CP/M/CPM_CDROM.iso/lambda/soundpot/p/vlu101.lbr/VLU.HZP/VLU.HLP

Text File | 1993-10-25 | 19.3 KB | 461 lines

:VLU101                            07/01-12/15/87
Copyright 1987, Esoteric Software            Michal Carson


This program is distributed through ZSIG.




VLU is a ZCPR3-specific library utility with crunch, uncrunch, and
unsqueeze capabilities.  It will allow the user to view,
uncompress, or extract library members or to view, uncompress
(uncrunch or unsqueeze, VLU will decide), or crunch disk files.
VLU will build libraries from disk files, crunching the files as
they are added.

The utility will display a list of disk files on the screen along
with a cursor and other information.  Placing the cursor next to
the name of a file with the extension .LBR and pressing 'O' for
Open will display the contents of the library and shift the cursor
into that directory.


What is a Library?


The Library file format was developed to overcome two persistent
limitations of CP/M disk storage capacity: limited directory
entries and large blocking.

Although CP/M writes files in units of 128 bytes (sectors), most
manufacturers have used larger blocks for storage on disk.  On a
Kaypro with double-sided disks, for instance, all files are stored
in 2K blocks; even a file one sector in length will occupy 2K on
the disk.  Because the Kaypro disk format allows only 64 directory
entries (files) on one disk, 64 of these 1-sector files (8K) will
fill a 390K disk.

In a library, a one sector file occupies one sector (plus 32 bytes
for internal directory information).  The library itself occupies
only one directory entry on the disk.  If 64 one-sector files are
placed into a library, the library will occupy 10K.

This is obviously an extreme example but illustrates the
usefulness of libraries.  Other reasons exist; for instance,
libraries keep related files together.  VLU will make files within
libraries more accessible.


In this Library


Two executable versions are distributed:  VLUxxx-R.COM is for
machines using reverse video as highlighting.  VLUxxx-D.COM is for
machines using dim video as highlighting.  VLU.FOR is a short
description of the utility; VLU.HLP is full documentation
compatible with the ZCPR3 HELP text display utility.


The Help display


Pressing "/" or "?" will evoke a display summarizing the commands
available to the user.  These commands change according to Wheel
status and directory choice (e.g., Delete is not available in the
library and is never available to non-wheels).  Pressing either of
these keys a second time will clear the display.


Invoking VLU


Use VLU as an extension to a ZCPR3 shell, such as ZFiler, invoked
through a macro.  To install it, one need only open the ZFILER.CMD
file with a word processor and enter a line of the form "1 vlu".
Thereafter, positioning ZFiler's cursor beside a library file and
pressing "1" (possibly preceded by [esc]) will bring up VLU with
the library already open.  A better thought is to assign this
macro to the "O" key--"O $d1$u1:;vlu" in ZFILER.CMD--so that [esc]
"O" will open the indicated library.

Some aspects of VLU were designed to make it an extension of
tools like ZFiler.  Most of these tools use the ZCPR system files
to store the name of the current file (the file the cursor was
pointing to on exit).  VLU checks these filenames and interprets
the current file (sys file 2) as a library.  On starting up, VLU
will try to open a library file of this name in the current
directory.

This allows the user to invoke VLU from the "Z" prompt of ZFiler
or through a macro, pass no parameters, yet open the current file
if it is a library (or shares the same name as a library though it
may have a different extension).  If a different library is opened
before returning to ZFiler, VLU will modify the filename in
system file 2 (and thus cause ZFiler to believe it was pointing to
this library when it exited).

As a command file, VLU can, of course, be invoked from the system
command prompt.  If a library name is entered on the command line,
that name will take priority over any name currently in system
file 2 and the library will be opened if it exists.  Even from
ZFiler's "Z" prompt, with the pointer on ABC.LBR, entering the
command "VLU DEF" will open DEF.LBR and place that name into
system file 2.

VLU can be re-entered with the GO command.


Changing libraries


When a library is opened, when VLU is invoked with a library name
in the command line, or when a new directory is logged in with a
library open, the VLU cursor will point into the library
directory.  Pressing the [esc] key will shift the cursor back into
the disk directory.  Opening a different library is as simple as
positioning the cursor in front of the name and pressing "O".


Cursor motion


Moving the cursor (pointer) in VLU is effected using the WordStar
cursor motion controls.  Ctrl-E moves the cursor up one line, ctrl-
X moves it down.  Ctrl-S moves the cursor left one file, ctrl-D
moves it right.  Ctrl-F brings a new directory onscreen if there
are more files in the directory (as if the display were moving
right by a directory), ctrl-A moves back toward the beginning of
the file list.  Ctrl-F will wrap around from the final directory
to the original.

The arrow keys will also function if they are properly defined in
the users Environment descriptor.  The symbols "+" and "-" (and
"=", the usual non-shifted counterpart of "+") have the same
effect on the directories as ctrl-F and ctrl-A, respectively.

The [esc] key shifts directories: from the library to the disk,
from the disk to library.  In most instances the cursor will
"remember" where it was when it last pointed into that directory.


Extracting and Uncompressing library members


Positioning the cursor beside the name of a member file within a
library and pressing "E" for Extract will cause the file to be
copied from the library to the disk with no change in form.  If it
is crunched or squeezed within the library, it will be crunched or
squeezed on the disk.

Pressing "U" for Uncompress will cause a crunched file to be
uncrunched onto the disk, a squeezed file to be unsqueezed onto the
disk, or an uncompressed file to be extracted sic.


Changing directories


Library members may be extracted to a disk and/or user area other
than the one which contains the library.  Open the library first,
then use the Login command to move to the destination directory
and perform the extraction or decompression.  The move is
accomplished by pressing "L" (cursor position makes no difference
with this command) and answering the prompt "Directory ".  The
user may enter a DU: specification (e.g., A0:, B14:, F:) or the
name of a ZCPR3 named directory to be found in the current system
(e.g., MODEM:, DUNGEON:).  The colon is not necessary in any case
and an invalid directory or denied access will relog the current
area.  No entry at all will also relog the current area to
facilitate disk changes.


Tagging files


The "T" command will tag an untagged file and the "Y" command will
remove the tag from a tagged file.  The tag appears as a hash (#)
immediately following the filename.  After a group operation
(actually, during the group operation) hard tags represented by
the hash are replaced by soft tags which appear as an apostrophe
(').  Soft tags may be transformed back into hard tags by the
retag command: "*".

Wildcard tagging is accomplished by pressing "W" and providing a
wildcard file specification in response to the prompt.  All files
in the directory, starting from the beginning, which match the
file spec will be tagged.

Group Tag ("GT") is equivalent to a *.* wildcard tag.

It may be convenient at times to untag all files.  This can be
accomplished by relogging the directory with the Login command.
Certain file operations which affect the disk directory (anything
that adds or deletes files) will also end by relogging the
directory and any remaining tags will be erased.  Group operations
obviously prevent this relogging until all files have been
operated upon.


Group operations


"G" will evoke the Group prompt.  From this prompt, several
commands are available to wheels.  Only the View command is
available to non-wheels and it will be executed immediately.  If
the wheel byte is not zero, the prompt will indicate by the first
letter of each command that View, Tag, Uncompress, crunch, and
either Extract or Delete and Build are available.  Any selection
is carried out on all tagged files.  The Group manager will check
for ctrl-C between each file and abort if it is seen.


Viewing files and library members


Crunched, squeezed, and uncompressed files may be viewed by
pressing "V" at the VLU prompt.  The screen will clear, the
file's name will appear at the top of the screen and the file will
be presented.  The display will stop with the prompt "[strike any
key]" after, in general, 22 lines.  The number of lines (the size
of a screen page) is taken from the ZCPR3 Environment descriptor.
The number provided there, by convention, is two lines less than
the screen height.  This should give the viewer two lines of
overlap with each page.  If this is unsatisfactory, the user's
Environment descriptor can be adjusted.

At any time during the viewing, pressing ctrl-S will pause the
display.  Pressing ctrl-C will abort the operation.  Under Group
control, ctrl-C will abort the entire operation and no more files
will be presented; the user will be returned to the file directory
display.  Unscreened files will remain tagged.  Ctrl-X may be used
to skip to the next file under Group execution; it has the same
effect as ctrl-C if only one file is being viewed; id est, we
abort.

At the "[strike any key]" prompt, pressing the period will bring
one more logical line to the screen.

Ctrl-Z will suppress the "[strike any key]" prompt and the file
will scroll continuously.  The viewer is then left with ctrl-S to
stop the display (and any key except ctrl-X and ctrl-C will
restart it).  Another Ctrl-Z will restore the paging mode and
stop the screen immediately.  This is handy for long files when
the interesting text is near the end.

Certain file extensions are proscripted (e.g., COM, LBR, ARK, SYS,
RCP, REL, PRL, etc.) and VLU will give the message "may not type"
followed by the file name.  Crunched files of proscripted types
may have a "stamp" of interest to the user.  If a proscripted file
has a "Z" in the extension (e.g., CZM, RZL, etc.) VLU will give
the filename as it appears and attempt to extract the original
filename and any stamp contained in the first record of the file.


Crunching disk files


The crunching faculty of VLU is incidental.  Because of the Group
operations, it may be quite useful and may become addictive, but
crunching files on disk is secondary to the project of crunching
files into libraries.  Selecting "K" at the command prompt will
cause VLU to crunch the file pointed to by its cursor.

VLU will first prompt for a "stamp."  By convention, this is a
message of up to 40 characters enclosed in square brackets.  The
message is imbedded in the first record of the crunched file to be
displayed when the file is either uncrunched or viewed.  Often,
the message reports the date of the crunching, the author or
origin of the file, or its expanded size.

VLU will allow the entry of up to 38 characters.  Two characters
are reserved so that VLU can insert the square brackets if the
user omits one or both.  VLU will remove any trailing spaces from
the message; if the user wishes the spaces to appear, the user
must enter at least the final closing bracket.

The crunching operation will be aborted if the file is already
compressed (either crunched or squeezed) or is of a proscripted
filetype.  Proscripted filetypes are LBR, ARC, ARK, BAD, and, if
the target is a library, FOR and CIM (vide infra).

VLU will allow the user to crunch a member out of a library onto
the disk.  There seems no harm in such an operation (and as little
use).


File size report


The size of a file in kilobytes is reported when the user presses
either "F" or carriage return.  If the file is a library member,
the size will also be reported in records.


Renaming disk files


VLU will not rename a library member.  To rename a disk file,
position the cursor beside the file and press "R".  Enter the new
name at the prompt.


Deleting disk files


VLU will not delete a library member.  To delete a disk file,
position the cursor beside the file and press "D".  The user will
be prompted to confirm that the file is to be deleted.  Under
Group execution, if the user selects Delete, the prompt will
appear for each file.  Currently, there is no provision to avoid
this prompt.


Building libraries


In order for VLU to build a library, all files to be included
must be located in the same directory.  The library may, if
necessary, be built in a foreign directory.

As distributed, VLU will crunch all files as they are added to the
library (unless the extension is unacceptable as previously
stated).  See the configuration section for possible attenuation
of this practice.

To initiate the construction, tag the files which are to be
included and then type "GB" for Group and Build.  VLU will prompt
for the name and directory of the "new library" and the number of
entries to allow.  A carriage return at the "entries" prompt will
build a library with the minimum directory size, only large enough
to accomodate the currently tagged files.  The largest library
that may be built with VLU is 255 entries.

VLU will then initialize the library directory area.  The
directory list (onscreen)  will be reset to the first screen; the
cursor will move to the first tagged file and a message will
display that the file is being crunched or added as appropriate.
If any files are to be crunched, the "stamp" prompt will appear
and the stamp thus entered will be in effect for all files
crunched into the library.

Under this operation, as under the Wildcard and other Group
operations, the directory list onscreen will shift through all
files searching for tags.  This will be more noticeable in larger
directories (which require more than one display) and during the
Building of libraries (because of the pause to close the library).


Configuration


There are five configuration bytes.  The first, at 10Ch, controls
the display of files whose system bit is set.  Zero value in this
location will display such files, any other value will suppress
their display.  Default as distributed is "not displayed."

The second byte was added in order to accomodate LDR v1.6.  This
version of LDR allows all ZCPR3 system segments to be packed into
a single library, saving disk and directory space.  If the byte at
10Dh is of zero value, all system segments will be crunched
according to the rules governing other files.  If the user wishes
to be prompted when a system segment is detected--given the option
of crunching or not--the byte at 10Dh should be not zero.  Default
as distributed is "prompt."

The third byte (10Eh) controls a prompt in the library building
routines.  If this byte is not zero, the user will always be
prompted before a file is crunched.  This gives the opportunity to
load uncompressed files to the library.  The fourth byte (10Fh) is
dependent on the third.  If the third byte is zero, there will be
no prompt and all files will be loaded to the library on direction
of the fourth byte.  If the fourth byte is zero, all files will be
loaded sic; if not zero, files which have passed VLU's other
criteria will be crunched.  The fourth byte has no effect if the
third byte is not zero.  Default as distributed is "no prompt,
crunch when possible."

The fifth byte (110h) is a bit map of fixed media.  The most
significant bit represents the A: drive; the least significant,
the H: drive.  If the bit is set (1), the drive will not be reset
on logging to a new directory.  If the bit is reset (0) a disk
reset (BDOS function 37) will be performed each time the Login
command is used.  This takes some time; users with Hard Disks and
RAM disks are encouraged to configure this byte to match their
system.  Users with only floppy disk drives should leave the byte
in its default as distributed: "no fixed media" (00h).

The value needed in this byte to indicate that the A: drive is not
to be reset is 80h.  The value for A: and B: is C0h.

Following the five configuration bytes, the user will note the two
file extents FOR and CIM.  This location contains a list of
filetypes which the user does not wish to be crunched in building
a library.  More filetypes may be patched into this list; the list
must be terminated by a null.


Option menu


The Option menu, accessed by typing "M" at the command prompt,
will toggle any of the first four configuration bytes.  This
allows temporary assignment of the options to display/suppress
system files, prompt before crunching system segments, and prompt
before crunching files into libraries.


Security


The Login command of VLU will use the Z33 parser when it is
available, thus behaving exactly as the operating system would in
allowing admitance to directory areas.  When Z33 is not available,
VLU allows immediate entry to any du: or dir: within the MAXDSK
and MAXUSR limits of the environment.  Dir: forms outside these
limits are also accepted; passwords, if present, are enforced.

Commands Delete and Rename and any commands that would create new
files are available only while the wheel byte is set.


Contributors


VLU directly incorporates the work of many "better makers."  My
thanks to all of them as much and more for the opportunity to read
and learn from their code as well as for their library releases.
Among them, the following:

Richard Conn, Howard Goldstein, Jay Sage, Al Dunsmuir et al. for
SYSLIB, Z3LIB, Z33LIB04 and VLIB--and ZCPR, itself.

C.B. Falconer and Steven Greenberg for USQREL, UNCREL, CRN, and
BUFFERS.

Steven Cohen for M24.

Martin Murray for NULU, the standard for these efforts.  And Gary
Novosielski for the library format.


Note from the programmer


Please notice that VLU is not a shell.  If there are good
arguments for making it a shell, please forward them to me.  Other
functions are planned; next upon the board is output to printer.
If you have requests or ideas, contact me.

VLU, its source code, and its documentation are copyright 1987 by
Esoteric Software.  VLU is distributed for non-commercial use
only; any commercial use or any re-distribution in association
with a commercial product or package requires the prior written
permission of the author.

I may be reached on Z-nodes 2 and 3--Al Hawley's Ladera and Jay
Sage's Newton Centre; both are available via PC-Pursuit.  I log
into these nodes approximately weekly.  If it is important to
reach me sooner, my home Z-node is #58, operated by Kent Mason in
Oklahoma City (405/943-8638).  You should check into this node
anyway; there aren't many Kaypros online with 1Meg of memory.