The PCW16 is an 8-bit computer using a 16MHz Z80. It is not supplied with CP/M, but you can download an implementation here. Its own operating system is called Rosanne.
In appearance, Rosanne looks very like Macintosh System 6. A "Task" menu allows switching between the built-in applications and the use of external programs. There is context-sensitive help, and a starfield screensaver is built in. The computer boots straight into the GUI (something I've only seen Macs do).
Memory is 1Mb of RAM, and 1Mb of Flash (similar to a non-volatile RAMdisc) which contains the BIOS, Rosanne, and the built-in software. Most of the Flash memory can be updated using software, but the first 64k (which contains the BIOS) can only be altered by plugging a reprogramming cartridge into the underside of the PCW.
The software includes a word processor, a diary, a spreadsheet etc. Supposedly the file manager can handle DOS discs (720k and 1.4M) and 720k PCW discs. New discs are formatted in DOS format; the file \PCW\CATALOG.TXT holds the mapping of the 31-character PCW filenames to DOS 8.3 names.
BIOS sound support is exactly twice as good as on the original PCWs; instead of just a beep, there is a beep and a click.
There is space on the main circuit board for an extra 1Mb RAM, an extra 1Mb flash, a hard drive interface and an interface to a colour VGA monitor. These would probably have to be fitted professionally. There is no expansion port as such; any expansion would have to be done either via the parallel port, or through the reprogramming socket in the base.
With detailed knowledge of Rosanne, it was fairly easy to implement a basic CP/M 2 BIOS for it. One point to note is that "common memory" is at the bottom of the memory map rather than the top, and the CP/M BIOS has to perform paging gymnastics to translate CP/M BIOS calls into Rosanne calls.
PCW16 pages