HP 65

Neither the HP 35 was the first scientific calculator of the world, nor the HP 65 was the first programmable scientific calculator of the world. This honor appertains the Compucorp calculators. Of course, the calculators by HP were smaller and more powerful, but they came into the market 2 or 4 years later. One of the most important features of the HP 65 was the integrated magentic strip reader helping to save the program memory.

By the way, the HP 65 had such serious deficiencies in the design, that it was soon replaced by the HP 67 and is therefore very rare today.