A GitHub project hosts a web-based emulator and operating environment for the IBM 1620 Model-2, a 1960s transistorized decimal computer. The system used a two-address, memory-to-memory architecture with no software-accessible registers. The Model 2 featured a 10µs memory cycle time and hardware division, while the Model 1 used 20µs cycles and table-lookup arithmetic.

Approximately 2,000 systems were produced, with the Model 2 supporting index registers and binary operations. The project aims to create a browser-based emulator and recover historical software for the platform. The contents are licensed under the MIT License.

Related resources include an emulator hosting site, a project Wiki, a blog, and documents at bitsavers. Software archives contain listings for the 1620 system. The IBM 1620 served as the computing component for the 1710 and 1720 process-control systems.

Programming was typically done using the SPS assembler or FORTRAN II. A simple batch operating system called Monitor was available for systems with the 1311 disk drive.