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ReadMe2
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1990-12-19
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> !DosFS.ReadMe2
DOCUMENTATION OF DOSFS-FILER
----------------------------
Author: Rob Schrauwen
Remark: Applies only to Filer2 Version 2.60 or later.
THE FILER
The DosFS-Filer is a program which has two functions. First of all,
it gives access to a filer window when the floppy-drive icon is pressed
and it allows the user to perform some DosFS-specific functions,
such as counting the number of bytes free, changing the volume label (disc
name) etc., when Menu is pressed.
Very early versions of the filer (submitted to various places without
my knowing that) were not able to do anything more.
The second function of DosFS-Filer is to provide a front end to the
DosFS filing system. It makes name and file conversions possible.
The transfer icon on the icon bar belongs to this part.
THE CONVERSION UTILITY
The DosFS-Filer, called Filer2 for historical reasons, supports file
conversion from DOS to RISC-OS and back. Instead of copying directly to
and from the DosFS filer window, drop one or more files on the conversion
icon, next to the floppy disc icon. A window is opened and it is possible
to enter various options, but by default the program will try to fill
in the options by itself. To finish, drag the file icon in this window to
the destination.
[If the Window manager would send messages through a vector, this extra
step of dragging 'through' the transfer icon, could be omitted.]
One can make 4 choices of file name conventions. It is also possible to
let the program make the choices automatically depending on the extension,
see further below.
NAME CONVERSIONS
- The RSDOS (conversion #0) and NoExt (conversion #1) options work as
expected. #0 uses the official RSDOS naming rules, used to get unique file names. It has the problem that names can become too long (the filer
will truncate those names). The NoExt (#1) option just omits the
extension, but this may result in two files getting the same name.
- The C (conversion #2) and TeX (conversion #3) options look for a
directory to put the files in.
As an example, think of a large number of ".c" and ".h" files for the C
compiler. These files are copied into the directories C and H,
respectively, depending on the extension. This is the format required by
the C compiler. So you don't need to select the ".c" file first, then
copy, and then do the same with ".h" files.
Warning: when using these conversion options, do not copy
a file into the directory C itself but to the parent, since otherwise a
directory C will be created within C. (Just try and see for yourself!)
Although this does not follow RISC-OS conventions, it is most useful
since it is likely that one wants to copy ".c" and ".h" files at the
same time, but their destinations are different.
The name "C" is used since the Acorn compilers use this format. "TeX" is
used because Graham Toal's implementation of TeX uses the reversed format,
where the directories are called after the name instead of the extension.
In the other direction, from ADFS to DosFS, the effect is similar, but
the RiscOS-Filer will not allow you to make selections in different
subdirectories at the same time.
In order to prevent errors, the Filer will cut names that are too long.
AUTOSELECTION of conversion modes
Depending on the extension of the RSDOS file, the program will use
a suitable conversion mode. This can be overruled if required. DosFS-Filer
will look for the existence of system variables of the form DosFS$@Ext_xxx
where xxx is an Dos-extension. These system variables are typically defined
in the !Run file. You can add your own ones and change existing ones. Their
function is best illustrated by some examples:
-- Set DosFS$@Ext_ARC DDC 1 B
This means that files with extension ARC will get file type DDC (Spark);
name conversion #1 will be used (= omit extension, the name conversions
are numbered from 0 to 3), and B indicates binary mode (i.e. do not
change end-of-line characters).
-- Set DosFS$@Ext_C FFF 2 A
For files with extension "C", use file type FFF (text), name conversion #2
(C-mode); A denotes ascii-mode (i.e. change CRLF to LF).
Other examples can be found in the !Run file, where several variables
are already set up.
Note that if for extension xxx no system variable DosFS$@Ext_xxx is
defined, the last selected setting is used, which can be changed by
clicking the options in the conversion window. However, if such a variable
does exist, the program will always use the settings described by that
variable, unless you switch of the Autoselection mode. So if you want
to transfer a C-file using name conversion #1 and the variable prescribes
#2, then clicking on the #1 icon has no effect unless the Autoselection
is switched off.
In general, a DosFS$@Ext_xxx system variable (where xxx is an up to
three character sequence) must consist of:
1) A three-digit hex number, denoting the file type followed by a space;
2) 0,1,2 or 3, denoting the name conversion number (RSDOS-naming, NoExt,
C-mode, TeX-mode), followed by a space;
3) A or B, denoting Ascii or Binary conversion (end-of-line characters
will be changed (only) with the A option).
It is necessary to use only uppercase letters.
The auto selection has no effect in the direction ADFS to DosFS.
FURTHER OPTIONS in the window
If no variable is defined for a certain extension, or when the AutoSelection
mode is switched off, the program will follow the manual selection.
- The end-of-line conversion changes CRLF in an RSDOS file to LF;
in the other direction both CR and LF are expanded into CRLF.
- It is possible to change the file type of the ADFS destination files.
One can only use the 3 digit hex number.
- When the 'Prompt for disc insertion' mode is switched on, the user
is prompted for disc insertions, which is useful for copying directly
between RSDOS and ADFS floppies in drive :0.
REMARKS
DosFS-Filer does not support formatting discs. There are separate programs
available (not written by me) that can do that.
If you think some options are missing, I would like to know. Of course
no-one prevents you from writing your own Filer program interacting
with DosFS. If you make changes to the Filer, please document this carefully
and call it Filer3; Filer2 should alway be retained.
© Rob Schrauwen 1990