Extract text from PC-98 disk images (HDM)
To convert HDM disk images to another format, you need Neko Project II or other Disk Image software.
To convert other file formats to the "Emulator Disk Image" file type, you need software like Neko Project II or a similar tool.
An .HDM file typically functions as a PC-98 floppy or hard disk image. These files store raw, bit-for-bit copies of physical storage media originally used in the NEC PC-9801 and PC-9821 series of Japanese personal computers. Enthusiasts use emulators like Neko Project II or Anex86 to run vintage software and games using these images. A secondary, much rarer use for the .HDM extension is the Handheld Device Markup Language (HDML) file format developed by Openwave, which delivered text content to early mobile phones before WAP and modern smartphones became the standard.
The primary disadvantage of .HDM disk images is their complete lack of native support in modern operating systems. You cannot double-click an .HDM file in Windows or macOS to view its contents. Because they rely on legacy file systems (like FAT12/FAT16 or custom NEC formats) and specific cylinder-head-sector (CHS) geometries, mounting them requires specialized third-party tools like Virtual Floppy Drive (VFD) or DiskExplorer (EditDisk). Furthermore, HDML files are completely obsolete and will display as raw, unformatted code in modern web browsers.
To make the data usable, users often need to convert .HDM PC-98 disk images to standard IMG, FDI, or HDI formats for broader emulator compatibility, or extract the internal files directly into an archive format like ZIP. For HDML files, converting to HTML or TXT is necessary for modern readability. Because these are specialized, closed, or obsolete formats, standard online converters fail to read the disk geometries or legacy markup correctly. Drag and drop your .HDM file onto convert.guru to identify whether it is a binary disk image or a text-based markup file, inspect its internal structure, and convert or extract its contents when supported.
Convert.Guru analyzes your HDM file, detects the exact format, and lets you read the text inside.
Users also converted HTM, HTML, PDF, UMD, VGA and D80 files.
If you want to convert HDM file to PDF, HTML, HTM, CSS, JS, PHP, ASP, ASPX, JSP, JSPX, PY or RB, you can use Neko Project II or similar software from the "PC-98 Disk Emulation" category. In the File menu, look for Save As… or Export….
To convert RSS, CSS, CGI, SITEMAP, PL, WEBMANIFEST, JSON, JS, XML, HTML, ICO or HTM files to HDM, try Neko Project II or another comparable tool in the "PC-98 Disk Emulation" category.
The history of Convert.Guru began over 25 years ago in California with Tom Simondi’s file-format database. A former contributor to Space Shuttle development and a software pioneer of the 1980s, Simondi established a trusted resource for file type analysis that was even referenced by Microsoft Windows XP. Today, we use modern technology to process and convert thousands of file formats while continually improving our HDM converter.