To do any serious programming under CP/M, the first thing you need is a good programmers editor. There aren’t many in the archives, but I have tried most of them and found ZDE to be the best. It is small, has lots of features, and uses Wordstar commands which are familiar to me and easy to learn.

Downloading files for ZDE

The ZDE 1.6 editor can be downloaded from Bo Zimmerman’s CP/M archive here. This file is in a .PMA archive, so we also need the utility,, to uncompress it, again from Bo Zimmerman’s site. These two files should be copied onto a floppy disk or disk image if using an emulator.

Unpacking ZDE

I am currently using an emulator which only has 8” SD disks which are not big enough to unpack ZDE onto and contain the compressed file. Therefore I will have the files and zde16.pma on a disk in my C: drive and will uncompress them to a blank disk in my B: drive. is a self-expanding archive so to expand it onto my B: drive from the archive on my C: drive, I run:

B> c:pmautoae

Then to extract the contents of the zde16.pma archive held on my C: drive to the B: drive, I run:

B> pmext c:zde16.pma b:

If your disks are big enough, then you can do the above all on one disk, say the B: drive; in which case do the above, but change references to c: to b:

Configuring ZDE

Before the editor can be used, it needs to be configured. The most important thing to configure is the Terminal type, which is done as follows:

B> zdenst16 zde16

Select t to configure the terminal, then l to list the terminals. Press return until your terminal is shown, then press y next to it. I am using z80pack so therefore choose ANSI standard. Now press ESC then s to save the changes. If you are unsure which terminal to select, try each in turn, then start ZDE to see if it works, pressing ESC q to quit.

ZDE should be ready to go at this point. To read the ZDE documentation, type the following:

B> zde16 zde10.doc

Using ZDE

The editor is started with the command zde16 and can be run with a filename as an argument. If a filename is supplied, the editor will try to open it, if it doesn’t exist then it will start a new file with the name supplied. ZDE uses the Wordstar key combinations which are explained in the ZDE documentation. On some machines the main command key CTRL+k is used as a cursor key, in which case ESC can be used instead. The most important commands are listed below:

ESC hBring up the command key help
CTRL+k q / ESC qQuit editor without saving
CTRL+k x / ESC xExist and Save
CTRL+k l / ESC lLoad a new file
CTRL+k s / ESC sSave the current file
CTRL+rPage up
CTRL+cPage down
CTRL+e / cursorLine up
CTRL+x / cursorLine down
CTRL+s / cursorCursor left
CTRL+d / cursorCursor right

ZDE is a great editor and well worth the time to learn. It has many facilities to make life easier for the programmer and will definitely help make your retro programming more productive.