That's "systems" Hungarian, developed by the one and only Microsoft. Putting the variable type inside the name is redundant, I think everyone can agree.

"Apps" Hungarian, on the other hand, is a wonderful system where the prefix describes the purpose of the variable (such as us for "usafe string" and ss for "safe string"). It also describes function naming convention (ss_from_us for "Safe string from unsafe string") so that you can easily tell if you're making a coding mistake. Compare:

  $ss_username = ss_from_us($us_username_field);

  $ss_username = $us_username_field;

Real easy to spot the mistakes.