How big is your library? > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Phil Karn > Sent: Friday, April 08, 2005 1:03 AM > To: Slim Devices Discussion > Subject: Re: [slim] Slim Devices SB2 disappointment & SB for sale. > > Robin Bowes wrote: > > > Can you show me where this claim is made? I'd be very surprised if > > this is true. For a start, the wired port on the SB1 is > only 10MB/s (I > > can't find a spec. sheet to confirm this, but the last > point here [1] says: > > > > - faster 100Mbps wired ethernet interface > > I do believe you're right; it's 10 Mb/s on the SB1. I checked > it by plugging it directly into my PowerBook and looking at > the interface settings, and also by plugging it into a > different hub that indicates link speed on the LEDs. > > But this doesn't really matter. A raw, uncompressed PCM audio > stream still takes up only 14% of a 10 Mb/s Ethernet port, so > there's no reason it should cause any kind of playback > interruption unless it's used on an ancient 10 Mb/s > non-switched hub with lots of contending traffic. I got rid > of all my hubs years ago. Every network port is switched and > supports full duplex up to 100 or 1000 Mb/s, depending on the > specific switch. The Linux box running SlimServer has a 1GB/s > connection, and nothing (server or network) is ever loaded > very heavily. > > > [1] http://www.slimdevices.com/su_faq.html#about2-difference > > > > I've got a wireless SB1, and until recently, I had no problems with > > dropouts caused by network bandwidth (I too play flac files > decoded on > > the server and streamed as raw PCM). > > I have two SB1s, but both are wired. I wanted to wait until > 802.11g was supported before buying a SB, so I got one of the > SB2s with wireless. > > But my playback interrupt problems were all over wired paths. > I would have expected problems on 802.11b, but not on an > all-wired path with plenty of capacity. > > > I agree with the point you make about threading and making the > > streaming part of slimserver work better, but I don't think > the SB or > > slimserver is particularly at fault in causing your > dropouts - there > > must be something in your environment that is causing the problem. > > Maybe the port you've got the SB plugged into is not auto-detecting > > the 10Base-T link? Have you checked? > > I'm quite sure all my LAN switches are working fine. The > playback interrupt problem is clearly due to sub optimum task > scheduling on the server. If I renice the slimserver and > related tasks up a few points, the playback interruptions > disappear, but at the expense of slowing down everything else > on the server whenever the Slimserver wants to do some > sustained maintenance activity like scanning the music > filesystem and rebuilding its database. The Slimserver code > should run at high priority only in its real-time-critical > sections, i.e., those directly involved in playing music. > Everything else (e.g., the UI) should run at normal priority. > Database reconstruction could even run at below-normal > priority, just to be nice to the other users. > > Another way to minimize playback interruptions is to use lots > of read ahead buffering inside the Slimserver playback path. > That covers you in case the disk is suddenly pre-empted by > another urgent I/O-intensive application. And if you can > decompress and buffer up a lot of raw PCM inside the server, > then you're also covered in case a high priority > compute-bound job comes along and pre-empts the FLAC/Ogg > Vorbis/AAC/etc decompresses (which are at least slightly > CPU-intensive). If you can manage to buffer up a lot of raw > PCM ready to transmit, then even if the server is busy > running other applications it should be able to spare the few > quick interrupt service calls needed to move that PCM to the > Ethernet transmitter and then to the Squeezebox. > > Obviously if the system running Slimserver doesn't have, on > average, enough disk I/O cycles and CPU cycles to supply a > full-rate stream to the Squeezebox, then none of this will > help much. But there's no reason why a fast, lightly loaded > machine like mine should have frequent problems keeping the > Squeezebox happy even when the occasional unrelated > load-burst comes along. > > Phil > _______________________________________________ > Discuss mailing list > [email protected] > http://lists.slimdevices.com/lists/listinfo/discuss >
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