The Datafile PD-CD 5/DATAFILE_PDCD5.iso/utilities/d/dosfs/!DosFS/ReadMe2

Text File | 1990-10-22 | 7.7 KB | 179 lines

> !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 selected.
It also allows the user to perform some DosFS-specific functions, such as
counting the number of bytes free on the disc, changing the volume label
(disc name) etc., when Menu is pressed on it. Very early versions of the
filer (submitted to various places, but not by me) were not able to do
anything more.

If your disc has a volume label (disc name), this will appear in the
pathname in the title bar of the directory viewer. In that case you can have
viewers on more than one disc open at the same time. But you'll have to
close the Filer window first if you want to view two nameless discs after
eachother. This is because Risc-OS thinks it is still the same disc. So the
program works better if you give your discs a name.


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.]


NAME CONVERSIONS

There are 4 name conversion options. In the direction Dos to ADFS,
DosFS-Filer will automatically set options depending on the extension,
whether you click on the buttons or not, *unless* you switch off the
AutoSelection Mode. So if you try to change a setting and this is overruled
(the program also beeped), then this is the reason. More details of this
later on.

The 4 conversions, numbered 0 to 3, are called RSDOS, NoExt, C and TeX.

- 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
unfortunately 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

Going from Dos to ADFS, DosFS-Filer will use a suitable conversion mode
depending on the extension of the RSDOS file. This can be overruled if
required. This works as follows: 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), and  B  indicates binary
mode (i.e. do not change end-of-line characters). [Of course, if you don't
want to keep the sparked file, you don't need to go via the transfer icon:
copy directly from the directory viewer to the Spark icon.]

-- 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: 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 whereas 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).

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. If the
AutoSelection mode is on and you try to change a setting, this will be
immedeately overruled if there exists a corresponding DosFS$@Ext_xxx
variable. The program will beep.

- 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

When more than one RSDOS-file is dropped onto the transfer icon, the
file type will show the file type of the last file in the selection.
This does not mean that the file types of the others is ignored, it will
be updated when copying is in progress.

Furthermore, if more than one RSDOS-file has been dropped onto the transfer
icon and the sprite icon is dragged onto an application instead of a filer
window, then only the FIRST file will be loaded and all the others will be
ignored.

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 always be retained.



© Rob Schrauwen 1990