Re: OctoRAM Memory upgrade

[David.Empson@bbs.actrix.gen.nz]

In article <1993Jan12.022552.27758@nuscc.nus.sg> ltchean@iss.nus.sg (Lim Thye Chean) writes:
> 
> Hi, any OctoRAM users out there?

Yep.  :-)

> I lost my OctoRAM manual, so I have to ask this in InterNet:
> 
> I am now using 2MB on my RAM card, all 8 rows filled with 256K simms. I plan
> to upgrade to at least 4MB.
> 
> 1. Can I upgrade to more than 4MB?

Yes.  You can use eight 1 megabyte SIMMs, but DMA compatibility might
be a problem.

> 2. Do I have to throw away all 8 rows of 256K simms and used all 1MB simms?

Yes.

> 3. Can I mixed both simms? For example, reserved 6 rows of 256K simms
>    (6 x 256K = 1.5MB), and used 2 rows of 1MB simms to get a total of
>    3.5MB? Or reserved 4 rows of 256K simms (4 x 256K = 1MB) and used 4
>    rows of 1MB simms to get 5MB?

No.  All SIMMs must be the same type.

> 4. Can I have the dip-switch configuration? 

In the following diagrams, L means 'jumper to the left' and R means
'jumper to the right', and the jumpers are listed top to bottom.

Using 256k SIMMs:

1 (256k)   L, L, L, L, L
2 (512k)   L, L, L, R, L
4 (1 MB)   L, L, L, R, R
8 (2 MB)   R, L, L, R, R     (This should be your current setting)

Using 1 MB SIMMs:

1 (1 MB)   L, R, R, L, L
2 (2 MB)   L, R, R, R, L
4 (4 MB)   L, R, R, R, R
8 (8 MB)   R, R, R, R, R

> 5. What precautions should I take? 

When buying the SIMMs, make sure you get ones that will work on a Mac
Plus, SE, or II.

IBM SIMMs (9 way) should also work, but I've heard of some people who
have had problems.


If you're installing less than 8, make sure you put them in the correct
slots.  The first SIMM goes in the top of the group of two slots, the
second below that, then fill the group of six slots from the top.

The only valid combinations are 1, 2, 4 or 8 SIMMs.
-- 
David Empson

Internet: David.Empson@bbs.actrix.gen.nz    EMPSON_D@kosmos.wcc.govt.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand