The JEIDA memory card
standard was a popular memory card standard at the beginning of memory cards appearing on portable computers. JEIDA
cards could be used to expand system memory or as a solid-state storage drive. Before the advent of the JEIDA standard, laptops had proprietary cards that were not interoperable with other manufacturers laptops, other laptop lines, or even other models in the same line.
The establishment of the JEIDA interface and cards across Japanese portables provoked a response from the US government, through SEMTEC, and thus PCMCIA was born. PCMCIA and JEIDA worked to solve this rift between the two competing standards. In 1991, the two standards merged, and became JEIDA 4.1 or PCMCIA 2.0.
Version 3 is a 68-pin memory card. It is also used in the Neo Geo
Version 4.1 unified the PCMCIA and JEIDA standards as PCMCIA 2.0. v4.1 is the 16-bit PC Card
standard that defines Type I, II, III, and IV card sizes.
Version 4.2 is the PCMCIA 2.1 standard, and introduced CardBus
' 32-bit interface in an almost physically identical casing.