At 1:59 AM -0400 6/19/2010, Mark Sokolovsky wrote:
I've noticed something. The government keeps us out of all of their
little secrets. 64-bit is not ever close to being new. The standard
computer out there today in best buy is 64-bit, while back in the
1960's [...]
Really, there were two big issues back in the day:
1) The military required environmental (chemical and radiation) hardening.
2) The fast high density parts were extremely expensive. $20K per
processor (4 chip set) didn't make you flinch - although breaking one
of those chips sure did!
Today, everything is relatively hardened. And due to the economies
of the latest fabrication technologies, parts cost a bit less.
64-bit is not ever close to being new. The standard computer out
there today in best buy is 64-bit, while back in the 1960's the
world's first 64-bit computer was overly protected by the government
and was operated by scientists or NASA.
Bus width or processor width...
Bus width is about the efficiency of moving x bits simultaneously - a
form of parallelism.
Processor or register width is about the efficiency of doing certain
mathematical operations, to enable you to perform complex algorithms
quickly. Most math can be done comfortably in 64 or 128 or 256 bits.
There aren't too many algorithms that really require things much
wider.
64-bit was old news in the 70s. By the late 70s, we were building
4096-bit wide processors. But then some technology changes occurred,
that made it worthwhile going back to lower bit widths.
Consider please a critical optimization: It takes time to load a
really wide register. A looooong time. If the processor is fast
enough, you can do the wide math in smaller chunks *faster* than that
wait.
...An offshoot of this type of optimization: Store data in
compressed form on a HD so you don't have to read so much. It's
faster to read that compressed data and decode/expand it on the fly
in the CPU than it would be to simply read the uncompressed data in
the first place. That's what the classic Mac OS did with fonts.
That's a new feature added to HFS+ volumes, in Snow Leopard!
- Dan.
--
- Psychoceramic Emeritus; South Jersey, USA, Earth.
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