Apple Computer Inc. yesterday confirmed that Steven P. Jobs, the company's co-founder and chairman, has resigned from the personal computer manufacturing firm and said it was considering "actions" to "assure protection of Apple's interests."

In a tersely worded statement, the Cupertino, Calif.-based company stated that " . . . Steven P. Jobs has resigned as chairman and director of the company, effective Sept. 18." Jobs had announced last week that he intended to launch a new computer venture with the help of five top Apple managers.

An Apple spokeswoman said that "legal ambiguities" in Job's original letter of resignation of Sept. 17 required the company to seek another letter of resignation from Jobs.

"In the letter Steve submitted, he didn't say he was resigning as a director," said the spokeswoman.

The company accepted Jobs' second letter, but declined to disclose the contents yesterday.

The resignation effectively severs all of Jobs' formal ties with Apple. He remains, however, the company's largest shareholder with 5.5 million shares -- roughly 9 percent of the 61.8 million shares outstanding.

Jobs submitted a letter of resignation Tuesday, saying that Apple had appeared "to be adopting a hostile posture toward me and the new venture."

At an Apple board meeting last Thursday, Jobs told the assembled directors he intended to launch a new computer venture. Jobs said he originally tendered his resignation at that meeting, but the board asked him to defer action for a week.

In Jobs' version of the meeting, he told the board that he would be recruiting some of Apple's managers. In Apple's version, Jobs did not reveal his hiring intentions. According to Apple, it wasn't until a meeting with the company's president John Sculley last Friday that Jobs disclosed his plans to take the other Apple employes with him. The five managers recruited by Jobs resigned last week.

Those defections from Apple provoked public criticism of Jobs by several Apple executives.

In yesterday's statement, the company said it "continues to evaluate whether any actions should be taken to assure protection of Apple's interests following Jobs' announcement that he plans to launch a new company."

The Apple spokeswoman would not say whether any legal action was being considered or even whether company counsel had instructed officers not to talk about the matter. Such instructions would indicate that legal actions were being formally considered.

Efforts to reach Apple executives for comment were unsuccessful. Apple's corporate counsel, Al Eisenstadt, could also not be reached.

Jobs' new venture has not been spelled out in detail, but it reportedly would develop and market computers specially designed for the higher education market. According to Silicon Valley lawyers, the project could be challenged in court by Apple on trade secrecy grounds if Apple can demonstrate that Jobs or any of his employes expropriated proprietary Apple technology.

Similarly, says one Palo Alto lawyer who asked not to be identified, Jobs may have been in breach of his "fiduciary responsibilities" as Apple's chairman when he began to set up a new company.

Jobs, whose home phone was disconnected, could not be reached for comment.