After Jack Tramiel was fired from Commodore and became the owner of Atari, I believe he offered jobs to a number of key technical people who followed him from Commodore. Who were the key people (if any) from Commodore and their contributions to the Atari ST? Was any Commodore technology alleged to be pilfered in the process?
The primary personality was Shiraz Shivji, a member of the C64 team who became the lead designer of the Atari ST. As per the linked Wikipedia article, he and three others — Arthur Morgan, John Hoenig and Douglas Renn — were accused by Commodore of intellectual property theft, specifically around the disk drive in Commodore's aborted Z8000-based UNIX machine, but cleared at trial.
Per Commodore: The Amiga Years, putting the Commodore side of the story:
[Robert Russell, senior Commodore engineer] became nervous that he would lose some of his key project engineers, so he made an agreement with Shiraz Shivji. "[Shiraz] called up and we discussed it after he had left the company," says Russell. "He said that he wasn't going to take those engineers." In particular, Russell wanted to retain a Z8000 engineer until they completed the project. "Shiraz promised me that he would let him wrap his stuff up."
In July 1984, Russell attended a meeting in the UK where anxious Commodore executives contemplated the thread posed by Jack Tramiel. "We were at a meeting in London. All the big general managers were there, maybe 20 people," says Russell. "I was there because I had the Z8000 project and I was doing reports to the board on engineering. The Amiga was part of it. I knew what was happening with Atari and Jack and their engineers."
While Russell was away, Shivji suddenly backed out of their agreement. "I was at a board meeting in London when this engineer just left," says Russell. "I got a phone call at the board meeting that he was gone, and that just pissed me off to no end. I thought I had an agreement with Shiraz."
Russell soon tipped off Commodore lawyers about possible theft of trade secrets. Russell thought it would be a good idea to inspect what the ex-employees were moving out of Commodore. "We put a lawsuit and we opened up their moving vans," recalls Russell. "They were taking people's personal goods. When the lawyers cracked open the moving truck, we found all kinds of Commodore documentation."
In a suit filed July 10 in Chester County Court, Commodore charged that Shivji and three other former employees had stolen information on new products Commodore was developing. A Washington Post article soon appeared with the headline, "Commodore Says Four Stole Trade Secrets". Commodore obtained a preliminary injunction against releasing a new Atari computer.
So I think that court case is the only formal allegation that Commodore made, netting them a nice preliminary injunction against Atari releasing a new machine. I can't find the Washington Post article, but per a very brief contemporaneous report from The New York Times:
A Pennsylvania judge today temporarily extended an injunction that prevents four former employees of Commodore International Ltd. from revealing any Commodore trade secrets at their new jobs with Atari Inc.
The suit charged that the four former employees had stolen trade secrets with an intent to divulge them to Atari, a rival home-computer maker that was recently acquired by Commodore's former president, Jack Tramiel.
The suit, filed Tuesday, contends that the defendants possess copies of specifications for products that are ''unique to Commodore'' and provide an advantage over the competition.
Neither Mr. Tramiel nor his new company was named in the suit.
One of them was Leonard Tramiel, one of Jack Tramiel's sons, who was in charge of the Atari staff who worked on the ST OS, and had contributed to the VIC-20 at Commodore. When I briefly worked for Perihelion in 1989, while they were designing the Atari Transputer Workstation for Atari, Leonard was the person in Atari who could give Jack bad news on technical things without getting fired.
Another was Shiraz Shivji who had been part of the design team for the Commodore 64 and later the director of engineering at Commodore. He became head of R&D at Atari, and the chief designer of the Atari ST, and was one of four ex-Commodore engineers who were charged, but acquitted, with theft of disk drive plans from Commodore.