Re: odd behaviour with harddisk - ata100 vs rpm
On Tue, 19 Nov 2002, Alvin Oga wrote:
> i expect that the disk running at 5400rpm that is rated at 100MB/sec
> will perform equally well as a a disk spinning at 7200rpm
> ( less platters ? )
Why would it have less platters? The 5400 could have 80 gig/platter
platters like the new MaxLine's from Maxtor, and beat a 7200 that has 40
gig per platter platters. Or it could go the other way. Either way, both
would have ultra/133 interfaces. Take a look at the MaxLine II and
MaxLine Plus II's at Maxtor, for example. Both are Ultra/133 drives. But
there's a definate speed difference between them.
Ultra/100 is only interface speed!
The drive has to retrieve the data from the platters!
I have a speedometer in my car that goes to 160mph. My previous car, a
Neon, had a speedometer that went to 160mph as well.
The neon won't hit 160mph, my current car will.
Just because the interface (spedometer) is rated at something, doesn't
mean the media(engine) can give you that datarate(speed)!
I could have a drive that spins at 1rpm, with a density of 50 bytes per
square foot. If it takes a millisecond to transfer that up to the
interface, and then the interface shoots it off to the PC at 100 meg per
second, does that make it a 100 meg per second drive? Reading the cache
is useless on a long term realistic situation.
See where Ultra66/Ultra100/Ultra133/Ultra320 become useless marketing
fluff?
You need to look at the raw media numbers. On a Cheetah 15k.3 that's
somewhere from 75 to 50 meg per second, depending on the zone you are in.
On an IDE WD200JB, that's somewhere around 60 to 40, again, depending on
zone.
We're vastly off topic :D
Mike
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