What is HMA?
| High Memory Area |
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When Intel designed the 80286 and 80386 microprocessors they where given a special mode of operation, called Real mode, to enable them to operate just like the earlier 8086/8088 processors. Those earlier processors could only contact or 'address' up to 1 Mb of memory (1,048,576 memory locations, each holding eight bits), while the later 80286 could address 16,777,216 locations (16Mb) and the 80386 a massive 4,294,967,296 (4Gb - more than any computer based on the chip can actually use). While the 286 and 386 processors are operating in Real mode, to look like a 8086/8088, they can address only the first lMb of memory (no matter how much may be fitted in the computer), plus - due to an oversight- an extra 64K. This extra memory is the HMA. |
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