Re: U5 RAM?

[Jochen Kunz <jkunz%unixag-kl.fh-kl.de@localhost>]

On Wed, 15 Jul 2009 19:57:56 +0200
doomwarrior <doomwarriorx%gmail.com@localhost> wrote:

> > 3.3V, I think. 
> yes 3.3V EDO buffered with ECC (sometimes called registered,
> but I think EDO it is always ECC)
You are mixing three things up that don't depend on each other.

EDO is the bus interface / protocol of the RAM chips and how they are
accessed.

Registered or buffered means there is an address buffer latch on the
DIMM. This increases lattency a bit, but reduces load on the address
drivers of the RAM controler / chipset so you can add more RAM slots.

ECC means there are more bits available then neded to store the data.
Usually DIMMs have 64 bits bus with per DIMM. If the DIMM has "ECC"
there is a total of 72 bits. The 8 excess bits are used to store the
Error Correction Code bits. This allows the chipset to detect
accidently fliped bits.

http://sunstuff.org/hardware/
Then click on "memory". There is a machine <=> RAM-type cross reference.

> You can also use memory from peecee systems,
I have done this, modulo the 10 / 11 bit CAS problem. If you are bitten
by the problem the machine will not detect any memory at all or it will
detect only half of the RAM. At least to my experience.

> So the best option is to buy Sun stuff here.
> But it isn't that expensive, because alot of US-2i systems and 
> highend-Enterprise-US1/2 machines uses this kind
> of configuration.
The problem is to get high capacity modules > 32 MB. With 32 MB DIMMs
you get a max. of 128 MB. Thats OK for a small headless server or
playground, but not enough to use it as a graphical desktop machine.
-- 


tschüß,
       Jochen

Homepage: http://www.unixag-kl.fh-kl.de/~jkunz/