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IBM pc hard drive problem

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Ozfer

Experienced Member
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Jan 15, 2014
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Connecticut USA
I have a IBM pc with full 640k ram, NEC V20 cpu and Intel FPU, 1 5 inch floppy drive, and 1 3.5 inch floppy for 720k disks. I recently wanted to install a hard drive to the system to install DOS and some programs onto so I could stop bungling around with 720k floppies. So I read about the XT-IDE cards and decided to build one.

I ended up making a Lo-tech 8-bit IDE Adapter rev.2. Ordered all the parts and put it together yesterday. Along with that I have a bracket to convert IDE to CF and a 4GB RiData CF card. All seemed to go well and the card flashed fine and shows every time its booted. Furthermore the card has 2 jumpers one for setting it to D800 or C800 and another that enables or disables the ROM. My cluelessness may show here since I have no idea what disabling or enabling the ROM does since it seems to boot XTIDE with or without it. I normally set it to C800 since that seems to make things go smoother. At any rate I think the hardware is working fine.

The problem is I can never get it to boot DOS from the CF card and I have no idea if my MBR is right or what I could do to fix it. I have tried installing DOS 5.0(last version on 720k floppies I could find) onto the hard drive. The disk format utility always throws out random numbers for the size of the CF card. I attempted to get it to format and I believe the dos 5.0 install formatted it as 4GB even though the numbers seemed off. After it finished installing I assume it should have made a MBR and should be bootable. Is 4GB just too much for DOS 5? Every time I boot now XTIDE goes through and then it says "Remove disks or " and hangs there.

When I put the CF card into my windows 8 Computer it shows all the DOS files on a 4GB partition and everything looks good. I have no idea what is going on and have never actually installed DOS from floppy before. Anyone have any ideas? Keep in mind I am limited to 720k floppies (it seems like there is not much software for 720k compared to 1.2 or 1.4).

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To update the MBR, run the command "FDISK /MBR"

Also, using FDISK check that the primary partition is marked as "Active". Change it to Active if it is not.

I'm guessing you probably already re-partitioned it with a 2GB partition or DOS would not even recognize the drive. Still, if the above fails you might try deleting the existing partition(s), and recreating it with FDISK.

Since you got the files on there, it sounds like the hardware is working OK.
 
MS Dos 5-6 only supports a 2gig FAT16 partition. You'll need to create 2 x 2gig FAT16 partitions to access the majority of the card in Dos 5

Wrt your comment about software on 720k disks. You can add a generic 16 bit multi i/o card with 1.4meg drive attached and run a small TSR program to access 1.44meg disks. Details are in this link https://sites.google.com/site/misterzeropage/ You wont be bale to boot from a 1.44meg formatted disk though. Apparently you can boot off one using DR Dos 7.02 and access the 1.44meg disk with out a TSR.
 
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Since you plan on using DOS 5, note that DOS 5 has a bug with partitions that use 256 sectors for the FAT. That happens for example with 2035 MB or larger partitions. See https://support.microsoft.com/en-us/kb/80496 Other tools have also have similar problems with similarly sized partitions so even getting the DOS patches may not prevent all potential issues.

To make life simpler, don't make a logical partition larger than 2000 MB. Sometimes, with a 4 GB drive, that mean having 3 drive letters: the primary partition which works for booting and an extended partition split into two logical volumes. The larger logical volume could also be about 2000 MB and the smaller logical volume would have whatever disk space remains.
 
Even 2GB is overkill for a PC. :) Think about how long it will take to return a prompt after the first DIR listing. It takes my XT about 30 seconds with a 128MB drive. :)
 
So I made 2 paritions under 2GB each (1800MB) since the card isn't a full 4GB. Formatted one, reinstalled DOS 5.0. Now when it boots XTIDE says Booting C>>C and then it just says ; and hangs at that. I suppose I could try again with a 100MB partition.
 
LOL I am stupid. I ran FDISK /mbr and it fixed everything. Now its booting up fine. I am probably going to have to shrink the partition size though.
 
How did you make the two partitions? How did you install DOS 5? You will need to have the boot partition be created by FDISK as a primary partition and be marked as active. That boot partition also has to be the first partition on the disk.

It often is best to attach the drive to the destination computer and boot from a floppy to run fdisk to create partitions and then run format on the partitions. That makes sure you have the correct partitions for the OS to be used instead of whatever tweaks to the format have happened in later OSes.
 
Stone said:
Even 2GB is overkill for a PC. :) Think about how long it will take to return a prompt after the first DIR listing. It takes my XT about 30 seconds with a 128MB drive. :)
Click to expand...

The size of the FAT is what matters, not the size of the partition. A single 2 GB partition would take about the same time as your 128 MB drive.
 
My only CF card I have was 4GB. It's not like I passed up on the perfect opportunity to use a smaller card I had laying around.
 
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