History of the PDP-8/E Simulator

• 22. January 2013: Version 2.0.d2
  Update of the Developer Preview with bug fixes and Mac OS X 10.8 “Mountain Lion” support.
• 8. August 2011: Version 2.0.d1
  Update of the Developer Preview with bug fixes and Mac OS X 10.7 “Lion” support.
• 5. April 2010: Version 2.0.d0
  Developer Preview of the Cocoa based reimplementation of the PDP-8/E Simulator running on PowerPC and Intel Macs with Mac OS X 10.4 “Tiger” and newer.
• 30. April 2006: Version 1.5.1
  The (probably never used) opcode 7233 (CLA CML IAC RTR) now correctly set L'AC to 0'6000 with L=0 and to 0'4000 with L=1 (before, L'AC was wrongly set to 0'3000 resp. 0'1000 due to missing parenthesis around the shift in i7233()). In file dialogs, now Mac OS X application bundles are recognized, and the user can choose a Mac OS X application in the preferences for viewing text and log files. The keyboard shortcut command-option-M for the “Minimize All Windows” item in the Windows menu is now functional. To conform to Apples Scripting Interface Guidelines (Technote 2106), the name of the real time clock types in the AppleScript terminology of the Real Time Clock plugin where changed, e. g. now “DK8EA 100 Hz” instead of “DK8EA_100Hz”. To avoid scrolling anomalies in memory inspectors, the inspector window now can only be resized to an even number of content lines when it displays a two line format. In the online help, the homepage URL of the PDP-8/E Simulator was updated.
• 7. February 2004: Version 1.5
  Minor user interface and compatiblity improvements for Mac OS X, esp. 10.3 “Panther”. The bulbs of the KC8-EA Programmer’s Console are now light-colored, no longer LED like orange.
• 30. October 2003: Version 1.5.b1
  Fixes a crash of the simulator that occurs with Mac OS X 10.3 “Panther”.
• 10. October 2003: Version 1.5.b
  TSC8-75 Board implemented to enable the simulated PDP-8/E to run ETOS. Improved emulation of the time sharing capabilities of the KM8-E. CAF (6007) now clears all interrupt mask flip flops but no longer clears UF and UB. When the KM8-E is present, the user mode interrupt mask is always set. JMP and JMS load UB to UF only when the newly added time sharing option (a jumper on the KM8-E hardware board) is enabled. Fixed a bug in opcode 261x (indirectly addressed ISZ on autoincrementing memory locations). Improved precision of the skip indicator when the CPU runs in user mode. Improved exactness of the display lights of the KC8-EA Programmer’s Console. Break opcodes now can be activated for user and system mode separately. Plugin API version 7 (source and binary compatible to version 6). A large number of small modifications for improved compatibility with Mac OS X 10.1 and 10.2, Mac OS 9.2, System 2.0 and earlier and the Mac 128K and 512K (the simulator no longer crashs these old Macs, but gives an apropriate “Mac too old” alert). Help tags implemented as a replacement for the old Balloon Help. Fixed a bug that caused a crash when the compressed PDP-8 memory content does not fit in 32 kB in a save operation, e. g. when quitting the simulator.
• 3. December 2002: PC8-E Plugin 1.2.1
  Fixes a bug of the Carbon version 1.2 of PC8-E Paper Tape Device that crashs the PDP-8/E Simulator when reading in a paper tape with the speed option set to 300 characters per second.
• 1. December 2002: Version 1.4.3
  Patch for the Carbon version of the simulator for improved compatibility with Mac OS 10.1 and 10.2 and CarbonLib 1.5 and 1.6.
• 2. July 2001: Version 1.4.2
  Patch to fix a crash of the Carbon version of the simulator that occurs when the simulator receives a “set” or “get” AppleEvent while a dialog box is displayed.
• 18. June 2001: Version 1.4.1
  Patch to fix a crash of the Carbon version of simulator that occurs when the user clicks in the background of an alert sheet.
• 24. May 2001: Version 1.4
  Minor modifications for improved compatibility with Mac OS 9.1 and Mac OS X 10.0.
• 23. December 2000: Version 1.4.b1
  Carbonized version of the simulator and the PAL-8 assembler that run on Mac OS X Public Beta. Many minor modifications to adapt the Aqua user interface of Mac OS X. Improved timing of the simulator when running in real time mode on fast G4 Macs. Plugin API version 6 (source and binary compatible to version 5). Many minor bugs fixed. New e-mail address of the author.
• 24. July 2000: Version 1.4.b
  Carbonized version of the simulator. (It probably it will not run on Mac OS X because it was not tested on that platform.) MPW now can be used to build the simulator and plugins. Plugin API version 5 (binary compatible to previous versions, but due to the Carbonization not source code compatible to previous API versions). The cursor keys are now functional in all scrollable windows. Minor bug fixes and modifications in the user interface. A sign error in the delay tasks of the 68K version of the RK8-E was fixed that sometimes caused the DLAG instruction to complete after some minutes instead of some milliseconds when the device runs with the real time speed option turned on.
• 25. February 2000: Version 1.3
  Minor bug fixes in the user interface. The simulator now is published under the GNU General Public License, and the sources are available. Plugin API version 4 (source and binary compatible to version 3).
• 20. December 1999: Version 1.3.b1
  Patch to fix an unimplemented trap crash on Macs with 128K ROMs running System 7.
• 26. November 1999: Version 1.3.b
  Plugin API version 3 (source and binary compatible to version 2). Options for the CPU and the I/O devices to run with the speed of the original DEC hardware. The CPU and the I/O devices now pass nearly all MAINDEC hardware diagnostics. KC8-EA Programmer’s Console rolled into the simulator distribution. Navigation Services used for file dialogs. Improved compatibility with Mac OS 8.6 and 9. Started to port the simulator to the Mac OS X Carbon runtime environment. Live scrolling in all windows. All custom CDEFs are now PowerPC native. Shift-clicking in an MRI opcode in the CPU window now displays a balloon with the operands of the MRI. When quitting the simulator, the current configuration is now saved in the preferences file; the “Do you want to save...?” question now only appears when a saved configuration is active. The RK05 disks are now dismountable while the PDP-8 runs. Improved AppleScriptability. A bug with the skip indicator and a lot of other minor bugs and typographic errors corrected.
• 3. January 1999: Version 1.2
  Plugin API version 2 (minor modifications to support the KC8-EA Programmer’s Console plugin; source and binary compatible to API version 1). ISZ now reads the (incremented) value back from memory before it performs the skip check (different behaviour when the operand is on a non-existing memory field). Minor inconsistencies with the display of the operands of the current instruction concerning autoindexing memory locations and field boundaries corrected. When the user inputs a FORTRAN II floating point 0.0 in a memory inspector, a wrong bit pattern was deposit in the PDP-8 memory. Clicking the “Clear all” button in the Fill Memory dialog box caused a crash when the PDP-8 had 32K words of memory. When the user drags the PC indicator arrow of the CPU window too far away from the arrows area, the PC now returns to its old value (“undo” option, like scroll bars). “Clear All Flags” and “Reset” no longer turns off the reader or punch of the ASR 33 Teletype. The Memory Extension renamed from MC8-E to KC8-E. Logo in the About box slightly modified. Many minor bugs in the user interface corrected. Improved compatibility with Mac OS 8.1 and 8.5. Many typographic errors corrected.
• 13. February 1998: Version 1.2.b
  I/O devices are now plugin modules. This required an overall rework and a slight modification of the user interface, but no principal redesign of the simulator. AppleScript support for the PDP-8/E and the I/O devices added. Skip and interrupt indicator in the CPU window added. Some minor improvements of the user interface and improved compatibility with Mac OS 8. Some other minor improvements. Three remarkable and a lot of minor bugs of version 1.1 fixed. No error was detected in the actual PDP-8/E emulating code since version 1.1. The PAL-8 Assembler no longer loops when assembling invalid expressions like “/ 4”. Expressions like “MYTAD=TAD” no longer define a 13-bit value with the MSB set, but a 12-bit value. The checksum of BIN format output is now calculated correctly (with the previous version, the field settings where included in the checksum, but they are ignored by the PDP-8 BIN reader when loading the paper tape). The cursor now spins clockwise while pass 1 and anticlockwise while pass 2 of the assembly. New e-mail address of the author.
• 25. January 1996: Version 1.1.1, PAL-8 Assembler 1.0.1
  Patches to fix a bug in the runtime libraries of the simulator and the PAL-8 assembler that causes the applications to crash on Macs with 68000 processor.
• 16. December 1995: Version 1.1
  6004 (GTF) now does not load the inhibit flag into AC(3) (the PDP-8/E was designed to load GTF into AC(3), but the hardware actually ignores this flag). 7417 (LSR) corrected: L is cleared in mode A, too. A bug of the 68K version with the GTF handling of 7415 (ASR) and 7417 (LSR) corrected. A bug with the activation of memory inspector windoids and the CPU window fixed. Look and feel of the zoom box of memory inspector windoids slightly modified. Improved compatibility with System 2, System 5, Copland and the Macintosh emulator Executor (version 1.99o or better required). Typographic errors fixed. The “Change to...” utilities now accept the usual keystrokes as shortcuts for clicking the buttons of the dialog box.
• 22. July 1995: Version 1.1.b
  PowerPC accelerated. Improved PDP-8/E speed (about 25 percent on fast 68K Macintoshs) and real time performance of the ASR 33 teletypes due to better timer handling. Assembler keyboard input for the PDP-8 memory. Memory inspector windoids. Menu items “Load Paper Tape” and “Clear All Flags”. Apple Events for “Reset” and “Load Paper Tape” (open the PDP-8/E Simulator with the AppleScript Script Editor to find out more about this). PC indicator arrow draggable. Improved handling of moveable modal dialog boxes. Improved scrolling of the help window. Bug with EAE instruction 7445 fixed (PC was incremented twice). Systematic bug with EAE instructions 7447, 7467, 7547, 7567, 7647, 7667, 7747, 7767 (combinations with SCA DVI (mode A) or SWBA (mode B)) fixed (in mode A, now SCA DVI is executed, in mode B, SWBA is ignored when microprogrammed with other EAE OPRs). Bug fixed which prevented the “Bootstrap Loader” dialog from loading the BIN loader into a field other than field 0. TTY input now sets the 8th bit (by ORing with 0200) of keyboard and pasted input (some PDP-8 software, e. g. paper tape SABR, checks for 8-bit ASCII). Bug fixed which caused the high speed paper tape reader to set L'AC to 1'7600 when 0200 was read (the paper tape SABR linkage loader complained about checksums errors). A memory leak with “Drag&Drop” fixed which caused memory of the size of text dragged away from TTY windows to be lost. Typographic errors in balloons and help items fixed. Help window texts slightly improved. PAL-8 Assembler, Pascal-S compiler (on the Pascal-S DECpack), FORTRAN IV math library (FORLIB.RL on the OS/8 System Disk) added. Documentation extended.
• 16. February 1995: Version 1.0
  First final release of the PDP-8/E Simulator. Minor errors fixed. Problems with Macintoshs without Color QuickDraw fixed (thanks to Helge Horch, Berlin, for remote debugging support). ASCII table and paper tape format description added to the help items. Help window resizeable.
• 8. December 1994: Version 1.0.b
  Initial beta release of the PDP-8/E Simulator.
• 1993
  Start of the development on a Mac Colour Classic based on Bill Haygoods PDP-8/E emulator.