244 lines
9.9 KiB
Groff
244 lines
9.9 KiB
Groff
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AMI 286 and 386 BIOS
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new release
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Release notes
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BIOS Release Date : 9-25-1988
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The new release of AMI 286 and 386 BIOS will have the following
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additional features and corrections over the AMI 286 and 386 BIOS released
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on 4-20-1988.
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new features
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Faster Video I/O...
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The Video input and output routines of interrupt 10 Hex are modified to
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make the video input and output faster by almost 25% over the previous
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release.
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Manufacturing Diagnostics option...
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Before going to boot the operating system, AMI BIOS goes through a
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process called the POST(power on self test). In the POST the BIOS
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performs diagnostic tests on the various hardware components in the
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system. This release of AMI BIOS has a special feature by which you can
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make the system go into an indefinite POST loop till it comes accross any
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FATAL errors with the system or you switch the power off. To get into
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this mode you will have to ground the keyboard controller pin 32 on your
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system board.
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Note:This feature requires customization in BIOS and the charges will be as
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per the licensing agreement.
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Easy Extended SETUP option for NEAT 286 and C&T 386 BIOS...
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With the Extended SETUP menu in 286 NEAT and C&T 386 BIOS, we have
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now added another option called the EASY SETUP. By using this setup
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option you can set up only a few necessasy parameters like DRAM wait
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states,clock sources and BIOS/Video shadow options which does not require
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much knowledge of the NEAT and C&T 386 chipsets.
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changes to accomodate Hardware Incompatibilities
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Additional Interrupt handlers for 386 Motherboards...
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In 386 BIOS we have added two dummy interrupt service routines for
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interrupt 0F Hex and 77 Hex doing only interrupt returns. This was
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necessary because at high speed some 386 motherboards generates these
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stray interrupt with no necessary reasons.
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Delayed CMOS status checking to get rid of CMOS CHECKSUM ERROR
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Message...
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In some motherboards at cold boot it takes more time for the CMOS to get
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power from the power source than it actually should. As a result the AMI
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BIOS gives CMOS CHECKSUM ERROR sometimes. To get rid of this problem
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we have introduced a little more delay in the BIOS between power on and
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checking the CMOS Status.
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Translating 80286 Loadall function call to work on 80386 to take care of
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problems related to using OS/2,RAMDRIVE and other Software programs...
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Some software programs like OS/2 and RAMDRIVE use 80286 loadall
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function calls. There is an incompatibility between the 80286 and 80386
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loadall function calls. As a result, these programs generate traps when used
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in 80386 based motherboards. These traps sometimes makes the system
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malfunction.
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In the new release of AMI BIOS we have taken care of this problem by
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internally translating the 80286 Loadall function to 80386 format in the
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BIOS exception handler routines. However the translation process requires
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at least 100 bytes of RAM space. To make this 100 bytes of RAM space
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available to BIOS we have given the user two options:-
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- BIOS to use the BIOS stack area between address 0:300h to
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0:400h. This might cause problem if any software tries to utilize this area
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for any other purpose.
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- BIOS to take out 1kb of memory from the top of the memory before
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the operating system gets control. Which means, in a system with 640kb of
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memory 639kb will be available to the operating system and user program.
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These options will be available only with the AMI 386 BIOS because such
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an approach is not necessary in 80286 based systems. The option can be
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selected through the CMOS SETUP program which will now ask one more
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question:-
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OS/2, RAMDRIVE, etc support (1/2)?
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Selecting option 1 will use the BIOS stack area at 0:300h and option 2 will
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reduce the available memory size by 1kb.
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Note: The RAM areas discussed above will only be used by the BIOS only if
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it is necessary i.e only if a software program like RAMDRIVE and OS/2 is
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used which requires a translation of the Loadall function call. So if you are
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not going to use these software programs you can always select option 1
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and still use the area between 0:300h to 0:400h for some other purpose. It
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is better not to select option 2 if you are not going to use any software
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program that is not going to use the Loadall instruction because there is no
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point is loosing the 1kb space at the top of the memory.
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Problem related to Some EGA cards and AMI BIOS CMOS SETUP Program...
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Because of a bug in the print string routine of the BIOS in a leading
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EGA/VGA card manufacturer we had to get rid of the bip in the AMI BIOS
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CMOS SETUP program when in displays the WARNING message just before
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you go into setting the hard disk drive types.
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System speed problem while using some protected mode software programs...
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On some mother boards using Keyboard controller pins 23 or 24 for clock
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switching it was observed that it is not possible to keep the system at a
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desired speed while using software programs like OS/2,VDISK,Novell
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network etc. This problem was occuring because in the IBM BIOS
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Specification the status on pin 23 and 24 of the keyboard controller is
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always made 1 when a software tries to go to protected mode using BIOS
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INT 15h function. So if you desire to keep the status of these pins 0 to
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attain a certain system speed it is not possible to do so if you are using
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one of the above software programs.
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With the new AMI BIOS, we have used a technique to keep these two pin
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status unchanged. However this method will work only if the software
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program goes into the protected mode using BIOS INT 15h routines. If the
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software program directly writes onto the keyboard controller ports, which
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programs like RAMDRIVE do, then this problem will exist.
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general Corrections
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Increased Compatibility with 80386 Exception handlers 6 and 7
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We have separated 80386 exception handlers 6 (invalid 80386 instruction)
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and 7 (invalid co-processor instruction) in this release. We have also made
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sure that proper action is taken for all such invalid instruction.
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CMOS SETUP program loosing time is taken care of...
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When you press <DEL> key to run SETUP program BIOS asks you the
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following question:-
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Want to Run SETUP Program(Y/N)?
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If there is a delay in answering this question, then the CMOS use to loose
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time if you go with the default value of the time displayed. This problem is
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taken care of in this release of the BIOS.
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Virtual to Real mode change method in 386 BIOS is changed...
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In previous release of AMI 386 BIOS changing between virtual and real
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mode was done through a facility called Shutdown. But the process use to
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clear the upper 16bit of the 32bit registers. In the new release we use
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80386 instruction for comming back to real mode from virtual mode which
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keeps the upper 16bit of all the registers intact.
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The technique of checking the optional Video ROM at C000:0 is changed...
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We have found out that lot of video cards have some initialization codes at
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C000:0 which does not have the video BIOS interrupt routines. In such
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cases the method used in CMOS SETUP program to find out the display
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type will fail. This forced us to change the technique of detecting the
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presence of a video BIOS at C000:0.
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OS/2 Boot from 1.44MB floppy drives...
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In the previous release of AMI BIOS OS/2 does not boot from 1.44MB
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floppy drives. However it boots from all other types of Boot devices. This
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release will solve the booting problem from 1.44MB floppy drives.
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Problems related to color display in portable systems with LCD Display...
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Some portable systems are capable of supporting both monochrome and color
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modes. The display mode can be selected using the Mono/Color switch on
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the motherboard. If this switch is used to switch from mono to color mode
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there will be a CMOS Display configuration mismatch. In such cases the
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BIOS goes into 40X25 mode and displays a message "Display Configuration
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Mismatch". Some portable systems with color display are not capable of
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handling 40X25 color modes so the new release of AMI BIOS will enter into
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80X25 mode if there is a Display Configuration Mismatch.
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Video SHADOW problem using EGA/VGA Display cards...
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Some VGA Display cards use to malfunction with AMI BIOS when the
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SHADOW RAM feature on the motherboard is used. This problem is taken
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care of in the new release.
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Other Modifications
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Modified error messages...
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To make room for enhancements to the BIOS we have reduced the length of
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certain error messages. The error messages as it will appear now is listed
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in appendix A at the end of this section.
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Default wait states for NEAT 286 and C&T 386 chipset based
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motherboards...
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The default wait states will now be 1 for NEAT 286 and C&T 386 BIOS.
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This change is done to make sure that system does not malfunction when
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a slow memory is used on the motherboard. However if you use faster
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memory and want to set it to 0 waitstate you can use the Simple or
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Advanced Extended SETUP program built into the AMI BIOS.
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Clock switching technique for NEAT 286 BIOS...
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The keyboard clock switching for NEAT 286 BIOS is changed such that
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switching clock will not affect the Bus speed. This change was necessary
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because a lot of NEAT 286 boards malfunction when the Bus speed is
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changed in real time.
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Appendix A
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List of New Error Messages...
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Fatal errors causing system halt
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1. CH-2 timer error
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2. INTR #1 error
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3. INTR #2 error
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4. KB CONTROLLER ERROR
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5. CMOS INOPERATIONAL
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6. 8042 GATE-A20 ERROR
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Non fatal errors reported
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1. Keyboard error
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2. KB/Interface error
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3. CMOS battery state low
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4. CMOS system options not set
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5. CMOS checksum failure
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6. CMOS memory size mismatch
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7. CMOS time & date not set
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8. CMOS display type mismatch
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9. Display switch not proper
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10. Keyboard is locked ... Unlock it
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11. CACHE MEMORY BAD, DO NOT ENABLE CACHE !
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12. FDD controller failure
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13. HDD controller failure
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14. C: drive error
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15. D: drive error
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16. C: drive failure
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17. D: drive failure
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