Microsoft's Z-80 SoftCard: How Microsoft's First Hardware Product Enabled CP/M on Apple II Computers
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Summary
The article details the Microsoft Z-80 SoftCard, Microsoft's first hardware product released in 1980, which was a plug-in expansion card for the Apple II computer that enabled it to run CP/M software. The card contained a Zilog Z80 processor (compatible with the 8080 processor required by CP/M) alongside the Apple II's native 6502 processor, allowing both processors to share the same memory through sophisticated memory management techniques. The article explains the technical challenges of getting two different processors to work together on the same system and how the SoftCard became Microsoft's largest revenue source at the time.
Key quotes
· 4 pulledThe Microsoft Z-80 SoftCard was a plug-in expansion card for the Apple II that added the ability to run CP/M software.
According to Wikipedia, it was Microsoft's first hardware product and in 1980 was the single largest revenue source for the company.
CP/M runs on an 8080 processor, but the Apple II has a 6502 processor. So how can you run CP/M on an Apple II? Answer: The card comes with its own 8080-compatible processor, the Zilog Z80.
The card contained a Zilog Z80 processor (compatible with the 8080 processor required by CP/M) alongside the Apple II's native 6502 processor, allowing both processors to share the same memory through sophisticated memory management techniques.
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