Linux on the server

Installer, with kernel 2.4 cannot found the CD-ROM. Kernel 2.6 when ACPI is turned on, hangs up in the begining of load. Manufacturer provides drivers for hardware RAID only for Red Hat and Suse with kernels 2.4.11-*. It's horrible.

I was faced with an interesting thing. Although, server have 1Gigs of RAM, kernel writes - "Warning only 896MB will be used".

Problem can be easily solved by recompiling kernel with support for more than 4 Gigs RAM. But it's still interresting - why it not works by default?

Host bridge: Intel Corp. Server Memory Controller Hub (rev 05)
VGA compatible controller: Intel Corp. Graphics Controller (rev 05)
PCI bridge: Intel Corp. 82801FB/FBM/FR/FW/FRW (ICH6 Family) PCI Express Port 1 (rev 03)
USB Controller: Intel Corp. 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #1 (rev 03)
USB Controller: Intel Corp. 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #2 (rev 03)
USB Controller: Intel Corp. 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #3 (rev 03)
USB Controller: Intel Corp. 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB2 EHCI Controller (rev 03)
PCI bridge: Intel Corp. 82801 PCI Bridge (rev d3)
ISA bridge: Intel Corp. 82801FB/FR (ICH6/ICH6R) LPC Interface Bridge (rev 03)
IDE interface: Intel Corp. 82801FB/FBM/FR/FW/FRW (ICH6 Family) IDE Controller (rev 03)
IDE interface: Intel Corp. 82801FR/FRW (ICH6R/ICH6RW) SATA Controller (rev 03)
SMBus: Intel Corp. 82801FB/FBM/FR/FW/FRW (ICH6 Family) SMBus Controller (rev 03)
Ethernet controller: Intel Corp. 82541GI/PI Gigabit Ethernet Controller (rev 05)
PCI bridge: Intel Corp. PCI Bridge Hub A (rev 09)
PCI bridge: Intel Corp. PCI Bridge Hub B (rev 09)