primary partition size

hi
I am trying to create primary,extended and logical partitions.
when I try to create a primary partition, I can give it maximum 1027M (1gb). Why?

Because You can?
If You want less, then specify less!

/Lakris

I mean I want to allocate more than 1027M but it is not allowed..

Are there any existing partitions?
How much free space does it say it has?

even I delete all partitions,
When I try to create a primary partion, I can allocate maximum 1027M.

How are you creating the partitions? I think there was a limitation around 15G for primary partition(s). But if you are deleting everything this is not the case.

What program are You using for partitioning? Could You describe in detail what You are doing?

fdisk dev/hda

then press 'n'
primary partition
and
maximum I can select 1027M

If You use the p command, does it list any existing partitions?
Does it say how big Your disk is?

no, there is no partition appears in p command.