What bootloader is that exactly, that allows the fast baud rate when using the UNO as ISP?
sTrider_7:
What bootloader is that exactly, that allows the fast baud rate when using the UNO as ISP?
The context of your question is difficult to divine from the way you quote. I assume you are referring to this...
• Uno running TinyISP
If that is the subject matter then the bootloader is irrelevant.
I suspect sTrider_7 is actually referring to this
• Uno with a 250K baud bootloader
which, given the topic context, he think is using the Uno as an ISP and programming w/o a bootloader (rather than comparing the performance of a fast bootloader on the Uno with various ISP programmers.)
• Uno with a 250K baud bootloader
Is this a optiboot that is not currently supplied with the Arduino IDE? Is there a link the code for this?
By the way Coded Badly, thanks for the break down of programmer speeds!
im also fascinated by relative speed of various programming methods. of the half dozen ive tried bootloader beats others hands down. lpt 4 wire slowest (probably due to 1us pc in/out penalty. however unlike coding i notice no difference between 115k and 230k. it would be interesting to see how those baud rates fit in with maximum theoretical atmel burn time. ie is there really any room for improvement over 115kb download of a hex file. btw i never verify because imo theres no point.
cyclegadget:
• Uno with a 250K baud bootloader
Is this a optiboot that is not currently supplied with the Arduino IDE?
Yes. It is not supplied with the Arduino IDE. The one that comes with the IDE is configured for 115200 baud.
Is there a link the code for this?
Unfortunately, no. I don't think I even kept a copy of it. I built it solely to answer two questions, "Does baud rate make a significant difference?" and "Is 250000 baud reliable?"
The answer to the second question is "yes", 250K baud is reliable. I suspect 500K is also reliable but I have not performed any testing.
The answer to the first question...
Arduino 1.0.1-rc2, Avrdude 5.11
#1: Uno, Optiboot 3.3, 115200 baud: 2821.8
#2: m328p on a breadboard w/ Pololu as converter, Optiboot 4.4, 115200 baud: 3403.1
#3: m328p on a breadboard w/ Pololu as converter, Optiboot 4.4, 250000 baud: 5313.9
The serial converter makes a difference (#1 versus #2). The Pololu appears to be a more efficient converter.
The baud rate makes a big difference (especially on the verify pass) (#2 versus #3).
By the way Coded Badly, thanks for the break down of programmer speeds!
You are welcome. If I ever have time, I'll write-up the details (and try to remember to post a link here).
Thanks for the info Coding Badly 
More details and Optiboot compiled for higher baud rates...
http://zygomorphic.com/arduino-tiny/?page_id=249
Thanks for the link! It is a good read but, it seems that the link for the bootloader files is no longer active. It leads to a page related to signing up to Rowdy Dog Software for information???
Ouch. Sorry about that. I'll get it fixed in a minute...
Fixed.
thanks for that link coding badly. i found it very informative. it explains why i didnt see a huge difference between 115k and 230k. at least not like the 100x-200x usbasp speed improvement i got with the version of avrdude bill perry built for me.
ps too bad he didnt include 57k. that might have been interesting too.
john1993:
thanks for that link coding badly.
You are welcome.
it explains why i didnt see a huge difference between 115k and 230k.
Should have seen some improvement (up to 24%).
at least not like the 100x-200x usbasp speed improvement i got with the version of avrdude bill perry built for me.
Skipping FFs?
yeah. it has already saved me literally man-days of staring at that cursed progress bar.
as far as the baud rate, more like 20% in my case. the difference between 5sec and 6sec is not noticeable to me.
Thanks Coded Badly!
I installed the 500,000 baud bootloader on two Uno's. The bootload went perfectly, and I couldn't be happier! I loaded the blink without delay sketch in a couple seconds! I know that is a small sketch but, it did seem to load a lot faster. If one's and zero's made noise, the best way to describe it was WAAAMMM done!