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Comment by fmajid | Hacker News Reader

Hi Kragen!

Don't forget Darcs, Bazaar and Mercurial. I think it's the needs of Open Source collaboration that drove this convergent evolution of DVCS, and the real conceptual breakthrough getting rid of RCS-like sequential revision numbers.

The commercial world lagged. Certainly Apple were late adopters and didn't support git in Xcode in 2010 when Subversion was the only choice, and Microsoft of course was a late if enthusiastic adopter because of its Ballmer-era aversion to anything Linux.

I personally prefer Fossil and used its forge-like CVStrac in the guise of Gittrac for years, but for better or worse Git's tooling integration won out.

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hi fazal!

i mostly agree, and certainly didn't mean to slight darcs, bazaar and mercurial; darcs in particular was my version tracker of choice before switching to git

but i think 'the needs of Open Source collaboration' are somewhat more plastic and historically contingent than you imply. if you read producing open source software you'll see a snapshot of the dominant social practices of open source collaboration in the world git and bazaar were born into (which of course you also experienced, but others reading this comment may not have). those practices still survive in places, like netbsd and debian

arch, git, and family were designed to support a different set of social practices, practices that were at the time marginal in part because of the practical difficulty of applying them without software support. tom lord's radical program was to change the software landscape on which open-source collaboration happened in order to make those social practices viable

i agree that globally sequential revision numbers are incompatible with decentralization in the pre-nakamoto world, because they demand consensus, and decentralized consensus was infeasible until nakamoto. it's still probably too costly for this purpose

I'm reading fmajid as meaning that decentralization is antithetical to the control that companies require - so it must grow elsewhere.

By "dominant social practices" I think you mean cathedral as opposed to bazaar? (esr)

So it looks to me like: internet adoption made decentralization possible; a decentralization practice arose, exemplified by linus and publicised by esr, thus creating decentralization-tool demand; and then, all the technical progress you mention was harnessed, including application of ideas from other fields, like merkle trees that were originally for encryption, created decentralizatiom supply.

I don't think decentralization is the issue, after all most companies adopted Git eventually (or a forked and rewritten Mercurial in the case of Meta). It's just they did not feel the burning need the way some distributed teams like the Linux kernel team did.

And Kragen is right that open-source communities vary widely in culture and processes. Linux has its email patch based workflow, as does Sourcehut. There is the popular pull request model invented or at least popularized by GitHub. OpenBSD still uses its bizarre CVS workflow and seems happy with it.

pretty much

keep in mind, tho, that teamware was decentralized version control in the 80s or very early 90s inside sun tho, so i don't think it's antithetical to something companies require

i've never used teamware and i don't have a good handle on how it worked

with respect to merkle trees, it's true that encryption was merkle's original intended use for them, but i don't know if anyone has ever used them for that except as an experiment. surely not since rsa was published

Good point about teamware, though I think sun was a very unusual company, and particularly network focussed. Also, the internet itself had a decentralized design (for military robustness, IIRC).

Maybe making the core data structure be a merkle tree (not a separate data structure for validation) was new... at least, for version control? It seems monotone used merkle trees as an overlay https://decomposition.al/blog/2019/05/31/how-i-learned-about...

I'm mainly going by larry, who told me that git's data structure wasn't from bitkeeper (but was "all his", IIRC). The significance is that this data structure can't model renames (of course, could do them as an overlay or decoration - though git doesn't)

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