Contemporary computers often have more than 100MB of physical memory.
Suppose the page size is 2KB. How many entries would an associative
memory need in order to implement a page table for the memory?
This is what I think the answer is:
· 100MB / 2KB = 51,200 page frames = number of entries. |
Request for Question Clarification by
denco-ga
on
21 Oct 2005 16:46 PDT
Howdy siball-ga,
Here is the answer from a Google cached Virginia Tech page.
http://64.233.161.104/search?q=cache:courses.cs.vt.edu/~cs3204/fall2003/ali/homework/homework3sol.html
"If the memory has 100M addresses, and each page is 2K, then there are
100M / 2K = 50K page frames in the memory. Each page frame requires one
entry, so the associative memory must have 50K entries."
If that would do as an answer for you, please tell me and I will post it
as such, along with my search strategy. Thanks!
Looking Forward, denco-ga - Google Answers Researcher
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Clarification of Question by
siball-ga
on
21 Oct 2005 17:31 PDT
Hi denco,
I already found that page through a search. The answer doesn't make
sense to me, although I am not saying that it is wrong.
100MB / 2KB is 51,200 NOT 50,000
Because:
100 MB * 1024 = 102,400KB
102,400KB / 2 = 51,200KB
If my answer is incorrect I would like to know why.
Thanks.
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Request for Question Clarification by
denco-ga
on
21 Oct 2005 19:23 PDT
Howdy siball-ga,
I believe the logic is:
100MB = 100,000KB
100,000KB / 2 = 50,000KB
http://whatis.techtarget.com/definition/0,,sid9_gci212542,00.html
"According to the IBM Dictionary of Computing, when used to describe disk
storage capacity and transmission rates, a megabyte is 1,000,000 bytes in
decimal notation."
Any reference to a computer having "100MB of physical memory" must be "old
school" when it comes to the definition of MB.
Looking Forward, denco-ga - Google Answers Researcher
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Clarification of Question by
siball-ga
on
21 Oct 2005 20:47 PDT
From Wikipedia.org:
1,000,000 bytes (10002, 106): This is the definition recommended by
IEC. It is used primarily in networking contexts and most storage
media, particularly hard drives and DVDs. This definition of 'mega-'
as a "binary prefix is consistent with the other SI prefixes, and with
many other uses of the prefix in computing, such as CPU clock speeds
or measures of performance.
1,048,576 bytes (1,0242, 220): This definition is used for nearly all
discussions of computer memory (as computer addresses are naturally
powers of two, and memory is most easily manufactured in power-of-two
capacities) and file storage. As of 2005, most software uses this
definition to express storage capacity (e.g. file size).
My question is regarding memory. I am not convinced my answer is wrong.
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Clarification of Question by
siball-ga
on
21 Oct 2005 20:49 PDT
And just noticed this on the Web site you listed:
As a measure of computer processor storage and real and virtual
memory, a megabyte (abbreviated MB) is 2 to the 20th power bytes, or
1,048,576 bytes in decimal notation.
My question is on virtual memory so now I am convinced my answer is correct.
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