Partiton Magic etc. - limitations with very large drives

[#1]

I am just starting to plan how to resolve some #110/116 errors...
I have two 1TB SATA drives running on PCI cards and I'm pretty sure I have always created and modified the partitions using PM8.
I also transferred some partitions to the second drive using Drive Image in another machine but using the same PCI card.
Both drives are coming up with errors, so PM8 (floppy version) will load but won't allow me to do anything or see the current partitioning.  The DI program will show the partitions, but I haven't yet tried it to create image files or copy drives on this machine.
I ran Partinfo to see what was going on and it seems that the partition table CHS values are correct and the Start & Num sector figures are correct but the 'actual' CHS values result in these errors - but where do these values come from?  I had always assumed there were just a direct calculation from the LBA sector numbers, but this doesn't seem to be the case or the figures would tie up...
I haven't yet been through the figures completely, but I did notice that a couple of cases show an error in the number of 'actual' cylinders that is a multiple of 65536 - all I can say now is that there is no 'actual' cylinder number shown with a value greater that 65536.  I am starting to wonder whether the claimed 300 GB partition size limit for PM8 might be based on the larger (typically 255 or 240) logical head numbers I've seen with ATA drives (this is my first experience with SATA drives).  The SATA drives have come up partitioned with geometry of 16 heads.
Windows XP seems perfectly happy.
I'll try to look through the partition tables using Ptedit sometime, to see if I can work out what is going on but, in the meantime, I wonder if anyone else has seen anything similar.

[#2]

You need to get yourself a bootable Linux "Live" CD.
Free.
I would suggest Ubuntu - it isn't easy to accidentally corrupt any disk or file.
The partition editor will display or allow changes to your partitions.
CHS is so last millenium.
Sector numbers can be converted into CHS - but it is obviously important that partitions are a multiple of a cylinder.
Both my discs are 255 heads, 63 sectors/track (512byte sectors) - ie one cylinder = 8,225,280 bytes.

[#3]

I stopped using Partition magic about 3 years ago when the boot disc wouldnt boot on my new PC with sata and had a look for alternatives and found G-Parted which did the job.
Since then I have started to use PartedMagic which contains G-Parted.

[#4]

@Taxisofevil!
So which partitioning program would you recommend to run under Linux?  I've used Linux rarely and only experimentally, but seem to recall that fdisk (or whatever it was called) wasn't dreadfully user friendly and didn't allow modifications to partitions without losing the data.
@Bud
I'll have a look at those suggestions.
In the meantime, I have discovered that PM8 does display all the partions when it is run from within Windows - so it is starting to look as though the issue is with the floppy rescue disk version running under DR-DOS, and so could be similar with Partinfo (I didn't get a chance to run the Windows version of Partinfo yet).
Thanks to you both.

[#5]

Under Ubuntu use gparted, it does it graphically like PM and can resize partitions etc without loosing any data (they recommend you backup first like all the partition software does)

[#6]

Thanks.  I got the PartedMagic iso and have run that from CD and transferred it to a USB stick.  Haven't tried it in anger yet as I'm not at home with the machine I was worried about.  I did notice on two machines here that the gparted program doesn't show the occupied size of some partitions: an NTFS partition on one (the only partition), and two FAT32 partitions on the other (including the USB stick) but does show the NTFS partitions OK.  I can't remember what the exact error was - something like  the filing system not being visible or accessible.  It does show them properly when they are mounted, though - so more investigation required...  Looks pretty useful anyway.

[#7]

Gparted - like this:-