Chinese, Japanese, Russian, and Roman Abaci. Inadequate collections databases

Many museums have online collection databases. This is particularly true of the US and the UK. Unfortunately, there are still important institutions whose collection databases are currently not accessible online: e.g. the Deutsches Museum in Munich, the Heinz Nixdorf Museumsforum in Paderborn, the Arithmeum in Bonn. There are considerable differences in the informative value of the respective entries. Sometimes the information is quite detailed, sometimes rather meagre. The description of artifacts is often difficult, especially if there is no documentation. Experience shows that many entries are quite incorrect and that technical terms are sometimes wrong. When visiting museums, you may also be surprised to discover that objects are displayed incorrectly so that they cannot be used. And they are incorrectly represented in databases. This is illustrated here by two examples, the abacus (bead frame, counting frame, counting board) and the replica of Wilhelm Schickard's calculating clock. The Chinese, Japanese, Russian, and Roman arithmetical frames are shown partly correctly and partly incorrectly. The illustrations are taken from the respective collection databases.