The PCW included a version of CP/M known as "CP/M Plus". This provided a range of facilities comparable to those of MS-DOS, but imposed a significant limitation: it could not address more than 64 KB of RAM. Since CP/M took 3 KB of this, the most that CP/M applications could use was 61 KB. The rest of the RAM was used as a RAM disk (exposed under the drive letter "M:" for "memory"), which was much faster than a floppy disk but lost all its data when the machine was powered off. On the other hand, the standalone Locoscript word processor program was able to use 154 KB as normal memory, and the rest as a RAM disk.