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The manufacturers of most compatibles have enhanced the motherboard ROM BIOS tables in three ways:
As mentioned earlier, most of the newer compatible BIOS versions have both the user-definable type feature and automatic detection for IDE drives.
One way around the drive-table limits is to purchase and install a new ROM BIOS. A Phoenix ROM BIOS set, for example, costs about $50. These ROMs include a user-definable drive-type setting, which is the most elegant solution to this problem. A new set of ROMs probably will give you additional features, such as a built-in setup program, support for HD or ED 3 1/2-inch floppy drives, and Enhanced Keyboard support.
RLL/ESDI System Configuration
RLL and ESDI drives usually are not represented in the internal drive tables of older BIOS versions. Consequently, the controllers for these drives often have an on-board ROM BIOS that either contains an internal list of choices for the interface or enables you to dynamically configure (define) the controller to the specific geometry of the drive.
If you have a motherboard BIOS with a user-defined drive type (recommended), you can simply enter the correct parameters and the drive will be supported. (Remember to write down the parameters that you use; if you lose them, you can lose access to the drive if you don't re-enter the parameters properly.) When using a user-definable type, you can disable the controller BIOS.
IDE System Configuration
Intelligent IDE drives can use the geometry that represents their true physical parameters, or they can translate to other drive geometries that have the same number of sectors or fewer. Simply select a type, or enter a user-definable type that is less than or equal to the total capacity of the drive.
SCSI System Configuration
Almost all SCSI drives use DRIVE TYPE 0 or NONE because the host adapter BIOS and the drive communicate to establish the drive geometry. The low-level formatting routines usually are accessed on the host adapter through a configuration, setup, and format program. All SCSI drives are low-level formatted at the factory.
Proper setup and formatting are critical to a drive's performance and reliability. This section describes the procedures used to format a hard disk drive correctly. Use these procedures when you install a new drive in a system or immediately after you recover data from a hard disk that has been exhibiting problems.
Three major steps complete the formatting process for a hard disk drive subsystem:
Considerations Before Low-Level Formatting
In a low-level format (LLF), which is a "real" format, the tracks and sectors of the disk are outlined and written. During the LLF, data is written across the entire disk. An improper LLF results in lost data and in many read and write failures. You need to consider several things before initiating an LLF.
Low-level formatting is the primary standard repair procedure for hard disk drives that are having problems. Because data values are copied to the drive at every possible location during an LLF, before performing and LLF you should back up any data on the drive if you will ever need access to that data again.
Because an LLF overwrites all the data on a drive, it is a good way to erase an entire drive if you are trying to ensure that nobody will be able to get data from it.
Sector header and trailer information is written or updated only during the LLF operation. During normal read and write activity, only the 512 bytes plus the Cyclic Redundancy Check (CRC) bytes in the trailer are written in a sector. Temperature-induced dimensional changes in the drive platters during read and write operations are not a problem with modern voice-coil actuators used today. However, it is still doesn't hurt to leave the system's power on for at least 30 minutes before performing an LLF on its hard disk. This step ensures that the platters are at a normal operating temperature.
Drive Operating Position
Another consideration before formatting a drive is ensuring that the drive is formatted in the operating position it will have when it is installed in the system. Gravity can place on the head actuator different loads that can cause mistracking if the drive changes between a vertical and a horizontal position. This effect is minimized or even eliminated in most voice-coil drives, but this procedure cannot hurt.
Additionally, drives that are not properly shock-mounted should be formatted only when they are installed in the system because the installation screws exert twisting forces on the drive's Head Disk Assembly (HDA), which can cause mistracking. If you format the drive with the mounting screws installed tightly, it may not read with the screws out, and vice versa. Be careful not to overtighten the mounting screws because doing so can stress the HDA. This usually is not a problem if the drive's HDA is isolated from the frame by rubber bushings.
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