Hewlett Packard HP-41C Programmable Calculator Mug Shots

Here are some mug shots of the HP-41C. The most obvious feature is the wedge-shape design.

This is a clever design to make the calculator slim and at the same time able to handle plugin modules. The resulting slant upwards toward the LCD display makes reading the LCD display much more easier when place on the desk.

Note the moulded serial number on the back of the lower cover. I am wondering if ever a cover is not use. This is probably a hallmark of HP just in time manufacturing practice where materials are made available just in time for use with the resulting low inventory overheads. Moulding the serial number on the casing does reduce manufacturing time and eventually cost making the production line more efficient. But it needs careful planning to prevent wastage. A smaller manufacturing outfit that lacks the resouces for such planning will probably use serial numbers on stickers as overruns in this case is less expensive( just discard the excess stickers ). But the extra time needed on the production line is a cost to be considered.

This is the physical look of the HP-41C calculator. The reason the HP-41C is so popular is the functionality which is defined by the CPU and the software thats runs it.

Note the plugs for the plugin modules which can be anything from memory to printers to card readers.

One of the port for the plugin modules is covered. The rest are plugin modules that are missing from this specimen.