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Using 500mb+ drive in Windows 3.1

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cmc

Experienced Member
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Feb 23, 2014
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South Bend, IN
Hi Helpful VCF Folks,

I have a rather standard 486 with the following specs:
DTK PKM-0038s E-1 motherboard
AMD 5x86 133mhz
36mb ram

I use a StarTech IDE compact flash adapter with a 4gb compact flash card attached as a disk. BIOS recognizes this card as about 1800mb. But I could never get it formatted to more than 503mb. Windows 3.1 only ever sees that 503mb.

I accepted this when I upgraded the machine to use a CF card a few years ago... after all, 500mb or so is all we had when it was new. But now I am starting to fill it (with old games, what else) and would like to migrate to more space, even if all I can get is the 1800mb that BIOS recognizes.

So, I wonder what advice you all might have for that? Could I just back up all the files, partition the CF card in another computer, and then move the files back (with appropriate MBR changes and such)? Will I need to install some software to Win3.1?

Thanks as always!
 
On a 486 the drive size will be limited to 512mb by the BIOS. (In some cases it may report the full size at boot or in setup but will still only provide 512mb to DOS).

The easiest way to get around this is to install dynamic drive overlay software such as that provided with Ontrack Disk Manager or similar tools.

Note that once a DDO is installed, you will only be able to see the hard drive if you boot from the hard drive or a special floppy that also contains the DDO software. Also note that overlays work by loading before DOS and "steal" a small amount of conventional RAM.

Although most of those are included with disk formatters, you should be able to install the overlay on your existing drive and then expand the partition with Partition Magic or add a second partition.
 
This may not be appropriate, but will your system NOT allow the CF 'drive' to be partitioned?

Even if the 1800 MB limit remained, you could at least get 3 drives of 502Mb, plus a smaller drive?

Maybe the IDE/CF adaptor will not allow this??

Geoff
 
Hmm, yes.

My reply above was based on my thinking that re-partition was a fairly trivial matter.

On my XP machine, using Avanquest's Partition Commander 11, it is. But this may NOT be the case on your machine, with Win 3.1, where you may have to copy everything, then use FDISK, then copy back, and depending on what space you have to copy to, this may be trouble.

You refer to 'partitioning the CF drive on another computer' - if this other computer will run something like the Avanquest system (which I got quite cheaply) then you could do so without having to copy off, as the package will allow re-partitioning, and protecting the existing data, and I have used the system to do that and it does work.

Also, I wonder if there are other systems (even older versions of the Avanquest system) that WILL do the job on your computer? The version I have is 11, what happened to 1 thru 10?

Geoff
 
You can not add another partition until a DDO is installed. If you add one on another machine, then DOS on the 486 will not be able to see it until a DDO is installed due to the machines BIOS limit.

Similarly, resizing the partition on another machine without the DDO will result in an unrecognized or unusable partition on the 486.

The 1800mb size reported at boot up is probably in error, and not really relevant.

You may be able to install the DDO on the 486 first and then use a different computer to resize the partition. But I would recommend using a tool like Partition Magic directly on the 486 to avoid any possible interoperability glitches. The earlier versions of Partition Magic have a nice boot floppy that does everything for you, and preserves data when resizing.
 
GeoffB17 said:
This may not be appropriate, but will your system NOT allow the CF 'drive' to be partitioned?

Even if the 1800 MB limit remained, you could at least get 3 drives of 502Mb, plus a smaller drive?

Maybe the IDE/CF adaptor will not allow this??

Geoff
Click to expand...
1) There is no 1800 MB limit.

2) You cannot get 3 drives of 502MB. Since the BIOS can see only 504MiB/528MB that's all you can use, no matter how you partition it.

3) The only options are:

a) Use a DDO

b) Upgrade the system's BIOS to a translating BIOS

c) Install an IDE interface card with a translating BIOS on it.

This hardware/firmware issue was resolved ~ 20 years ago and nothing has changed since.
 
Well, something in the above is not correct? Or needs qualification??

One of my old PCs is a 486sx. This has an AMI BIOS 1993.

This machine has been happily using a 1.2Gb HD for a long time, and I'm sure it's never needed any sort of DDO (I installed the HD, and subsequent memory managers, etc).

The HD is partitioned into two, and part of the second partition is then used for a Stacker drive.

The HD is recognised within the BIOS as type 'USER', and has had the parameters entered manually (prob by me, ages ago). The BIOS shows the total size OK.

This machine has always been used for DOS, and has always had MSDOS 5.0, which fully recognises this drive, with it's partitions, etc.

So, maybe it's nothing to do with the 486, and nothing to do with DOS. Were there different BIOS chips around at the time, some would accept bigger drives (like mine) and some would not (like the OP's)?

Just trying to clarify, for my own information.

Geoff
 
Last edited:
GeoffB17 said:
Well, something in the above is not correct? Or needs qualification??

One of my old PCs is a 486sx. This has an AMI BIOS 1993.

This machine has been happily using a 1.2Gb HD for a long time, and I'm sure it's never needed any sort of DDO (I installed the HD, and subsequent memory managers, etc).
Click to expand...

That depends on BIOS version. Some motherboards got older BIOSes which lacked support for larger hard drives.

It seems odd that the OP's motherboard is one such. The 586 appeared years after the 528MB limit was breached. The information I have suggests that the DTK PKM-0038s is a rebrand of the Gemlight 486-SG which has 3 different methods of identifying IDE drives:
NORMAL with a maximum of 528 MB
LARGE with a maximum of 1 GB
LBA with a maximum of 8 GB
The manual does nothing to explain how to choose a specific mode.
 
krebizfan said:
That depends on BIOS version. Some motherboards got older BIOSes which lacked support for larger hard drives.

It seems odd that the OP's motherboard is one such. The 586 appeared years after the 528MB limit was breached. The information I have suggests that the DTK PKM-0038s is a rebrand of the Gemlight 486-SG which has 3 different methods of identifying IDE drives:
NORMAL with a maximum of 528 MB
LARGE with a maximum of 1 GB
LBA with a maximum of 8 GB
The manual does nothing to explain how to choose a specific mode.
Click to expand...

Does not the HD itself need to support LBA?
 
I don't think so.

LBA is an easy cheat. The drive had three parameters, sectors per track, tracks, and sides (?). On larger disks, one of these exceeds the limit for that specific parameter, but usually another parameter has plenty of space. LBA allows the param with the free space to be doubled, with a simple calc mapping the doubling onto the parameter that is being exceeded. The HD doesn't need to know.

Geoff
 
GeoffB17 said:
I don't think so.

LBA is an easy cheat. The drive had three parameters, sectors per track, tracks, and sides (?). On larger disks, one of these exceeds the limit for that specific parameter, but usually another parameter has plenty of space. LBA allows the param with the free space to be doubled, with a simple calc mapping the doubling onto the parameter that is being exceeded. The HD doesn't need to know.

Geoff
Click to expand...

You may want to check the wiki on that.

https://en.wikipedia.org/wiki/Logical_block_addressing
 
GeoffB17 said:
I don't think so.

LBA is an easy cheat. The drive had three parameters, sectors per track, tracks, and sides (?). On larger disks, one of these exceeds the limit for that specific parameter, but usually another parameter has plenty of space. LBA allows the param with the free space to be doubled, with a simple calc mapping the doubling onto the parameter that is being exceeded. The HD doesn't need to know.

Geoff
Click to expand...
That sounds like the BIOS option of "Large", described on page 88 (PDF page 98) of the book at [here].
Still CHS, but no LBA.
LBA description is on page 90.
 
Stone said:
You almost sound like you know what you're talking about. :)
Click to expand...

Hm, 'almost'??

Yes, I'm mixing up 'Large' with LBA. LBA is actually something else entirely.

Going back to the OP's original query, I wonder if the CF drive/device actually presents the 'normal' Cyl/Head/Sector data, and if it does not, then how would any translation work. It must present something, to work at all?

Geoff
 
Wow, thanks everyone!

When I said I could "partition it on another computer," I was referring to a Linux workstation. It is no trouble for me to take the CF card out of the 486 and put it in the modern machine for partitioning/formatting on modern Linux. This happens to also be the easiest way to transfer large files, BTW.

So if I install DDO software, do I need to reinstall Windows 3.1? Or is it sufficient to install the program and then resize the partition? I can resize FAT partitions on Linux with the fatresize utility.

I will point out that around 2001 I had Slackware installed, and it was able to use all of an 8gb drive. I don't know if that is useful information here or not.
 
Stone said:
IIRC, the DDO will format the drive during installation. So all that Linux crap is useless.
Click to expand...

Hmm, ok but my question is whether I can do the following:
1) back up the current contents (Win3.1 etc) of the CF on a different computer
2) repartition and format
3) install DDO software, DOS, Win3.1
3) copy backed up Win3.1 to the new partitions

I ask this because if all the DDO software is doing is modifying the MBR, then the changes should be transparent to the OS. If so, I can just restore Win3.1 to the new, bigger partition.

But if the DDO software modifies the OS somehow, then the "back up and restore" solution is not so simple.

I read the README file for Anydrive, and it *seems* to suggest that all it is doing is modifying the MBR, but it is not clear.
 
DDOs are loaded before DOS even loads (it hijacks the boot sector). It does not modify DOS. For all practical purposes it does not modify Windows 3.1 either. Although some may also install an additional 32-bit protected mode disk access Windows 3.1 VxD, you can still run without it.

But it is a good idea to back everything up just in case.
 
cmc said:
Hmm, ok but my question is whether I can do the following:
1) back up the current contents (Win3.1 etc) of the CF on a different computer
2) repartition and format
3) install DDO software, DOS, Win3.1
3) copy backed up Win3.1 to the new partitions
Click to expand...
Yes, but the CF will have to be in the 486 and you'll need to boot from it before you can copy anything to it. IOW, you won't be able to perform the transfer from within the modern machine exclusively.
 
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