RE: disk arms (was RE: Tips for user ASP)

[vhamberg@xxxxxxxxx]

I'm rapidly getting out of my depth here. Is a write
cache a place to put things while waiting for a resource
to be available? Like a buffer on a serial connection,
kind of? That seems different from another use of cache,
where recently used items are placed so they don't need
to be retrieved from a slower resource?

Am I close?
> -----Original Message-----
> From: midrange-l-admin@midrange.com
> [mailto:midrange-l-admin@midrange.com]On Behalf Of vhamberg@attbi.com
>
> >Isn't cache about saving frequently-used data? Writing
> >to cache is going to add cycles to the process, in order
> >to get benefit in other places (which I don't know about
> >yet).
>
> Vernon,
>
> I think it is the opposite. Where reads are concerned, I would guess that
> the entire main store memory is a cache.  It is on the write side of the io
> operation that disk cache can provide its function, that is as a non
> volatile ( permanent ) place to store the dasd data. ( theoretically, the
> entire "disk" could be non volatile ( bubble ) memory ).
>
> Steve
>
>