**>> ZX3.DOC <<**

ZX.COM is a horiZontal directory eXtended and integrated with other
common file management utilities.  Filenames are listed in
alphabetical order.  Here's the directory display:

A>zx
=ZX v3.0==1:ZX2     DOC==2:ZX3	   DOC=
: APPEND  .COM	1k : CHAR    .DEF  1k : CHAR	.GTH  1k : CHAR    .ZIG  1k
: COPY	  .COM	8k : EDFIL8  .COM 11k : FIND51	.COM  3k : FINDBD54.COM  2k
: MERGPRIN.OVR	8k : NSWP    .COM 12k : PRN	.COM 29k : RAMDISK .COM  9k
: RESQ	  .COM	9k : SETDISK .COM  6k : SMK	.COM  4k : SORTV   .COM  2k
: TOON12  .COM	1k : TXTTOWS .COM  2k : UNERA	.COM  1k : USFT1C  .COM  6k
: WC	  .COM	2k : WS      .COM 14k : WS0	.DEF  1k : WSMSGS  .OVR 26k
: WSOVLY1 .OVR 27k : ZX      .COM  3k
A: 195k total  194k used  1k left
A>

In addition to the DIRECTORY, ZX also contains a file ERASE
function, a SCROLL function for printing files with simultaneous
text display, a TYPE function for viewing text in segments for
reading, a sector-oriented text EDITor, a COPY function for
duplicating files, a RENAME function for changing file names, and an
UNERASE function for recovery from errors in file erasures.  There
is also a HELP screen, which summarizes these functions.  ZX
remembers recently entered file names, and provides single-
keystroke reentry of the same names.  Where it might be useful, file
operations are followed automatically by the directory to confirm
the operation, or to assist in recovery from errors.  ZX3.COM is
smaller than 3k.  ZX's small disk footprint is well-suited to any
situation where space should be conserved.  ZX is useful on any CP/M
2.x system which has a Z80 CPU and an 80-column screen.

		      **>> NEW IN ZX3 <<**

ZX, ZX1, and ZX2 are the predecessors of ZX3.  The differences in
ZX2 and ZX3 are:

1. ZX3 has a unique filename memory. Recently used filenames can be
re-entered with a single keystroke for later operations.

2. ZX3 has improved copy logic, and also accepts ambiguous filenames
so that multiple files may be copied with a single command.

3. ZX3 has a new UNERASE function, to correct mistaken file
erasures.

4. ZX3's TYPE function allows you to step backward through a file
using the new ^B (Back) command.

5. ZX3's COPY, ERASE, and RENAME now handle R/O files.

6. ZX3's SCROLL now accepts ambiguous filenames, so that a document
in several sections, or all files of a given type, may be printed
with a single command.

7. ZX3 gives improved disk space statistics, handling files to 496k
and disk space to 9999k.


		       **>> USING ZX <<**

FILENAME MEMORY in ZX3 is used in all other operations, and so
will be described first.  Note the names in the header line of the
directory display above.

=ZX v3.0==1:ZX2     DOC==2:ZX3	   DOC=

Listed after ==1: and ==2: are the filenames most recently used in
the first and second positions on the command line.  These names are
listed in a distinctly different format from the directory to avoid
confusion between them.  ZX's commands all have the format:

     A>ZX <NAME(S)> <OP>      -> FILENAME(S) and OP-eration in <>

When new names are entered by the user on the command line, they
are automatically put in the ==1: and ==2:  blanks in the header
line, as appropriate.  Afterward,

     A>ZX 2 1 C 	      -> means copy ==2: NAME to ==1: NAME
     A>ZX 2 E		      -> means erase the file named in ==2:

This one-stroke entry of ambiguous or unambiguous filenames reduces
the work of entering repeated commands, and makes error recovery, for
example, much easier.  ZX remembers its filenames through repeated
invocations of ZX, through other programs, and through disk changes.
On some computers, ZX remembers through warm boots, and even through
cold boots!  It all depends on how your system handles memory during
the reset.  On battery-powered portables with continuously refreshed
memory, ZX may remember for years if you don't enter new names.  Try
it and see. In fact, because filename memory is an unusual facility,
it will take a few trials to absorb the usefulness of remembered
filenames when entering commands.  Now that I am accustomed to
filename memory in ZX, I miss it in other programs.

The stored filenames are kept in a seldom-used place.  But they are
in memory, of course, and can be overwritten by other programs which
use memory in an unusual way, or by the operating system during
boots.	ZX monitors the header line, and when it finds gibberish
instead of filenames, it will replace the names with blanks and
start over.  If your header line mysteriously empties, and you have
not turned power off, this is what has happened.


COPY requires two file names, followed by C or c (but see autoname,
below):

  A>ZX B:FL.ONE D:FL.TWO C    -> copies, finishes with a directory
			      of D:, then returns to A: for commands.

AUTONAMING is a second feature of ZX intended to reduce the
keystroking required to enter command lines.  Unlike filename
memory, autonaming applies only to operations like copying and
renaming, which require two filenames (and perhaps two disk
specifications).  Autonaming is explained here, but used
throughout the examples.  The essence of it is that ZX3 will
supply the second file name or disk specification if the user
omits it.  In the example below,  ZX autonames the target disk for
a copy operation, making it the same as the first named disk.

  A>ZX FL.ONE FL.TWO C	      -> makes A:FL.TWO, but

  A>ZX B:FL.ONE FL.TWO C      -> will make B:FL.TWO, not A:FL.TWO.

If you do not want to think about this, just specify the disks to
use, as in the first example above, and ZX3 will always follow your
explicit instructions.

Because most copies use the same file name for the new file, but
put it on another disk, ZX3 autonames files in the same way, in
order to save the keystrokes required to type the second file name:

  A>ZX *.FLS B: C	     -> makes B:*.FLS, using the names
			     of the files on A:

Filename memory and autonaming are useful together:

  A>ZX 1 D: C		      -> copies the FILE(S) named in ==1:
			      to disk D:

Copies of a R/O (Read Only) file are made without notice to the
user,  and a R/O file which is the target of a copy operation is
revised in the same way.  Copies of a R/O file have their previous
attributes, except that they are R/W (Read or Write).


DIRECTORY functions are performed in standard CP/M style:

     A>ZX				     -> directory of A:
     A>ZX D:				     -> directory of D:
     A>ZX A.FL				     -> show A.FL only
     A>ZX 2				     -> show ==2: only
     A>ZX *.COM 			     -> all .COM files on A:
     A>ZX B:??.*			     -> B:files with 1 & 2
					     letter file names

Invocation of ZX3 automatically logs in all disks present, to avoid
BDOS errors and to insure that all directory and space information
is up to date.


ERASE is indicated by putting E or e after the file name:

     A>ZX BAD.TXT E			     -> erases A:BAD.TXT,
					     then shows directory
     A>ZX B:*.BAK E			     -> erases all .BAK
					     files on B:, confirms
					     with B: directory
     A>ZX B:1 E 			     -> erases ==1: on B:,
					     does directory

R/O (Read Only) files are erased by ZX3 without muss, fuss, or notice
to the user.


HELP is a screen summarizing these commands:

     D>ZX ?				     -> list of ZX commands


RENAME requires two file names on the command line, then R or r:

     A>ZX ZX3.COM ZX.COM R		     -> recommended rename
     A>ZX B:APT.TXT BAD.TXT R		     -> renames B:APT.TXT to
					     B:BAD.TXT, then shows the
					     directory to confirm
     A>ZX D:2 1 R			     -> yep, both files on D:

Renaming a file clears all attributes (flags in the filename), so
renamed R/O files will become R/W.


SCROLL is started by S following the file name:

     A>ZX PRINT.FL S			     -> scrolls text with
					     no breaks.  NOT followed
					     by directory.  Useful
					     for speed readers, or
     A>ZX PRINT.FL S^P			     -> for ^Printing the file.
     A>ZX CHAPT?.* S			     -> scrolls CHAPT1, CHAPT2,
					     ...in order found on disk.

A file scroll may be halted by using the standard CP/M signal: type
^S to stop, and ^Q to restart, cycling as many times as you wish.  If
you wish to bail out in the middle of a long scroll, type ^S to stop,
then ^C to warm boot.


TYPE is initiated by T or t after the file, and stopped by ^X:

     A>ZX WHICH.TXT T			     -> each keypress
					     shows one sector of
					     WHICH.TXT, ^X exits
					     to a directory, ^B
					     steps back a sector.

If you wish to print a subsection of a file, it is convenient to use a
repeating key to TYPE fast-forward to the right stuff (using ^B to step
back if you overshoot).  Then type ^E to invoke EDIT.  You are not
going to edit, but the edit mode gets CP/M's attention, so that you can
start the printer with ^P, then <cr>.  This will not alter the file,
but will send the text following to the printer.  You can eXit with ^X
when you have printed enough.  Text in files which are typed and
scrolled is shown with the high bits of characters reset, so that
WordStar text files will appear as normal text onscreen, and also
print correctly.


EDITing is done from within the TYPE function, by typing ^E after
display of the sector which you want to alter:

----------- This section contains lines with 80 characters -------------

D>ZX PRUNE.LET T			-> ZX called to Type PRUNE.LET
Dearest Prunella, please do me the honor of being my wife.
I can't continue to live without your company.
Ardently,
Fahrqhar				-> ZX types first sector, stops
					-> Any key continues, ^X quits
=Edit below=				-> ^E edits, retypes text
Dearest Prunella, please do me the honor of being my wife.[]I can't continue to
live without your company.[]Ardently,[]Fahrqhar
     Friend Pru:  =================favor====feeding my dog. []C=================
feed him during vacation. ==Regards, ==========
					-> Edited text typed in, cr
					-> ZX displays edited sector
     Friend Pru:  please do me the favor of feeding my dog.
Can't continue to feed him during vacation.  -> Any key continues display
Regards,				-> Re-edit with ^E
Fahrqhar				-> Exit to directory with ^X
					-> Automatic dir at end of text
: PRUNE   .LET	1k : PRUNE1  .LET  1k : PRUNE2	.LET  1k : PRUNE3  .LET  1k
D: 254k total  6k used	248k left

---------------------- Example EDIT session ----------------------------

Please examine the edit in the illustration above, which uses a
document only one sector (128 characters) long for simplicity.	ZX
is called from CP/M to TYPE prune.let. It displays the first sector,
then stops.  At this point ^X (Control-X) will exit directly to the
directory display.  A ^E will invoke the edit function in order to
change the characters just displayed.  Fahrqhar typed ^E.  The
sector is then redisplayed for editing in linear form, without
carriage returns(cr) or line feeds(lf).  Instead, cr's are written
as '[' and lf's as ']'.

The stretched out, left-justified editing display is convenient
because new text is typed immediately below the characters being
replaced.  There are three special editing characters:

     '=' leaves the character above it unchanged
     '[' puts a carriage return in the edited text
     ']' puts a line feed in the edited text.

The '=' enables you to edit only sections which need changing.	The
'[' and ']' enable you to put new line breaks in the text, if
required.  Check the example above.

A carriage return (or typing off the end of the sector) terminates
editing, and redisplays the newly-edited sector with normal line
breaks.  If the retyped section doesn't look right, another ^E will
repeat the edit.  If the edit seems OK, any other key continues with
more text, ^B goes back, or ^X exits to the directory.

The same text editing functions used when typing CP/M commands are
also available while editing in ZX.  When you reach the end of the
first line just keep typing and let the monitor wrap the display
around under the 48 characters in the second line (80 first line +
48 second line).  When you type "return" to quit editing, characters
beyond the quitting point are left unchanged.

Like many other things in computing, text editing with ZX is easier
done than said.  While no one is likely to edit his novel using ZX,
the mini-editor is well-suited to changing a date, altering a
phrase, or revising a note in an existing document.


UNERASE returns files which have just been erased by ZX or elsewise:

     A>ZX GONE.LF U			     -> unerases the .FL,
					     confirms with dir
     A>ZX 1 U				     -> recovers erase error
					     automatically
     A>ZX *.TXT U			     -> try to recover all
					     erased .TXT, then DIR

Unerasure is a function you need only occasionally, but then you
REALLY need it.  UNERA was invented by Gene Cotton, in Interface
Age, Dec, 1981, p.96, and his article is worth reading as an example
of stylish assembly language.  ZX borrows shamelessly from UNERA.
Not everything can be successfully recovered.  The BDOS may have
written over your file, if you did something else before ZX...u.
Some files, which have multiple erased directory entries, cannot be
sorted out by ZX, and the simultaneous reactivation of duplicate
entries leaves a wreck.  So check the file before you use it.
Immediate unerasure works 98% of the time.

If ZX cannot recover your file, byte-by-byte disk editing with a
disk editor like DU can probably do it, but this is much work, and
only can be justified for a very important file.


		     **>> MESSAGES <<**

The area to the right of the stored filenames, in the header line,
is ZX3's message area, where notes on the progress of operations
will appear.

     =No file=	indicates that a filename supplied does not exist.
The same message appears when a directory is requested for an empty
disk.  A =No file= is always followed by a directory display in
order to assist the user in typing the correct file name.

     =File exists=  indicates that you have tried to rename a file
to a file name which already exists.  The message is (of course)
followed by a directory.

     =* in filename=  is the most mysterious of the error
messages, but means that an ambiguous file name (containing * or ?)
has been supplied for renaming.  Because the directory will be
scrambled if this command is taken literally, ZX will trap such
attempts, without restricting the uses of amgiguity in other
operations.  To assist in finding the specific file name, =*  in
filename= is followed by a full directory (surprise!).

     =File names identical=  You are trying to copy a file into
itself.  If carried out, this command trashes the directory
entry, so ZX3 notes it, backs out, then shows the directory to
assist whatever you were trying to do.	ZX3 detects subtle
examples of this difficulty like: A>ZX D:FL.ONE FL.ONE (recall
that the target disk is autonamed D:), and will give this
message.

     =ZX ? for help=  The command character at the end of the input
line is not on ZX3's list.

     =Copying=	The command line has cleared all tests.  This
message is repeated at the start of each file during a multi-file
copy operationn.

     =Directory full=, =Disk full=.

     =File close failed=  It takes great agility to see this
message, which means that the new file ZX3 made to copy TO has
somehow disappeared before ZX3 could finish writing it.

     =Edit below=  Edit mode has been invoked.	Align the new
text below the original text.

     =Unerased=  ZX found the file(s) you asked it to reactivate.
Look the recovered file over carefully before asking it to do
anything important.

     =Dir R/W error=  Whoops! ZX has had a disk error while trying
to unerase.  Check the directory that ZX automatically shows after
the error.  If it looks OK, try again.


		    **>> ZX3'S USES <<**

ZX3 can serve as the sole file utility in any situation where disk
space should be conserved.  As the notes say, it is a "light power
tool" whose small disk footprint is better suited to portable
computers, or to data or archive disks, than are larger programs
like NSWEEP.

I hope that you find ZX3's command-driven, directory-oriented style
engaging in its own right.  It provides the most economical way, in
time and keystokes, to perform many of the most frequent file
operations, and gives many forms of aid to the user.  ZX3 follows
most functions with the updated directory to pave the way for the
next step, and to confirm that you have done exactly what you
intended.  ZX3 orders all operations from a consistent and simple
command format, unlike the CP/M utilities which do similar things.
ZX3 provides several unusual aids to the entry of concise command
lines, like filename memory and autonaming.  It is very powerful in
batch files, like those executed by SUBMIT, EX, or MAKBATCH, where
ZX3's ability to take a set of varied and complex orders from the
command line makes any desired batch operation easy.  ZX3's many
functions and small size are very appropriate in batch files also.
Its 3k of code make ZX3 fast-loading where it counts, in
applications which may be repeated hundreds of times.

Besides, there is something likeable about ZX3's relentless
helpfulness.  As you can see from the directory which heads these
notes, I now keep ZX and Dave Rand's wonderful NSWEEP on utility
disks, but only ZX on data disks.  I hope you also find ZX helpful.
Please direct comments and bug sightings to:

					     Mike Yarus
					     2231 16th Street
					     Boulder, CO 80302
January, 1986				     Compuserve 73145,513