Apple faces a lawsuit accusing it of promising more available storage space than it actually delivers in iPhones, iPads, and iPod touch devices. The suit filed early this week in US District Court in Northern California argues that while Apple touts 16 gigabytes of digital storage on lower price models of gadgets such as hot-selling iPhones, about a fifth of that is eaten up by the latest operating software.

The suit charges Apple with being deceptive in advertising that represents devices as having much more storage space than is really available to people who purchase devices.

Apple offers all iCloud users five gigabytes of free storage, which offsets the amount that the lawsuit contends is eaten up by the operating system.

Apple declined to comment.