Society of Eight-Bit Heathkit Computerists
A web site dedicated to preserving the Heathkit 8 bit computers
H8D FORMAT
The H8D image format is the standard 10 sector 40 track disk format for
Heathkit H-8 and H-89 computers. This image format stores the disk
tracks as groups of 256 byte sectors starting with track 0 and ending
with track 39. Track 0 occupies the first 2560 bytes (10 sectors, 256
bytes per sector) followed by track 1 and so on. There are a couple ways
to use these disk images with your Heathkit computer:
First, you can find and buy an
SVD. It is an electronic floppy drive that works with several different computer models including the Heathkit H-8 and H-89. You plug the SVD into the floppy cable as if it were
a floppy disk drive and upload the disk images to it. The computer then thinks it is talking to a floppy drive with a Heathkit disk inside.
Second, you can use Dwight Elvey's H89LDR program and my
H8D Utility
to transfer disk images back and forth to a real floppy disk. Do this by
connecting your Heathkit computer to a PC using a serial cable and then
use the software to send/receive disk images. This method will work with
a real floppy disk inserted into your computer's disk drive.
Third, you can use
H8DIMGR running on a real
Heathkit computer and my
H8D Utility V1.51 or later to
transfer hard sector disk images of any size to and from a floppy disk
in your Heathkit computer via a serial port.
For high density hard sector disks the format is as follows: track 0
side 1 2560 bytes, track 0 side 2 2560 bytes, track 1 side 1 2560 bytes, track 1 side 2 2560
bytes, etc. This applies to both HDOS and CPM 200K and 400K disks.