Previous is a NeXT Computer emulator that can boot NeXTStep 0.x to 4.0 beta and OpenStep 4.2 For Mach.
Previous is a NeXT Computer emulator based on the Atari emulator Hatari. It uses the latest m68k emulation core from WinUAE and the i860 emulator from Jason Eckhardt. Previous is confirmed to compile and run on Linux, Mac OS X and Windows. It may also work on other Systems which are supported by the SDL2 library, like FreeBSD, NetBSD and BeOS.
Previous emulates the following machines:
- NeXT Computer (original 68030 Cube)
- NeXTcube
- NeXTcube Turbo
- NeXTstation
- NeXTstation Turbo
- NeXTstation Color
- NeXTstation Turbo Color
- NeXTdimension Graphics Board
For using Previous, you need to have installed the following libraries:
Required:
- The SDL library v2.0.5 or later (http://www.libsdl.org)
- The libpng PNG reference library (http://www.libpng.org)
- The zlib compression library (http://www.gzip.org/zlib/)
Don't forget to also install the header files of these libraries for compiling Previous (some Linux distributions use separate development packages for these header files)!
For compiling Previous, you need a C compiler (preferably GNU C), and a working CMake installation (see http://www.cmake.org/ for details).
CMake can generate makefiles for various flavors of "Make" (like GNU-Make) and various IDEs like Xcode on Mac OS X. To run CMake, you've got to pass the path to the sources of Previous as parameter, for example run the following if you are in the topmost directory of the Previous source tree:
cmake .
If you're tracking Previous version control, it's preferable to do the build in a separate build directory as above would overwrite the (non-CMake) Makefiles coming with Previous:
mkdir -p build
cd build
cmake ..
Have a look at the manual of CMake for other options. Alternatively, you can use the "cmake-gui" program to configure the sources with a graphical application.
After cmake finished the configuration successfully, you can compile Previous by typing "make". If all works fine, you'll get the executable "Previous" in the src/ subdirectory of the build tree.
Previous is stable, but some parts are still work in progress. Some hardware is not yet emulated. Status of the individual components is as follows:
CPU good (but not cycle-exact)
MMU good
FPU good
DSP good
DMA good
NextBus good
Memory good
2-bit graphics good
Color graphics good
RTC good
Timers good
SCSI drive good
MO drive good
Floppy drive good
Ethernet good
Serial dummy
Printer good
Sound good
Keyboard good
Mouse good
ADB dummy
Nitro dummy
Dimension partial (no video I/O)
There are remaining problems with the host to emulated machine interface for input devices.
- Un-emulated hardware may cause problems when attempted to being used.
- NeXTdimension emulation does not work on hosts with big endian byte order.
- The MO drive causes slow downs and hangs when both drives are connected, but only one disk is inserted. This is no emulation issue but a bug in NeXTstep.
- DSP sound has timing related issues. playscore under NeXTstep 0.9 sometimes produces bad audio in variable speed mode. ScorePlayer under NeXTstep 2.x produces distorted sound in normal CPU mode.
- Shortcuts do not work properly or overlap with host commands on some platforms.
- CPU timings are not correct. You may experience performance differences compared to real hardware.
- 68882 transcendental FPU instructions produce results identical to 68040 FPSP. The results are slightly different from real 68882 results.
- Changing network connection settings while a guest system is running sometimes causes permanently lost connections, especially under NeXTstep 2.2.
Previous v1.0:
> Initial release.
Previous v1.1:
> Adds Turbo chipset emulation.
> Improves DSP interrupt handling.
> Improves hardclock timing.
Previous v1.2:
> Adds support for running Mac OS via Daydream.
> Improves mouse movement handling.
> Adds dummy Nitro emulation.
> Improves dummy SCC emulation.
Previous v1.3:
> Adds Laser Printer emulation.
> Introduces option for swapping cmd and alt key.
Previous v1.4:
> Adds NeXTdimension emulation, including emulated i860 CPU.
> Improves timings and adds a mode for higher than real speed.
> Improves emulator efficiency through optimizations and threads.
> Improves mouse movement handling.
> Improves Real Time Clock. Time is now handled correctly.
Previous v1.5:
> Adds emulation of soundbox microphone to enable sound recording.
> Fixes bug in SCSI code. Images greater than 4 GB are now supported.
> Fixes bug in Real Time Clock. Years after 1999 are now accepted.
> Fixes bug that prevented screen output on Linux.
> Fixes bug that caused NeXTdimension to fail after disabling thread.
Previous v1.6:
> Adds SoftFloat FPU emulation. Fixes FPU on non-x86 host platforms.
> Adds emulation of FPU arithmetic exceptions.
> Adds support for second magneto-optical disk drive.
> Fixes bug that caused a crash when writing to an NFS server.
> Fixes bug that prevented NeXTdimension from stopping in rare cases.
> Fixes bug that caused external i860 interrupts to be delayed.
> Fixes bug that prevented sound input under NeXTstep 0.8.
> Fixes bug that caused temporary speed anomalies after pausing.
> Improves dummy RAMDAC emulation.
Previous v1.7:
> Adds support for twisted-pair Ethernet.
> Adds SoftFloat emulation for 68882 transcendental FPU instructions.
> Adds SoftFloat emulation for i860 floating point instructions.
> Improves 68040 FPU emulation to support resuming of instructions.
> Improves Ethernet connection stability.
> Improves efficiency while emulation is paused.
> Improves device timings to be closer to real hardware.
> Fixes bug in timing system. MO drive now works in variable speed mode.
> Fixes bug in 68040 MMU that caused crashes and kernel panics.
> Fixes bug in 68040 FPU that caused crashes due to unnormal zero.
> Fixes bug in FMOVEM that modified wrong FPU registers.
> Fixes bug that sometimes caused hangs if sound was disabled.
> Fixes bug that caused lags in responsiveness during sound output.
> Fixes bug that caused a crash when using write protected image files.
Previous v1.8:
> Removes support for host keyboard repeat because it became useless.
> Fixes bug that caused FMOVECR to return wrong values in some cases.
> Fixes bug in timing system that caused hangs in variable speed mode.
For running the emulator, you need an image of the boot ROM of the emulated machine.
While the emulator is running, you can open the configuration menu by pressing F12, toggle between fullscreen and windowed mode by pressing F11 and initiate a clean shut down by pressing F10 (emulates the power button).
Previous was written by Andreas Grabher, Simon Schubiger and Gilles Fetis.
Many thanks go to the members of the NeXT International Forums for their help. Special thanks go to Gavin Thomas Nicol, Piotr Twarecki, Toni Wilen, Michael Bosshard, Thomas Huth, Olivier Galibert, Jason Eckhardt, Jason Stevens, Daniel L'Hommedieu, Vaughan Kaufman and Peter Leonard! This emulator would not exist without their help.
If you want to contact the authors of Previous, please have a look at the NeXT International Forums (http://www.nextcomputers.org/forums).