I've been slowly documenting these differences with a series of Wiki articles. Generally though, there's three major "families":
* The original Dartmouth BASIC turned into a wide variety of mainframe versions. These are marked by the use of the CHANGE statement and supporting the MAT statements.
* HP's dialect had array-based strings (like C) and string slicing... LET A$[1,6]="HELLO.
* Timeshare's SUPER BASIC, which turned into BASIC-PLUS, which turned into MS BASIC, lacked those features and instead used MID/LEFT/RIGHT.
There's many other more minor changes from dialect to dialect, but those are the main differences.
* The original Dartmouth BASIC turned into a wide variety of mainframe versions. These are marked by the use of the CHANGE statement and supporting the MAT statements. * HP's dialect had array-based strings (like C) and string slicing... LET A$[1,6]="HELLO. * Timeshare's SUPER BASIC, which turned into BASIC-PLUS, which turned into MS BASIC, lacked those features and instead used MID/LEFT/RIGHT.
There's many other more minor changes from dialect to dialect, but those are the main differences.