Boot Process; Four Key Reset; Cold Booting; Bios Code Is Shadowed - Intermec PEN*KEY 6400 Programmer's Reference Manual

Reference, System Information

Boot Process

The following paragraphs describe the various methods used to boot the 6400
Computer. Also described are the options that are possible during the boot
process, which you exercise by holding a key down during the boot phase or by
reconfiguring a CMOS setting.

Four Key Reset

The 6400 Computer can be reset by pressing four keys simultaneously for
approximately one second:
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Cold Booting

A cold boot cycle normally should never be performed by a customer. A cold boot
is defined as a boot cycle in which power is applied for the first time (when the
6400 Computer contains no backup battery or main battery, and no external
power is being applied). A cold boot is normally done only at the factory. The
only time you would need to be perform a cold boot, would be after a situation
where the main battery pack has drained, no backup battery was installed, and
no external charge is applied. The following paragraphs describe some of the
basic steps that occur during a cold boot.

BIOS Code is Shadowed

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 write-protects 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.

Power-On Self-Tests (POST) are Run

A series of tests is performed on the hardware to ensure that the system is
functioning properly. For the most part, these tests are performed without any
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, refer to the Audible
Error Codes paragraph, in the section entitled, Reference.
Video BIOS is Enabled
Early in the Power-On Self-Test (POST) phase, the video BIOS is given control to
initialize the screen. From that point, errors are reported by messages on the
screen rather than by beeps.
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PEN*KEYR 6400 Programmer's Reference Guide
BLUE shift plane key
GOLD shift plane key
ENT (left enter)
ENT (right enter)
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