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- Newsgroups: comp.sys.next.hardware
- Path: sparky!uunet!tcsi.com!iat.holonet.net!bwilliam
- From: bwilliam@iat.holonet.net (Bill Williams)
- Subject: Re: Acorn 610 as processor/coprocessor?
- Message-ID: <BxE6uH.IEt@iat.holonet.net>
- Organization: HoloNet (BBS: 510-704-1058)
- References: <1992Nov6.222037.2710@kakwa.ucs.ualberta.ca>
- Date: Sun, 8 Nov 1992 10:08:40 GMT
- Lines: 39
-
- misconceptions regarding number of IC gates (transistors) on large scale
- CPU chips....
-
- A MC68000 was labled such a name because it had a whopping 68,000 or so
- transistors. Since that era, CPUs have been supplied with larger and
- larger DAta and Code caches, memory management, floating point processors
- (with trancendental table aids),barrel shifters, etc. etc. But the LARGEST
- PERCENTAGE of the transitors on a one million transistor CPU chip are used
- to support 4K data cache and 4K code cache. These caches are sometimes
- larger and such but from what I was told long ago 7 gates are needed
- minimum for retaining a single bit of memory storage and 4K + 4K = 8K; 8K
- is 8192 bytes (65536 bits of cache storage). This cache storage if using
- the minimalistic 7 gates per bit is over HALF A MILLION GATES!!!!!!
-
- You see then there is absolutely nothing special about a 32000 gate CPU or
- a 68,000 gate CPU that is not precisely on par with complexity of the
- million gate chips of todays era. The reason is because the majority of
- the gates ar just simple minded arrays of memory storage (usually machine
- designed and layed out) No football field sized blueprints, No million man
- hours of research and development. Nothing.
-
-
- This foolish and reoccuring fallacy regarding the complexity of a CPU
- based on its gate count annoys the shit out of me. I read it in MacWeek,
- Byte, Dr. Dobbs, etc at least 4 times of year, and have NEVER seen anyone
- stop and point out that a huge portion of the gates are merely used for
- cache storage.
-
- I have no real background in hardware (I am a software developer) but I
- can use a calculator easily enough as the next guy to burst the bubbles of
- these COMPLEXITY=NUMBER-OF-GATES fallacies.
-
- Once you see what can be done with just 68000 transistors, you will
- realize that the Acorn 610 is not totally deviant from the engineering
- realm of possibilities with its claim of merely 32000 transistors.
-
- Bill Williams
-
-
-