[comp.sys.amiga.tech] Why put Kickstart on A3000 ROM?

leblanc@eecg.toronto.edu (Marcel LeBlanc) (09/02/90)

>In article <1990Aug29.203331.25529@agora.uucp>, billsey@agora.uucp (Bill Seymour) writes:
>> In article <1990Aug28.192905.13813@nmt.edu> dksnsr@nmt.edu (Dino Khoe) writes:
>> :My friend recently bought an A3000 and upon setting it up and doing an
>> :avail, it showed the maximum FAST ram to be 512K!  So we checked the chips
>> 
>> 	On the EPROM versions of the 3000 (read that, any 3000 before 2.0
>> has been installed as a ROM) the Kickstart is loaded into memory and
>> executed from there. That makes it easy for you to update differing versions

There's been lots of discussion (read: complaints) about the fact that
Kickstart uses up 512K of RAM on an A3000.  Why is this bad?  If you put
Kickstart on ROM, you have to pay for 512KBytes worth of ROM/EPROM.  I'd
much rather pay for an extra 512K of RAM!  The RAM costs less than the ROM,
and has much faster access times (especially the SC RAM).  Remember that all
A3000 are shipped with at least 50MB of HD space.  There's no need to insert
a Kickstart floppy - and 512K of hard disk space is much cheaper than both
RAM or ROM.  Besides, I expect that most A3000 owners will copy Kickstart to
RAM anyway (using setcpu, or whatever).

It's easy to understand why Kickstart is on ROM in A2000s and A500s, but I
don't understand why you would want to put it on ROM in an A3000 when it's
clearly not necessary.  Every time an OS upgrade comes out, I'll have to
change the ROM to get the new version.  The A3000 is nothing like the A1000 -
it takes very little time to load kickstart from the HD.

So, anybody know why it's been done this way?  It would be nice to know that
Commodore would continue to support HD loaded kickstarts for future OS's for
those who don't want an OS ROM.

Anxiously awaiting the arrival of my A3000-25/50,

Marcel A. LeBlanc  --  Electrical Engg Computer Group, Univ. of Toronto
-----------------------------------------------------------------------
leblanc@eecg.toronto.edu		else: uunet!utcsri!eecg!leblanc

amc@ai.wustl.edu (Adam M. Costello) (09/02/90)

In article <1990Sep1.133213.6765@jarvis.csri.toronto.edu> leblanc@eecg.toronto.edu (Marcel LeBlanc) writes:
>much rather pay for an extra 512K of RAM!  The RAM costs less than the ROM,
>and has much faster access times (especially the SC RAM).  Remember that all

RAM costs less than ROM?  I'm surprised.  How much less?  RAM is faster than
ROM?  I'm surprised.  How much faster?  It seems to me that ROM must be simpler
than RAM, so it should be easier and cheaper to make it faster.  Why isn't it?
AMC

leblanc@eecg.toronto.edu (Marcel LeBlanc) (09/04/90)

amc@ai.wustl.edu (Adam M. Costello) writes:

>In article <1990Sep1.133213.6765@jarvis.csri.toronto.edu> leblanc@eecg.toronto.edu (Marcel LeBlanc) writes:
>>much rather pay for an extra 512K of RAM!  The RAM costs less than the ROM,
>>and has much faster access times (especially the SC RAM).  Remember that all

>RAM costs less than ROM?  I'm surprised.  How much less?  RAM is faster than
>ROM?  I'm surprised.  How much faster?  It seems to me that ROM must be simpler
>than RAM, so it should be easier and cheaper to make it faster.  Why isn't it?

"Why" is a good question, but I don't have the answer (maybe somebody else
will post an answer).  The best guess that I can offer is that ROM must be
custom produced.  Each ROM must have a separate custom mask (probably
metalization), and is only produced in relatively small quantities, whereas
RAM is mass produced at commodity prices.  However, I do know that my
company can buy 1Mb EPROMs (more expensive than ROMs if you have high enough
volumes to recover the ROM NRE costs) for ~$10 each (1000 quantity) with
200ns access times.  1Mb DRAMs can be bought for ~$6-$7 with <100ns access
time (so <200ns cycle time).

This is probably why Commodore distibutes the "SetCPU" program to copy the
Kickstart ROM to SC RAM even on the A3000 (note the SC DRAM has a best cycle
time below 40ns).  If somebody has more info, please post.

>AMC

Marcel A. LeBlanc  --  Electrical Engg Computer Group, Univ. of Toronto
-----------------------------------------------------------------------
leblanc@eecg.toronto.edu		else: uunet!utcsri!eecg!leblanc

johnhlee@svax.cs.cornell.edu (Johnny H. Lee) (09/05/90)

In article <1990Sep1.133213.6765@jarvis.csri.toronto.edu> leblanc@eecg.toronto.edu (Marcel LeBlanc) writes:
[...]
>Kickstart uses up 512K of RAM on an A3000.  Why is this bad?  If you put
>Kickstart on ROM, you have to pay for 512KBytes worth of ROM/EPROM.  I'd
>much rather pay for an extra 512K of RAM!  The RAM costs less than the ROM,
>and has much faster access times (especially the SC RAM).  Remember that all
[...]

Just a little correction here...

ROM's have a high initial cost to make the initial masks, but the per-unit
costs are very low.  In the quantities that Commodore orders, ROM's are quite
a bit cheaper to use than RAMs.  Also, the ROMs are quite a bit faster than
RAMs.

-------------------------------------------------------------------------------
The DiskDoctor threatens the crew!  Next time on AmigaDos: The Next Generation.
	John Lee		Internet: johnhlee@cs.cornell.edu
The above opinions of those of the user, and not of this machine.

daveh@cbmvax.commodore.com (Dave Haynie) (09/05/90)

In article <1990Sep1.190150.5880@cec1.wustl.edu> amc@ai.wustl.edu (Adam M. Costello) writes:
>In article <1990Sep1.133213.6765@jarvis.csri.toronto.edu> leblanc@eecg.toronto.edu (Marcel LeBlanc) writes:
>>much rather pay for an extra 512K of RAM!  The RAM costs less than the ROM,
>>and has much faster access times (especially the SC RAM).  Remember that all

>RAM costs less than ROM?  I'm surprised.  How much less?  RAM is faster than
>ROM?  I'm surprised.  How much faster?  It seems to me that ROM must be simpler
>than RAM, so it should be easier and cheaper to make it faster.  Why isn't it?
>AMC

RAM does cost more than ROM, and it's a bit faster.  However, you're not going
to see the kind of speedups with FASTROM kinds of things on the A3000 as you
would on an A2500; that's 32 bit ROM, and it's a bit faster than the ROM of the
A2000.  You can get 512K (256K x 16) for a couple of dollars or so in large
quantities, while that much memory (four 256K x 4 DRAMs, for example) will
probably run you $25 or more, and RAM has come WAY down this last year (in '88
or so that might have run you $75-$100).

By the way, ROM isn't that much simpler than DRAM -- a DRAM stores a single
bit with a single transistor and capacitor, while ROMs and EPROMs typically 
use one bit, no capacitor.  You CAN get much faster ROMs, but not in these
densities.


-- 
Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests"
   {uunet|pyramid|rutgers}!cbmvax!daveh      PLINK: hazy     BIX: hazy
      Get that coffee outta my face, put a Margarita in its place!

akcs.clemon@wcbcs (Craig Lemon) (09/06/90)

Lines: 30

>>> 	On the EPROM versions of the 3000 (read that, any 3000 before 2.0
>>> has been installed as a ROM) the Kickstart is loaded into memory and
>>> executed from there. That makes it easy for you to update differing
>>versions
>It's easy to understand why Kickstart is on ROM in A2000s and A500s, but I
>don't understand why you would want to put it on ROM in an A3000 when it's
>clearly not necessary.  Every time an OS upgrade comes out, I'll have to
>change the ROM to get the new version.  The A3000 is nothing like the A1000 -
>it takes very little time to load kickstart from the HD.


   IMHO, I feel that there is another possibility.  Instead of ROMs in the
A3000, some sort of EEPROM could be used.  Make the Kickstart disk actually
be an autobooting disk with EEPROM installation code on it.  You could put a
protect switch on the rear of the case so that a weird, incredibly
destructive new type of virus doesn't come about.  To upgrade : switch to
WRITE, insert KS disk, turn on power.  Remove disk when instructed, reset
switch and reboot.  This would also possibly make things like UNIX easier to
live with.  Just have a different type of KS if needed.  Heck, someone with
a lot of brains, money and expansion could even have the first chip burned
to produce a menu for different systems (much like the 2620, 2630 and demo
A3000s).  Simply having it on disk would allow this to a certain extent BUT
WHAT HAPPENS WHEN THERE'S A HARDDRIVE CRASH???  How do you boot the machine
to run that pesky backup program.  I don't own a 3000 so I don't know
exactly how they work in the booting respect but I can see this as a problem.

NOTE the mail address is different than my current sending address!
--
 Craig Lemon - Kitchener, Ontario. Amiga B2000/10--2400 bps--AmigaUUCP 1.03D
 lemsys!clemon@xenitec.on.ca  or  ....!{uunet}!watmath!xenitec!lemsys!clemon