I read some books saying that upper memory is between 640K and 1024K, but then it also seems like it is made using part of expanded memory? I'm not clear on these concepts, so please give your little brother here some guidance. Thanks in advance~~~~~~~~~
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中国DOS联盟论坛 » DOS学习入门 & 精彩文章 （教学室） » Question about upper memory, extended memory, and expanded memory concepts
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Posted 2003-09-19 00:00 · 中国 广东 江门 联通
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Posted 2003-09-20 00:00 · 中国 广东 广州 教育网
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Upper memory, that is, UMB, is indeed the memory between 640KB and 1024KB (that is, 1MB);
Extended memory, that is, XMS, is memory above 1MB, usually provided for DOS by HIMEM.SYS or a similar memory manager;
Expanded memory, that is, EMS, is divided into two types: one is physical expanded memory, and the other is virtual. The former is provided by a dedicated expanded memory board, while the latter is provided by EMM386 by virtualizing EMS using part of XMS.
Extended memory, that is, XMS, is memory above 1MB, usually provided for DOS by HIMEM.SYS or a similar memory manager;
Expanded memory, that is, EMS, is divided into two types: one is physical expanded memory, and the other is virtual. The former is provided by a dedicated expanded memory board, while the latter is provided by EMM386 by virtualizing EMS using part of XMS.
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