Files And File Names - Epson PX-8 User Manual

software and hardware are handled by the different versions of CP
1M
written
for the different computers. This is the reason why CP
1M
has been chosen as
the operating system for the PX-S. The huge library of CP
1M
based software
can be installed on the PX-S, making it easy for the user to find the particular
application he requires. This increases the power and versatility of the com-
puter since it is only a machine to run software - a tool to extend the mind much
as a hammer is a tool to extend the body.
If you are a beginner to computing, CP
1M
can be a little frightening. You will
find that the terms used to communicate ideas to the computer are not as near
to normal human communication as one would like. There are a number of
jargon words which will have to be learnt. This chapter has been written in such
a way that as far as possible you only have to think about the current task.
If
necessary, use the index to direct you to the appropriate part of the chapter
to find out about anything you do not understand. Any difficulties you ex-
perience will disappear with practice, and you will find using CP
1M
will soon
be second nature to you.
The only way to learn to use CP
1M
is to tryout the examples given. This manual
cannot hope to cover the finer points of the system, but fortunately there are
a number of books which describe all aspects of CP
1M
at all levels, from the
absolute beginner to the most advanced user. A list of some of these are given
at the end of Chapter 3.
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3.2 Files And File Names
In a standard CP
1M
system each drive holds floppy disks which are used to
store programs. The PX-S has some drives which do not contain floppy disks.
For the purposes of using them under CP
1M,
the RAM disks, Microcassette
drive and the ROM drives behave as if they were standard disk drives. There
are a few specific differences, e.g. the ROM drives cannot be used to store in-
formation. The use of the Microcassette drive is described in Chapter 4.
The programs and data are stored in files. A file is simply a collection of infor-
mation which is related as a unit. Files fall into two main categories. Program
files are a set of instructions, for example a wordprocessing program. Data files
store information which is used by a program, for example text used by the
wordprocessor or the information used by an accounts program. Files are stored
by name. To make it easier to understand which files are which, the name is
divided into two parts. The first part consists of up to eight characters which
are used to give a distinctive name to the file.
All of the printable characters can be used except:
< > , . ; : =
?
* [ ]
and the space character
The secondary part of the name is used to describe what type of file is stored.
Secondary names are frequently referred to as file types or extensions. This part
of the name is used in the MENU to select the type of file to be displayed on
the MENU in the file name area.
It
is possible to store a file without an exten-
sion but this can cause problems. Applications programs frequently add the
exte~sion
to the primary name you have given the file so that you know which
files belongs to that program. The extension is separated from the primary file-
name by a full stop.
Examples of file names with extensions are:
BASIC.COM
STAT.COM
SAMPLE.ASM
MEMO.DAT
Note that all filenames are given in upper case letters. Even if you type them
in lower case, they are stored on the disk as upper case.
If
you are using the
filename, CP
1M
will understand if you type the file you want in lower case
or even a mixture of upper and lower case. Note also that the separator in front
of the extension is printed next to the primary file name. This may not always
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