Fortran Wiki
Fortran 90

Fortran 90 was a major revision to FORTRAN 77. It introduced many new features and, although it didn’t delete any features, several were identified as “obsolescent.”

The full text of the Fortran 90 standard is available in PDF format here from Fortran Standards Work Group JTC1/SC22/WG5: https://wg5-fortran.org/N001-N1100/N692.pdf.

New Features

• Free form source input.
• Dynamic memory allocation via the allocatable attribute and the allocate and deallocate statements.
• Modules

Old Features that had never been standardized before

• Namelist input

Obsolescent Features