Microsoft is considering offering Windows 7 on USB flash drives to make upgrades easier for systems without optical drives, a source claimed on Friday. The unnamed contact explains to CNET that the company is looking at the move to make it easier to upgrade netbooks in particular, which currently need either an external drive or else the elaborate creation of a bootable USB drive. Whether this would involve copy protection beyond a CD key isn't known.

Other options are still on the table and wouldn't necessarily involve removable storage. As Microsoft already allows Vista downloads, it may extend that to Windows 7 and automate the process of creating a bootable USB stick from the file. Alternately, customers could visit retailers like Best Buy and have technicians perform the upgrade. These may do it anyways as the move from XP to 7 doesn't allow an in-place upgrade, instead requiring a complete reinstall and a backup of valuable data.

Microsoft hasn't committed to any one strategy but has acknowledged the problem of moving some systems up to the new OS without a DVD or CD reader.

A release on USB would mark the first by any major OS vendor and is a potential solution for Apple and other companies to including an operating system with a netbook or an ultraportable. Some computer designers still include the operating system on a disc with these systems but usually have to count on the owner buying an add-on drive. Apple's solution with the MacBook Air was to develop Remote Disc and draw on another computer's optical drive over the local network.

Using flash storage has been cost-prohibitive so far as modern operating systems often need multi-gigabte storage that in USB form costs significantly more than CDs or DVDs.