In the 1990s, when the @ sign was first tried to be translated into Russian, there were many equal options - "krakozyabra", "squiggle", "frog", "ear" and others. True, at the present time they have practically disappeared, and the "dog" has spread throughout the Runet and remained, because any language seeks to have only one universal word to denote anything. The rest of the names remain marginal, although there may be a lot of them. For example, in English, the @ symbol is called not only commercial at, but also mercantile symbol, commercial symbol, scroll, arobase, each, about, etc. Where did the association between the main computer icon and a person's friend come from? For many, the @ symbol does indeed resemble a curled up dog.
One of the versions of the origin of the name "dog": on alphanumeric monitors of personal computers of the DVK series (1980s), the "tail" of the image of this symbol drawn on the screen was very short, which made it look like a schematically drawn dog. The @ symbol was displayed every time the DCK computer was turned on, after which the user had to select a bootloader.
According to another version, the origin of the name "dog" is associated with the computer game Adventure, in which the player was accompanied by a dog that could be sent from intelligence missions and which was denoted by the @ symbol. Also, the first Soviet users of computer networks could see this symbol on the Fidonet emblem, which depicts a dog, where the @ sign is located in the center of the muzzle and acts as a nose.