///\/\/\/\/\_____________________

Data     :FF00F000FF00FFF0FF00FFF0F000FF00
Waveform :MM__M___MM__MWM_MM__MWM_M___MM__