# Running the original versions

There are five independent DOS installations under `installs/`. Run `./run.sh` to see the available shortcuts, then pass the version you want:

| Command | DOS engine build | Why keep it |
| --- | --- | --- |
| `./run.sh demo` | 27 July 1995 | The playable prerelease demo, with its own menu and Korea scenario. |
| `./run.sh 1995` | 11 August 1995 | Our earliest retail engine, with German campaign text. |
| `./run.sh v2` | 6 September 1996 | European V2 baseline before the later engine and asset changes. |
| `./run.sh us` | 18 September 1996 | Distinct US engine, model data and mission revisions. |
| `./run.sh reference` | 12 January 1998 | The DOS build from our selected October 2000 European disc. |

The full directory names also work as arguments. The script changes to the workspace directory, then calls the system `dosbox` with mount and launch commands. DOSBox loads its normal configuration; the script supplies no emulator settings.

Each game gets its own writable C: drive. D: is its retained source directory mounted as a CD-ROM. Settings, pilot logs and scores stay inside that version's installation. The first retail launch opens the original Preferences screen for setup.

The C++ reconstruction remains a separate program. Its execution reference is the **14 January 1998 Windows software engine** from the same selected disc; this launcher runs the original DOS executables.

## The demo

The demo contains 229 supplied files, totaling 7,171,663 bytes. Its original `INSTALL.BAT` only copies the tree to `C:\APCHDEMO` using `XCOPY /S /E`. DOSBox does not supply XCOPY, so the installation was made with an equivalent file copy and every file was checked against its source hash.

Its menu offers **Arcade**, **Invincible**, **Top Ten** and **Preferences**. The only supplied mission is `MISSDATA/QS_K.DTA`, with the Korea terrain. The accompanying `APCHDEMO.TXT` describes a ten-minute flight limit, and says Invincible mode does not record a high score. The original menu and Arcade flight have been checked in DOSBox.

![The demo menu](reference/installations/demo_1995_07_27/menu.png)

![The demo running in flight](reference/installations/demo_1995_07_27/flight.png)

Of the 229 demo files, 195 are identical to corresponding files on our August 1995 retail disc, 13 differ, and 21 paths are absent there. Against European V2 those counts are 176, 31 and 22; against the selected 1998 game they are 128, 79 and 22. Later root files under `FILES/` and `FILESD/` are compared at their installed locations. Several absent paths are loose sound files; later releases use sound banks, so these counts alone do not establish new recordings. [File comparison](reference/installations/demo-comparison.json).

## Installation records

The three new retail installations were made by running their original DOS installers, then checked at the first-run Preferences screen. Their game files match the source media. Generated preferences, installation logs, pilot records and empty swap files are listed separately in each `installs/<version>/installation.json`.

The existing reference installation was preserved. None of the writable installs shares file inodes with the read-only source collection.

[Installation summary and hashes](reference/installations/index.json) · [1995 installer completion](reference/installations/cd_1995_de_1997_disc/installed.png) · [V2 first run](reference/installations/cd_1996_09_eu_v2/first-run.png) · [US installer completion](reference/installations/cd_1996_09_us_2019_repack/installed.png)

The Japanese edition is Windows-only and remains available as extracted media. Patch executables and the 3dfx builds remain in the collection for comparison; this launcher does not mix those into the DOS installs.