Viglen Vig644M Manual page 13

Real-Time Clock, CMOS SRAM, and Battery
A coin-cell battery (CR2032) powers the real-time clock and CMOS memory. When the
computer is not plugged into a wall socket, the battery has an estimated life of three
years. When the computer is plugged in, the standby current from the power supply
extends the life of the battery.
The clock is accurate to ± 13 minutes/year at 25 ºC with power applied through the
power supply 5V STBY rail.
NOTE: If the battery and AC power fail, date and time values will be reset and the user
will be notified during POST. When the voltage drops below a certain level, the BIOS
Setup program settings stored in CMOS RAM (for example, the date and time) might not
be accurate. Replace the battery with an equivalent one.
BIOS
The BIOS provides the Power-On Self-Test (POST), the BIOS Setup program, and the
PCI/PCI Express and SATA auto-configuration utilities. The BIOS is stored in the Serial
Peripheral Interface (SPI) Flash memory device.
SATA Auto Configuration
If you install a SATA device (such as a hard disk drive) in your computer, the auto-
configuration utility in the BIOS automatically detects and configures the device for your
computer. You do not need to run the BIOS Setup program after installing a SATA
device. You can override the auto-configuration options by specifying manual
configuration in the BIOS Setup program.
PCI/PCI Express Auto Configuration
If you install a Conventional PCI or PCI Express add-in card in your computer, the
PCI/PCI Express auto-configuration utility in the BIOS automatically detects and
configures the resources (IRQs, DMA channels, and I/O space) for that add-in card. You
do not need to run the BIOS Setup program after you install a Conventional PCI or PCI
Express add-in card.
BIOS Security Passwords
The BIOS includes security features that restrict whether the BIOS Setup program can
be accessed and who can boot the computer. A supervisor password and a user
password can be set for the BIOS Setup and for booting the computer, with the following
restrictions:
 The administrator password gives unrestricted access to view and change all Setup
options. If only the administrator password is set, pressing <Enter> at the password
prompt of Setup gives the user restricted access to Setup.
 If both the administrator and user passwords are set, you must enter either the
supervisor password or the user password to access Setup. Setup options are then
V1.0 Vig644M Motherboard Manual
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