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                                 ZFILER Notes


PLEASE READ THE PROGRAM NOTES BELOW.  MANY PEOPLE ARE COMPLAINING TO ME
ABOUT THINGS THAT ARE EXPLAINED IN THE DOCUMENTATION.

As usual, I am eager to get bug reports and suggestions from users.  I can be
reached in the following ways:

    in writing:        1435 Centre Street
                Newton Centre, MA 02159

    voice telephone:    work: 617-863-5500 x4704
                home: 617-965-3552

    modem:            Z-Node #3 (mine) at 617-965-7259
                Lillipute Z-Node #2 (Chicago)

My Z-Node in Boston is accessible via PC-PURSUIT.  It is possible that the
sysop of a Z-Node near you is a PCP subscriber and can forward messages to my
node for you.

                Jay Sage


-----------------------------------------------------------------------------

ZFILER Version 1.0b Notes -- January 13, 1987

BIGGEST NEWS: ZFILER now supports DateStamper.  On file copies (and moves)
the time and date stamp of the source file is carried to the destination
file!

I have now rewritten the directory logging ('L' and 'N' commands) code to
properly respect the environment with respect to allowing access by drive and
user number.  The code should now work properly and conveniently in a system
that enforces security by not allowing drive/user access to areas that are
not accessible using a named directory reference.

ZFILER always translates a requested directory -- whether entered using DU or
DIR form -- into a drive and user.  If the DUOK flag in the environment is
set, then these values are checked against the maximum values allowed by the
environment.  If they pass, all is well and the directory is logged in.  If
they fail or if DUOK is not set, then the drive/user value is converted into a
named directory and checked against the NDR buffer.  If the directory is found
there, it will be logged in after appropriate password checking.

Steven Mendelson discovered an interesting problem that occurs when a shell
like ZFILER is rerun from the command line using GO.  Because ZFILER derives
its own name from the external file control block, it thinks its name is "GO"
and stores that in the shell stack entry.  This can cause grave problems
later.  To protect against this, ZFILER now replaces its initial JP opcode at
100H with a RET opcode so that an attempt to use "GO" will simply return one
to the command processor.  I recommend that this technique, which costs only 5
bytes, be used in all programs which are not designed to work correctly when
rerun by "GO".  NOTE: this means that ZFILER cannot be cloned by using the
SAVE command as I have suggested in the past.  I will eventually either add
a 'clone' command (as in MEX) or produce a full configuration source file.

A small, but significant, bug was corrected in the macro script expansion code.
The script '$c', where 'c' is any non-parameter character, should have been
expanded to 'c' but was not for the lack of an INC HL instruction!

-----------------------------------------------------------------------------

ZFILER Version 1.0a Notes -- January 1, 1987

Since the changes I have been introducing into VFILER have taken that program
way beyond what it used to be, I have decided to release it as a new program
through the ZSIG organization (which I strongly encourage all Z-System
hobbyists to join).  This will relieve Echelon of any responsibility to
support it and will allow us hobbyists to follow our own goals.  As with
VFILER41 and the first stages of the now abandoned VFILER42, I will be
releasing a series of test versions of the program with letter subversion
designations.  This first one is version 1.0a.  When a final version is
released with the source, the letter subversion will be dropped.  The main
changes since VFILER version 4.2b are as follows:

MAJOR COMPATIBILITY CHANGES - PLEASE TAKE NOTE.  I have changed the macro
parameter designator character from '%' to '$' to be consistent with all the
other script-building programs.  Besides renaming your VFILER.CMD macro file
to ZFILER.CMD, you will have to edit the macro scripts.  You will have to
change all '%' characters to '$'.  You will also have to change any resulting
'$$' to '$P'.  I have eliminated the old '%$' alternate to '%P' for the
complete file specification for the currently pointed-to file.  Since '$$' is
now needed for a dollar sign, only the '$P' form can be used for the file.

I have made major changes to the way the 'V' command pages in response to a
suggestion from Carson Wilson.  He noted that he often wanted to get to the
end of a file.  Hitting repeated carriage returns would not only carry one to
the end, it would carry one past the end and on to the next file or back to
the files display.  Now, after one reaches the end of a file, only the
commands ^x (continue with next file) and ^c (abort 'V' command) will be
recognized.  In addition, I added a ^z option that can be used at any page
break to turn off paging and scroll continuously to the end of the file.  I
have not yet implemented ^s pausing but plan to.

Charlie Kestner complained about having to use a shifted key ('#') to get the
macro menu screen, and right he was!  Of course, it was always an assembly
option.  Now you can use the macro lead-in character.  When the lead-in
(default ESC) is pressed once, you get the 'Macro: ' prompt.  Press it again
and you get the help screen (it fakes a '#' key).  Press it a third time and
you are back to the files display (there had been a bug in the code that I
discovered when I tried this).

A very important change has been made in the way the shell stack has been
used.  I have been trying for some time to promote a new viewpoint on the use
of the shell stack, and I have now carried it to its logical conclusion.
Basically, the shell stack should not be viewed only as a command line for the
command processor.  It must, indeed, have such a command line, but information
need not (and should not) be passed to the shell as part of that command line.
Instead, parameters needed by the program should be kept in whatever form is
convenient and efficient in the part of the shell stack entry after the
command-line null.  Remember that a program know whether it has been invoked
as a shell by the command processor or manually by the user.  In the latter
case, it must parse information from the command line, but in the former case
it can get that information in an entirely different way.

ZFILER pushes only the name of the program (default ZFILER) followed by a null
as the command.  By not prefacing it with a DUU: or DIR: but instead relying
on the path to find it, it avoid problems with systems that do not recognize
either or both of those forms.  All other parameters are derived from other
data on the shell stack or from the system file names in the environment.

When ZFILER is first invoked by the user, the current directory and any
requested directory and file mask included as a parameter on the command line
are stored in the shell stack entry.  The two directories are stored in binary
form as used by the SYSLIB routines.  This saves code and avoids any problems
with recognizing DU and DIR forms.  It also avoids problems with returning to
a directory with a password.  Once one has been admitted to a directory,
subsequent accesses are automatic.  (The 'L' command still needs some work,
and that is next on my list.  It presently cannot deal properly with systems
that do not allow the DU form or with logins to named directories beyond the
maxdu/maxuser values specified in the environment.  These fixes should be
fairly easy to code.)

By keeping the original DU on the shell stack, ZFILER can return to the
directory from which the user invoked it no matter how many other directories
were subsequently logged in as the result of macro executions or 'Z' commands.

In the past, after executing a command line from the 'Z' command, the shell
wait flag was always set and one was always greeted by a "strike any key"
prompt before returning to VFILER.  With ZFILER if you enter a command line
starting with a space, then shell waiting will be disabled and you will return
directly to ZFILER without any delay.

Terry Carroll, I believe, made the following suggestion about the handling of
file attributes on copies: if the file already exists in the destination
directory, then use its attributes for the new file; otherwise use the source
file attributes.  A new option has been added in ZFILER to implement this (use
the 'O' command).

I have not yet added an automatic skip option in file copying to bypass a file
if it exists in the destination (like the /N option in MCOPY).  It is still on
my list.

Two changes in group operations have been made.  Many people complained to me
that VFILER group operations often did not work but acted on the first tagged
file only.  It turned out that they were answering a prompt (such as the
verify prompt) with a 'Y' or 'N' followed by a carriage return.  The carriage
return was not needed by the prompt but caused the group operation to be
aborted before the next file.  I changed the group-abort code so that any key
EXCEPT CR will cause an abort.

I also found a bug connected with the GA (group archive) operation.  I
frequently use the GA command to tag unarchived files.  When asked for a
destination directory for the copy, I just hit carriage return.  This leaves
only unarchived files tagged and I can proceed to do whatever I want with them
(for example, GV or GC -- the latter if I want to copy them somewhere without
setting the archive bit on the source file).  I discovered that the file-
replace query option for GC was not being honored.  An archive flag, once set
by the GA command was never being cleared.  Now it is cleared on entry of the
'G' command.

-----------------------------------------------------------------------------

VFILER Version 4.2b Notes -- September 29, 1986

Many people requested that the "Z" command be made to log into the displayed
directory before running the command line.  This cannot be done if the user
number is greater than 15, so I made a compromise.  The code checks the user
number, and if it is less than 16 the directory is logged in; otherwise the
directory is left unchanged.  The first configuration byte after the string
'CONFIG' in the first page of the code controls this function.  Set it to 0 if
you prefer the old way.  As distributed, the files have this option enabled.

You should note two significant drawbacks to logging in the current area.  If
you run a VFILER.COM file that is in the current directory and not on the
search path, after you select another display directory and execute a command
with "Z", the shell will abort because the VFILER.COM file will not be found
(you have changed the default directory).  With the old system, you actually
stayed in the original directory, and so there was no problem.  The second
drawback is that the disk system has to be reset in order to change the logged
in directory (unless someone can tell me how to get around this).  The trouble
is that VFILER is running as a subroutine under the CPR and normally
terminates by returning to the CPR with a RET instruction.  Even if the BDOS
has logged in a new area, the CPR still remembers the original one and
restores it.  There is nothing VFILER can do about it.  One must do a warm
boot to get around that.  This slows down any operations run from the "Z"
command.

I have made some significant changes to the rename, copy, move, and unsqueeze
commands.  The rename command now preserves all file attributes, as I think it
should (any views to the contrary?).  So does the move command.  The way the
copy command treats file attributes is controlled by two new options under the
"O" command.  One option (default is on) causes all attributes of the source
file to be carried to the destination file.  Another option (default on) is in
addition to the first and causes the archive attribute to be set in the
destination file (Joe Wright's arguments convinced me, but I made it a user
option here).  With unsqueezing, the attributes are always turned off, except
that the archive attribute is controlled by the same option flag that applies
to copied files.

These changes were precipitated by a bug report that renaming a file twice in
succession would give a BDOS error.  I tried that on my BigBoard system, and
sure enough, it gave a ZRDOS error #2.  When I tried it on the Ampro system at
work, however, there was no problem.  Now for the weird part -- the problem no
longer appears on the BigBoard either (with the same VF42A that I tried this
morning)!  I can no longer reproduce the error, so I cannot tell if I fixed
it.  I did make some changes to the rename code to correct what I thought
might be a problem (the disk number byte in the ring is normally 1, 2, 3, and
so on, but after renaming in previous versions of VFILER, the drive was
changed to 0.  I don't see why that would matter, but I modified the code to
leave that byte unchanged.  If anyone sees the error again, please try to
document it very carefully and precisely so I can track it down.

For those who are trying to make patches to VFILER, a section of the source
code is reproduced below.  Note the pointers to the three command tables.  If
the control-j I used for the new 'jump again' command is not convenient for
you, you can go to CTAB1, the table for commands that can be used only when
the display is not empty.  Its structure is quite clear (if not, see the full
source to VFCMDS1.Z80 in the VFILER41 release), and you can find the entry
with control-j and patch in a value of your choice.

;---------------------------------------------------------------------------

; Configuration and reference data

    dw    ctab1        ; Addresses of command tables for reference
    dw    ctab2
    dw    gtable

    db    'CONFIG'    ; Marker in code

logfladr:
    db    logfl        ; Login current directory with "Z" command
leadadr:
    db    mleadin        ; Macro leadin character here
npause:
    db    tdelay        ; Delay time on screen refresh after macro error
macfladr:
    db    macflag        ; Allow immediate execution of macros 0..9


OPTIONS:            ; Begin options configurable with 'O' cmd
                ; DO NOT CHANGE ORDER

qryrepa:            ; #1
    db    qryrep        ; Single file replace query option
qrygrpa:            ; #2
    db    qrygrp        ; Multiple file replace query option
qryarca:            ; #3
    db    qryarc        ; Query on archive replacement
qryvfya:            ; #4
    db    qryvfy        ; Verify query option
vflag:                ; #5
    db    vfydflt        ; Verify default if no query or no answer
nosysa:                ; #6
    db    nosys        ; Supress display of SYS files
defalfa:            ; #7
    db    defalpha    ; Initial file sorting mode (FF for name)
attrfla:            ; #8
    db    attrfl        ; Copy attributes with files
arcfla:                ; #9
    db    arcfl        ; Set ARC attribute in destination file

shwait:                ; Flag also saved on stack with options
    db    0

nopt    equ    $ - options    ; Number of option flags to save/restore

;---------------------------------------------------------------------------


VFILER Version 4.2a Notes -- September 19, 1986

Added "^J" (control-J) command to jump to next file that matches the last mask
specified in a previous "J" command.  This allows one to jump easily to the
second or third file that matches a simple file spec.  For example, suppose
the directory has just a few files of type DOC and you want to find one called
"ZCPR3NEW.DOC".  You could give this exact name in reponse to the prompt from
the "J" command, but it would be much faster to answer the prompt with a
simple ".D" or ".DOC".  If that left you on an earlier DOC file in the
display, just press control-J (linefeed) and you will move to the next
matching file.  The command "^J" is the same as "J" except that you are not
prompted for the file mask and the file pointer is not initialized to the
first file on the screen before the search starts.  Instead it uses whatever
mask is left over in the mask buffer, and it works its way in circles through
the file ring.


Fixed bug in "M" and "GM" commands that allowed source file to be deleted even
when copy had not been performed.  Now if you answer "N" in response to a
prompt about overwriting the destination file (or if the disk fills up or if
the copy verification shows an error), the source file will not be erased.


Added "GR" group reverse function to reverse file tags.  Tagged files become
untagged; untagged files become tagged; and soft-tagged files remain soft-
tagged.  [I have gotten no comments on my question about what to do with soft-
tagged files under the "GR" command.  The other reasonable possibility is to
untag them also.  What do you think?]


Cleaned up log command ("L" or "N").  Removed special handling of answer "x"
for directory name (no longer needed) and changed error handling code.  I hope
I got all this correct.  I eliminated some things that appeared not to be
necessary (to shorten code and speed execution), and there is always a chance
that I overlooked some situation that required that code.  One thing I did
leave in that I think could possibly be eliminated is the resetting of the
drive when only the file mask is changed.  I guess that that is there for when
one swaps diskettes and logs the new one in with a simple ":" response to the
log prompt.  Without it one would have to name the drive in the login prompt
(might be just as easy).