Mac OS 9 Printer Driver and PPD Setup Guide

This article provides an overview of how the classic Mac OS 9 operating system managed printing architecture, focusing on the installation of printer drivers, the handling of PostScript Printer Description (PPD) files, and device configuration using the Chooser and Desktop Printing utilities.

The Role of Printer Drivers in Mac OS 9

In Mac OS 9, printer drivers operated as system extensions. Unlike modern operating systems with centralized driver frameworks, classic Mac OS relied on individual driver files placed directly into the Extensions folder inside the System Folder.

There were two primary categories of print drivers:

  1. QuickDraw Drivers: Used primarily for consumer inkjet and non-PostScript printers (such as Epson Stylus or Canon BJC series). These drivers converted screen graphics directly into rasterized dots using the Mac's processor and proprietary rendering engines.
  2. PostScript Drivers: Used for professional, commercial, and office network printers. The default, universal driver provided by Apple was LaserWriter 8, which translated print commands into standard PostScript code understood directly by the printer hardware.

Installing a driver was typically accomplished via an automated installer (often based on Installer VISE or Apple's native Installer utility). However, drivers could also be manually installed by dragging the driver file directly onto the closed System Folder, which automatically placed it into the Extensions directory.

How PPD Files Were Handled

A PostScript Printer Description (PPD) file is a standardized text file that tells the PostScript driver (LaserWriter 8) what features a specific printer model supports—such as available paper trays, duplex printing units, custom resolutions, and color separation options.

  • Storage Location: All PPD files were stored in a specific subfolder: System Folder:Extensions:Printer Descriptions.
  • File Structure: PPDs were cross-platform plain-text files, but in Mac OS 9, they required a proper classic Mac file type and creator code (Type: PPD , Creator: pdos or generic text) so the operating system could identify them without relying solely on file extensions.
  • Installation: Installing a new PPD simply required copying the .ppd file into the Printer Descriptions folder. Once placed there, LaserWriter 8 could immediately read it without requiring a system restart.

Configuring Printers via the Chooser

The Chooser desk accessory, located in the Apple menu, served as the primary interface for selecting and configuring active printers.

The setup process followed these steps:

  1. Open the Apple Menu and select Chooser.
  2. Click on the appropriate driver icon in the left pane (e.g., LaserWriter 8 for PostScript printers, or a vendor-specific icon for non-PostScript printers).
  3. Select the connection type or physical port. For networked printers, this meant selecting an AppleTalk zone and choosing the detected printer. For local devices, users selected the physical Printer/Modem Port (serial) or a connected USB device.
  4. Click the Setup button.
  5. Select the PPD. If the printer supported bidirectional AppleTalk communication, clicking Auto Setup allowed the system to query the device directly and automatically select the matching PPD from the Printer Descriptions folder. If the printer was offline or connected via standard TCP/IP, the user clicked Select PPD to manually browse the list of available definition files.

Desktop Printers

Once configured via the Chooser, Mac OS 9 created an interactive Desktop Printer icon directly on the user's desktop. This icon represented the configured output queue.

Users could print files by dragging documents directly onto the Desktop Printer icon, double-click the icon to view and manage active print queues, or change default printers by simply clicking a different desktop printer icon and selecting "Set Default Printer" from the system's "Printing" menu.