Standard Cmos

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Standard CMOS Setup

This page describes the fields and options found in this section of the Setup. If the motherboard is already installed and working in a computer, this section will only need changed if the hardware configuration changes, the on board battery fails or information stored in the CMOS is is lost or damaged.

Primary Master/Primary Slave/Secondary Master/Secondary Slave

The onboard PCI IDE connectors provide Primary and Secondary channels for connecting hard disks or other IDE devices. Each can support two devices. The first is the Master and the second the Slave.
To enter the specifications for a hard disk you must first specify a type. There are 45 predefined types and 4 user definable types, used for an Enhanced IDE BIOS. Type 1 to Type 45 are predefined, and only appears on older motherboards. Type 'User' is user-definable. IDE HDD Auto Detection sets the related information automatically. If your hard disk drive type is not listed in the 45 predefined types (on older motherboards), or is not auto detected, you can use type 'User' to define your own drive type manually.
If a hard drive is not installed slect 'None'.
If you select type 'Auto', the system will auto detect your hard disk at boot up. If you select type 'User', the following related information is asked.

CYLS: The number of cylinders.
HEAD: The number of read / write heads.
PRECOMP: Write precompensation.
LANDZ: Landing Zone.
SECTOR: The number of sectors.
MODE: Used to select if drive is greater than 528 MB.

This information is usually provided in the hard drive manual or on the drives case. The specifications of the drive must match the table. If you enter incorrect information in these fields the hard drive will not work properly.

Write Precomp

In modern HDD this entry is not necessary. Set it either to -1 or the number of cylinders (a common value is 65535). For E-IDE (Integrated Device Electronics) hard drives it is not necessary to enter a WP cylinder, the drive will know its own parameters.

Landing Zone

The address of the landing zone. Set it to 0 or the number of Cylinders.

Mode

Normal: Use this mode for drives less than 528 megabytes.
Large: For drives that do not support LBA and have more than 1024 cylinders.
LBA: Logic Block Addressing mode which considers logic blocks instead of heads, cylinders and sectors for drives >528MB. Some older motherboard BIOS do not support LBA and need DOS drivers to function.

Drive A / Dive B

These fields identify the types of floppy drive that has been installed in the computer system. The available options are 360KB, 720KB, 1.2MB, 1.4MB or 2.88MB which relate to a disk size of 5.25 inch, 3.5 inch, 5.25 inch, 3.5 inch and 3,5 inch.

Floppy 3 Mode Support

This is the Japanese standard floppy disk and stores 1.2MB diskette. There are four options in this field.

Disabled: No mode 3 floppy drive installed
Drive A: Installed mode 3 floppy as drive A.
Drive B: Installed mode 3 floppy as drive B.
Both: Installed mode 3 floppy as drive A and B.

Video

This field selects the type of video card installed in the computer system. The following video display modes are available. This option must match the display card and monitor. Although secondary monitors are supported you do not have to select the type.

EGA/VGA: For EGA, VGA, SEGA, SVGA or PGA monitor adaptors.
CGA 40: Power up in 40 column mode.
CGA 80: Power up un 80 column mode.
MONO: For Hercules or MDA monitor adaptors

Error Halt

This field will determine if the computer system will halt if an error is detected during power up. The following are the options available.

No errors: Whenever the BIOS detects a non fatal error the system will stop and the user will be prompted.
All errors: The system boot will not be halted for any error that may be detected.
All, But Keyboard: The system boot will not be halted for a keyboard error, but will stop for all other errors.
All, But Diskette: The system boot will not be halted for a disk error, but will stop for all other errors.
All, But Disk/Key: The system will not be halted for a keyboard or disk error, but will stop for all others.

Memory

This category is for display only and is determined by POST.

Base memory: The value of the base memory is typically 640KB for computer systems with 640KB or more memory installed.
Extended memory: This is the amount of memory located above 1MB in the CPU memory address map.
Expanded memory: An expanded memory device driver is needed to use memory as expanded memory. Many standard DOS programs could not use memory over 640 KB, so EMS swaps memory in frames or sections so as all of the system memory can be used.
Other memory: This refers to memory located in the 640 KB to 1MB address space. DOS uses this area to load device drivers so as as much base memory is free for applications or Shadow RAM.
Total memory: This is the sum of the above memory.