Why not use ICMP echo instead?
on
Parasitic Computing
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· Score: 3, Interesting
ICMP echo packets (ping packets) also includes a checksum. By using the ICMP checksum instead of the TCP checksum, almost every computer connected to the Internet could be used for computation, not only web servers.
Nope, WAP does not run on top of TCP/IP. Take a look at this slide from an overview presentation of WAP (slide from the official WAP site, wapforum.org). Even if the address you enter in your WAP phone is an IP address, it does not necessaraly mean that WAP uses IP. WDP might use the same address format as IP, or they are using some IP -> WDP address translation.
This is why WAP needs to have a proxy - even if WAP sites could speak WML natively over HTTP/TCP/IP, it still has to be translated into WAE/WSP/WTP/WTLS/WDP by the WAP proxy.
> A protocol built on top of UDP could interpret lost packets however it chose to.
The problem is that you'd nevetheless have to use some form of congestion control - i.e., to lower your sending rate when buffers in routers are overflowed. If a major application didn't use congestion control, the Internet would go into congestion collapse as it did in the 80's.
TCP uses packet drops as a sign of congestion. This works well in wired networks where packets seldom are dropped due to bit errors on the links and almost all packets are dropped by routers who's buffers are full. Wireless links on the other hand may have masses of bit errors from time to time, which makes TCP's assumption turn out pretty bad. Of course, it does not matter that it is TCP that makes this assumption; any application using UDP would have to make the same assumption.
The real problem is that there is bad feedback from the network. The end-points cannot know that a packet was dropped due to congestion or to bit errors. ECN (Explicit Congestion Notificaton) is a way to add active congestion feedback, and there are other proposals to add stuff like ELN (Explicit Loss Notification) to the Internet, or at least to add it in those parts of the Internet where wireless links are used.
Solaris is not a derivative of Berkeley's work. Earlier versions of SunOS was BSD-based, but Solaris 2.x and upwards (with SunOS 5.x) are based on System V which has evolved from AT&T's closed versions of Unix.
I haven't read those new RFCs, but from what I've heard one thing that has been added is better "batch processing". Old SMTP requried quite a few round trip-times in order to send a message; first the TCP handshake, then the HELO with its answer, the RCPT with its answer, then the DATA and an answer.
The new RFCs should apparently make it possible to make the HELO, RCPT and DATA in one round trip-time. This would benefit those space-travellers with their long round trip-times!
Yepp, and it is also worth noting that the RFCs that describe IP version 4 (RFC791), ICMP (RFC792) and UDP (RFC768) are even older (they are from 1980 and 1981). Ok, ICMP has changed a lot since RFC792 and a few options has been added to IP, but UDP is the same.
I've been reading about embdedded Linux from time to time, but I've never really understood why we should be so excited about it. No, I'm not a troll, all I am saying is that whlie I understand why people are excited about Linux for PCs, I don't really see how Linux in my washing machine should be that cool. Myself, I run nothing but Linux and BSD on my PC and I am into the free software thinking and all that.
But don't really see what we gain by putting Linux in every toaster everywhere. Why should we fight for free software in embedded systems, where we never even get in touch with the code?
Of course, free software is philosophically more correct than propriatary software, even in embedded systems. But still, what does it give us in return? We can never change the software in our toasters or our stereos, so why should we go out and put Linux in there?
What do we (the free software movement) gain from this? The makers of embedded systems get a lot of good software for free, but does it give us something in return? The software for embedded systems is very closely tied with the hardware, which is proprietary. So any source code they have to publish will be nothing but drivers for their specialized hardware.
I tried bash the other day, and being a regular tsch:er, I was surprised that bash didn't have programmable completion. I have always found that this is one of the largest benefits in tcsh. But, now one might try out the zsh!
Also, zsh probably is a lot better for scripting than tcsh.
An IPv4 stack needn't be that large. There are many IPv4 implementations out there that are suitable for small devices. My own IPv4 stack lwIP is between 10k and 20k (depending on your configuration) and is optimized for using low amounts of RAM. It has hooks for implementing IPv6 as well, and the extra code will probably not be that large.
Moreover, there is no need to implement all of IPv6 in a small device, only the bare bones functionality should suffice.
As a side note, CPUs are getting faster and less power consuming, and memory is getting cheaper so in the near future our cell phones will be nearly as powerful as yesterday's PCs.
Wouldn't it be possible to patent or copyright your surfing habits? You could say that your surfing habits are an artwork made by you, and therefore belongs to you. If the web ad companies use the information of your surfing habits, you would be able to sue them for copyright infringement or make them pay you licencing money for using you patent. Stranger things have been patented lately, so it doesn't seem *too* impossible.
This would not only make it possible for us normal web users to make a few bucks, but should also shut down this act of privacy violation rather quickly!
"The earliest (and most popular) renditions of the BSD Daemon were created by John Lasseter. [...] The copyright holder and creator of the daemon image is Marshall Kirk McKusick." (Emphasis mine.)
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ICMP echo packets (ping packets) also includes a checksum. By using the ICMP checksum instead of the TCP checksum, almost every computer connected to the Internet could be used for computation, not only web servers.
Nope, WAP does not run on top of TCP/IP. Take a look at this slide from an overview presentation of WAP (slide from the official WAP site, wapforum.org). Even if the address you enter in your WAP phone is an IP address, it does not necessaraly mean that WAP uses IP. WDP might use the same address format as IP, or they are using some IP -> WDP address translation.
This is why WAP needs to have a proxy - even if WAP sites could speak WML natively over HTTP/TCP/IP, it still has to be translated into WAE/WSP/WTP/WTLS/WDP by the WAP proxy.
> A protocol built on top of UDP could interpret lost packets however it chose to.
The problem is that you'd nevetheless have to use some form of congestion control - i.e., to lower your sending rate when buffers in routers are overflowed. If a major application didn't use congestion control, the Internet would go into congestion collapse as it did in the 80's.
TCP uses packet drops as a sign of congestion. This works well in wired networks where packets seldom are dropped due to bit errors on the links and almost all packets are dropped by routers who's buffers are full. Wireless links on the other hand may have masses of bit errors from time to time, which makes TCP's assumption turn out pretty bad. Of course, it does not matter that it is TCP that makes this assumption; any application using UDP would have to make the same assumption.
The real problem is that there is bad feedback from the network. The end-points cannot know that a packet was dropped due to congestion or to bit errors. ECN (Explicit Congestion Notificaton) is a way to add active congestion feedback, and there are other proposals to add stuff like ELN (Explicit Loss Notification) to the Internet, or at least to add it in those parts of the Internet where wireless links are used.
Solaris is not a derivative of Berkeley's work. Earlier versions of SunOS was BSD-based, but Solaris 2.x and upwards (with SunOS 5.x) are based on System V which has evolved from AT&T's closed versions of Unix.
I haven't read those new RFCs, but from what I've heard one thing that has been added is better "batch processing". Old SMTP requried quite a few round trip-times in order to send a message; first the TCP handshake, then the HELO with its answer, the RCPT with its answer, then the DATA and an answer.
The new RFCs should apparently make it possible to make the HELO, RCPT and DATA in one round trip-time. This would benefit those space-travellers with their long round trip-times!
Yepp, and it is also worth noting that the RFCs that describe IP version 4 (RFC791), ICMP (RFC792) and UDP (RFC768) are even older (they are from 1980 and 1981). Ok, ICMP has changed a lot since RFC792 and a few options has been added to IP, but UDP is the same.
I've been reading about embdedded Linux from time to time, but I've never really understood why we should be so excited about it. No, I'm not a troll, all I am saying is that whlie I understand why people are excited about Linux for PCs, I don't really see how Linux in my washing machine should be that cool. Myself, I run nothing but Linux and BSD on my PC and I am into the free software thinking and all that.
But don't really see what we gain by putting Linux in every toaster everywhere. Why should we fight for free software in embedded systems, where we never even get in touch with the code?
Of course, free software is philosophically more correct than propriatary software, even in embedded systems. But still, what does it give us in return? We can never change the software in our toasters or our stereos, so why should we go out and put Linux in there?
What do we (the free software movement) gain from this? The makers of embedded systems get a lot of good software for free, but does it give us something in return? The software for embedded systems is very closely tied with the hardware, which is proprietary. So any source code they have to publish will be nothing but drivers for their specialized hardware.
Could somebody please enlighten me!
I tried bash the other day, and being a regular tsch:er, I was surprised that bash didn't have programmable completion. I have always found that this is one of the largest benefits in tcsh. But, now one might try out the zsh!
Also, zsh probably is a lot better for scripting than tcsh.
An IPv4 stack needn't be that large. There are many IPv4 implementations out there that are suitable for small devices. My own IPv4 stack lwIP is between 10k and 20k (depending on your configuration) and is optimized for using low amounts of RAM. It has hooks for implementing IPv6 as well, and the extra code will probably not be that large.
Moreover, there is no need to implement all of IPv6 in a small device, only the bare bones functionality should suffice.
As a side note, CPUs are getting faster and less power consuming, and memory is getting cheaper so in the near future our cell phones will be nearly as powerful as yesterday's PCs.
Wouldn't it be possible to patent or copyright your surfing habits? You could say that your surfing habits are an artwork made by you, and therefore belongs to you. If the web ad companies use the information of your surfing habits, you would be able to sue them for copyright infringement or make them pay you licencing money for using you patent. Stranger things have been patented lately, so it doesn't seem *too* impossible.
This would not only make it possible for us normal web users to make a few bucks, but should also shut down this act of privacy violation rather quickly!
... this sounds kinda insane to me... but then, what do I know?
This page from over at freebsd.org states:
"The earliest (and most popular) renditions of the BSD Daemon were created by John Lasseter. [...] The copyright holder and creator of the daemon image is Marshall Kirk McKusick."
(Emphasis mine.)
> ...and start seriously thinking about proper
> change control - perhaps a CVS system instead
> of randomly throwing out tarballs.
Are you seriously saying that they don't use CVS?
Running ident(1) on some of the kernel files shows that atleast someone is using either RCS or CVS.
Perhaps I am missing your point. Do you mean that there should be a public anoncvs that allows the users to check out the newest version?
Would public schools be able to afford this computer along with a telephone line?
In that case, this project could be a success in that respect.
BIND apparently has a BSD-style licence so Microsoft may very well have used BIND code in their "own" software.
They have done similar things with the BSD TCP/IP stack.