I'll simplify it. RAM is somewhat random access. It is better than Flash memory with Flash's multi-KB minimum erase size. But RAM has a huge delay for the 1st 8 byte random read/write. The next 4 to 8 (depending on RAM design), 8 byte blocks, are free. If after the 1st 8 byte block, you request another block, before you get 1st block of 2nd random request, the time to have delivered blocks 2-4 of the 1st random read will have gone by with the RAM bus being idle. You might as well have listened for blocks 2 thru 4 and put them in CPU cache speculatively, otherwise you just wasted RAM bus time.
Core 2 CPUs have a cacheline of 64 bytes. That design hints that the CPU will read sequentially all the data that it can (16/32/64 bytes) so the RAM bus doesn't go idle. It also means to read 1 random byte from RAM is to read atleast 16 bytes from ram. You might as well use bytes 2 to 16 for something as a C programmer.
-
Are you posting in the right place? Check out Where do I post X? to know for sure.
-
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big>
<blockquote> <br /> <dd>
<dl> <dt> <em> <font>
<h1> <h2> <h3> <h4>
<h5> <h6> <hr /> <i>
<li> <nbsp> <ol> <p>
<small> <strike> <strong>
<sub> <sup> <table>
<td> <th> <tr> <tt>
<u> <ul>
-
Snippets of code should be wrapped in
<code> tags not
<pre> tags. In fact, <pre>
tags should generally be avoided. If they must
be used, extreme care should be
taken to ensure that their contents do not
have long lines (<70 chars), in order to prevent
horizontal scrolling (and possible janitor
intervention).
-
Want more info? How to link
or How to display code and escape characters
are good places to start.
|