Use of large harddisks in PC's with BIOS size limit
There are certain limitations why you could not use the full capacity of your harddisk right from the beginning.
Your mainboard BIOS lacks support for large harddisks (540MB / 2GB / 8GB / 16GB / 32GB limit). This is when your harddisk is reported as unsupported [AutoDetect reports None] or with wrong sizes in the BIOS setup. Even when your computer stops starting.
Your harddisk features an UltraDMA mode not known to the harddisk or vice versa. Therefore no communication can be established.
Your operating system does not support partitions larger than 2GB.
For all limitations workarounds exist.
Your mainboard manufacturer may provide a new BIOS binary for download to update your current version with a Flash utility. To identify your mainboard at least a manufacturer name and product name or a BIOS ID is needed.
Info on how to find the BIOS ID and manufacturer
If you use an operating system like Windows 95, 98, ME, 2000, Linux, MacOS... you can manually enter harddisk data in the BIOS to limit your HD to 2GB. This will prevent your BIOS from autodetecting your harddisk and will limit BIOS access to your harddisk to the first 2GB. During boot-up your BIOS will report this "wrong" size. This is only important up the point when the BIOS hands over control to your operating system (e.g. Windows 95 IO.SYS / COMMAND.COM). Then your operating system uses it's own method to access the harddisk and is indepented from your BIOS limitations. Creating partitions is more difficult when using this solution as FDISK does rely on proper initialization of your harddisk during boot up.
You can download a partition tool to create partitions with every size and file system you like here:
FAQ for solving problems or questions:
Some harddisks provide a jumper to limit harddisk size visible to your BIOS to 2GB (sometimes 8GB or 32GB). That would be easier than the above given solution to enter manually data into BIOS settings.
Most harddisk manufacturers provide a software tool to do both parts (using fake settings for the BIOS and translating harddisk size correctly to its full capacity). Please specify your harddisk type to guide you to a download location. This solution works with legacy operating systems, too.
IBM DiskManager 2000 (v 3.10.14)
Seagate DiscWizard 2000
Full version for all harddisks by OnTrack (59.95$)
Change UDMA mode for your harddisk. As your chipset is based on VIA 82C586B southbridge all modes above UDMA33 are useless, because this chipset can only handle up to UDMA33. So limiting your harddisks firmware to UDMA66 or UDMA33 does NOT decrease performance. Problem could be that your harddisk can't get initialized as it features an UDMA mode unknown to the BIOS / chipset.
Fujitsu UDMA changer
Microsoft DOS based operating systems like Windows 3.1, Windows 95 implement a file system called FAT16. This file system can only handle partitions up to 2GB:
65525 cluster (max) * 32768 Byte (max) = 18.104.22.168Byte
So you would end up with 10 partitions with 2GB each when using a 20GB disk. Newer releases of Microsoft Windows like Windows 95 OSR 2, Windows 98 and later use a new file system called FAT32 which can have partitions larger than 2GB. Windows 95 and Windows 95 SP1 don't feature FAT32 (see Properties of MyComputer for version of Windows95 -> 950 or 950A have no FAT32). All in all you can use harddisks with 20GB in your PC but you might end up with ten partitions named C:, D:, E: ... all with 2GB each. If this is OK for you no further activities are necessary. If you want to use one partition with more than 2GB upgrade to an operating system with support for different file systems like FAT32 (Windows95 SP2, Windows98/ME, Windows 2000), NTFS (Windows NT, Windows 2000), HPFS (MacOS), extFS (Linux) etc.