[brudgers]

The same criticism with equivalent merit could be leveled against TCP because it lives as far the Physical Layer (OSI Layer 1) as HTTP lives from the transport layer...e.g. "TCP is implementing Ethernet's responibilities."

But of course, though we rarely worry about Token Ring these days, we do run TCP over IEEE 802.11 all the time.

Likewise, HTTP is run over other Transport Layer protocols even if it is less common, e.g. UPnP uses HTTP over the UDP transport layer protocol. http://en.wikipedia.org/wiki/Universal_Plug_and_Play#Protoco...

OSI's higher levels are abstractions. As is the case with all useful abstractions, they serve to implement the functionality of lower levels without requiring attention to their actual implementation. Not having to manage TCP allows a lot of useful JavaScript to be easily written.

[monstermonster]

That's a disingenuous and self contradictory description of how the OSI stack works.

There are upwards guarantees at each layer that the stack makes. All implementations within the layer must be equal to the next layer even if one of the implementations provides capability of higher layers. Nothing is said however about adding further guarantees in layers 8, 9, 10, 11, 12...and so forth because they have already been made.

I suppose I shouldn't use parity bits on serial connections then?

"Not having to manage TCP allows a lot of useful JavaScript to be easily written"

That's absurd. It makes no difference.

As for UPnP, which I know well having written an entire UPnP stack, it's a broadcast messaging layer, not a connection based protocol. All the HTTP messages stay within the size of a UDP datagram and it is expected to be wholly unreliable. Even though it's ugly, it's hardly a comparison.

I get the feeling a lot of people here are web developers with little experience of protocol stacks and not system programmers!

[brudgers]

I suppose I shouldn't use parity bits on serial connections then?

If you're writing at the level of serial connections and parity, by all means pay attention to those details. If you're writing at higher level, consider abstracting away such details in an interface, library or module.

I miss Wildcat BBS as much as the next person: by which I mean, not very much. HN is full of really fucking smart people not the idiots implied by your comment.

[monstermonster]

Huh? I think you missed something.

This is nothing to do with BBS's or code abstractions. On the former, there is no OSI stack; it's terminals down serial connections. On the latter, it's datagrams or sockets. It's about the guarantees that the link layer makes or doesn't. Parity doesn't pass up the layers because the guarantees are made further up (TCP).

You can still run token ring, serial, thick ether, thin ether, paper aeroplanes thrown between buildings. It doesn't matter above the data link layer.

Yes there are really fucking smart people here, as you put it but it appears there is a normal distribution of people as well.