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CP/M 3 User's Guide 4.4 How CP/M 3 Searches for Files
If you include a drive specifier before the command keyword, you are telling
CP/M 3 precisely where to look for the program file. Therefore, CP/M 3 searches
only two locations: the directory for the current user on the specified drive, and then
for user 0 on the specified drive, before it repeats the command line with a question
mark. For example, if you enter
4C>A:SH0W [SPACE]
CP/M 3 looks on drive Al, user 4 and then user 0 for the file SHOW.COM.
If you do not include a drive specifier before the command keyword,CP/M 3
searches directories in a sequence called a drive chain. When you first receive
CP/M 3, there is only one drive in your chain, the default drive. Unless you change
the chain with a SETDEF command, CP/M 3 looks in two places for the program
file. For example, if you enter
7E>SHOW [SPACE]
CP/M 3 searches the following locations for the file SHOW.COM:
1. drive E, user 7
2. drive E, user 0
Remember that a SHOW.COM file under user 0 must be marked with the SYS
attribute or else CP/M 3 cannot find it. Use a SET command to give program files
under user 0 to the SYS attribute because they can then be accessed automatically
from all other user areas. You do not have to duplicate frequently used program files
in all user areas on all drives.
When you use a SETDEF command to define your own drive chain, include the
default drive, and the drive that contains your most frequently used utilities. For an
example, assume you defined your drive chain as * (the default drive) and drive A.
When you enter the following command:
2D>SH0W [SPACE]
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