Towns has no on-board operating system at all and you must launch the OS from software. Generally that will be from floppy disc, CD or hard drive.
While it is possible to launch operating system from hard drive after it’s installed, the operating system is always launched from software generally on CD or floppy disc. For example, let’s take a look at Street Fighter 2!
Track 1 is Data. Tracks afterwards are audio and meet ISO9660 specification. The system files that are important to note are the AUTOEXEC.BAT, TBIOS.SYS, TBIOS.BIN, RUN386.EXE and IO.SYS. All Towns self-bootable software has this to include your floppy discs!
EXP files are what we can call executables for TOWNS. That is the actual game file itself! So once you click that game file the game runs. In this case you can also see there is a way to install SSF2 to the hard drive with the HDINST.BAT.
ITM files are generally shortcuts or we can think of them as shortcuts. Let’s look at the binary in IDA PRO.
So we see that the ITM file is a shortcut to the HDINST.BAT file. So it merely functions as a shortcut.
Now examining other software let’s look at Super Ultra Mucchin Puripuri Cyborg Maririn DX….I call this Maririn for short since it’s quite a crazy name!
So what do you notice about Maririn? There are no auto-boot operating system files! Even in the DX folder it just has game files for sound and video. You’re to place the floppy disc in the computer after you load TownsOS. I’m speculating that the developer JAST didn’t want to pay Fujitsu licensing fees! But we have an ITM file and when we disassemble it…
It’s a shortcut leading us directly to the game EXP file! So with this software we are supposed to launch towns OS first maybe booting from a hard drive….and then click that shortcut icon. Unfortunately I cannot show you that yet due to the fact that this specific floppy software has copy protection yet to be unlocked. Perhaps another post I can explain this.
Asuka in this case has all the operating system files requires to autoboot. This disc requires multiple floppies to be inserted in the computer and will prompt you.
2 thoughts on “FM Towns File Structures”
I’m trying not to be overly-pedantic, but I believe that Towns PCs do have an embedded OS of a sort – an embedded version of DOS running from a ROM chip which is used to load the CD drivers which are a precursor to loading the OS from CD. It was quite a clever design considering they found a way to effectively boot from CD years before the El Torito extension to ISO9660 added bootability to the CD-ROM standard some time in 1994. If I’ve got that wrong, let me know.
Close. I wouldn’t say Towns has On-board operation system. More of a BIOS with a minimal IPL system (like your CD driver) to constantly scan mediums to load TBIOS