Backwards Compatibility

View Github Repository Open presentation in a new window

a10nik

See all presentation from a10nik

Backwards Compatibility

0 0

eng-the-back-compat

On Github a10nik / eng-the-back-compat

Backwards Compatibility

Artyom Desyatnikov

title. going to explore the book...

Points

Backwards Compatibility

  • Concept
  • Why it is hard
  • What if we don't

Concept

  • Versioning
  • Consistence between versions
  • Stable API
is not enough
versioning in software systems phenomenon in versioning problem urgent in low-level software development. low-level: other software relying on it to func consistently as it usually goes, devs of the reliable software do understand their product is going to be so since its very design stage. concieve it to have a stable API drives me to the second point of the talk

Why it is hard

  • Undocumented behaviour
  • Sim City & Windows 95
stable consistent API is sometimes not enough a strict sense of it should not only be the API which is to conform to the previous version behaviour but also the every single piece of information on the underlying software accessible to a user. to say nothing about responding to interactions undocumented or even prohibited in the API contract. consider an example of a notorious city simulator game under the name of SimCity. on market since MS-DOS times turned out not to work with Win95. used memory after freeing it. MS spent resources to introduce a specially designed mode of memory management. turning to my next point i'll try to clarify why such policy is the way to go in the OS development.

What if we don't

  • Loss of customer base
  • The whole companies
imagine what would have happened if they had refused to support the game in the new windows. considering the game was having its rise in popularity, it would have cost them a solid amount of their customers who will buy win95 just to discover their game is not supported there. refund. it's the whole approach of microsoft versioning. what's more, lots of companies can't do without a program or two which are quite outdated. managers will not update if they are told that it's not working on the new version. thousands of computers. microsoft could not afford to let such a great sum of money go.

Points

Backwards Compatibility

  • Concept
  • Why it is hard
  • What if we don't

THE END

Backwards Compatibility Artyom Desyatnikov title. going to explore the book...