Swain Chen at http://lists.debian.org/debian-kerne.../msg00151.html reported for a Dell Dimension 4700
"Using the acpi=off option would get me past the RTC and "Setting the
Hardware clock..." steps but then I got some IRQ 193 error, which said "No
one cares". "

Tomaz at http://lists.debian.org/debian-kerne.../msg00596.html
noted that the driver rtc.ko had to be removed from the kernel for getting a working installation:
".6.8, .9 and .10 (686-SMP and -UP) kernels all hang on rtc module during boot on Dell Optiplex G280 with A03 BIOS, 3.0 HT P4, SATA. When omitting the rtc module I was able to boot.
Contrary, 2.4.* boots OK _with_ rtc module included"

Further info http://lists.us.dell.com/pipermail/l...ber/023021.htm

And what is RTC ?
Explained e.g. here: http://www.linux.com/howtos/Battery-...powermgm.shtml
RTC stores time in GMT (CONFIG_APM_RTC_IS_GMT): If you want to store GMT (Greenwich Mean Time) in your RTC (Real Time Clock).
Advanced Power Management (APM) allows your computer's BIOS to control your system's power management.
Advanced Configuration and Power Interface (ACPI) is the successor to APM, which places the responsibility of power management away from the BIOS and into the hands of the operating system. ACPI Linux is newer than APM Linux.