# dd if=/dev/zero of=sets.fs bs=1024k count=50
50+0 records in
50+0 records out
52428800 bytes transferred in 2.081 secs (25194041 bytes/sec)

# vnconfig -v -c vnd0 ~gps/Bochs/sets.fs 
/dev/rvnd0d: 52428800 bytes on /home/gps/Bochs/sets.fs

# fdisk -u /dev/vnd0
fdisk: invalid fdisk partition table found
Disk: /dev/vnd0dNetBSD disklabel disk geometry:
cylinders: 50 heads: 64 sectors/track: 32 (2048 sectors/cylinder)

BIOS disk geometry:
cylinders: 50 heads: 64 sectors/track: 32 (2048 sectors/cylinder)

enter a sysid of 169 (NetBSD)
start = 0
size = 100352 = 49 * 2048

# newfs /dev/vnd0a 
/dev/vnd0a:     102400 sectors in 50 cylinders of 64 tracks, 32 sectors
        50.0MB in 2 cyl groups (47 c/g, 47.00MB/g, 6336 i/g)
super-block backups (for fsck -b #) at:
    32, 96320,

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$ dd if=/dev/zero of=hd.fs bs=1024k count=400
400+0 records in
400+0 records out
419430400 bytes transferred in 18.218 secs (23022856 bytes/sec)


# vnconfig -v -c vnd0 hd.fs
/dev/rvnd0d: 419430400 bytes on hd.fs

# fdisk -u /dev/vnd0d 
fdisk: invalid fdisk partition table found
Disk: /dev/vnd0d
NetBSD disklabel disk geometry:
cylinders: 400 heads: 64 sectors/track: 32 (2048 sectors/cylinder)

BIOS disk geometry:
cylinders: 400 heads: 64 sectors/track: 32 (2048 sectors/cylinder)

size = 399 * 2048 = 817152

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Read the /usr/pkg/share/doc/html/bochs documentation, so that I do the size properly in my bochsrc.
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 dd if=/dev/zero of=hd.img bs=512 count=967680

 Size    Cyl      Heads  Sectors       Sectors Total
 483MB   1024      15    63            967680

ata0-master: type=disk, path="483M.fs", cylinders=1024, heads=15, spt=63

 #62MB image
 dd if=/dev/zero of=sets.img bs=512 count=127840

 Size    Cyl      Heads Sectors       Sectors Total
 62MB    940       8     17            127840

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