Altirra v2.1 is released. Altirra is an Atari 8 bit Emulator on the Windows/DOS platform. Altirra emulates several models of the 8-bit Atari computers. This includes the the 800, 800XL, and 130XE versions. It has a lot of options, and compatibility is decent especially given the emulator's early stages. It also supports some copy protected games properly in emulation.

Altirra v2.1 Changelog:

[features added] SlightSID emulation support. Covox emulation support. 1200XL emulation support. BASIC programs can now be booted. Fast boot option now accelerates timeouts for powered down disk drives. Disk: Added support for format skewed ($66) command. Disk: Format commands ($21, $22) now support high-speed operation. Disk: Added emulation profile modes for various disk drives. Disk: Reduced ACK-to-complete delay when accurate sector timing is off. Disk: Added rotation and seek sound emulation. Disk: Accurate disk timing prediction is now preserved when burst I/O transfers are enabled. Debugger: Added .sum (sum memory area) command. Debugger: Added .warmstart command. Debugger: Added ap (alias pattern) command for adding aliases with patterns. Debugger: Added additional aliases to a8 command (set Atari800-compatible command aliases). Debugger: Added alternate L>addr syntax for setting an address range length based on an end address. Debugger: Added heat map support. Debugger: Added .basic_dumpline command. Debugger: Enter now repeats the last command. Debugger: .dumpdlist command now collapses runs of identical commands. Debugger: Unassemble and dump commands now support continuation from the last address. Debugger: Added deref signed byte (dsb) expression operator. Debugger: Added %c and %y formatting specifiers to .printf command. Debugger: Added .dmamap command to show ANTIC DMA pattern over the course of a frame. Serial: 1030 Modem support. Display: Added scanline display mode. Display: Added integer-multiple version of preserve aspect ratio sizing mode. Display: Added sharp bilinear filter mode. Display: Text can now be copied out of ANTIC modes 2, 3, 6, and 7 (GR.0, 1, and 2). Display: Added CIO intercept based enhanced text mode. HDevice: Added minimal support for SDX Get Current Directory command ($30). HDevice: Added support for H6-H9: text translation modes. HDevice: Implemented rename, get/set/create/remove directory, and get file length commands. HDevice/PCLink: Fixed lock command not setting read-only flag. Cartridge: Added MicroCalc 32K cartridge type support. Cartridge: Added cartridge type autodetection. UI: Screenshot command now adjusts for interlacing and 14MHz dot clock rendering. UI: The program is now marked as high DPI aware in the application manifest. Simulator: Added support for MapRAM MMU modification. [bugs fixed] Increased paste keyboard timer to reduce dropped keys on line processing delays. Fixed startup crash on Sandy Bridge CPUs on Windows XP. Simulator: Inhibit FP math acceleration hooks when PBI ROM overlay is active. Simulator: BASIC disable Option key hold is now released more quickly to reduce cartridge conflicts. Debugger: "read" and "write" terms can now appear more than twice in a conditional breakpoint expression. Debugger: Fixed .tracecio off not working. Debugger: Fixed execution stopping on TRACE statements. Debugger: Breakpoint clear (bc) command no longer interprets breakpoint numbers as hex. Debugger: Fixed console entry window not always disabling properly. Debugger: .pokey command now reports correct status for secondary POKEY. Display: Fixed crash on some XP systems on display mode change. Display: Added workaround for ps1.1 precision issue on Intel graphics cards. Display: Fixed bicubic scaling in OpenGL mode. ANTIC: Fixed line buffer addressing to correctly handle aliasing of buffered data to different modes. POKEY: Fixed glitching in high-pass filtering. POKEY: Fixed wrong bit in SKSTAT being set for serial input overruns. POKEY: Fixed asynchronous receive mode not resetting timers 3+4 that are already running. Disk: Fixed handling of XF551 high-speed sector skew format commands ($A1/$A2). Disk: Format command now sends back ACK+ERROR+buffer instead of NAK on a read-only disk. Disk: Adjusted step rate of 810 drive to 5.3ms. Disk: Fixed forced sector ordering command (.diskorder) for .pro images. Disk: Step delays were not always reflected correctly in command delay time (only rotational position). Disk: Fixed inverted write protect bit status. Disk: Attempted writes to a write protected disk now return errors instead of a NAK. Disk: Fixed command response when accessing a drive with no disk. Disk: Fixed error return for unsupported Write PERCOM Block requests. Disk Explorer: Fixed case sensitivity issue allowing duplicate file creation on DOS 2 file systems. Input: Fixed bug in keyboard repeat detection code. Input: Improved Caps Lock key support. Cartridge: An error is now thrown when attempting to save a cartridge image in .CAR format with an unsupported mapper. Cartridge: Fixed switchable XEGS cartridge modes. Display: Fixed display mode matching when /f is specified on the command line. Display: Improved behavior of interlaced mode when frames are dropped. CPU: Fixed cycle behavior of ASL/LSR/ROL/ROR abs,X instructions in 65C02 mode. HLE Kernel: Fixed BUFADR being overwritten by CIO, which broke the DOS XE executable loader. IDE: Fixed banking in KMK/JZ V1 mode and added 3K ROM support. IDE: Fixed multiple sector read requests of exactly 32 sectors. VBXE: Fixed memory not being cleared on cold reset with randomize function disabled. Serial: Fixed incompatibility with Ice-T XE and the R: handler's STATUS handler. Misc: Fixed upper 4 bits for some R-Time 8 register reads. HDevice: Fixed NOTE and POINT commands. Cheats: Fixed 16-bit option not being tracked properly for manually entered cheats. GTIA: Sprites are now triggered properly from within horizontal blank. GTIA: Fixed sprite image overlap result. Cassette: Loading a new tape didn't press 'play' on the emulated player until the next cold reset.

Download: Altirra v2.1
Source: Here