Справочное Руководство для Intermec 6100

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These paragraphs describe various methods that boot the 6100 Computer.  Also

described are the possible options during the boot process, which is done by holdĆ

ing a key down during the boot phase or by reconfiguring a CMOS setting.  TopĆ

ics covered include cold booting, warm booting, and the masterĆmode boot cycle.

A cold boot cycle is usually never performed by the customer, unless the handĆ

held computer is shipped with no backup battery or main battery.  A cold boot is

defined as a boot cycle in which power is applied for the first time.  A cold boot is

normally done only at the factory, when the batteries are installed.  The only

time you would perform a cold boot, is after a situation where the main battery

pack has drained, no backup battery was installed, and no external charge is apĆ

plied.  These paragraphs describe the basic steps that occur during a cold boot.

As one of the first steps, the BIOS copies itself, the video BIOS, and ROM DOS 5

into the first megabyte of system memory and then writeĆprotects that memory.

This is known as BIOS shadowing.  The RAM used in this process is called

shadow RAM.  Shadow RAM is different from conventional memory in that a

hardware mechanism prevents the shadow RAM from being modified once code

is copied there.  BIOS code is copied into shadow RAM primarily to enhance

performance.  Running from system memory is faster than running from flash

memory directly.

A series of tests is performed on the hardware to ensure the system is functionĆ

ing properly.  Mostly, these tests are performed without indication that they are

running.  If a test fails, an error message is displayed on the screen or a series of

beeps is sent to the speaker.  The beep codes are used only for those errors that

might occur before the screen can be enabled.  For a description of all the beep

codes that may be generated, see the Audible Error Codes table on page 7Ć8.

Early in the POST phase, the video BIOS is given control to initialize the screen.

From there, errors are reported by messages on the screen rather than by beeps.

Once the screen is enabled, version numbers are displayed for the ROM BIOS

and any other hardware components that have version designations that can be

read by software.

A portion of CMOS memory contains a value known as a checksum signature;

and indicates whether CMOS memory, as a whole, is valid.  At the time of a cold

boot, none of the memory in the system is initialized, including the CMOS

memory.  Consequently, because the signature is not correct, the ROM BIOS can

determine that a cold boot has occurred and initialize CMOS and the associated

realĆtime clock hardware to reflect a standard set of powerĆon defaults.  It also

records in EEPROM that a cold boot has occurred.  Since the standard powerĆon

defaults do not include a RAM drive, no RAM drive is present after a cold boot.