[LINUX] I tried backing up MSX programs from cassette tape on Ubuntu

I protected the cassette tape containing the game program of the MSX software "Mystery House" at a used game store, so I tried to salvage the data inside.

The appearance of the cassette tape. It is a wonderful dish that traps the air of the early days of the game industry.

• Click here if you are asking "What does it mean to have a program on a cassette tape?" Https://ja.wikipedia.org/wiki/%E3%83%87%E3%83%BC%E3%82 % BF% E3% 83% AC% E3% 82% B3% E3% 83% BC% E3% 83% 80

please note

• The content covered in this article is a backup record of the media you own. Please note that copying software that you do not own is illegal.
• Game screenshots are used within the scope of the quotation.
• There is a concern that digital archaeological assets will disappear without being properly protected unless the copyright protection period is shortened.

What to prepare

• Cassette tape (Mystery House)
• Radio cassette player
• Audio cable *Audacity(https://www.audacityteam.org/) *MSXcastools(http://home.kabelfoon.nl/~vincentd/) *PC

Connect the earphone of the radio cassette player and the microphone jack of the PC with an audio cable

Launch Audacity

Set sampling frequency to 44100

48000 seems to be fine

Record

Start recording in Audacity

Start playing with radio cassette player

Take a look at the waveform

Use the CTRL + wheel to zoom in on the display to see the audio waveform. It's a so-called square wave. On the other hand, another tape contained a sine wave-like waveform.

Think about volume

In the case of a square wave, it seems that there is no problem even if the waveform swings up and down a little, but for a sine wave, it seems better to adjust the volume so that the apex of the mountain valley does not swing off. Let's record several times while adjusting the volume. If you can record nicely, select 16bit PCM from this menu.

Save to file

File> Export> Export as WAV MSXCastools

Wine installation

MSXCastools is originally software for Windows and cannot be started by general methods. Therefore, here, install the compatibility layer "Wine (https://ja.wikipedia.org/wiki/Wine)" that can start software for Windows on Linux. sudo apt-get install wine

Launch MSXCastools

Start the command line, move to the MSXCastools folder, and start it with the following command. wine MSXcastoolsUI.exe

Open WAV file

If you drag the Wav file you saved earlier to the part where "Drag file here" is written, the main screen will be displayed.

tuning

Both check boxes at the top of the window are ON for the time being Click the button labeled "Push Here to canvert to cas" to save the cas format file. Adjust the three knobs and save several times until the file size is maximized.

Take a peek at the file

Start the console and change to the directory where the cas file is saved. Let's display the inside of the file with the hexdump command. (Sudo apt-get install hexdump if not installed)

hexdump -C ./MisteryHouse.cas

I can see what seems to be a command used in the game. It seems that the data was successfully retrieved.

Try starting with emulation.

There are various MSX emulators, but for the time being, the WEB version of https://webmsx.org/ is convenient.

File loading

Select Load tape image from the icon at the bottom and select the cas file you created.

cload When you enter the command "cload" to read data from the cassette and press the enter key, it seems that it was read successfully. run! To run the loaded program, type run and press Enter or F5. Ah!

It has started! It's a success!

afterwards

However, the additional load after the title screen was not successful. Looking back at the original audio data after a lot of trial and error ...

Hmmm, it seems that the tape has deteriorated and some parts of the signal are incomplete.

However, I'm lucky to be able to extract some data from media that is more than 30 years old. If you still have the cassette tape of that time, please try it once before the playback method disappears.

See you soon!