Steve Jobs, in pain and too weak to climb stairs a few weeks before his death, wanted his children to understand why he wasn't always there for them, according to the author of his highly anticipated biography.

"I wanted my kids to know me," Jobs was quoted as saying by Pulitzer Prize nominee Walter Isaacson, when he asked the Apple Inc co-founder why he authorized a tell-all biography after living a private, almost ascetic life.

"I wasn't always there for them, and I wanted them to know why and to understand what I did," Jobs told Isaacson in their final interview at Jobs' home in Palo Alto, California.

Isaacson said he visited Jobs for the last time a few weeks ago and found him curled up in some pain in a downstairs bedroom. Jobs had moved there because he was too weak to go up and down stairs, "but his mind was still sharp and his humor vibrant," Isaacson wrote in an essay on Time.com that will be published in the magazine's Oct. 17 edition.

Jobs died on Wednesday at the age of 56 after a long battle with a rare form of pancreatic cancer.

Outpourings of sympathy swept across the globe as state leaders, business rivals and fans paid respect to the man who touched the daily lives of countless millions through the Macintosh computer, iPod, iPhone and iPad.

Jobs had struggled with health issues but said very little about his battle with cancer since an operation in 2004. When he stepped down in August, handing the CEO reins to long-time operations chief Tim Cook, Jobs said simply that he could no longer fulfill his duties as chief executive.

Apple has been similarly guarded about the circumstances of his death, saying only that their chairman was surrounded by his wife Laurene and immediate family. Jobs had four children from two relationships.

Funeral arrangements have not been disclosed and it is uncertain when the company will hold a planned "celebration" of Jobs' life. Officials in Sacramento said there will be no state or public funeral. – Reuters