SUDDEN DESU

disassemblies・digital archaeology・data preservation

Hidden Menu in Miyasu Nonki No Quiz 18kin

Hidden Menu in Miyasu Nonki No Quiz 18kin

Yet another adult arcade quiz game, this time with some pretty well-drawn and amusing artwork by eromanga artist Miyasu Nonki! A while back I found the text for an alternate test menu, with object and background checks. I could never really track it down properly with the standard MAME disassembly. Maybe I just wasn’t trying hard enough, because when I gave it another go yesterday, this time in IDA, I was finally able to find the routine as well as the non-hacked method for activating it.

┇Disassembly / Analysis
🖉 by Ryou

English Text in Kōtetsu Yōsai Strahl

English Text in Kōtetsu Yōsai Strahl

I’m pretty burnt out on tackling Super Gem Fighter / Pocket Fighter right now. I took a little break and did some more research on something quite interesting I had found a while back: English text in Koutetsu Yousai Strahl, a horizontal shooter and a favorite among shmup fans.

EDIT 2018-11-28: As of MAME 0.203, there is a world region dump of Strahl. It contains the English text that was found in the Japanese version, making this article relatively useless. Oh well.

┇Disassembly / Analysis
🖉 by Ryou

Oops.

The Atari File Management Subsystem (FMS) is the filesystem on an Atari 810 floppy disk.

The 720 sectors of the disk were numbered from 1 to 720, but (perhaps due to poor communication between the different development teams at Atari) the FMS filesystem was designed to support sector addresses in the range from 0 to 719, which meant that sector 720 was not addressable but a nonexistent sector 0 was. This resulted in the filesystem only using the 719 sectors in the overlap between what is addressable and what actually exists, so sector 720 is unused (a waste of a perfectly good 128 bytes).

(Source)

┇Article
🖉 by Ryou