I have an old year 2000 instrument which has a 340MB hard drive. I am trying to clone the hard drive but I am having major issues.

First the instrument uses iRMX and MSDOS the bios is using the CHS address method not LBA. This means I can clone the drive using linux DD easily and the linux system will display the new drive okay since it is using LBA.

The problem is when I try the new drive out in the instrument it fails. The old harddrive has settings:

Cylinders 692, Heads 16, Sectors 60

The new drive has settings:

Cylinders 993, Heads 16, Sectors 63

The difference in the sectors has a major effect.

The old hardrive has 3 partitions. 2 partitions are FAT16 but the third is a iRMX partition which is the active partition and this partition has the intel iRMX stage two bootloader.

I think I have fixed the MSDOS issues by using MSDOS FDISK to generate and format the two FAT16 partitions on the new drive and then copy the files across from the old HDD.

The big problem is the iRMX partition. Since this was created with a hardrive using 60 sectors I do not know how to convert this for 63 sectors.

I have found a RDISK.EXE program on the second dos fat16 partition and this lists the hardrive partitions. When I use RDISK on the new formatted harddisk using 63 sector the partition details match with the old HDD. This suggests my issue is the iRMX boot partition.

If I use linux wxHexEditor to check the new HDD contents with the old HDD content the iRMX boot partition has copied across okay.

RDISK output for new HDD: Rdisk output

Anybody any ideas?


  • 1
    Did you try to force the CHS geometry on Linux? See e.g. here.
    – dirkt
    Commented Jul 14, 2023 at 13:27
  • Thanks. I can read the HDD fine using linux. The problem is that the bios on the older machine use CHS addressing. This means a cloned HDD using sectors set to 63 can not be read when the old HDD was formatted with sectors set to 60. I can format the new HDD using dos fdisk and copy the old HDD files across and this works okay. The problem is the clone of the iRMX boot partition, this fails to load on the new HDD which has 63 sectors. Anyone have any experience of iRMX boot process? Commented Jul 14, 2023 at 16:34
  • 2
    Can you set (force) the new drive to use geometry with 60 sectors? I mean not just tell BIOS but actually tell the disk. Then you could clone the original contents by maybe 60 sector blocks and then skip writing 3 sectors on the target.
    – Justme
    Commented Jul 14, 2023 at 18:05
  • Yes. So force the CHS setting on the new harddrive (where you write to) as well as the old, use the same same CHS setting in the BIOS of the old machine when booting from it, and see if then the sectors match.
    – dirkt
    Commented Jul 15, 2023 at 12:04
  • Thanks for the ideas. Not sure how to force a hdd to change geometry. I think this is hardwired in its firmware. Commented Jul 16, 2023 at 7:51


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