2. Microsoft RAMCard for Apple II (1980)

Microsoft produced the Apple II RAMCard as an accessory card for its Z80 SoftCard, which when plugged into one of an Apple II's free slots and provided 16KB of additional system memory for the running CP/M programs.

3. Microsoft RAMCard for IBM PC (1982)

When plugged into an IBM PC, this card served as both a memory expansion and a solid state RAM disk. When coupled with Microsoft's RAMDrive software, it made a traditional disk drive to operate at around 50 times faster due to its solid state nature. It was available in sizes from 64KB to 256KB.

4. Microsoft SystemCard (1983)

SystemCard was a multifunction ISA card that served as a replacement of at least four separate plug-in cards. An IBM PC user got six slots free. Like the RAMCard, the SystemCard contained 64KB to 256KB of RAM that could serve as a RAM disk. But it also included a parallel printer interface, a print spooler, an RS232 serial port and a real-time calendar/clock chip.