[tz] [PROPOSED PATCH 2/2] Use lz format for new tarball

Deborah Goldsmith goldsmit at apple.com
Thu Sep 1 18:56:51 UTC 2016

Comments below.


> On Aug 30, 2016, at 5:21 PM, Paul Eggert <eggert at cs.ucla.edu> wrote:
> Deborah Goldsmith wrote:
>> What is the goal for making these changes to the distribution format?
> 1. Simplifying the distribution process. This can be seen in the proposed changes to tz-link.htm describing how to download and extract the release. The current tz-link.htm uses five shell commands to do that; the proposed tz-link.htm cuts this to two. These simplifications will make configuration errors less likely, as well as make it easier for newcomers.

It’s going to require changing (multiple) existing workflows that are working just fine. If support for the existing format is discontinued, this will be a substantial amount of work for many.

> 2. Shrinking the distribution tarball. This matters less, but while we're doing (1) we might as well do (2). Not everyone is as well-off and well-connected as Apple and UCLA.

Is there any evidence anyone cares about the minor differences we’re discussing? The difference between bz2 (widely supported) and lz (not as widely supported) is 43K. Why put the onus on consumers of the data to find an implementation of a less-known compression scheme their platform doesn’t support?

> > It’s going to cause a lot of work for a lot of people.
> It'll be a bit of work at the start, to change unpacking scripts. But the changes are small, and it should save some work in the long run. And there's no rush, as the old-format tarballs will continue to be distributed.

You’re making assumptions about how people are consuming these files. Not everyone is using an “unpacking script.” Other people have already chimed in with comments along these lines. There are all sorts of different workflows consuming this data beyond the canonical one.
>> most customers of tz would be quite happy for the distribution to continue in its current form forever.
> Change is such a pain! :-) That being said, the distribution format has changed over time and it will change in the future. This is inevitable in any successful, longrunning project.

RFCs are still plain text. .tar format hasn’t changed in decades. Bytes are still 8 bits. Most of us still type on QWERTY keyboards. Widely-used standards change slowly or not at all, with very good reason.

Yes, change is a pain. Change is certainly warranted when the benefits outweigh the costs. I don’t think the costs are being weighed properly, though, and the benefits don’t seem that great. Are there any significant benefits beyond an easier format for newcomers?

> Alexander Belopolsky wrote:
> > If the size of data distribution is a concern, it looks like one can
> > achieve a much better compression by simply discarding comments
> But the comments are the best part! :-)

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