"M.I.5¾" <no.one@no.where.NO_SPAM.co.uk> wrote in message
news:4827ecc3$1_1@glkas0286.greenlnk.net...
Just looked it up in a paper catalogue and the wording from NEC is rather
more vague. They guarantee the life of block 0 (the houskeeping block) for
100,000 erase write cycles. However, they specifically state that they make
no guarantee as to the life of any other blocks but that they have a typical
average life of 1000 erase/write cycles.

M.I.5¾ wrote:
OK. But that is what really counts, I expect, for most of us (using flash
drives). So perhaps an averaged lifetime figure of 10,000 - 100,000 cycles
is more "realistic" for typical consumer use. (What you explain below is
not what the typical consumer will see in normal use).

"M.I.5¾" <no.one@no.where.NO_SPAM.co.uk> wrote in message
news:4827ecc3$1_1@glkas0286.greenlnk.net...
Also found AMD paper spec. It stated that the memory was guaranteed for
100,000 cycles with no apparent qualification, except that an a note number
directed to the bottom added the qualifier 'only applicable to Block 0'. No
life data was offered for the non block 0 cells.

"Bill in Co." <not_really_here@earthlink.net> wrote in message
news:OIyM5SOsIHA.1236@TK2MSFTNGP02.phx.gbl...
Although no guarantees are offered for the non block 0 memory cells, many
manufacturers quote life based on actual usage patterns. Depending on how
memory is used, the blocks are usually written on a rotating basis, so that
although the actual life of an individual block is quite short, actual
combined lives of many thousands of hours are often quoted. These are
however, often based on an idealised useage which no one is actually likely
to achieve in practice. The calculations are also often based on the
principal that certain types of writes don't require an erase cycle first
and with a bit of cunning, it is possible to spread the writes throughout
the memory. In theory it would be quite possible to perform 4,194,304
individual writes to the memory but only use up a single erase/write cycle.
However, in practice nobody is ever likely to use a memory this way.

"Walter Wall" <me@privacy.net> wrote in message
news:48280ed8$1_1@glkas0286.greenlnk.net...
Although you didn't say, I assume that your example is for a 4GB memory
chip.

"Bill in Co." <not_really_here@earthlink.net> wrote in message
news:e7dfvhAtIHA.5268@TK2MSFTNGP06.phx.gbl...
I think that depends. If you tend to repeatedly write relatively small
files, the real world life is likely to be much longer than if you
repeatedly write larger files which will exercise more of the blocks at a
write, with an obvious lower life limit of writing the whole memory at one
go. Another factor will, of course, be the number of blocks any particular
chip contains, more blocks giving a longer life if small files are written.

"M.I.5¾" wrote in <news:4822a6a4$1_1@glkas0286.greenlnk.net>:

Doesn't take much cogitation to realize that memory is accessed
directly. There is no need to move heads past other sectors trying to
get at the data. The address goes directly to the data. Yeah, the
system memory in your computer is also fragmented since 4K pages of it
are allocated at a time and they may not be contiguous with each other
for use within one application but then they don't need to be
contiguous. Memory does NOT get fragmented because addressing and
access are *random*, not sequential.