Anex86 PC98 floppy image

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== FDI file image contents ==
 
== FDI file image contents ==
 
The remaining portion of the file is a raw dd-style image of the disk. In the case of an HDM image, you can prepend a 4096-byte header onto the image to turn it into an FDI (see example below).
 
The remaining portion of the file is a raw dd-style image of the disk. In the case of an HDM image, you can prepend a 4096-byte header onto the image to turn it into an FDI (see example below).
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== Software ==
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* [https://github.com/barbeque/pc98-disk-tools PC98 Disk Tools]
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* [https://hp.vector.co.jp/authors/VA013937/editdisk/index_e.html DiskExplorer]
  
 
== Examples ==
 
== Examples ==

Latest revision as of 12:46, 21 September 2020

File Format
Name Anex86 PC98 floppy image
Ontology
Extension(s) .fdi

The FDI disk image format for NEC PC-98 disk images seems to originate from the Anex86 PC98 emulator.

Contents

[edit] FDI File Header

The FDI header is 4096 bytes long, Intel little-endian, and starts with this 32-byte header.


   typedef struct {
       BYTE   dummy[4];
       BYTE   fddtype[4];
       BYTE   headersize[4];
       BYTE   fddsize[4];
       BYTE   sectorsize[4];
       BYTE   sectors[4];
       BYTE   surfaces[4];
       BYTE   cylinders[4];
   } FDIHDR;


The next 4,064 bytes of the header seem to always be pad bytes.

fddtype values:

   0x10         1MB/640KB    2DD
   0x30 0xb0    1.44MB       2HD
   0x50 0xd0    320KB        2D
   0x70 0xf0    640KB        2DD
   0x90         1.2MB        2HD

[edit] FDI file image contents

The remaining portion of the file is a raw dd-style image of the disk. In the case of an HDM image, you can prepend a 4096-byte header onto the image to turn it into an FDI (see example below).

[edit] Software

[edit] Examples

For a 1261568-byte "2HD" disk image (like *.HDM format), the header is as follows:

Field Value Comment
dummy 0
fddtype 144 Unsure what this value actually means
header size 4096 Includes the 32-bytes in the header
fdd size 1261568
sector size 1024
sector count 8
surfaces 2 double-sided disk
cylinders 77
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