Mail Archives: opendos/2000/12/02/05:40:16
X-Comment-To: Patrick Moran
No!
2-δΕΛ-2000 02:04 pmoran22 AT yahoo DOT com (Patrick Moran) wrote to
<opendos AT delorie DOT com>:
PM> I am checking up on XMS memory now, in the book "DOS beyond 640K" It does
PM> refer to XMS memory in it but was not listed in the index. It is extended
PM> memory and from what I have read so far, it is NOT swap memory, it is in
PM> fact extended memory.
XMS is _not_ an memory.
PM> But I need to poke around the book some more about it.
PM> I think some of the comments made about XMS is untrue. It should be much
PM> faster than EMS because there is no window to swap memory through I believe
You prosecute me as liar?!
PM> that Task Manager is using DPMS through the extended memory created by XMS.
1. When "real mode" app works with EMS it can create and handle it data
directly in EMS window without any _additional_ copying, as this is required
for XMS. 2. XMS _not_ create any memory.
PM> What I can't figure out is why do you even need a memory manager at all for
PM> extended memory.
Because "real mode" apps have "native" access only to 1M of memory.
PM> It already exist, all you have to do is use it. DOS,
This shows you don't know machine laguage of x86. "Real mode" apps have
access to 64k segments (because 16 bit offset) with 64K of "paragraphs"
(64K*16=1M). To access additional memory "real mode" apps _must_ use
additional hardware (expanded memory boards or copying/mapping extended
memory fatures, present in memory managers).
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