🚀 go-pugleaf

In article <205@mipos3.UUCP> kds@mipos3.UUCP (Ken Shoemaker ~) writes:
>In article <280@husc6.HARVARD.EDU> hadeishi@husc4.UUCP (mitsuharu hadeishi) writes:
>>P.S. BTW, have you guys heard about the 78000 (!?)  See Nanobytes in
>>the latest BYTE (the //GS issue).  This is a RISC uprocessor with a
>>rated speed of 20 (VAX-equivalent?) MIPS . . . this kind of speed
>>totally blows away the RT PC (note: the RT PC performed just a hair
>>better than an PC AT in benchmarks . . . see PC World or PC magazine
>>of a month ago. . . not very impressive . . .)
>
>Oh, this is great.  Yet another paper product.  This one, they haven't
>even had a press release on!  I guess it must be more than a year 
>away (:-)).

Ken has a right to be skeptical on this one! It also illustrates the silly
ways in which 3rd and 4th-hand information propagate around.  I quote what
the Byte issue says: "Sources with Motorola's microprocessor group (Austin, TX)
confirm that two new central processing units will be released by that
company in the near future. (Stuff on 68030)...Due in the first quarter of
next year is the 20-MIPS 78000 CPU.  Sources said the 78000 is a RISC processor
that represents an evolutionary progression of the 68020."

What we have is: a) Somebody from Moto talking off-the-record to somebody
on the Byte staff. It is possible that not all Moto people would agree.
b) Byte prints this, so now it looks official-looking.  c) Somebody else
mentions it in the net, and now, a chip that (I'd guess) hasn't yet been
taped out "totally blows away the RT PC." Now it sounds like it exists right
now...  No wonder people get confused between claims and reality!

One has to wonder what even the 2 sentences in the article actually MEAN?
"Due in the first quarter.."  Does that mean:
	a) Appears in a machine you can login on?
	b) Appears in a board?
	c) Production quantities?
	d) Sample quantities?
	e) First silicon?
	f) Announcement of when any of a-e will happen?

"20-MIPS 78000 CPU"  Does that mean?
	a) Runs at 20Mhz, and can do peak 1 instruction per cycle?
	b) Is 20X a VAX 11/780 doing real work?
Note that the conversion from peak MIPS to VAX-equivalent MIPS (or any other
kind of real-live MIPS) can take on radically different factors: for example,
on 68020s, the division factor seems like 4 (i.e., 16.67Mhz designs gives
8 peak Mips (2 cycles/instr) ==> 2 VAX mips. Clippers have a factor of
about 6.6 (33 peak Mips ==> 5 Mips (according to published claims)).
Depending on what the 78000 really will be, it might be as low as a 5Mips
part (one would expect it to be higher).

"RISC processor that represents an evolutionary progression of the 68020."
What does this mean?
	a) Does it run 68020 object code?
	b) Does it run a subset of the 68020 instructions?
	c) Is it different object code, but "philosophically like the 68020"?

Sigh.  As one can see, if one reads the literature uncritically, things
that sound like information can be found to be rather content-free,
i.e., "real" information is found to be "virtual."

Note: none of this is meant as an attack on the 78000, but on the weird
process by which information leaks around and is jumbled up.  As far as I
know, the 78000 hasn't been announced by anyone for the record, and is mostly
discussed with Moto customers (existing or potential) who want to do high-end
systems and show signs of picking other vendors' micro-processors.
Perhaps someone from Motorola might care to comment on the original article:
one can choose to believe a vendor or not, but nobody should ascribe high
credibility to 3rd-hand off-the-record comments, or knock the vendor for
such "information".
-- 
-john mashey	DISCLAIMER: <generic disclaimer, I speak for me only, etc>
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