Z-80 SoftCard

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Not to be confused with Softcard (formerly ISIS Mobile Wallet).

Z-80 SoftCard
File:Microsoft Softcard Z80 coprocessor for Apple II.jpg
DeveloperMicrosoft
Release dateApril 2, 1980; 46 years ago (April 2, 1980)[1]
Operating systemCP/M
CPUZ80
PlatformApple II
SuccessorPremium Softcard IIe

The Z-80 SoftCard is a plug-in Apple II processor card developed by Microsoft to turn the computer into a CP/M system based upon the Zilog Z80 central processing unit (CPU). Becoming the most popular CP/M platform and Microsoft's top revenue source for 1980, it was eventually renamed the Microsoft SoftCard, and was succeeded by Microsoft's Premium Softcard IIe for the Apple IIe.

Overview

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Released on April 2, 1980 as Microsoft's first hardware product,[1][2] the Z-80 SoftCard is an Apple II processor card that enables the Apple II to run CP/M, an operating system from Digital Research. This gives Apple II users access to many more business applications, including compilers and interpreters for several high-level languages. 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 Intel 8080-compatible CPU, which the Zilog Z80 is, but which the Apple's CPU, the MOS Technology 6502, is not.[3] The SoftCard has a Zilog Z80 CPU plus some 74LS00 series TTL chips to adapt that processor's bus to the Apple bus. As CP/M requires contiguous freely usable RAM from address zero - which the Apple II does not have, since its own 6502 CPU's call stack and zero page and its text mode screen memory cannot be outside the lowest 4 KiB of RAM - addresses are translated in order to move reserved-RAM and non-RAM areas to the top of memory.[4] The card was bundled with CP/M and the Microsoft BASIC programming language.[5]

History

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The SoftCard was Paul Allen's idea.[6] Its original purpose was to simplify porting Microsoft's computer-language products to the Apple II.[7] The SoftCard was developed by Tim Paterson of Seattle Computer Products (SCP). SCP built prototypes,[8] Don Burtis of Burtronix redesigned the card, and California Computer Systems manufactured it for Microsoft.[9] Unsure whether the card would sell, Microsoft first demonstrated it publicly at the West Coast Computer Faire in March 1980.[5][7]

Microsoft also released a version for the Apple IIe, the Premium Softcard IIe. The card has functionality equivalent to the Extended 80-Column Text Card, including its 64 KB RAM, so would save money for users who wanted CP/M capability, additional memory, and 80-column text.[10] Its 2.26 BIOS has fewer bugs than the earlier card's, the CPU is three times faster, 32K of RAM is used as a CP/M print spooler, and the card uses its own firmware for 80-column display that is faster than Apple's.[11]

Reception

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Compute! witnessed the SoftCard's debut in March 1980 at the West Coast Computer Faire, calling it "an Apple breakthru".[2] InfoWorld 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."[3] BYTE wrote, "Because of the flexibility that it offers Apple users, I consider the Softcard an excellent buy .. The price is reasonable, and it works".[9]

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.[10]

Sales

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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;[7] Compute! reported that the company was "inundated" with orders.[2] The SoftCard became the company's largest revenue source in 1980,[12] selling 5,000 units in three months at $349 each, with high sales continued for several years. For a while, the SoftCard was the single most-popular platform to run CP/M,[13] and Z-80 cards became very popular Apple II peripherals.[14] By 1981 Microsoft, Lifeboat Associates, and Peachtree Software published their CP/M software on Apple-format disks,[9] and Microsoft stated in 1982 that one fifth of all Apple IIs used the Microsoft SoftCard.[15]

Alternatives

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Following Microsoft's success, several other companies developed Z80 cards for the Apple II as well, including Digital Research with Apple CP/M (de) and a CP/M card developed by Advanced Logic Systems (ALS) 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).[16][17] Microsoft sued ALS in February 1982 for copying its BIOS.[18] Other independent designs came from Applied Engineering, PCPI (with their 6 MHz Appli-Card), Cirtech, and IBS. There were also about a dozen SoftCard clone manufacturers.

Microsoft announced a SoftCard for the Apple III in June 1982, stating that it would be available in October.[19]

The Xedex Baby Blue CPU Plus card provides similar functionality to the IBM PC, allowing that computer to run CP/M-80 software like WordStar;[20][21][22][23] the Baby Tex is the TI Professional version.[24] The first version of the Diamond Computer Systems Trackstar, an Apple II emulation card for the PC, includes a Z80 and also supports CP/M.[25]

References

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  • AppleLogic website, showing peripheral cards for the Apple II, including the Microsoft Softcard
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