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1. What is the difference between a programme executing on a harddrive
and one executing on a ROM. Why is only the latter considered to be
embedded?

2.How is coded stored in ROM. Is it via magnetisation to give binary 0
and 1.
Floppies and hardrives use magnetization. CD's use light. What do ROMs
use.
What is the material that supports the code made of?

thanks

s

Re: Newbie questions
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None.

  Why is only the latter considered to be
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They both can be.

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No, it depends on the technology but in general it is stored as charge.

Ian


Re: Newbie questions

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I think the access time for the next memory location might just be a
relevent factor (to OP, you need to find out about caching[1] techniques,
sorry don't have time now to find a relevant reference)

[1]or is it cacheing?

tim


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Re: Newbie questions
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Except the code 'executing' on a hard drive will need to be loaded into
RAM before it can actually be executed.  Once there, there is no real
difference with code execution in ROM

Ian


Re: Newbie questions
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Code commonly doesn't execure "on" a harddrive, it is loaded into RAM and
executed there. Code stored in ROM is often copied to RAM for execution too,
but it can be executed directly from ROM. When executing from ROM one would
normally build the software differently than for RAM execution - i.e. you
need to ensure it's built for the right location in memory [if the code is
position dependent], and ensure the code is statically linked etc.

As to "Why is only the latter considered to be embedded?" - the answer is
mu.

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Depends on the ROM, but normally it's either a stored charge or masked into
the semiconductor at fabrication time. Magnetisation is not normally
involved.

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Electronic switches.


Silicon.

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