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Show HN: ZFS Implementation in Python

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Re: Show HN: ZFS Implementation in Python

#81

Post by pjmlp »

nine_k wrote: post #57
cure wrote: post #16

Earlier quoted context omitted.

PyPy is faster than Python, yes. But Go, C and many other (compiled) languages are way faster than PyPy. Plus, if you use a language like Go or Rust then you avoid Python's GIL and you'll have much more reasonable memory usage. Best of all, deploying is a matter of copying a binary, rather than having to deal with the absolute disaster that is Python packaging.

Go? A GC'd language in kernel? (Well, yes, this has been done, from Lua to Haskell, but only experimentally.)

I wouldn't consider the workstations sold by Xerox, TI, Connecting Machines, the OS research department at ETHZ or the Microsoft’s natural language search service for the West Coast and Asia, just experiments.

Re: Show HN: ZFS Implementation in Python

#82

Post by pjmlp »

twa927 wrote: post #78
auscompgeek wrote: post #70

Earlier quoted context omitted.

CPython and PyPy are both VMs, similarly to the JVM.

I meant the inside of a VM (its implementation), which is coded in C/RPython. Java's VM is coded in C++, but I don't think C++ is used for any regular library functions, while C is used heavily for Python's stdlib.

Not all JVMs are implemented in C++.

It is a specification with multiple implementations, some of them are even bootstrapped in Java.

Re: Show HN: ZFS Implementation in Python

#83

Post by deaddodo »

cure wrote: post #16
j88439h84 wrote: post #6

Earlier quoted context omitted.

Dont forget, pypy is fast.

PyPy is faster than Python, yes. But Go, C and many other (compiled) languages are way faster than PyPy. Plus, if you use a language like Go or Rust then you avoid Python's GIL and you'll have much more reasonable memory usage. Best of all, deploying is a matter of copying a binary, rather than having to deal with the absolute disaster that is Python packaging.

> Plus, if you use a language like Go or Rust then you avoid Python's GIL

No, but then you run into Go's GC and green threads. File systems fit squarely in the realms of "systems programming" (old definition [1], not new). Languages like Ada, Pascal, C/C++, Rust and D (without GC).

[1] - https://en.wikipedia.org/wiki/System_programming_language

Re: Show HN: ZFS Implementation in Python

#85

Post by twa927 »

mehrdadn wrote: post #65
j88439h84 wrote: post #6

Earlier quoted context omitted.

Dont forget, pypy is fast.

I routinely fail to get speedup on PyPy. In fact I frequently get slowdowns. I imagine it's only fast if your code is slower than it needs to be to begin with.

It works well for tight loops processing much data, or heavy object-orientation (multiple levels of class hierarchies). It probably won't work well for regular Django webapps or scripts. Also, real-world Python numerical/AI code uses numpy/ML libs so there's not much to optimize in Python...

Re: Show HN: ZFS Implementation in Python

#86

Post by fnord123 »

cure wrote: post #16
j88439h84 wrote: post #6

Earlier quoted context omitted.

Dont forget, pypy is fast.

PyPy is faster than Python, yes. But Go, C and many other (compiled) languages are way faster than PyPy. Plus, if you use a language like Go or Rust then you avoid Python's GIL and you'll have much more reasonable memory usage. Best of all, deploying is a matter of copying a binary, rather than having to deal with the absolute disaster that is Python packaging.

>PyPy is faster than Python, yes.

Python is only slow if you use it wrong:

https://apenwarr.ca/diary/2011-10-pycodeconf-apenwarr.pdf

Re: Show HN: ZFS Implementation in Python

#88

Post by zymhan »

atomicwrites wrote: post #60
mfsch wrote: post #49

Does someone know whether it would be legal for someone to go through the ZFS code and write a specification of the features this author hasn’t figured out yet? I.e. could someone write a detailed description of the missing functionality that doesn’t include any details about the implementation so other people can implement it in non-CDDL code?

That's called a clean room implementation and was the standard way to make x-compatible products (like for example, the bios on an IBM PC clone). Not sure what the current legal standing of that method is. EDIT: Ninjad because I left the reply in a tab without posting.

Reverse engineering is legal in the US, but you had better have detailed records proving no one who knew the insides of the original product ever influenced the clone. And be prepared to explain that in court.

Re: Show HN: ZFS Implementation in Python

#89

Post by Someone »

mfsch wrote: post #49

Does someone know whether it would be legal for someone to go through the ZFS code and write a specification of the features this author hasn’t figured out yet? I.e. could someone write a detailed description of the missing functionality that doesn’t include any details about the implementation so other people can implement it in non-CDDL code?

The on-disk format is available (http://www.giis.co.in/Zfs_ondiskformat.pdf)

That PDF says ”Unless otherwise licensed, use of this software is authorized pursuant to the terms of the license found at: http://developers.sun.com/berkeley_license.html”*. That link is broken, but it seems that’s Berkeley license (whatever that means for a specification, and for which variant?)

According to http://open-zfs.org/wiki/Developer_resources, its outdated, but still useful.

I think I would use that, rather than spend months diffing disk images.

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