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Warn-then-exit if the motherboard BIOS (if identified) is known not to support BIOS expansion ROM's. (Usually, 1981 and 1982 dated motherboard BIOS'.) |
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Warn-then-exit if unable to find the XUB in memory space. |
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Warn-then-exit if XUB is found at multiple locations in memory space. |
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Warn-then-exit if XUB is found in segment 'A' or segment 'B'. |
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(Segments A and B are reserved for video RAM. Any BIOS expansion ROM code [e.g. XUB] placed there will not be found by the motherboard BIOS.) |
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Warn-then-exit if XUB is found in segment 'F'. |
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(Segment F is for motherboard BIOS ROM's. Note that on an IBM 5150, address space F0000-F3FFF is used by the motherboard - see here.) |
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Warn (but do not exit) if XUB is found in conventional memory. |
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(No exit is done because perhaps the XUB was placed there via 'optromloader' software.) |
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Warn-then-exit if the XUB is at an address that is not a multiple of 2 KB, e.g. D0400. |
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(The motherboard BIOS searches for BIOS expansion ROM code in increments of 2 KB.) |
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Warn (but do not exit) if the XUB is at an address that is not a multiple of 8 KB. |
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(That is unusual because the ROM address switches/jumpers on XT-IDE cards set an address that is a multiple of 8 KB, however, maybe the XUB is somewhere other than on the XT-IDE card.) |
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Warn-then-exit if the declared size (third byte of BIOS expansion ROM) is zero. |
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Warn-then-exit if the declared size (third byte of BIOS expansion ROM) is not a multiple of 2 KB. |
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Warn-then-exit if the declared size (third byte of BIOS expansion ROM) is less than 4 KB. |
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Warn-then-exit if the declared size (third byte of BIOS expansion ROM) is greater than 32 KB. |
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Warn-then-exit if the 8-bit checksum of the declared size is not 00. |
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Warn-then-exit if AT version of the XUB running on a PC or XT class computer. |
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Warn-then-exit if the string "XTIDE Universal" is in the header of a segment, but the first two bytes of the segment are not AAh and 55h. (Indicating a particular case of corrupted ROM contents.) |
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If IBM 5170 BIOS, and 01/10/84 motherboard BIOS found, warn of possible 01/10/84 BIOS incompatibility with XUB. (See note 1 at the bottom of here). |
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If IBM 5170 BIOS, and XUB found at E0000 (i.e. in sockets U17/U37 of IBM 5170 motherboard), warn-then-exit if the 8-bit checksum of segment 'E' is not 00. |