• implemented IDE hard disk emulation, with support for up to 4 2 GB image files in raw or VHD format; a 126 MB disk image with 4 FAT12 formatted 31.5 MB partitions is also included for use with the emulator
• more accurate Z80, video memory, and NICK I/O port timing;
  note that this change breaks demo compatibility with previous versions
• improved NICK emulation: all possible video modes, including undocumented and "invalid" ones, are now emulated, and some bugs have been fixed as well
• a 4-channel 8-bit external DAC is emulated at ports F0h to F3h

* new TV emulation mode when using OpenGL video output; it is activated by setting the 'quality' parameter to 4, and requires OpenGL 2.0 or later with shader support. This mode emulates S-video output on a PAL display (Y/C filtering, delay line, and phase error), but the quality is also improved by using 32-bit textures instead of 16-bit

• it is now possible to load and use epmemcfg format memory configuration files, which allow for avoiding the limitations of the GUI based memory configuration; the file format is documented in README
• DAVE sound emulation fixes
• the 'motor on' bit of WD177x is emulated (the RockDigi demo now runs)
• on Windows, native file selection dialogs are also used in tapeedit.exe
• machine configurations generated by makecfg automatically enable or disable the 'virtual file I/O' setting, depending on whether epfileio.rom is included
• the debugger prints more detailed information about syntax and runtime errors in Lua scripts, and there is a new button to insert an empty breakpoint callback function
• fixed interlace in single buffered OpenGL mode at quality=0
• fixed compile error on Linux when building without SDL, or using old SCons or Lua versions
• some other minor bug fixes, and optimizations

• Various improvements have been made to the debugger:
  
  • memory read watchpoints can have a type of r or x to break on data or Z80 instruction reads only; the Ignore data reads button has been removed
  • new "step" buttons for stepping to the target of any conditional branch instruction (Step into), the 16-bit address at the top of the stack (Return), or any 16-bit address specified by the user (Step to)
  • the memory dump, CPU, and I/O register displays include more information now
  • in addition to the default hexadecimal format, it is also possible to specify numbers in the monitor in binary (e.g. %1010), octal (12o), and decimal (10l) format
  • the Step over button can also be used to skip conditional JP and JR instructions
  • fixed the flickering window effect while using the step buttons
• Several new GUI keyboard shortcuts have been added; since these shortcuts can only be triggered while the Alt key is pressed, in the default configuration only the right Alt key (and, on Windows, the menu key) are bound to the Enterprise emulation now.
• Native file dialogs are used instead of FLTK on Windows.
• Some improvements have been made to the installer:
• many new ROM files and machine configurations are installed
• on Windows, it is possible to associate snapshot and demo files with the emulator
• ROM images are downloaded as a single compressed archive, rather than separate uncompressed .rom files, for faster installation
• the Win32 emulator executable has an icon and includes file information now
• FILE: is the default device on startup when using the epfileio.rom extension.
• Floppy drive emulation improvements: implemented the 'write track' command (formatting), image file I/O is buffered for improved performance when using real disks, and a few emulation bugs have been fixed.
• In the memory configuration, ROM files can also be loaded to segments 40h to 43h.
• Video display improvements and bug fixes; the screen is no longer blanked while the emulator is paused; interlace effect is also displayed at lower quality settings (1 and 2) in OpenGL mode.
• Some NICK emulation fixes (note: the timing of demos recorded with older emulator versions may possibly be incorrect).
• If there is an error initializing the display in OpenGL mode on Linux, the emulator will automatically switch the buffering mode, or fall back to software video to fix the problem.
• Screenshots are saved in 256 color RLE compressed BMP format now, instead of TGA.
• A few minor user interface improvements in the display, sound, and disk configuration windows.
• The process priority of the emulator can be set in the menu (this is currently only implemented on Windows).
• If not specified by the user, the extension is automatically added to file names by the file dialogs when saving files.
• New 'Gtk+' GUI theme (-colorscheme 3).
• Various minor bug fixes.

Changes in version 2.0.5:

• changed the debugger window layout so that there is a larger window
  with only two tabs; also more information is displayed, and the
  mouse wheel can be used for scrolling the disassembly and memory
  dump views
• implemented Lua scripting in the debugger; this makes it possible to
  write complex rules for breakpoints, but can have other uses as
  well, since the script can read and write memory, I/O ports, and CPU
  registers, in addition to having access to the standard Lua library
  functions
• added a simple monitor to the debugger; the supported commands
  include assemble, disassemble, trace, memory and I/O port dump and
  modify, printing and changing CPU registers, memory compare, copy,
  fill, search, load and save, and more (use ? to print the list of
  available commands, or ? N for help on command N)
• improved the audio quality of AVI recording, at the expense of
  making it somewhat slower
• added new command line option for selecting the GUI style and colors
• a few minor bug fixes and improvements

Changes in version 2.0.4:

• keyboard map can be configured with the GUI
• external game devices like joysticks and gamepads are supported, and can be assigned in the keyboard map like normal keys
• video and audio output can be recorded to AVI files
• it is now possible to use audio files (WAV, AIFF, etc.) as tape images, with support for all tape features except markers; a simple linear phase FIR filter can also be applied to the input signal
• improved television vertical sync emulation
• new command line option for loading a snapshot or demo file on start-up
• added hue shift to the display options
• emulation speed percentage and floppy drive LEDs are now displayed on the GUI; it is also possible to change the emulation speed
• various minor bug fixes and improvements

Changes in version 2.0.3

• fixed interrupts in Spectrum emulator
• other minor fixes, including changes to allow for compiling with Microsoft Visual Studio 2005

Changes in version 2.0.2

• implemented Spectrum emulator
• implemented real time clock
• in the default keyboard map, Home can also be used now as HOLD, and End as STOP; the original keys (Pause/Break and PrintScreen/SysRq) did not work on some machines
• keyboard matrix state is no longer cleared on soft reset
• NICK registers are initialized to random values on start-up
• added new ROM images and machine configuration presets
• the makecfg utility now asks for an installation directory if started without command line arguments, and automatically creates directories
• minor improvements to GUI menu layout

Changes in version 2.0.1

• improved timing accuracy of Z80 memory and NICK port accesses (this is still not perfect); note that when playing demo files recorded by previous releases, the timing may go out of sync because of this change
• DAVE internal sample rate can now be changed with the sound clock frequency option
• removed video memory latency option
• implemented 'ignore' watchpoints in the debugger; these can be defined by using the 'i' suffix. Watchpoints and single step mode will not stop the emulation and open the debugger while the program counter is at any address for which the ignore flag is set
• added I/O tab to the debugger (displays the state of I/O registers)
• the disassembler now supports the undocumented SLL instruction, and also prints RST 30 as 'EXOS nn'
• added 'step over' button to the debugger; it is similar to 'step', but when encountering any subroutine call or looping instructions, it will continue program execution until the subroutine returns or the loop is finished
• disassembly view address is automatically updated when the debugger is opened by a watchpoint being triggered or using the step buttons; the current tab is also remembered and not changed to 'general'
• new 't' debugger command for copying memory
• added limited (read-only) support for EPTE/TAPir format tape files
• fixed direct floppy disk access on Windows
• improved autodetection of disk geometry parameters; with a disk image that contains a FAT filesystem, none of the parameters need to be specified explicitly (all can be set to -1)
• added workaround for FLTK bug that resulted in the right shift key being interpreted as left shift on Windows
• various minor improvements in the software video driver, such as reduced aliasing when using a display resolution of 1152x864, and slightly lower CPU usage with exact integer scaling ratios (i.e. resolutions 384x288, 768x576, 1152x864, and 1536x1152 with the pixel aspect ratio set to 1.0)
• when loading large ROM images, the GUI now automatically sets the file name and offset for all segments
• minor bug fixes

Changes in version 2.0.0

• removed Plus/4 emulation (moved to a separate plus4emu project)
• implemented new video mode that resamples the video output to the refresh rate of the monitor; enabling this allows smoother display update at the expense of higher CPU usage and some latency in the video output
• screenshots can be saved in 8-bit RLE compressed TGA format
• quick loading of clock frequency and timing configuration presets with PageUp/PageDown keys (useful for switching between normal and fast Z80 speed)
• virtual file I/O can be disabled in the machine configuration
• bug fixes in NICK emulation
• attempt to fix OpenGL crash that occurs on some machines
• added some hacks to the audio driver to reduce timing jitter on Windows; this still needs improvements
• various minor bug fixes

Changes in version 2.0.0 beta1 (since version 1.6.1)

• graphical user interface using the FLTK library
• a GUI debugger with support for listing CPU registers, memory dump,
  disassembly, setting watchpoints, and more
• new audio and video drivers with more features and improved quality
• new ROM module that implements a FILE: EXOS device for direct file
  access
• improved tape emulation
• demo recording (snapshot and keyboard events stored in a file)
• external joystick emulation (using the numeric keypad)
• various internal code changes to allow for the emulation of multiple
  machine types
• added Commodore Plus/4 emulator mode with high accuracy and support
  for SID emulation, as well as 1541 and 1581 floppy drives