Early Versions of PKZip for Windows

24 May 2018

Right click. Send to. Compressed folder. A ZIP file is created, lickety-zip. Microsoft Windows included ZIP file support as a shell extension in the Windows 98 plus pack, which was included as a standard component since Windows Millennium Edition. It hasn't changed much since then. But what about before? ZIP files have been around since the earliest 90s, as part of the compression standard established by Phil Katz.

The MS-DOS programs pkzip and pkunzip were the original way to create and uncompress ZIP files. These required a slightly fiddly syntax, so much so that multiple pages of help screens existed to help you figure out which switches to use. Thankfully, a front-end program was made to make it simpler - WinZip by Niko Mak.

It was not glamorous, and needed helper programs to support archive formats. But it made using ZIP archives so much easier than at the command line. I suspect that PKWARE was quite pleased at anything that increased its use over other archive formats (remember arj, ace, lha, zoo?). However, when WinZip incorporated the free Info-Zip software into its product in 1993 the pkzip programs became unnecessary. I suspect that's what spured them into writing their own Windows GUI based version of PKZip.

PKZip for Windows 2.70 with some zip files open.

PKZip for Windows 2.70: The last version released by Phil Katz.

The first version released to the public was 2.01 for Windows 3.1 in February 1996. It used an MDI layout, so you could have multiple ZIP files open at once. You could not move files between archives directly, though.

Let's look at the two main objectives of this program: to compress files, and uncompress them.


One easy way is to drag and drop some files from File Manager (or Windows Explorer) onto the main program window. It'll ask for a filename. After that, the archive is created and opened. Not quite as smooth as using WinZip's extensions, but it works.

To create a new file within the program. You'll get a blank archive that you can add files to with the appropriate menu option. This way has the most options:

Add Files dialog.

The last way is to use the wizard (introduced in 2.60). It steps you through creating the archive and adding files to it. Functionally it's the same as any other method, except there are fewer options.


Extract files dialog.

Open the archive, then select the files you want with the cursor. It behaves exactly like a spreadsheet. Press the extract button, enter a destination, then done. Not much to it.

File Format Support

The program is mostly a ZIP affair, but it does have the ability to open TAR and GZIP files. It can also decode various binary-to-text formats, like UUE and HQX (used on Apple Macintoshes to preserve resource forks and creator information).

Version Matrix

For reference, here is a list of versions and dates (as reported in about box) for all the 2.x releases for Windows.

Version Date Supported Platforms
2.01 16-bit 1996-02-15 3.1
2.50 16-bit 1996-09-15 3.1
2.50 32-bit 1996-09-15 95, NT 3.51, NT 4.0, Win32s (Unofficially)
2.60 16-bit 1997-12-15 3.1
2.60 32-bit 1997-12-15 95, NT 3.51, NT 4.0
2.60.2 16-bit 1998-07-15 3.1
2.60.2 32-bit 1998-07-15 95, NT 3.51, NT 4.0
2.60.3 16-bit 1998-11-01 3.1
2.60.3 32-bit 1998-11-01 95, NT 3.51, NT 4.0
2.70 1999-06-01 95, NT 3.51 (Unofficially), NT 4.0

There's something special about using the program written by the original author of the format it works with. His initials, PK, are stamped in the header of every ZIP file created to this day. As his file format is still in common use, surely he earns a place with the greats who changed the face of computing.

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