Apple has patented a low-profile memory slot that could find its way into a tiny subnotebook computer from the Cupertino-based company. Apple's latest patent, titled "Method and apparatus for linear insertion and removal of a memory module in a computer system," describes a means of inserting memory using much less space than existing methods. The patent describes an "access door" that users can open to insert new memory modules into a computer, presumably sliding the memory chip in lengthwise through the door rather than opening the computer's case altogether to insert the memory in a traditional "top-down" style. The invention would greatly ease the process of upgrading memory in a small, compact computer -- such as the rumored subnotebook that industry watchers expect to debut some time this year.

Apple in mid-August was discovered to have filed a patent for retractable notebook ports, which include all of the laptop's connectivity options including RJ45 (Ethernet networking) and FireWire. The patent details a small molded panel that folds into the base of the notebook, hiding all ports until the need arises to connect a peripheral.

The patents further reinforce Apple's dedication to trimming down the size of its portable computers, and could describe technology used a subnotebook that is allegedly under development by the system builder.

Apple abandoned its line of subnotebooks in early 1997 when the company retired its wildly popular PowerBook Duo. Apple has since offered small full-sized notebooks like its iBook G3 models and 12-inch PowerBooks, but has not released a true subnotebook for more than 10 years.

Subnotebook plans discovered?

Nevertheless, one industry analyst earlier this year reported that Apple was increasing its use of NAND flash memory in its future product development plans, and that the computer manufacturer was already designing a new subnotebook that utilizes NAND flash memory as its primary source of storage. Flash storage is much faster and more reliable -- though more expensive -- than hard drive-driven devices, and uses much less power than mechanical storage means that rely on moving parts. American Technology Research senior analyst Shaw Wu predicted in early March that Apple was planning to introduce its subnotebook in the second half of this year.

Design concepts point to tiny MacBook

Japanese concept designer Isamu Sanada late last month pieced together several modern technologies with Apple's newer designs in a rendering of what he believes Apple's new subnotebook will look like. The rendering depicts a tiny laptop with a built-in DVD drive that spans nearly all of the laptop's base, and points to a touch-sensitive keyboard which would further reduce the size of a would-be subnotebook.

A forthcoming subnotebook from Apple could utilize the tubular structore of the company's recently released Bluetooth keyboard, as well as the LED display backlighting first introduced in the new 15-inch MacBook Pro laptops. Subnotebooks from Apple would likely make use of Flash-based storage, according to Sanada, or perhaps a small hard drive to reduce the thickness below any existing subnotebook on the market.

Apple's chip supplier Intel has already illustrated the possibility of an ultra-thin subnotebook through its Metro concept, which details a system with no optical drive that uses mechanical keys rather than a touch-sensitive keyboard approach.