On Tuesday 26 February 2002 10:40, you wrote:
> And when I throw this switch a light will come on,,, and they all laughed!!
>
> I apreciate your humor, but I want reasons it would not work in some
> fashion,,, come on now think outisde the box!! read my later post.
>
> Michael C. Rock
>
At the risk of ruining a perfectly good thread hijacking, If you mark it as
read-only, how are you going to get anything on it to read?
Okay ... that one was too simple and you've probably got an answer already.
So let me walk through a data cycle with you.
You read a data file from the HD to the ram disk (RD) and then mark the RD as
read-only. Cool. you're covered so far. You are "in the hole" for a
pre-emptive and possibly speculative read, plus the time to mark the RD as
read-only. Probably only happen once so not a big deal.
Later, you access that data, modify it and save it to the HD. Still good
beans. You got the data read at near wire speed and that is usually a sign of
happy camping. You haven't gained a thing, speedwise but you should on the
next iteration, right?
Later on, you access it again, make a different change and save that to the
HD. Cool ... things are startin to rock ... yeah ... just one disk access per
read / write cycle. Groovin'
But what, do tell, happened to the first change you made to the data on the
HD the first time? You remember, we read from the RD, wrote to the HD.
Re-read from the RD and OVERWROTE to the HD. Hmmmm. Back to the drawing board.
IF you are determined to use a RD, I'd like to suggest you only use it for
executable programs ... that you leave the data on the HD 100%? There is
generally no need to write to an executable program. If you lose power
unexpectedly, no data is at risk and the operating state of the program can
be recaptured at reboot.
But, as others have pointed out, Linux does such a good job of swapping
programs around in ram that, if you have a reasonable amount of ram, you may
never go to the HD except for data reads / writes ever again.
I ran a ram disk on my XT with MS-DOS 3.2 and Seagate 251-1 MFM 40meg HD and
aftermarket 2 meg ram board. It made sense there. It doesn't make nearly as
much sense with Linux.
-----
We now return you to the regularly scheduled thread hijacking already in
progress. :-)
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