Bulletin #10 rev. 03/30/93
How to use PKZIP and PKUNZIP
PKUNZIP is the program that reconstructs or extracts compressed files.
In addition to reconstructing a complete ZIP file, it can selectively
release individual files, show files on the screen for fast viewing, or
print them out on a printer.
A ZIP FILE holds file information that has been reduced in size for
better storage. It is sometimes called a compressed file or a
A ZIP FILE can be made up of either one or more files compressed
and stored together under one file name.
| A ZIP file contains one or more files. |
| MANUAL.ZIP contains --> chap1.txt toc.txt app.txt cov.txt |
| BIG.ZIP contains --> Huge.Wks |
| This is a very large worksheet that |
| has been shrunk in size for better |
| storage and faster telecommunications. |
FILE RECONSTRUCTION or FILE EXTRACTION refers to the process of
recreating files that have been previously compressed.
USING PKWARE WITH HARD AND FLOPPY DISK SYSTEMS
PKware works BEST on a hard disk system.
1. Even though you are making files smaller, the process used to shrink
them can BRIEFLY DOUBLE the storage space needed. When a ZIP file is
being modified (e.g. files being added), the process creates a new
ZIP file which will be used as a REPLACEMENT for the old version.
Both the OLD and the NEW versions will be on your disk until just
prior to the completion of the process.
2. When you reconstruct a ZIP file, the amount of space needed to
hold that file can double. A large hard disk drive normally insures
that enough storage area is available.
Many compressed files are stored on floppy disks. The limit to
floppy storage is the number of characters your floppy system will
Standard double density floppy 360K
High density floppy 1.2 meg
3-1/2" floppy .7 or 1.4 meg
You may have problems either ADDING files to a ZIP file stored on a
floppy disk, or reconstructing files to a floppy disk system when
the number of characters in the ZIP file is more than 50% of the
available storage space on the floppy disk.
Consider a standard floppy disk system:
| Standard Floppy Disk Drive of 360K |
| A:> BIGFILE.ZIP has 250,000 characters |
| 1. In order to ADD files to BIGFILE.ZIP, you need |
| 500,000 of space. The extra space is used to |
| hold a NEW updated ZIP file created BEFORE the |
| old ZIP file is deleted. |
| 2. When BIGFILE is reconstructed it might require |
| 400,000 of space, but the available space on the |
| disk restricts it to 360,000. |
There are a number of ways to avoid the limitations. A thorough
knowledge of PKware Programs will show you how to:
1. Selectively reconstruct files from a ZIP file. Instead of
extracting everything at once, you can view file size information
and then select SPECIFIC files to be reconstructed to a floppy.
2. If you have two floppy drives, create the ZIP file file on your
second disk drive so that you have the full 360K available to you.
3. Use the special -b command option, which routes the NEW file to
an alternate disk drive during the compressing process then copies
it back to the floppy disk upon completion.
GENERAL RULES AND DEFAULT SETTINGS
1. PKware programs MUST be located in:
A. The drive you are working on, OR . . .
B. Any directory accessible through the PATH= setting.
In this example, PKware is in the Utils Directory. The computer
will find and execute the program even though you are in a
different directory or drive because any commands entered will be
run through the PATH. Consult your MS-DOS documentation for more
C. Any directory through the use of PATH notation if you are using
MS-DOS 3.0 or later.
C:>B:PKZIP -a OldFile.ZIP *.* PKZIP is located on the
C:>\UTILS\PKZIP -v Stuff.ZIP PKZIP is located in \UTILS
as indicated in the PATH
2. All PKware program commands are typed at the prompt.
3. Typed information can be in CAPS, lower case, or a mixture.
4. The DEFAULT is *.* or ALL FILES when specific files are not named
(except for the -d delete files option).
5. It is NOT necessary to type the extension .ZIP when processing a
ZIP file, it will be assumed. The extension is used in this
documentation for clarity.
6. A help screen is displayed when you type the program name at the
prompt then press . Also typing -h on the command line
will call up the help screen.
C:>PKZIP enter gives you HELP
C:>PKUNZIP " " " "
7. The notation PKUNZIP * or *.ZIP will reconstruct all ZIP files
within the given area.
8. During the reconstructing process, the notation *.* will tell
PKUNZIP to attempt to reconstruct ALL files whether they are ZIP
files or not. This would waste time, but will not damage any files.
9. The default area for the temporary second ZIP file that is created
while the original is being updated, is the same path and directory
location as the original ZIP file. As this can cause a space
shortage on a floppy disk, the -b option is recommended. (See
10. The compressing function will STOP if specific, pre-specified files
are not found.
11. All MS-DOS file handling procedures can be used:
Filename.ext Full file name designations
*Name.ext Names with wild card markers
SUPER QUICK |
QUICK START- Extracting a File from a BBS |
Use of PKware in Telecommunications -