ProDOS Drivers

What are ProDOS drivers/modifications?

The ProDOS operating system for the Apple II executes the first .SYSTEM file found in the boot directory on startup. A common pattern is to have the boot directory contain several "driver" files that customize ProDOS by installing drivers for hardware or modify specific parts of the operating system. These include:

• Real-time Clock drivers (e.g. No-Slot Clock, Cricket!, AE DClock, etc)
  • In ProDOS 1.x, 2.0 and 2.4 the Thunderclock driver is built-in.
• RAM Disk drivers (e.g. RamWorks)
  • In ProDOS 1.x, 2.0 and 2.4 only a 64K driver for /RAM is built-in.
• Quit dispatcher/selector (BYE routines)
  • In ProDOS 1.0 through 1.7 a simple selector prompting ENTER PREFIX (PRESS "RETURN" TO ACCEPT) asked for a path.
  • In ProDOS 1.9 and 2.0 Bird's Better Bye is built-in.
  • In ProDOS 2.4 Bitsy Bye is built-in.

Early versions of these drivers would often invoke a specific file on completion, sometimes user-configurable. The best versions of these drivers simply execute the following .SYSTEM file, although this is non-trivial code and often did not work with network drives.

This repository collects several drivers and uses common code to chain to the next .SYSTEM file, suporting network drives.

How do you use these?

The intent is that you use a tool like Copy II Plus or Apple II DeskTop to copy and arrange the SYSTEM files on your boot disk as you see fit. An example boot disk catalog might include:

• PRODOS - the operating system, e.g. ProDOS 2.4
• NS.CLOCK.SYSTEM - install No-Slot Clock driver, if present
• CRICKET.SYSTEM - install Cricket! clock driver, if present
• RAM.DRV.SYSTEM - install RamWorks RAM disk driver, if present
• BUHBYE.SYSTEM - install a customized Quit handler to replace the built-in one
• QUIT.SYSTEM - invoke the Quit handler immediately, as a program selector

Alternately, you might want to install some drivers then immediately launch into BASIC. In that case, put BASIC.SYSTEM after the drivers in place of QUIT.SYSTEM.