SmartBASIC 1.x was a major rewrite of the SmartBASIC 1.0 interpreter for the Coleco ADAM computer, and it provided the programmer with around 40 new commands and functions. This version of the interpreter was developed by Randall Hyde of Lazer Microsystems.

Some of the features and improvements included in the rewrite were:

* Performance enhancements: SmartBASIC 1.x was faster and more efficient than the original version, which improved overall performance.

* Enhanced graphics and sound support: The rewrite included expanded capabilities for handling graphics and sound, allowing for more advanced programming.

* Increased compatibility with Applesoft BASIC: SmartBASIC was already largely compatible with Applesoft BASIC, and the rewrite likely improved this compatibility further to allow programmers to more easily port programs.

* File handling improvements: Some changes were made to how the interpreter handled file operations, particularly on disk-based systems, which corrected errors and improved functionality.