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Exceptionally Slow SD Card Upload Speeds

Posted: Sun Dec 08, 2013 7:58 pm
by Christian79
1) I have a iMAC and for the most part cannot print from it because the printer will eventually starve for data and kill the print.
2) I have no idea why this happens but as a work around I have been removing the SD card and saving directly to it.
3) The reason I remove the card is because it takes FOREVER to upload a file if I try to do it with the card in the MAX. ~= 2 Min/MB
4) My connection speed is 250k.

Any thoughts?

As a side note, since I upgraded to the most recent firmware, I keep getting 4096 byte "ghosts of my files.
For example iphhldr.gcd would have its own ghost called ip~dr.gcd

Re: Exceptionally Slow SD Card Upload Speeds

Posted: Sun Dec 08, 2013 9:21 pm
by Polygonhell
Christian79 wrote:1) I have a iMAC and for the most part cannot print from it because the printer will eventually starve for data and kill the print.
2) I have no idea why this happens but as a work around I have been removing the SD card and saving directly to it.
3) The reason I remove the card is because it takes FOREVER to upload a file if I try to do it with the card in the MAX. ~= 2 Min/MB
4) My connection speed is 250k.

Any thoughts?

As a side note, since I upgraded to the most recent firmware, I keep getting 4096 byte "ghosts of my files.
For example iphhldr.gcd would have its own ghost called ip~dr.gcd

Unfortunately that's normal, it's a combination of two issues, the SDCard is connected to the arduino by a SPI interface which is less that stellar, but the bigger issue is the USB connection between the computer and the arduino, because very small packets are sent, the USB latency becomes dominant.

The solutions as you've discovered is to plug the card into the computer and copy the file that way.

Re: Exceptionally Slow SD Card Upload Speeds

Posted: Mon Dec 09, 2013 3:08 pm
by Lochemage
I think most of the reason it is slow, is because when it copies to the SD card, it is actually simulating the print job. If you upload your gcode file to the SD card through the printer, and take a look at the manual control panel, you should see that every print move, heat setting, and fan toggle actually shows up on the screen as if it were printing the entire file. It does this in simulation mode so your printer doesn't actually move, but it still takes quite a long time.

Re: Exceptionally Slow SD Card Upload Speeds

Posted: Mon Dec 09, 2013 4:00 pm
by cope413
No, it's just slow because there's no processing power. It's an 8-bit board... It takes a looooonnnngg time to transfer 5-10mb of data with an 8-bit processor and 256k of RAM