Thanks for Dave's suggestion. I can send file smoothly now by using rz first
in gumstix side.
By a way, I am using a serial-2-usb adapter and my CPU speed is 2.4G Intel
thanks for Cliff anyway.
On 7/19/06, Cliff L. Biffle <cliff@...> wrote:
> On Jul 19, 2006, at 6:49 AM, Dave Hylands wrote:
> > You didn't mention starting rz fromk the console before doing the
> > zmodem send? I always start rz manually and then initiate the file
> > transfer.
> This isn't technically necessary, as the initial handshake sequence
> in a ZMODEM send starts with "rz\n".
Yeah, but if it starts sending characters too quickly after the rz but
before the command has a chance to run, then initial characters might
get dropped (which it shouold recover from, but it might also confuse
Loading rz the first time will also take considerably longer than
loading it the 2nd and subsequent times (I don't think rz is part of
Many serial-to-USB drivers do weird buffering which can screw up
z-modem. We did a whole lot of testing with the usb-serial gadget and
noticed some of this behaviour as well.
We observed similar problems with several commercial USB adapters.
Fundamentally, the problem is flow control. If you have a fast host,
it's possible for the host to deliver data faster than the processor
can process it. Admittedly, we were running a 150 MHz ARM processor at
Using rz to write to ram disk gives much more predictable behaviour
than using rz to write directly to flash, especially for the larger
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