Microsoft SoftCard

The Microsoft SoftCard (formerly Z-80 SoftCard or just SoftCard) is a plug-in developed by Microsoft's Consumer Products division to turn the  computer into a  system based upon the  central processing unit (CPU). The card became the most popular CP/M platform and Microsoft's top revenue source for 1980. It was succeeded by Microsoft's Premium Softcard IIe for the.

Overview
Released on April 2, 1980 as Microsoft's first hardware product, and bundled with the Microsoft BASIC programming language, the Z-80 SoftCard is an that enables the  to run, an operating system from. This gives Apple II users access to many more business applications, including s and s for several s. CP/M, one of the earliest cross-platform operating systems, is easily adaptable to a wide range of auxiliary chips and peripheral hardware, but it requires an -compatible CPU, which the Zilog Z80 is, but which the Apple's CPU, the, is not. The SoftCard has a CPU plus some   chips to adapt that processor's  to the. As CP/M requires contiguous memory from address zero, which the Apple II doesn't have, addresses are translated in order to move non-RAM areas to the top of memory.

History
The SoftCard was Paul Allen's idea. Its original purpose was to simplify Microsoft's computer-language products to the Apple II. The SoftCard was developed by Tim Paterson of (SCP). SCP built prototypes, Don Burtis of Burtronix redesigned the card, and California Computer Systems manufactured it for Microsoft. Unsure whether the card would sell, Microsoft first demonstrated it publicly at the in March 1980.

Microsoft also released a version for the, the Premium Softcard IIe. It was designed for Microsoft by Burtronix in 1983. The card has functionality equivalent to the, including its 64 kB RAM, so would save money for users who wanted CP/M capability, additional memory, and 80-column text.

Sales
The SoftCard's immediate success surprised Microsoft. Although unprepared to take orders at the West Coast Computer Faire, a Microsoft executive accepted 1,000 business cards from interested parties on the first day; Compute! reported that the company was "inundated" with orders. The SoftCard became the company's largest revenue source in 1980, selling 5,000 units in three months at $349 each, with high sales continued for several years. The SoftCard was the single most-popular platform to run CP/M, and Z-80 cards became very popular Apple II peripherals. By 1981 Microsoft,, and published their CP/M software on Apple-format disks.

Critical reception
Compute! witnessed the SoftCard's debut in March 1980 at the West Coast Computer Faire, calling it "an Apple breakthru".  in 1981 called the SoftCard "a fascinating piece of hardware". While criticizing the "computerese" of the CP/M documentation, the magazine wrote "if you need a lightweight, portable Z80 computer, the Apple/SoftCard combination is a perfect pair."  wrote, "Because of the flexibility that it offers Apple users, I consider the Softcard an excellent buy .. The price is reasonable, and it works".

InfoWorld in 1984 also favorably reviewed the SoftCard IIe, approving of its ability to also replace the Extended 80-Column Text Card. The magazine concluded that it "is a good system among several good systems on the market", especially for those who wanted to run Microsoft BASIC or wanted functionality beyond CP/M.

Alternatives
Following Microsoft's success, several other companies developed Z80 cards for the Apple II as well, including Digital Research with and a CP/M card developed by Advanced Logic Systems named "The CP/M Card" (with a 6 MHz Z80 and 64 kB RAM) and Digital Research's CP/M Gold Card for CP/M Pro 3.0 (with 64 or 192 kB RAM). Others independent designs came from, PCPI (with their 6 MHz Appli-Card), Cirtech, IBS. There were also about a dozen SoftCard clone manufacturers.