🚀 go-pugleaf

Path: tekfdi!mhorne
From: mhorne@tekfdi.TEK.COM (Mike Horne)
Newsgroups: mod.computers.68k
Subject: Re: Memory?
Message-ID: <799@tekfdi.TEK.COM>
Date: 26 Feb 87 02:33:53 GMT
Reply-To: mhorne@tekfdi.UUCP (Mike Horne)
Distribution: world
Organization: Tektronix, Inc., Beaverton, OR.
Lines: 86

Yup, another followup....

"In a recent article, mwm writes..."

>> Think about what you just said.  "Save 10%."  Now, what if we had just put
>> in 2 MB of DRAM and a swapper with an 16MB swap space.  Now, think about
>> how much that additional 14 MB of DRAM is going to cost if you have a 16 MB
>> system.  Try (using 1Mb DRAM chips) 20 bucks per chip times 8 chips times
>> 14 sets.  That's 2240 buckaroos, bud.  Oh, and don't forget the price of
>> the support chips.  I think I can find a pretty good MMU for that price,
>> plus maybe a 200 MB hard drive (OEMs can get a 200 MB hard drive for < $1500
>> quantity 100 or so) too.  Simple math.  Of course, the price of RAM will
>> drop.  But so will MMUs and HDs.
>
>Simple math, but I don't like the numbers you started with. I was
>offered 2Meg for $150 today. Multiply by eight, you and get that 16Meg
>costs all of $1K. Support system is about $500. For that, I can get
>maybe a 60 Meg HD + disk subsystem. But I'd rather have the memory.
>
Aaaahhhhh...  You're working with 256Kb DRAMs, though!  Yes, they are cheaper,
but it takes 4 times as many chips!  Lemmeesee...

8 chips = 256K
4 x 8 = 32 chips per MB.
32 x 16 = 512 chips per 16MB

Hmmm....  I guess I could pack 512 chips into my new computer design.  But
wait, what about board space?  What about power supply requirements?  Do you
know what 512 chips looks like, side by side?  Yes, you could get SMD (surface
mount device) parts, but no company in its right mind would tackle a design
like that.  Oh, and are you going to prototype one of these up using
wirewrap?  Good hairy luck!  The reality is that companies do *NOT* use old
technology if new technology can do it in 1/4th the board space (or 1/3,
or 1/2), even if it costs more.  For example, one can find 1K X 4 SRAM
chips for a dime a piece, but just because they are cheap doesn't mean
they are a good idea to use in a design (at least, not any more!).
Eventually the 1 MB DRAM chips will be cheap enough to meet the quoted prices
that you had above.  But it will be at least a year or two (following past
experience).  Of course, the 4 and 16 MB DRAM chips will be out then.  NEC
and other Japanese companies have already shown that they can produce the
4 MB DRAM chips, and they are already working on the 16 MB chips.


>Low-end home computers (those which have 68K's being the _topic_ of
>this newsgroup).

Note:  Anything having to do with the design of a computer system around
a 680X0 is relevent to this newsgroup (MMUs, DRAM, etc.).

>Yah, but I bet you don't see the "new" technology before 1988 ("new"
>== 68030 and whatever intel has in the pipe). Not in consumer-priced
>machines, anyway. By which time the next newest chip will also have
>neat features you want. Sorry, but I want a system now, not year after
>next.

Well, then you get a 68000 with 1MB of DRAM, no VM, a 700 dollar 20MB HD,
etc.  If this suits you, fine.  BUT, if you want more ram, VM, more power,
etc., it is being developed NOW.  You gotta wait.  I'm totally happy with
my 68010, 2MB DRAM, VM, etc. for now.  But you would never get me to go back
to something without an MMU.  Put it this way:  Once you have tasted the
soup, you don't want the dry toast.

>Sure, if you offered to give me a system with an MMU, I'd probably
>take it over one without.  But until the price drops to something
>reasonable (say, a system with an MMU for < $1K), I'll keep what I've
>got. With enough memory, it's a more pleasant environment than my Sun,
>and at 1/3rd the cost.

I agree.  Use what you have.  But realized that the next generation of
machines will have VM.  The next generation is just around the corner.

>there way back into Unix.  So which do you expect to be the better OS?

Well, I feel that UNIX is, right now.  But as people keep learning from
existing software and past experience, other OSs will eventually replace
UNIX.  I think we agree on the same thing here, just different time frames.

Mike

(P.S. Speaking of new chips, watch for Motorola's 78000:  25 MIPs)

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