snarlydwarf Wrote: > Guess I should explain jitter for grins and cause I'm bored :P > A hard drive doesn't (assuming it works) have that problem: it has > external timing. In addition to the 8-64 bits that it transfers at > once (oooold MFM drives like the ST506 transferred 8 bits at a time but > they haven't been used on PC's in 20 years), there is a "okay, the data > bits are valid ... NOW!" bit which is set when all the bits are driven > properly on the bus, so the controller knows that it can read them. > Timing isn't an issue: which is why you don't have to swap hard drive > controllers when moving from a slow 3600rpm drive to a 7200rpm drive or > faster. The timing is delivered with the data. The only thing you'd > notice when swapping between fast and slow drives is that the disc is > either faster or slower... the bits would still be the same. (And even > a slow hard drive is fast enough to drive 44.1kbps.) > >
Thanks for explaining most of the important bits (haha) Even better these days is SATA, which turns the bits into a stream of checksumed packets, which is even better. I will note that I once found a drive in a machine that would randomly corrupt 4 bytes of a file. I had a good copy of the file, would write it to disk, read it back and do a binary diff (hexdump+diff) of the two files.. same 4 bytes.. different each time I would write that one file.. that was messed up.. This is why I store all my music in FLAC. FLAC uses internal checksums to verify file integrity, you can use the command line utility flac -t to test. If you're really paranoid, you could generate md5sums of the whole file and store them redundant off-site.. maybe in a gmail account. md5sum *.flac | mail -s "sums for $(pwd)" [EMAIL PROTECTED] :) A good friend of mine makes his living building tube amps (shameless plug for atma-sphere.com) and we had a long argument one night over single-speed belt-drive CD transports, and just using an IDE drive with cdparanoia. After much debate, he went off and did some tests, and determined that riping/enoding to flac, and playback through a good digital output card to a good quality dac (he uses a bel canto dac 2) is one of the best solutions. I also was talking to him recently about the bel canto dac 3.. which has a USB input, which should eliminate the whole no clock problem with SPDIF. :) -- SuperQ ------------------------------------------------------------------------ SuperQ's Profile: http://forums.slimdevices.com/member.php?userid=2139 View this thread: http://forums.slimdevices.com/showthread.php?t=24616 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/audiophiles
