W3bbo said:
Heywood_J said:
*snip*

Service Packs include all previous updates as well as often (but not always) featuring some kind of behavioural change to Windows (which is why you often see software requiring a specific SP level, as was especially the case with NT SP4 and SP6).

 

Update Rollups are just consolidated installers.

 

So a hypothetical UR for Windows XP would require you to:

 

* Install Windows XP

* Install SP3

* Install UR

 

as opposed to a hypothetical SP4:

 

* Install Windows XP

* Install SP4

 

Guess which one requires a lot more development work and testing?

 

But that's not entirely true.

I just installed a XP machine a week a go and I forgot my CD of XP with SP3, since I had the CD for SP3  I decided to install an old copy (no SP) and then install SP3, guess what, SP3 requires SP1, in the end I waste some time downloading the  damn thing anyway.

 

Juan Zamudio