* What this does is make the CCP (command line processor) look for SUB and COM files on the IDE drive C: before the currently logged disk. So if you are on A: and you issue the command BASIC (to load BASIC), it will be loaded from the IDE drive rapidly, even if there is a copy on A:. In fact, it looks on M: first, and a submit file like BASIC.SUB takes precedence over the real executable BASIC.COM.
=== Public USER 0 (SYSTEM files) on the PCW ===
Another useful trick is to make the CP/M COM files in user area 0 into SYSTEM files. This means that they won't be visible when you do a DIR, and they will be executable from all user areas on the same disk. So:-