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0 pointsthesz3mo ago0 comments

They build channels on top of these "promises" and "futures" and this made them square into communicating sequential processes category. Also, you can look at promise-future pair as a single-element channel, again, it's CSP.

BTW, Erlang does not implement CSP fully. Its' interprocess communication is TCP based in general case and because of this is faulty.

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yetihehe3mo ago

It is not TCP based. In Erlang processes have mailboxes. But they don't have promises, you send a message and wait for response with timeout or do something else. And TCP is only used between nodes (vm instances). But you can use any communication channel (UDP, unix sockets, tls, serial port, some other process doing funny things).

> Its' interprocess communication is TCP based in general case and because of this is faulty.

What? It's faulty because of TCP? No, in Erlang it is assumed that communication can be faulty for a lot of reasons, so you have to program to deal with that and the standard library gives you tools to deal with this.

theszOP3mo ago

There is no such thing as "Communicating Sequential Processes with faulty channels and processes." I tried to find something like that, fruitlessly.

This means that Erlang does not implement CSP, it implements something else.

Again, general case of communication between Erlang processes includes communication between processes on different machines.

pmarreck3mo ago

> BTW, Erlang does not implement CSP fully.

Specific evidence?

> Its' interprocess communication is TCP based in general case

No, it is not. Only between machines is that true.

> and because of this is faulty.

LOL, no. Why are you rolling with "speaking a whole lot of BS based on ignorance" today?

On the other hand, I now understand that one impediment to Elixir adoption is apparently "people repeating a lot of bullshit misinformation about it"

theszOP3mo ago

  >> Its' interprocess communication is TCP based in general case
  > No, it is not. Only between machines is that true.

It is true for communication between two VMs on same machine, isn't it?

The general case includes same-VM processes, different VM processes and also different VMs on different machines.

  > Why are you rolling with "speaking a whole lot of BS based on ignorance" today?

TCP is unreliable: https://networkengineering.stackexchange.com/questions/55581...

That was acknowledged by Erlang's developers before 2012. I remember that ICFP 2012 presentation about Cloud Haskell mentioned that "Erlang 2.0" apparently acknowledged TCP unreliability and tried to work around.

theszOP3mo ago

Here, page 31 on: https://wiki.haskell.org/wikiupload/4/46/Hiw2012-duncan-cout...

Erlang circa 2012 was even less reliable than TCP on which its interprocess communication was based.

Namely, TCP allows for any prefix of messages m1,m2,m3... to be received. But Erlang circa 2012 allowed for m1,m3... received, dropping m2.

It may be not case today, but it was case about ten years ago.

j / k navigate · click thread line to collapse

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yetihehe3mo ago

> Its' interprocess communication is TCP based in general case and because of this is faulty.

theszOP3mo ago

There is no such thing as "Communicating Sequential Processes with faulty channels and processes." I tried to find something like that, fruitlessly.

This means that Erlang does not implement CSP, it implements something else.

Again, general case of communication between Erlang processes includes communication between processes on different machines.

pmarreck3mo ago

> BTW, Erlang does not implement CSP fully.

Specific evidence?

> Its' interprocess communication is TCP based in general case

No, it is not. Only between machines is that true.

> and because of this is faulty.

LOL, no. Why are you rolling with "speaking a whole lot of BS based on ignorance" today?

On the other hand, I now understand that one impediment to Elixir adoption is apparently "people repeating a lot of bullshit misinformation about it"

theszOP3mo ago

  >> Its' interprocess communication is TCP based in general case
  > No, it is not. Only between machines is that true.

It is true for communication between two VMs on same machine, isn't it?

The general case includes same-VM processes, different VM processes and also different VMs on different machines.

  > Why are you rolling with "speaking a whole lot of BS based on ignorance" today?

TCP is unreliable: https://networkengineering.stackexchange.com/questions/55581...

theszOP3mo ago

Here, page 31 on: https://wiki.haskell.org/wikiupload/4/46/Hiw2012-duncan-cout...

Erlang circa 2012 was even less reliable than TCP on which its interprocess communication was based.

Namely, TCP allows for any prefix of messages m1,m2,m3... to be received. But Erlang circa 2012 allowed for m1,m3... received, dropping m2.

It may be not case today, but it was case about ten years ago.

j / k navigate · click thread line to collapse