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Hi,
I'm kinda new to LUGNET, so if I get this wrong - sorry!
I'm interested in this LNP idea that seemed to be floating around a few months
ago. Is it still alive, and if so what state has it got to? I would be
grateful if someone can post or e-mail me the current state of LNP (even if it
has died!) & where I might find more info on the work & thoughts up till now.
Also:
In lugnet.robotics.rcx.legos, Jacob S. Barrett writes:
>
> 32+PAYLOADLEN-32+PAYLOADLEN+16: CRC16 was an idea thrown out as a
> solution. Might be overkill?
I'm curious here. Was CRC16 thrown out coz it was too CPU intensive? If so,
may I suggest the following algorithm (Minus typos!):
unsigned short
checksum(
unsigned char *data,
unsigned length
) {
unsigned char a = 0xff;
unsigned char b = 0xff;
while (length > 0) {
a = a + *data;
b = b + a;
data++;
length--;
}
return a + (b * 256);
}
It may look simple, but it is about as effective as CRC16 (It is actually
derived, if my memory serves me right, from somewhere within OSI protocol
Level 4). Even if it doesn't end up in LNP, it is worth sticking in your
software toolbox, as it is soooo easy & quick to implement.
Kevin.
}
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Message has 1 Reply:
 | | Re: LNP Repost
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| (...) I remember that! But aren't you supposed to do it mod 255 for maximum effectiveness? Cheers, Ben. -- (URL) grandfather once told me that there are two kinds of people: those who work and those who take the credit. He told me to try to be in (...) (25 years ago, 27-Jul-99, to lugnet.robotics.rcx.legos)
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Message is in Reply To:
| | LNP Repost
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| I thought it might be good to repost this with some changes... Okay a little smaller... Only a 4 byte header... |0|1|2|3|4|5|6|7|0|1...3|4|5|6|7| ---...--- | 0xF | VER | TOADDR | PORT| FRADDR | PORT| PAYLOADLEN | ---...--- / PAYLOAD / ---...--- / (...) (25 years ago, 16-Apr-99, to lugnet.robotics.rcx.legos)
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