Apple Computer has issued an update to its Mac OS X operating system just three weeks after the software's debut. The official release of the update, a collection of bug fixes and minor new features, arrives two weeks after a pirated version of the update appeared on the Web. The update follows the release of Apple's latest Mac operating system by about three weeks. The update improves USB connectivity, boosts the stability of older software applications and fixes minor glitches, according to Apple's Web site. It also puts Mac OS X through a "system optimisation" procedure that can greatly improve performance. Posted last Friday, Apple's update raises Mac OS X to version 10.0.1 and Build 4L13. People who downloaded the leaked update, or Build 4L5, must delete the file "10.0.1Update.pkg" from the Receipts folder found in Library before Mac OS X will download and apply the fix. The update does not deliver CD-rewritable capability, something Apple chief executive Steve Jobs said the company would provide by the end of April. In a controversial move, Apple shipped Mac OS X without support for CD-RW, DVD playback and DVD recording -- all features touted in either current or past promotional campaigns. "It's kind of like a nickel-dime approach to upgrades," said Technology Business Research analyst Tim Deal. "What people are really waiting for is support for optical drives. While it is important to have this kind of performance update, what people really want is support for all the gadgets they have on their brand-new Macs." Mac OS X is the first complete overhaul of the operating system since its release in 1984. Apple moved to Unix at the core, bringing Mac OS X on par with other mature operating systems, such as Linux, Windows 2000 and Be OS. Mac OS X is less crash prone than earlier versions and offers improved memory management and greater ability to run multiple programs simultaneously. But not everyone is convinced Mac OS X is built on the right foundation. Linux creator Linus Torvalds recently trashed the version of Unix that Apple used to build Mac OS X, calling it "a piece of crap," but later tempered his comments in an email to ZDNet UK Mac OS X also adds multiple-processor support in what could be an indicator of new systems to come. Apple stopped selling the Power Mac G4 667 on Friday, leading to speculation that at least one new dual-processor system could appear later this month. With Mac OS X, Apple joins Microsoft in adopting an update plan that could present difficulties for some software users. Apple is delivering software updates through a tool in Mac OS X. But unlike with Mac OS 9, Apple does not offer an easy way for most people to independently download a file with updates that can be used again and again. In addition, average Apple customers must download updates for each machine they use, which could be an inconvenience for people with more than one Mac and slower dial-up connections. Microsoft has long used a similar strategy for delivering Windows updates. Apple on Friday also posted a technical support document addressing recent problems with third-party memory chips. On March 23, Apple issued updates intended to make many of its Mac systems Mac OS X-compatible. But the firmware upgrade unexpectedly disabled memory on some systems. Firmware is software resident on a computer's hardware that manages hardware functions, typically independently of the operating system. Developers continue to release early versions of software applications for Mac OS X. AOL Time Warner released the Mac OS X beta, or test, version of AOL 5.02a on Friday, but only to a select group of testers signing up for a trial. A Mac OS X beta of AOL Instant Messenger is already widely available. Eudora last week also released a second Mac OS X beta of its popular Eudora e-mail program. Have your say instantly, and see what others have said. Click on the TalkBack button and go to the ZDNet news forum. Let the editors know what you think in the Mailroom. And read other letters.