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 FIXSHIFT.COM Requires /I to Install; Detailed Explanation - Q77835
 
 FIXSHIFT.COM is a Terminate-and-Stay-Resident (TSR) program that
 corrects a ROM BIOS problem that may be present in some vendors'
 hardware, including Compaq hardware.
 
 FIXSHIFT.COM modifies the scan codes returned for the SHIFT keys to
 correctly maintain the shift states.
 
 To install FIXSHIFT.COM, you must use the /I switch. For example:
 
    fixshift /i
 
 More Information:
 
 FIXSHIFT.COM corrects a problem in Compaq and possibly other hardware
 vendors' ROM BIOS that causes the SHIFT states to be maintained
 incorrectly when using a 101-key keyboard.
 
 The 101-key keyboard generates "false" key up/down strokes for the
 left and right SHIFT keys to simulate the original keyboard that did
 not have as many keys. Many ROM BIOS's handle these "false" keystrokes
 correctly, but some do not. The problem is that some ROM BIOS's read
 the "false" keystrokes as changes to the state of the real SHIFT keys,
 therefore it is impossible for an application program to know when the
 real shift keys are down.
 
 To solve this problem, FIXSHIFT.COM maintains two sets of state
 information for the SHIFT keys. One state is the real state of the
 SHIFT keys, and the other is the combination of the real and the false
 SHIFT key transitions (up/down). When a real SHIFT key transition is
 detected, both the real and the combined shift states are updated;
 when a false transition is detected (false transitions are always
 preceded by a special code), only the combined state is updated.
 
 FIXSHIFT.COM hooks the keyboard interrupt to maintain the shift
 states. When FIXSHIFT.COM gets a keyboard interrupt, it first sets the
 ROM BIOS shift state (a documented memory location) to what the
 ROM BIOS expects (the combined real and fake shift states). FIXSHIFT
 then passes on the interrupt to the interrupt handler that was
 servicing the keyboard interrupt before FIXSHIFT revectored that
 interrupt. The ROM BIOS is unaware that FIXSHIFT.COM has done
 anything because its shift states are the same as if this program
 were not present. When the ROM BIOS's interrupt handler returns,
 FIXSHIFT sets the ROM BIOS's shift state to the real shift states, so
 when an application looks at this, it will reflect the true state of
 the SHIFT keys.
 
 If FIXSHIFT.COM is executed without any command line parameters, it
 tests the machine to see if FIXSHIFT is required. First it checks if a
 101-key keyboard is attached to the machine; if not, FIXSHIFT is not
 required. It then checks if the ROM BIOS problem is present by turning
 on NUM LOCK and asking the user to type a down arrow using the
 dedicated down arrow key (not the DOWN ARROW on the numeric keypad).
 If the shift states reflect that the left SHIFT key is down, then the
 ROM BIOS has the problem. Pressing the down arrow key while NUM LOCK
 is on generates a fake left shift down that the problem ROM BIOS will
 record in the shift states. Regardless of the outcome of this test,
 FIXSHIFT.COM will not install unless you invoke it with the /I command
 line option.