Original sentence: System 7 was a major upgrade to the Mac OS, but the core of the OS remained the same as in prior versions.The other significant change that System 6.This significantly altered the extent and design of the underlying graphics architecture (and its APIs), but it is a credit to Apple that most users were largely unaware of this.Time was given to the background applications only when the foreground (or "running") applications gave it up (cooperative multitasking), but in fact most of them did via a clever change on the OS's event handling.x OS's included a huge number of "high level" additions, considered by some observers to be less well thought out than they might have been.x brought to the Mac was Color Quickdraw, which debuted with the Macintosh II in 1986
Edited sentence: System 7 was a major upgrade to the Mac OS, but sadly the core of the OS remained the same as in prior versions.Time was given to the background applications only when the foreground (or "running") applications gave it up, but in fact most of them did via a clever change on the OS's event handling.x OS's included a huge number of "high level" additions, many of which were poorly thought out