by Solomon Swift
Last month we discussed an easy way to make a backup copy
of CP/M. This is vital. Once youve made the backup, put
the original away and work ONLY with the backup.
When working with any sophisticated piece of software you
need to master the fundamentals first. As obviously simple as
this sounds, most of us aspiring hackers too often allow ourselves
to be overcome with eagerness. Admittedly, having a firm background
in SmartBASIC and some experience with Z80 encoding will augment
your understanding of CP/M. However, youll find this powerful
operating system to be most useful if you conquer
it in a logical step by step process. For many of you, these
first few articles will only be review. In due time, though,
well delve into the more rewarding aspects, such as modifying
CP/M and creating machine code programs.
THE BUILT-IN COMMANDS
The DIR command is used to display a list of the files on
a specific storage medium. Simply typing DIR and pressing [RETURN]
will display the filenames on the current drive. To see the
filenames in another drive without changing the default drive,
follow DIR with a space, the drive label (A, B, C, or D), and
a colon. Then press [RETURN]. For example,
DIR B: [RETURN]
will display the files in drive B. You can now type DIR (without
a drive label) to see the directory for the default drive.
To change drives, simply enter the drive label, a colon, and
then press [RETURN]. Now you can enter DIR or whatever command
you prefer on the most recently selected drive.
If there are no files in the directory, youll get the
message NO FILE. The DIR command does not reveal
whether or not a data pack or disk has the operating system stored
on it (as by dint of SYSGEN).
The DIR command can also be used to search for a specific
filename. For example,
DIR B:EXAMPLE.TXT [RETURN]
will search for the EXAMPLE.TXT file on drive B (without changing
the default drives). If the filename is not found, the NO
FILE message will be displayed.
From the October
1986 issue of Nibbles & Bits (PDF)
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