On Jun 30, 2011, at 10:15 , Marcus Denker wrote: > On Jun 30, 2011, at 9:57 AM, Fernando Olivero wrote: > >> Why do people still use an older image? Even as older as Pharo1.1 and 1.2. >> >> It doesn't take much to update to Pharo1.3 or Pharo1.4, and its >> totally worth the nuisance of updating a couple of classes references >> and uses, because of the many many many improvements that get >> integrated ( thanks for Marcus and Stef for the continuos improvements >> integration and fixes) > > In a commercial setting, things are different... people need to really think > hard > to move to a new system. Time is money, bugs are expensive, there is always > a deadline more important...
Exactly. When you have systems of the size >1000 classes that have been grown over years and have to work reliably, just "updating a couple of classes [sic] references and uses" is not easy. First of all, you have to figure out *what* to change. Changes like a modified Dictionary/Set hierarchy can subtly break your code (leading to data corruption in our case [1]). Or, just because you are one of the first to use the new code under high load, you see problems others haven't seen before (leading to unresponsive images in our case [2]). Those are obvious external bugs, but we also ran into issues with our code just not being compatible anymore with new semantics (e.g., Number class>>#readFrom:). That's why in a non-trivial setup, upgrading is costly, and at times painful (in particular when you missed problems in testing and then experience them in production). [1] http://code.google.com/p/pharo/issues/detail?id=3658 [2] http://code.google.com/p/pharo/issues/detail?id=3498 Cheers, Adrian
