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286 with an 8Gb Drive

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NicolasF

Experienced Member
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Jun 28, 2006
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Hi, I recently aquiered a 25 MHz 286 with an AMI BIOS. I'm trying to install an 8Gb Samsung SV0844AA hard drive but MS-DOS 6.22 detects the hard drive as 504 Mb. Do I need some special driver to do this??

Thanks!
 
NicolasF said:
Hi, I recently aquiered a 25 MHz 286 with an AMI BIOS. I'm trying to install an 8Gb Samsung SV0844AA hard drive but MS-DOS 6.22 detects the hard drive as 504 Mb. Do I need some special driver to do this??

Thanks!
Click to expand...

After you solved that one, you probably will hit another one :)

See here:
http://www.storagereview.com/guide2000/ref/hdd/bios/sizeMB504.html

More advanced OS's solve that (Linux), but that that won't run on your machine.
Are you planning to run DOS? One of the later versions of Ontrack diskmanager might help.
 
I remember having the same issue.

I believe that FAT16 only allows for 2gb partitions.
What I had to do, was F3 out of DOS setup, then enter FDISK.

I had a 4gb drive and after creating two 2GB partitions, I formatted both partitions. DOS would then allow me to install on the 2GB partition, and also recognize the other partition as D:

Although this was on a 486 machine.
 
Hi, I formatted the drive using Ontrack Disk Manager 9.57 and it created 4 2Gb partitions.

Thanks!! :D
 
I think some of the earlier versions of DOS only allowed no bigger than a 500mb partition. If you havn't, try upgrading to the newest version of DOS (6.22) and your partition size will be increased to 2GB.

Barney
 
barney said:
I think some of the earlier versions of DOS only allowed no bigger than a 500mb partition. If you havn't, try upgrading to the newest version of DOS (6.22) and your partition size will be increased to 2GB.

Barney
Click to expand...

DOS 4 and above will do 2gb partitions, see the MS KB article here for details.
 
There has never been a 500 MB PARTITION size limit in DOS.
Yes, there is similar limit (528 MB or so) of WHOLE DISK size, resulting from combination of IDE limitations and DOS limitations, but it's easy to overcome by using translation in BIOS, or - when no new BIOS is available - in software like Ontrack Disk Manager.

Actual PARTITION size limits are:
PC DOS/MS-DOS 2.x - 16 MB
PC DOS/MS-DOS 3.x - 32 MB
PC DOS/MS-DOS 4.0..7.0 - 2 GB
 
Hmmm, I thought the DOS 7 limit was 2TB using FAT32.

To clarify,

Under DOS 4 and later, the maximum partition size is 4GB, but the maximum FAT16 filesystem size under MS-DOS 4 and later is 2GB.

MS-DOS limits FAT16 cluster size to 32KB, where NT, FreeDOS and Enhanced DR-DOS limits FAT16 cluster size to 64K, giving a 4GB maximum FAT16 partition size.

Edit I don't know if FreeDOS will run on a 286, however.

Even my digital camera handles a 4GB FAT16 file system, so why MS-DOS was never upgraded is a mystery (not really!).
 
Last edited:
Chuck(G) said:
Hmmm, I thought the DOS 7 limit was 2TB using FAT32.
Click to expand...
Depends...
PC DOS 7.0r0, PC DOS 7.0r1 (aka PC DOS 2000), MS-DOS 7.00 (aka Windows 95) - only FAT16, ie. 2 GB
MS-DOS 7.10 (aka Windows 95 OSR2 and Windows 98) - also FAT32, ie. 2 TB (but Scandisk can't cope with more than 127 GB)
 
Chuck(G) said:
Hmmm, I thought the DOS 7 limit was 2TB using FAT32.

To clarify,

Under DOS 4 and later, the maximum partition size is 4GB, but the maximum FAT16 filesystem size under MS-DOS 4 and later is 2GB.

MS-DOS limits FAT16 cluster size to 32KB, where NT, FreeDOS and Enhanced DR-DOS limits FAT16 cluster size to 64K, giving a 4GB maximum FAT16 partition size.
...
Click to expand...
Are you talking strictly about logical partitions? The extended partition can be up to 8GB, no?
 
MikeS said:
Are you talking strictly about logical partitions? The extended partition can be up to 8GB, no?
Click to expand...

Microsoft claims that under DOS 4.0 and earlier, 4GB is the limit. I wonder if it has something to do with their arithmetic falling apart after 4GB (32 bits worth of bytes).

I'll have to see if I can fdisk a larger partition under DOS 4.0.
 
Marrr said:
Depends...
PC DOS 7.0r0, PC DOS 7.0r1 (aka PC DOS 2000), MS-DOS 7.00 (aka Windows 95) - only FAT16, ie. 2 GB
MS-DOS 7.10 (aka Windows 95 OSR2 and Windows 98) - also FAT32, ie. 2 TB (but Scandisk can't cope with more than 127 GB)
Click to expand...

Ah, okay--a communication issue--I was taking "DOS 7" to mean 7.x.
 
Chuck(G) said:
Microsoft claims that under DOS 4.0 and earlier, 4GB is the limit. I wonder if it has something to do with their arithmetic falling apart after 4GB (32 bits worth of bytes).

I'll have to see if I can fdisk a larger partition under DOS 4.0.
Click to expand...
Aren't we talking about 4.0 and *later*? I've read that 4GB limit a few times as well, but usually "later" only refers to 5.0; did 6.xx maybe change something?

I've always understood that the total disk size is limited to 8GB and each logical partition is 2GB max., so the primary can be up to 2GB and the extended can be 8GB minus the primary, divided into several logical partitions no greater than 2GB each.

I have several 8GB DOS 6.22 systems with a 100MB primary for DOS etc. and a 7.9 GB extended with several logical partitions containing applications, data, backups, etc.; I assume Nicolas' 4 2GB partitions are one 2GB primary and a 6GB extended with three 2GB logicals.
 
Microsoft says:

Microsoft MS-DOS versions 4.0 and later allow FDISK to partition hard disks up to 4 gigabytes (GB) in size. However, the MS-DOS file allocation table (FAT) file system can support only 2 GB per partition. Because of this fact, a hard disk between 2 and 4 GB in size must be broken down into multiple partitions, each of which does not exceed 2 GB.
Click to expand...

I dunno. Time to get out a spare drive and see what DOS FDISK creates for partitions.
 
i recommend EZ-Drive. it's free from WD. (although i can never seem to find it on their site, i'm pretty sure i got it from vetusware - but it's still nice and legal as it's freeware.)

sounds like you got it solved with the ontrack software though, at least the BIOS limitation. if you want to use all 8 GB in one partition, download DR-DOS 7.03 from www.drdos.net and use it's fdisk to create a single FAT32 partition.

direct link to the images: ftp://ftp.fsn.hu/pub/OpenDOS/DR-DOS.703/images/

you only need to get disk01.144 through disk05.144 - you do not need the ldisk ones. they can be written with any normal floppy imaging utility like winimage. i usually just use linux's dd command.
 
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