red bit vs. green bit

[eBob.com]

A beginners SQL book which I have purchased tries to explain, in Chapter 2,
green bit and red bit assemblies. Maybe it is trying to explain the
difference between them, but that is not clear. (So far as I can tell this
is a framework, not an SQL, question. If not I apologize.)

I figure that anything in Chapter 2 of a beginners book must be something
pretty fundamental. And since I do not understand the explanation in the
book I am hoping that someone here can help me out.

The terminology, green bit and red bit, suggest that they are somehow
opposites. But Green bit assemblies in a framework version, to the best of
my understanding, are compatible with an earlier version of the framework.
(Although the explanation in the book never uses the work "compatible".)
And red bit assemblies "ship as either part of the platform or part of a
development tool." But to my mind those two things are not opposites as a
platform or development tool can ship compatible or incompatible assemblies.

I'm really confused and if someone can help me out here I'd appreciate it.

Thanks, Bob

 

[Cowboy \(Gregory A. Beamer\)]

Green bit assemblies are completely new and do not change anything in an
underlying framework. For example, anything in 3.0 that was completely new
was green bit. This includes a lot of WinFX (WCF, WF, WPF, etc), although
there are some core red bit assemblies necessary, especially in the 3.5
framework.

Red bit assemblies are like service packs, as they change the underlying
assemblies. In 3.0 and 3.5, there are both green bit assemblies (no
underlying changes to 2.0) and red bit assemblies (changes to 2.0). And,
with 3.5, there are red bit assemblies that only change 3.0 assemblies.

Hope this helps.

--
Gregory A. Beamer
MVP; MCP: +I, SE, SD, DBA

*************************************************
| Think outside the box! |
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[eBob.com]

Thank you Cowboy, that helps a lot. Can you tell my why a .NET developer,
outside of Microsoft, would need to be aware of this? Do red bit assemblies
break existing applications?

Thanks again, Bob

 

[Pavel Minaev]

Thank you Cowboy, that helps a lot. Can you tell my why a .NET developer,
outside of Microsoft, would need to be aware of this? Do red bit
assemblies break existing applications?

Red bit assemblies do not break anything. However, _changes_ to red bit
assemblies (e.g. System.dll) can break your applications, since they will
reference those assemblies. On the other hand, new green bit assemblies
cannot possibly break existing applications, since they just don't reference
those new assemblies.

 

[Cowboy \(Gregory A. Beamer\)]

Thank you Cowboy, that helps a lot. Can you tell my why a .NET developer,
outside of Microsoft, would need to be aware of this?

In general, no. You debug and fix errors the same way whether it is a
downline red bit assembly or your own code. But you do have to realize that
restricting version in config may cause a break if there is a red bit
assembly in use, as the version number changes. This gets pretty deep,
however, and is unlikely to impact the majority of developers.

I believe you should be aware that config can break things anyway, so the
fact there are red bit assemblies means very little to me, except perhaps to
win at Microsoft Trivial Pursuit (ie, the technical interview with
"Einstein"). ;-)

--
Gregory A. Beamer
MVP; MCP: +I, SE, SD, DBA

*************************************************
| Think outside the box! |
*************************************************