Z-80 SoftCard
Encyclopedia
The Z-80 SoftCard was a plug-in card supplied by Microsoft
for use with the Apple II
personal computer
, which did not have a Z-80 compatible processor and could not run CP/M. It had a Zilog
Z80 CPU plus some 74LS00 series
TTL
chips to adapt that processor's bus to the rather different bus system used in the Apple. The card was eventually renamed the Microsoft SoftCard.
It enabled the Apple II to run the Digital Research
CP/M
operating system
, at the time an industry-standard operating system for running business software and many compiler
s and interpreter
s for several high-level languages on microcomputer
s. CP/M, one of the earliest cross-platform operating systems, was easily adaptable to a wide range of auxiliary chips and peripheral hardware, but it required an Intel 8080
-compatible CPU, which the Zilog Z80 was, but which the Apple's CPU, the MOS Technology 6502
, wasn't.
This CP/M
capability conferred by the Z80 SoftCard transformed the Apple II into a viable platform for running a much broader range of business software applications than had been possible until then.
The "SoftCard" was Paul Allen
's idea and was developed jointly between Tim Paterson
of Seattle Computer Products
(SCP) and Bill Gates
and Don Burtis of Microsoft, after SCP developed the initial prototypes. Microsoft received most of its revenue from selling language compilers and interpreters for CP/M systems at this time, which was before Microsoft's MS-DOS
operating system (for 8086-compatible processors as used by the IBM PC
and other microcomputers) was introduced and became the company's best-selling product. A copy of the Microsoft BASIC
programming language was included in the Softcard package. It was first demonstrated publicly at the West Coast Computer Faire
in March 1980.
It was an immediate success; 5,000 cards, a large number given the microcomputer market at the time, were purchased in the initial three months at $349 each, and the card sold well for several years. The SoftCard was the single most popular platform to run CP/M.
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
for use with the Apple II
Apple II
The Apple II is an 8-bit home computer, one of the first highly successful mass-produced microcomputer products, designed primarily by Steve Wozniak, manufactured by Apple Computer and introduced in 1977...
personal computer
Personal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...
, which did not have a Z-80 compatible processor and could not run CP/M. It had a Zilog
Zilog
Zilog, Inc., previously known as ZiLOG , is a manufacturer of 8-bit and 24-bit microcontrollers, and is most famous for its Intel 8080-compatible Z80 series.-History:...
Z80 CPU plus some 74LS00 series
7400 series
The 7400 series of transistor-transistor logic integrated circuits are historically important as the first widespread family of TTL integrated circuit logic. It was used to build the mini and mainframe computers of the 1960s and 1970s...
TTL
Transistor-transistor logic
Transistor–transistor logic is a class of digital circuits built from bipolar junction transistors and resistors. It is called transistor–transistor logic because both the logic gating function and the amplifying function are performed by transistors .TTL is notable for being a widespread...
chips to adapt that processor's bus to the rather different bus system used in the Apple. The card was eventually renamed the Microsoft SoftCard.
It enabled the Apple II to run the Digital Research
Digital Research
Digital Research, Inc. was the company created by Dr. Gary Kildall to market and develop his CP/M operating system and related products. It was the first large software company in the microcomputer world...
CP/M
CP/M
CP/M was a mass-market operating system created for Intel 8080/85 based microcomputers by Gary Kildall of Digital Research, Inc...
operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
, at the time an industry-standard operating system for running business software and many compiler
Compiler
A compiler is a computer program that transforms source code written in a programming language into another computer language...
s and interpreter
Interpreter (computing)
In computer science, an interpreter normally means a computer program that executes, i.e. performs, instructions written in a programming language...
s for several high-level languages on microcomputer
Microcomputer
A microcomputer is a computer with a microprocessor as its central processing unit. They are physically small compared to mainframe and minicomputers...
s. CP/M, one of the earliest cross-platform operating systems, was easily adaptable to a wide range of auxiliary chips and peripheral hardware, but it required an Intel 8080
Intel 8080
The Intel 8080 was the second 8-bit microprocessor designed and manufactured by Intel and was released in April 1974. It was an extended and enhanced variant of the earlier 8008 design, although without binary compatibility...
-compatible CPU, which the Zilog Z80 was, but which the Apple's CPU, the MOS Technology 6502
MOS Technology 6502
The MOS Technology 6502 is an 8-bit microprocessor that was designed by Chuck Peddle and Bill Mensch for MOS Technology in 1975. When it was introduced, it was the least expensive full-featured microprocessor on the market by a considerable margin, costing less than one-sixth the price of...
, wasn't.
This CP/M
CP/M
CP/M was a mass-market operating system created for Intel 8080/85 based microcomputers by Gary Kildall of Digital Research, Inc...
capability conferred by the Z80 SoftCard transformed the Apple II into a viable platform for running a much broader range of business software applications than had been possible until then.
The "SoftCard" was Paul Allen
Paul Allen
Paul Gardner Allen is an American business magnate, investor, and philanthropist. Allen co-founded Microsoft with Bill Gates...
's idea and was developed jointly between Tim Paterson
Tim Paterson
Tim Paterson is an American computer programmer, best known as the original author of MS-DOS, the most widely used personal computer operating system in the 1980s....
of Seattle Computer Products
Seattle Computer Products
Seattle Computer Products was a Seattle, Washington microcomputer hardware company which was one of the first manufacturers of computer systems based on the 16-bit Intel 8086 processor...
(SCP) and Bill Gates
Bill Gates
William Henry "Bill" Gates III is an American business magnate, investor, philanthropist, and author. Gates is the former CEO and current chairman of Microsoft, the software company he founded with Paul Allen...
and Don Burtis of Microsoft, after SCP developed the initial prototypes. Microsoft received most of its revenue from selling language compilers and interpreters for CP/M systems at this time, which was before Microsoft's MS-DOS
MS-DOS
MS-DOS is an operating system for x86-based personal computers. It was the most commonly used member of the DOS family of operating systems, and was the main operating system for IBM PC compatible personal computers during the 1980s to the mid 1990s, until it was gradually superseded by operating...
operating system (for 8086-compatible processors as used by the IBM PC
IBM PC
The IBM Personal Computer, commonly known as the IBM PC, is the original version and progenitor of the IBM PC compatible hardware platform. It is IBM model number 5150, and was introduced on August 12, 1981...
and other microcomputers) was introduced and became the company's best-selling product. A copy of the Microsoft BASIC
Microsoft BASIC
Microsoft BASIC was the foundation product of the Microsoft company. It first appeared in 1975 as Altair BASIC, which was the first BASIC, and the first high level programming language available for the MITS Altair 8800 hobbyist microcomputer....
programming language was included in the Softcard package. It was first demonstrated publicly at the West Coast Computer Faire
West Coast Computer Faire
The West Coast Computer Faire was an annual computer industry conference and exposition most often associated with San Francisco, its first and most frequent venue. The first fair was held in 1977 and was organized by Jim Warren and Bob Reiling. At the time it was the biggest computer show in the...
in March 1980.
It was an immediate success; 5,000 cards, a large number given the microcomputer market at the time, were purchased in the initial three months at $349 each, and the card sold well for several years. The SoftCard was the single most popular platform to run CP/M.
External links
- AppleLogic website, showing peripheral cards for the Apple II series of computers, including the Microsoft Softcard