Origins
86-DOS was created because sales of the Seattle Computer Products (SCP) 8086 computer kit, demonstrated in June 1979 and shipped in November, were languishing due to the absence of an operating system. The only software which SCP could sell with the board was the stand-alone Microsoft BASIC-86, which Microsoft had developed on a prototype of SCP's hardware. SCP wanted to offer the 8086 version of CP/M that Digital Research had announced, but its release date was uncertain. This was not the first time DRI had lagged behind hardware developments; two years earlier it had been slow to adapt CP/M for new floppy disk formats and hard disks. In April 1980 SCP assigned 24-year-old Tim Paterson to develop a substitute for CP/M-86.
Paterson designed 86-DOS with an API that was compatible with legacy CP/M programs. At the same time he made a number of changes and enhancements to address what he saw as CP/M's shortcomings. CP/M cached file system information in memory for speed, but this required a user to force an update to a disk before removing it; if the user forgot, the disk would be corrupt. Paterson took the safer but slower approach of updating the disk with each operation. CP/M's PIP command, which copied files, supported several special file names that referred to hardware devices such as printers and communication ports. Paterson built these names into the operating system as device files so that any program could use them. He gave his copying program the more intuitive name COPY. Rather than implementing CP/M's file system, he used BASIC-86's FAT filesystem to maintain compatibility with systems that SCP had already shipped.
[edit] IBM interest
In October 1980, IBM was developing what would become the original IBM Personal Computer. CP/M was by far the most popular operating system in use at the time, and IBM felt it needed CP/M in order to compete. IBM's representatives visited Digital Research and discussed licensing with DRI's licensing representative, Dorothy McEwen Kildall, who hesitated to sign IBM's non-disclosure agreement. Although the NDA was later accepted, DRI would not accept IBM's proposal of $250,000 in exchange for as many copies as IBM could sell, insisting on the usual royalty-based plan.[1] In later discussions between IBM and Bill Gates, Gates mentioned the existence of 86-DOS and IBM representative Jack Sams told him to get a license for it.
[edit] Creation of PC-DOS
Microsoft purchased a nonexclusive license for 86-DOS from Seattle Computer Products in December 1980 for $25,000. In May 1981, it hired Tim Paterson to port the system to the IBM-PC, which used the slower and less expensive Intel 8088 processor and had its own specific family of peripherals. IBM watched the developments daily, submitted over 300 change requests before it accepted the product and wrote the user manual for it.
In July 1981, a month before the PC's release, Microsoft purchased all rights to 86-DOS from SCP for $50,000. It met IBM's main criteria: it looked like CP/M, and it was easy to adapt existing 8-bit CP/M programs to run under it, notably thanks to the TRANS command which would translate source files from 8080 to 8086 machine instructions. Microsoft licensed 86-DOS to IBM, and it became PC-DOS 1.0. This license also permitted Microsoft to sell DOS to other companies, which it did. The deal was spectacularly successful, and SCP later claimed in court that Microsoft had concealed its relationship with IBM in order to purchase the operating system cheaply. SCP ultimately received a 1 million dollar settlement payment.
AtW. Just a little reminder now.
86-DOS was created because sales of the Seattle Computer Products (SCP) 8086 computer kit, demonstrated in June 1979 and shipped in November, were languishing due to the absence of an operating system. The only software which SCP could sell with the board was the stand-alone Microsoft BASIC-86, which Microsoft had developed on a prototype of SCP's hardware. SCP wanted to offer the 8086 version of CP/M that Digital Research had announced, but its release date was uncertain. This was not the first time DRI had lagged behind hardware developments; two years earlier it had been slow to adapt CP/M for new floppy disk formats and hard disks. In April 1980 SCP assigned 24-year-old Tim Paterson to develop a substitute for CP/M-86.
Paterson designed 86-DOS with an API that was compatible with legacy CP/M programs. At the same time he made a number of changes and enhancements to address what he saw as CP/M's shortcomings. CP/M cached file system information in memory for speed, but this required a user to force an update to a disk before removing it; if the user forgot, the disk would be corrupt. Paterson took the safer but slower approach of updating the disk with each operation. CP/M's PIP command, which copied files, supported several special file names that referred to hardware devices such as printers and communication ports. Paterson built these names into the operating system as device files so that any program could use them. He gave his copying program the more intuitive name COPY. Rather than implementing CP/M's file system, he used BASIC-86's FAT filesystem to maintain compatibility with systems that SCP had already shipped.
[edit] IBM interest
In October 1980, IBM was developing what would become the original IBM Personal Computer. CP/M was by far the most popular operating system in use at the time, and IBM felt it needed CP/M in order to compete. IBM's representatives visited Digital Research and discussed licensing with DRI's licensing representative, Dorothy McEwen Kildall, who hesitated to sign IBM's non-disclosure agreement. Although the NDA was later accepted, DRI would not accept IBM's proposal of $250,000 in exchange for as many copies as IBM could sell, insisting on the usual royalty-based plan.[1] In later discussions between IBM and Bill Gates, Gates mentioned the existence of 86-DOS and IBM representative Jack Sams told him to get a license for it.
[edit] Creation of PC-DOS
Microsoft purchased a nonexclusive license for 86-DOS from Seattle Computer Products in December 1980 for $25,000. In May 1981, it hired Tim Paterson to port the system to the IBM-PC, which used the slower and less expensive Intel 8088 processor and had its own specific family of peripherals. IBM watched the developments daily, submitted over 300 change requests before it accepted the product and wrote the user manual for it.
In July 1981, a month before the PC's release, Microsoft purchased all rights to 86-DOS from SCP for $50,000. It met IBM's main criteria: it looked like CP/M, and it was easy to adapt existing 8-bit CP/M programs to run under it, notably thanks to the TRANS command which would translate source files from 8080 to 8086 machine instructions. Microsoft licensed 86-DOS to IBM, and it became PC-DOS 1.0. This license also permitted Microsoft to sell DOS to other companies, which it did. The deal was spectacularly successful, and SCP later claimed in court that Microsoft had concealed its relationship with IBM in order to purchase the operating system cheaply. SCP ultimately received a 1 million dollar settlement payment.
AtW. Just a little reminder now.
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