This section of the BIOS is used to control the various ports of the computer, including parallel, serial, and IDE ports. Since a PC only has 15 IRQs, some of these settings can be used to free some up if you don’t need them.
Lets go through the settings. Of course, the names, etc. do vary depending on the BIOS version you have.
- IDE HDD Block Mode
Speeds up hard disk access by transferring data from multiple sectors at once instead of using the old single sector transfer mode. When you enable it, the BIOS will automatically detect if your hard disk supports block transfers and configure the proper block transfer settings for it. Up to 64KB of data can be transferred per interrupt with IDE HDD Block Mode enabled. Since virtually all hard disks now support block transfers, there is normally no reason why IDE HDD Block Mode should not be enabled. - Master/Slave PIO Mode
This function allows IDE drive to transfer several sectors at a time. Several modes are possible. Mode 0 means one sector at a time. Mode 1 is no interrupts. Mode 2 means sectors are transferred in a single burst. Mode 3 means 32-bit instructions at up to 11.1 MB per sec. Mode 4 is 16.7 MB/sec. and Mode 5 is up to 20 MB/sec. Standard for most drives today is PIO Mode 4. But, many BIOS’s offer an AUTO setting that will automatically make the best call for your drive. These modes must be set for each drive, including primary master, slave, secondary master, slave. - Master/Slave UltraDMA
Set to Auto. Enable if your drives are UDMA capable. Keep in mind that to use this feature also requires it to be set up via the operating system. - On-Chip PCI IDE, or IDE Controller
Used to either enable or disable your either of your on-board IDE controllers. You can disable one of these if you do not need it, freeing up resources. For example, if IDE-2 is unused, you can disable it, thus freeing up IRQ 15 so something else can use it. - SMART
Some BIOS offer this option to enable or disable a hard disk’s SMART capability. SMART stands for Self Monitoring Analysis and Reporting Technology. It is used to detect and report impending disk problems. Some utilities use this technology to make disk diagnostics. - USB Controller
Enable or disable your motherboard’s on-board USB controller. - USB Keyboard Support
Many boards have a separate setting for USB keyboards, so you will need to enable this if you use one. - USB Mouse Support
Same as keyboard, but sometimes you see one for mice, too. - FDD Controller
Enable or disable your motherboard’s on-board floppy disk controller. You probably want this enabled. - OnBoard Serial Port
Used to enable or disable the serial ports. Setting to AUTO will usually default to IRQ 4, and 3F8 (COM 1) or IRQ 3 and 2F8 for COM 2. Disabling will, of course, free up the IRQ’s. - Onboard IR Function
If you have an infrared device connected to the motherboard, you can enable IR here. IrDA (HPSIR) mode, ASK IR (Amplitude Shift Keyed IR) mode, and disabled are the available options. Sometimes you might see an SCR mode, for smart card readers. Choose the mode used by your IR device. This setting is usually linked to Serial port 2, so if that is disabled, this option may not show up. Sometimes this option is called UART Mode. - Duplex Mode
This will determine full duplex or half duplex transfer modes for your IR port, if enabled. - Parallel Port
There are four options. The default value is Normal (SPP) which will work with all parallel port devices but is very slow. Two faster bidirectional modes are available, namely the ECP (Extended Capabilities Port), used for devices with large data transfers, and EPP (Enhanced Parallel Port), for devices that switch directions alot. ECP uses the DMA protocol to achieve data transfer rates of up to 2.5Mbits/s and provides symmetric bidirectional communication. On the other hand, EPP uses existing parallel port signals to provide asymmetric bidirectional communication. There is usually an EPP+ECP mode for users who don’t know which mode to choose, but this can also take up an extra IRQ. - ECP Mode use DMA
Controls the DMA channel used for ECP transfers. DMA 3 is default. You can set to 1 if there are conflicts. - Init Display First
Used to control whether to initialize an AGP or a PCI video card first on start-up. Only relevant to users who use both types of vid cards with one monitor. - Power On Function
Some motherboards allow you to turn on the system via a variety of alternative ways other than the normal power switch. Examples include mouse buttons, button only (normal), or by keyboard. Select whichever option you want.
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