Borland Turbo Basic

Turbo BASIC started life as BASIC/Z and written by Robert "Bob" Zale. It was the first interactive compiler running on the CP/M operating system, but in 1987, Borland purchased it and published it for MS-DOS. It was sold only for a couple of years, before being discontinued, so Bob bought the rights back to continue it under the title PowerBASIC.

Aside from being a compiler rather than just an interpreter, it also permitted much larger executable programs to be created. GWBASIC was limited to .BAS (BASIC interpreter code) files of no larger than 64 KB. With Turbo BASIC you could create files of any size as long as it fit into available memory.

One of the most popular features of Borland's compilers was that they featured an IDE, or Integrated Development Environment. At the time, some referred to these as "Edit-Compile-Run" development environments. While it may not seem any better than, say, GWBASIC, in these days a compiler was a professional tool and it was more typical to use your favourite text editor to write code and then run the compiler and linker from the command-line to create a .EXE file. Within the IDE you could write and format your source code, configure all of the compiling options such as memory usage and then either run it "in-memory" or compile it to an executable. When compiling, it would create an object code file as well - an intermediate file between the high-level language you program in and the binary executable file. These would have a .OBJ file extension.

While in Borland's control, several versions were released.