Understanding and learning about the BIOS system (from excerpts)

Introduction and learning of BIOS system

The BIOS (basic input output system, which is the basic inputs and outputs) plays a very important role in the computer system, which is the lowest setting of the computer system, and the BIOS setup program is a set of programs that are cured to the ROM chip on the motherboard of the computer. Its main function is to provide the lowest, most direct hardware setup and control for the computer. The BIOS setup program is stored in the BIOS chip and can be set only at boot time. CMOS is mainly used to store the parameters and data set by the BIOS setup program, while the BIOS setup program mainly manages and sets the basic input and output system, and using the BIOS setup program can also troubleshoot the system or diagnose system problems.

The BIOS program is divided into the award BIOS program, the AMI BIOS program, the PHOENIX BIOS program, and other BIOS programs that are specific to the manufacturer, such as IBM, and so on. Below, the basic Setup method of award BIOS program is introduced emphatically--
Enter BIOS settings and basic options.

When you turn on your computer or restart your computer, when the screen displays "Waiting ...", press the "Del" key to enter the CMOS setup interface. Note that if you press too late, the computer will start the system, and then only restart the computer. You can immediately press and hold the DELETE key until you enter the CMOS. After entering, you can use the arrow keys to move the cursor to select the CMOS settings interface options, and then press ENTER to enter the secondary menu, with the ESC key to return to the parent menus, the page up and PAGE DOWN keys to select specific options, F10 key to retain and exit the BIOS settings.

Standard CMOS Setup (CMOS setting)

The standard CMOS settings include the date and time settings, where you can set the times and dates on your computer.
The following is the hard disk condition settings, the list exists PRIMARY master first set of IDE master device, PRIMARY SLAVE first set of IDE slave device, secondary master second group IDE Master device, secondary SLAVE second group IDE from device. The IDE device includes IDE hard disk and IDE optical drive, the first, second set of devices refers to the first and second IDE data cable on the motherboard, generally near the chip is the first set of IDE devices, and the master device, slave device refers to the two devices connected to an IDE data cable, Everyone knows that each data line can be connected to two different devices, master, slave device can be adjusted by the hard drive or the rear jumper of the optical drive.
The following is the IDE device type and hardware parameters, type is used to describe the types of hard disk devices, we can choose Auto, USER, none of the operating mode, auto is the system to detect the type of hard disk, in the system stored 1-45 types of hard disk parameters, in the use of the setting value no longer set other parameters If we use a hard drive other than the predefined, then we should set the hard disk type to USER, and then enter the actual parameters of the hard disk (these parameters are usually on the surface of the hard disk), if not installed IDE device, we can choose the None parameter, so as to speed up the system startup speed, In some special operations, we can also shield the system from the automatic check of some hard drives.
Size indicates the capacity of the hard disk, the number of cylinders of the cyls hard disk, the head number of the head hard disk, Precomp write the pre-compensation value, Landz landing area, that is, the head stop sector. The last mode is the hardware operating mode, we can choose the mode of operation is: normal normal mode, LBA logic block address mode, large large hard disk mode, auto Auto Select mode. Normal mode is the original IDE, in this way access to the hard disk BIOS and the IDE controller for any conversion of the parameters, the maximum supported capacity of 528MB. The maximum hard disk capacity managed by the LBA mode is 1GB for the maximum capacity supported by 8.4gb,large mode. Auto mode is the working mode of the hard disk selected by the system.
The other parts of Figure 2 are the drive A and the drive B floppy drive settings, and if there are no B drives, then none of the drives B is set. We can choose our floppy drive type here, of course we do not have to modify this setting in most cases.
The VIDEO setting is used to set the display mode, that is, the EGA/VGA mode of operation.
HALT on this is the error stop setting, all ERRORS BIOS: will stop when any error is detected, no ERRORS: When Bio detects any non-critical errors, the system does not stop, all but KEYBOARD: except for keyboard errors, The system detects any errors that will be stopped; all but diskette: In addition to the disk drive errors, the system detects any errors that will stop, all but disk/key: except for disk drives and keyboard errors, any errors detected by the system will be down. This is used to set the system self-test to encounter an error in the shutdown mode, if the above error occurs, then the system will stop the boot and give the error prompt.
We can notice that Figure 2 also has the system memory parameters: Base memory: Basic RAM, extended extended memory, other memory, total memory

BIOS FEATURES Setup (BIOS function setting)
Enabled is on, disabled is disabled, and using page up and PAGE down can switch between the two. CPU INTERNAL CORE speed:cpu current running speed, VIRUS WARNING: Virus warning, CPU INTERNAL cache/external CACHE (internal and external fast access), CPU L2 gache ECC CHEC KING (CPU L2 "second-level cache" Fast access memory error check correction); quick POWER on self test (fast boot ego detection) This option adjusts the self-test step of detecting memory capacity three times during some computer self-test; CPU UPDATE Data (CPU update data function); boot from LAN first (network boot) This option wakes the computer remotely. Boot SEQUENCE (Boot priority order) This is the function we often adjust, usually we use the order is: A, C, SCSI, if you do not need to boot from A, then you can adjust to only C, that is, only from the C-drive boot. BIOS FALSH PROTECTION (BIOS write protection), PROCESSOR SERIAL number (System automatically detects Pentium processor), swap floppy drive (swap floppy drive letter), VGA boot from (boot display selection) Boot up floppy SEEK (whether the floppy drive is automatically detected when booting), boot up numlock status (keypad area setting at boot), typematic rate SETTING (keyboard repeat speed setting), Typematic rates ( Chars/sec, Bytes/sec); typematic delay (setting first delay time) SECURITY OPTION (detect password mode) If set to setup, the screen prompts for a password every time the machine is turned on (normal user password or superuser password, Ordinary users do not have permission to modify the BIOS settings), do not know the password can not use the machine, if set to system, the user will be prompted to enter the BIOS settings only when the superuser password. Memory Parity Check: If no parity is configured on the machine, the key must be set to disable, and the memory of most computers (including branded machines) is not parity-checked except for the server.
PCI/VGA PALETTE SNOOP (color correction), ASSIGN IRQ for VGA (assigns IRQ to VGA) IRQ is the system interrupt address. OS SELECT for DRAM>64MB (set OS2 use memory capacity) if the OS/2 system is being used and the system memory is greater than 64MB, the entry should be enable, otherwise the memory above 64MB is unusable, typically DISABLE.;HDD S.M . a.r.t. Capability (hard disk self-detection) This option can be used to automatically detect the performance of the hard disk, and if the hard disk is about to become corrupted, then the hard disk self-detection program will issue an alert. Report NO FDD for WIN95 (assigned IRQ6 to FDD) FDD is the floppy drive. The VIDEO BIOS SHADOW (using the VGA BIOS SHADOW) is used to improve the display speed of the system and is generally selected to open. C8000-cbffff Shadow: This block area mainly to map the expansion card (network card, decompression card, etc.) on the ROM content, put it in the host RAM to run, to improve speed.

BIOS error messages and workarounds
1. CMOS battery failed (CMOS battery failure)
Reason: The power of the CMOS battery is insufficient, please replace the new battery.
2. CMOS check sum Error-defaults loaded (CMOS performs all checks when error is found, so load preset system setpoint)
Cause: This usually happens because the battery is low on electricity, so try changing the battery first. If the problem persists, then there may be a problem with the CMOS RAM, preferably sent back to the original processing.
3. Display switch is set incorrectly (show shape switch configuration error)
Cause: The older motherboard has jumpers to set the display as monochrome or color, and this error indicates that the settings on the motherboard are inconsistent with the settings in the BIOS and can be re-set.
4. Press ESC to skip memory test (RAM check, can be skipped by pressing the ESC key)
Cause: If you do not set a fast power-up self-test in the BIOS, then the boot will perform a memory test, if you do not want to wait, you can press the ESC key to skip or into the BIOS to open the quick Power on the auto test.
5. Secondary Slave hard fail (detects slave disk failure)
Cause: 1 CMOS improperly set up (for example, there is no slave from the disk but there is a slave in the CMOS) 2 hard drive line, the data cable may not be picked up or the hard drive jumper set improperly.
6. Resuming from Disk,press tab to show post screen (resume boot from hard drive, press TAB to display post).
Cause: Some motherboard BIOS provides the suspend to disk (suspend to disk) function, when the user is suspend to disk's way to shut down, then the next time you turn on the display this prompt message.
7. Override Enable-defaults Loaded (current CMOS setting fails to boot system, load BIOS preset to boot system)
Reason: Maybe your BIOS settings are not suitable for your PC (like your memory can only run 100MHz but you let it run 133MH)
Then enter the BIOS settings to re-adjust.
8. Press TAB to show POST screens (tab key to toggle screen display)
Cause: Some OEMs will replace the BIOS preset display screen with their own design, and this tip is to tell the user to press TAB to switch between the manufacturer's custom screen and the BIOS preset splash screen.

Understanding and learning about the BIOS system (from excerpts)