I have not checked PMP market since I purchased my last player. The market is changing so quickly. Today I am impressed by the brand new MID-like PMP (Smart Q5/Q7) by Zhiqi, China.

Portable Ubuntu for Windows is a compact yet complete Ubuntu system that can be executed directly in Windows as if it were a regular software application designed for that operating system.

Embedded Linux Resource Center from EECatalog.

Maybe debug tools are weakness of embedded Linux development.

The embedded Linux applications usually require networking services, actually it is another reason why Linux becomes so popular in embedded systems.

There are so many bootloaders available that we can not describe them in detail.

When the RFS content and storage media are ready, the developer can setup and mount RFS.

Most of the embedded systems are using memory devices rather than HDDs.

Basically the developer can define his own hierarchy standard for RFS - Root File System, but it is always a better practice to follow common hierarchy standard, which is called Filesystems Hierarchy Standard (FHS).

Kernel keeps growing to support new hardware and devices. The developer should study the kernel very carefully to check the availablity of specified features in the kernels.