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Need help to get DOS 6.3 FDISK to make 8GB Partition

S

Springbok

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Aug 9, 2013
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Orlando, FL
Hey guys.

Have the following situation.

I have an ASUS P5A-B Mobo. I installed an PCI->SATA card and to that, I attached two SATA drives housed in a dual removable drive enclosure. On boot, the BIOS recognizes and identifies both of the drives as a Raid array. I have the boot order set so that my 1.44 is the primary boot, and the 1st SATA slot is the secondary boot drive.

I have 3 SATA drives. My intention is to put DOS on the 8GB, Windows SE on one 80GB, and Windows XP on the other. The goal is to simply select the OS to boot to by plugging a SATA drive in the first slot.

I have run into my first issue. When running FDISK, it is only allowing me to create 1 primary partition of 512MB. I know that there is an option in the BIOS (I think its is LDA or something like that), that allows you to configure a drive so that it can be partitioned to 8GB. However, since the 8GB is being recognized as a RAID array, I can't figure out how or what to change to allow me to partition the drive to 8GB?

Can anyone provide some direction?

Thanks.
 
You won't be able to do that. 2GB is the maximum as far as I am aware. I'm not sure about the limit of 512 cropping up, you'd need to mess with the BIOS on your SATA card, probably something to do with PIO, LBA or 32-Bit Transfer.

If you unplug that RAID array to switch OS you'll break the array. Also, you won't get any advantage using that SATA card, PCI simply isn't that fast.
 
2 GB is the max for FAT16. FAT32 will do what you want so you can use any of the DOS versions after 6.xx. I use WIN98SE DOS for my tweener with FAT32 and large hard drive capability but OSR2, Win98, or WINME will do also.
 
If you're stuck with DOS 6.x, you can create a large extended partition and stick as many <2GB logical drives in it. In any case, the file size limit for FAT16 or FAT32 is still 2GB, regardless of the logical drive size.
 
I'd suggest just setting it up to dual boot Windows 98 SE, and Windows XP. Then use Windows 98's DOS mode (MS-DOS 7.1). You can set up a menu option in the Windows 98 startup to let you boot directly to Win 98 DOS, optionally with extra DOS drivers you may need.

With the exception of non FAT-32 aware disk utilities and running Windows 3.1 with 32-bit file access, this will get you almost 100% compatibility with DOS application.
 
Chuck(G) said:
If you're stuck with DOS 6.x, you can create a large extended partition and stick as many <2GB logical drives in it.
Click to expand...
Not quite. DOS 6.22 and earlier do not support Int13h extensions and cannot use hard disks over 8.4 GB in size. So, four 2GB partitions is all you can get.
 
Stone said:
Not quite. DOS 6.22 and earlier do not support Int13h extensions and cannot use hard disks over 8.4 GB in size. So, four 2GB partitions is all you can get.
Click to expand...
Not quite. The total useable space on the hard disk is indeed 8.4GB in DOS<7.0, but the extended partition can be up to that entire 8.4GB in size; within that extended partition you can have as many logical drives as you have available drive letters, as long as they all fit within the extended partition and none of them is >2GB.
 
Mike is almost right. A plain-Jane BIOS can address about 8GB--you run out of sector numbers (1024 cylinders, 63 sectors, 256 heads). So the master partition table can't provide relative sector numbers beyond the 8GB limit.

However, there were a couple of dodges used to skirt that one.

One can increase the sector size (block 512 byte sectors up into 1024, 2048, 4096 byte logical sectors). It's not bug-free and can really eat memory, but at one time it was pretty much all you had.

One can use a BIOS that will logically split a drive up into several smaller drives.

One can also partition the first 8GB of a drive as drive C:, then use installable device drivers to create additional logical drives on the remainder of the physical drive.

People were always looking for ways to get past the problems of 24-bit sector number limitations of INT 13.
 
Chuck(G) said:
Mike is almost right. A plain-Jane BIOS can address about 8GB--you run out of sector numbers (1024 cylinders, 63 sectors, 256 heads). So the master partition table can't provide relative sector numbers beyond the 8GB limit.
Click to expand...
Well, I was talking about a plain-Jane BIOS and Dos' FDISK ;-)

One can also partition the first 8GB of a drive as drive C:, then use installable device drivers to create additional logical drives on the remainder of the physical drive.
Click to expand...
Interesting! Tell us more about these drivers...
 
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FYI... decided to abandon the SATA card. I ordered a DUAL sata to IDE card today. I had a single SATA to IDE card, and tested it out. Was able to partition the 8GB SSD to have a 2GB primary mapped to C, then mapped 4 logical drives in the remaining extended partition.
 
There are lots of little challenges when using large SATA drives under DOS :) The FDISK of W98SE for example can't properly handle drivers larger than 60 or so GB. The capacities will be off.

So on a 250GB drive for example you can use SUPER FDISK to create a single 30GB FAT 32 partition. Then install your MS-DOS 7.1 manually (I did a video guide on YT if you want to know how). I recommend 30GB because some command line utilities don't work correctly with larger partitions.

However I never tried multi-partition setups.
 
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