Pascal #17
SYSTEM.APPLE Patch V2.0

Revised by Dan Strnad (March 1990)
Written by Dan Strnad (May 1988)

This Technical Note documents the Apple Pascal SYSTEM.APPLE patch version 2.0 (available as part of the Apple Pascal 1.3 package from APDA), which fixes two Pascal system bugs found in the 64K and 128K, regular and run-time, version 1.2 and 1.3 Pascal systems. A companion program confirms the correct installation of these patches.


SYSTEM.APPLE patch 2.0 corrects the following two bugs:

  1. UNITSTATUS calls to device numbers six, seven, and eight malfunction in Apple II Pascal 1.3.
  2. On Apple IIGS machines, disk access to 5.25" drives may fail under Apple II Pascal.

The following limitations exist with these patches:

  1. Keyboard input from an external terminal does not work; however, SYSTEM.APPLE patch 1.0 is also available to support external terminals. SYSTEM.APPLE patch 1.0 fixes only the UNITSTATUS problem; it does not address the 5.25" drive problem on the Apple IIGS.
  2. Type-ahead buffering may drop keystrokes under the following circumstances:
    1. On an Apple IIGS if the user has enabled keyboard buffering from the Control Panel.
    2. On an Apple IIc series computer, if an Apple II Pascal program directly accesses the firmware-level keyboard buffering.

Apple II Pascal 1.3 (and 1.2) still provide type-ahead keystroke buffering on all Apple IIs.

To use the patch program, X)ecute it from Pascal with the name PATCH. To confirm the proper installation of the patch, perform an X)ecute with the name CONFIRM.


This and all of the other Apple II Technical Notes have been converted to HTML by Aaron Heiss as a public service to the Apple II community, with permission by Apple Computer, Inc. Any and all trademarks, registered and otherwise, are properties of their owners.