SUMMARY: Memory Limit?

From: Garrett, Thom (
Date: Fri Feb 02 1996 - 00:51:08 CST


After speaking with the vendor of our SPARC-10 (ie., FORCE Computers), I
was reminded of where I saw the memory limitation reference for SunOS
4.1.something mentioned in my post. It is included in Mark's reply, below.
I guess that I was not out in the sun as long as some of you may have

Obviously, for a standard Sparc, the # of memory banks is the limitating



>>>Mark Stull writes:

We are aware of one memory configuration which causes Solaris 1.1.2 (aka
SunOs 4.1.4) to panic. On a Sparcstation 5, the following configuration
should not be used with Solaris 1.1.2:

        membank0 8MB
        membank1 8MB
        membank2 32MB
        membank3 32MB
        membank4 not used
        membank5 not used
        membank6 32MB
        membank7 32MB

During the boot phase, SunOS builds page table entries(PTEs) in memory.
SunOs builds these pages just below the 8MB level in bank0. As you add
more memory, more PTEs need to be created. For the 144MB memory
configuration shown above, the PTEs which are still in use by Open Boot
Prom will get overwritten.

Sunsoft verified that SunOs could have problems over 128MB. Sunsoft
acknowledgesthis bug but there are no plans to fix it. Please note if
membank0 and 1 where configured with 32MB each and banks 2&3 were
configured for 8MB each, this problem does not exist. Also note that
Solaris 2.x does not have a problem with the configuration above. All
other memory configurations work as expected with either Solaris 1 or
Solaris 2.

We are currently shipping a 192MB CPU-10. Our CPU-5V is also capable of
memory configurations up to 192MB. Both boards operate under Solaris 1, 2,
and vxWorks.

>>>Ray Brownrigg <> writes:

I have been running a SPARC 10 with 160MB memory on SunOS 4.1.3_U1, and
it is all seen at boot time. Of course this does not guarantee that it
is actually being used!

>>>Glenn Satchell writes:

Never heard that rumour! The SS10 has 8 slots which can take 16 or 64
megabyte simms in any combination as long as the first slot (nearest
the rear of the chassis) has a 64MB simm in it if you mix the sizes.

Thus maximum memory limits are 128MB (8 * 16) or 512 (8 * 64) megabytes.

>>>Claus Assmann writes:

We have a SPARC 20/712 running SunOS 4.1.4 with 318MB RAM.
And we can use all of it...
And my SPARC 10/41 had 256MB RAM for some time (wo problems).

>>> Stephen Potter <> writes:

Strange sunspot activity caused "Garrett, Thom" <> to
| We may have a need to increase the memory on our Sparc-10. I know it
| can be increase to 128MB running SunOS 4.1.3_U1, but I *think* I once read
| that memory past 128MB can be installed by not be accessed (it can in
| 2.x however). [There are seveal system parameters based on *physmem*]

I don't know where you think you read that, but I've never seen it. I had
an SS10 with 512M of core at my last client. That's your limit, because
you've only got 8 slots and the largest memory module is 64M.

>>>Bert Shure writes:


you have eight simm slots. max memory is 8 x 64 = 512mb ram.

with solaris 1, you have to have swap equal to real ram in order for real
ram to be used. this is changed in solaris 2, where swap is used for
swap and you don't need to waste swap equal to real ram.

i was running a solaris1 system with 4mb real ram and 32mb swap. it took
me a while to figure out the problem.

>>>Martin Oksnevad <> writes:

A SS10 can take 8 memory SIMMs beeing 16mb and/or 64mb SIMMs.

You can combine 64mb and 16mb SIMMs and the maximum configuration
is 128mb with 16mb SIMMs only and 512mb with 64mb SIMMs only.

Maximum memory in a SS10 is 512mb for all SunOS and Solaris versions.

The first 64mb SIMM must be in SIMM position 1. If you have
a SS10-SX (frame buffer on motherboard as a SS20-SX) or are using
a Prestoserve NVRAM you will loose 1 or 2 out of 8 memory SIMM slots.

A SS10 can't use a 32mb SS20 memory SIMMs.

I will strongly advice you to buy SS20 type of memory (60ns) instead
of SS10 type of memory (80ns) for a SS10. SS20 memory can be used
in SS10, SS20 and the new Ultra machines but SS10 memory can only be
used in SS10 machines. With SS20 memory there is a lot higher chance
that you will be able to reuse the memory after a possible future
upgrade or replacement.

>>>Bismark Espinoza <!bismark@uunet.UUCP> writes:

In a sparc 10, you may have up to
256MB in the SIMMs area. You may also
install up to 3 S-bus boards with
memory(256 MB each).
A grand total of 1 GB.

>>>Michael Blandford <!mikey@uunet.UUCP> writes:

We have a 4.1.3_U1 machine with 288 megs of memory and it works
just fine.


Thanks to the following:

Mark Stull <>
Claus Assmann <!ca@uunet.UUCP>
Stephen Potter <>
Glenn Satchell <!Glenn.Satchell@uunet.UUCP>
Martin Oksnevad <>
Bismark Espinoza <!bismark@uunet.UUCP>
Michael Blandford <!mikey@uunet.UUCP>
Bert Shure <>
Ray Brownrigg <>
Martin Achilli <!martin@uunet.UUCP>

Original Post:

>System: SPARC-10
>OS: SunOS 4.1.3_U1
>Memory: 64MB
>We may have a need to increase the memory on our Sparc-10. I know it
>can be increase to 128MB running SunOS 4.1.3_U1, but I *think* I once read
>that memory past 128MB can be installed by not be accessed (it can in
>2.x however). [There are seveal system parameters based on *physmem*]
>Is this true?

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