Well, I started my first really big transfer to my empeg last night, and I wake up (7 or 8 hours later) and it is still going! (Although it has made some serious progress.) I figured it would take a while, and this normally wouldn't be a problem, except for the fact that I'm supposed to leave on a really long (19 hr) car trip in an hour and a half, which looks like may (or may not) cut off the transfer. So my question is, what ill-effects occur if I have to unplug that usb cable when I have to leave? Does it stop neatly, or am I going to corrupt the filesystem or something? Will I be able to play all the playlists that have transferred so far?

Also, I'm correct in assuming the USB is faster that the 10 Mbps Ethernet transfer, yes?
And the 10 Mbps ethernet is limited (from 100 Mbps) in hardware, not software right? It would be nice to speed up those displayserver backups :) (btw Frank, impressive program, thanks)

Thanks,

John

30 GB - Mk2a (Rio Car) - BLUE

Im not sure what will happen if you interrupt the transfer, but in the future, you may want to try ethernet because its faster :-)

Sean

I have had mine freeze during a sync and the files that had already been transferred show up fine

usb = 12 Mbps (1.5 MB) ethernet = 10 MBps

I know it sounds strange, but I think emplode does a lot of error checking on usb that it doesnt need to do for ethernet. Thus, its slower.

Sean

USB (v1.1) = 12Mbps
10Base-T Ethernet = 10Mbps

Mbps = Megabits per second

Edwin de Vaan
mk2 rev.7 # 080000263 (queue 1232) 6+20Gb blue/red

sorry I thought it was in bytes for ethernet

Yeah, but don't let the numbers fool you, ethernet is faster.

(list 6284, Mk1 S/N 00299 4GB blue [for sale]. Mk2 S/N 080000094 6GB blue)

Yeah, what he said.

Sure, the theoretical maximum bit rate for USB is higher than for ethernet. But in practice, ethernet's long-term sustained transfer rates are higher when sending files to the Empeg.

I don't know exactly why, but I'm sure there's several good reasons for it.

___________
Tony Fabris

When putting files to the empeg via TCP/IP, you don't have to worry about error correction and resend (That's part of the TCP layer).

With USB you have to do your own packet validation, which slows down the protocol at both ends, and means you have to send more data (all the checksums).
Also (at least in windows) USB has some reserved bandwidth settings (By default, my windows installation reserves 10% of the bandwidth for "system")

Mind you, if you have lots of ethernet devices on your network, you'll likely see a slowdown due to collisions...
YMMV...

Jazz
(List 112, Mk2 12 gig #40. Mk1 4 gig #30. Mk3 1.6 16v)

FWIW:

Transferring 8 mp3 files, first via USB and then via ethernet:

USB:



        emptool --usb /dev/ttyUSB0



Result:



        Transferred 13511068 bytes in 30.389429 seconds, 444597.625013 bytes/sec

        Transferred 13445716 bytes in 29.717606 seconds, 452449.507041 bytes/sec

        Transferred 14333458 bytes in 32.297737 seconds, 443791.400804 bytes/sec

        Transferred 15438454 bytes in 34.266193 seconds, 450544.763591 bytes/sec

        Transferred 10144620 bytes in 22.350897 seconds, 453879.773807 bytes/sec

        Transferred 10930186 bytes in 24.453403 seconds, 446980.151950 bytes/sec

        Transferred 11847606 bytes in 27.390331 seconds, 432547.013906 bytes/sec

        Transferred 11962999 bytes in 26.944464 seconds, 443987.273970 bytes/sec



Average:



                    12701763 bytes in 28.476258 seconds, 446097.188760 bytes/sec



Ethernet:



        emptool empeg-car



Result:



        Transferred 13511068 bytes in 23.165836 seconds, 583232.472382 bytes/sec

        Transferred 13445716 bytes in 23.202858 seconds, 579485.338259 bytes/sec

        Transferred 14333458 bytes in 24.696688 seconds, 580379.772991 bytes/sec

        Transferred 15438454 bytes in 26.170258 seconds, 589923.655114 bytes/sec

        Transferred 10144620 bytes in 16.904146 seconds, 600126.139664 bytes/sec

        Transferred 10930186 bytes in 18.598417 seconds, 587694.416907 bytes/sec

        Transferred 11847606 bytes in 20.452353 seconds, 579278.397740 bytes/sec

        Transferred 11962999 bytes in 20.248751 seconds, 590801.831932 bytes/sec



Average:



                    12701763 bytes in 21.679913 seconds, 586365.253124 bytes/sec

I think this means:

Ethernet is 31.4% faster and takes 23.8% less time than USB.

Alternately:

USB is 23.9% slower and takes 31.3% more time than Ethernet.

Six of one, half a dozen of the other, take your pick.

YMMV.

Disclaimer: Tests were run on hardware of dubious reliability under the watchful eye of JAFI, and may require a suitable application of a PCR Tool. Don't take internally. May cause drowsiness. Brush after every meal. Signal before merging.

As far as I know the Ethernet is limited to 10MB becuase the Strongarm processer does not support DMA. I heard somewhere that the 100Mb Ethernet chipsets all use DMA to achieve those speeds. I could be wrong though. --Aaron

[stop the technology madness]

As far as I know the Ethernet is limited to 10MB becuase the Strongarm processer does not support DMA.

I heard it differently.

As I understand it, the reason the Empeg's ethernet is only 10mbps is because it only uses an ISA bus. In order to use the faster 100mbps ethernet chips, they would have had to re-do the entire motherboard to support a (more expensive) PCI bus.

At that point, whether or not the ARM processor does DMA or not is a moot point, I think.

___________
Tony Fabris

I just want to know when we'll see 802.11b in this baby

Can't wait until I can just sit in my apartment and upload mp3 files over wireless ethernet to my car outside.

--Chris Willenbrock
MK2 | 12GB | Queue Registration # 2 (really!)

You can already . The empeg guys did a nice demo in Amersfoort of a wireless LAN connection to their demo car - they have a Apple AirPort hub sitting in the back of the car on top of their Subwoofer (there are pictures somewhere) and a cable running from that forward to the empeg. The AirPort hub runs on 12V DC anyway, which makes it all pretty easy really . There are plenty of other posts here on the subject if you are keen on doing it yourself.

(list 6284, Mk1 S/N 00299 4GB blue [for sale]. Mk2 S/N 080000094 6GB blue)

Also search the board for "Orinoco" which is the wireless kit myslelf and some others are using. Advantage is that you don't need a hub in the car.

- --
Rod, UK Mk2 64gig Red S/No.341 2xDell RioReceiver

Hmmm...I was only half serious ;)

I'm certainly intrigued by the idea, but it's probably much more of an undertaking than I can handle. You guys are smarter than I am ;)

I'm curious though...wouldn't the empeg lose power when the car is off? The empeg would have to be powered before it could actually do anything. I'm sure it can be arranged, but I'm sure it's a lot more involved than I'm gonna get right now.

--Chris Willenbrock
MK2 | 12GB | Queue Registration # 2 (really!)

USB slave chipsets are generally awful, and USB has a lot else that eats into transfer time - this is why USB is slower than ethernet on the empeg.

The ethernet chipset has 16-bit wide access to it, a decent amount of buffer, and generally is happy with saturating the wire (it doesn't on the carplayer due to some mmap bugs in linux 2.2 - these may be addressed in a future release which will give more speed over ethernet)

Hugo

Well, the empeg already does a polling thing on ethernet. But even just starting up and polling takes a bit of power for wavelan. More than I'd be comfortable with, anyway. I don't really see the appeal, though. That's probably because I rarely buy/get any new music, so I rarely need to upload anything.


Fly me to the moon...

yeah well...i have a lot more music to add to the player, but if i can't order another drive for my player it's a moot point.

then, there is the geek factor in getting wireless networking working. gives you bragging rights among your techie friends.

--Chris Willenbrock
MK2 | 12GB | Queue Registration # 2 (really!)

Absolutly

- --
Rod, UK Mk2 64gig Red S/No.341 2xDell RioReceiver

Oh, no question is wireless a great technology. I've been using it for years now, originally with a zoomair card in a linux desktop configured as a base station. The freedom of moving around with one's laptop...and less cable clutter..wonderful. I just don't see it as a good idea for my car since I'm 9 floors up in my apartment building, anyway. ;) And the previously stated reasons of course.

Fly me to the moon...