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NeXT Hardware RAM FAQ

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Subject: NeXT-Hardware-RAM-FAQ
Date: 6 Mar 1995 08:39:18 GMT
Organization: Yale University, Department of Computer Science, New Haven, CT
Lines: 286
Approved: [email protected]
Expires: Fri, 7 Apr 1995 00:00:00 GMT
Message-ID: <[email protected]>
Reply-To: [email protected]
Summary: Frequently Asked Questions about NEXTSTEP and NeXT machines.
Originator: [email protected]

Archive-name: NeXT-Hardware-RAM-FAQ
Last-modified: Mon Mar  6 03:03:59 EST 1995
Version: 3.1

These FAQs are under significant construction,
and may well change form and content over the
next weeks.

These FAQs focus on various aspects of OpenStep,
NEXTSTEP, and NeXT machines.  

The FAQs are kept on-line at several ftp sites,

Many FAQs, including these, are available (www, ftp,
email) on the archive site in the
directory pub/usenet/news.answers.  The name under
which this FAQ is archived appears in the
Archive-nameline above.

Within each section each question will be preceded by
a "Subject:" field, allowing news readers to break up
the file into separate questions.  Each question has
its own unique number. Items that appear within
sections are not in any particular order, and get added
and removed over time.  Questions marked with a "+"
are new to this issue, and questions with changes since
the last issue are marked by a "!".

Submissions, corrections, comments, input, etc.,
should be directed to Nathan Janette
<[email protected]>. 

Some important NEXTSTEP & OpenStep Information WWW sites:

NeXT, Inc.


Stepwise NEXTSTEP/OpenStep Information Server


N1.		What type of memory may be installed in a NeXT?
N2.		What is the NeXT SIMM tool?
N3.		Where can I purchase memory for a NeXT?


Subject: N1. What type of memory may be installed in a NeXT?

References: NeXTanswers' hardware.620, 92_spring_bulletin
"Announcing NeXTstation Turbo and NeXTcube Turbo"  

NeXT Computer (68030-25MHz/68040-25MHz),
NeXTcube (68040-25MHz):

Number SIMM slots: 16
SIMM group size: 4
SIMM type: 30-pin low profile
SIMM access rating: 100 ns
SIMM capacity: 1, 4 MB (1x8/1x9, 4x8/4x9)
Maximum RAM: 64 MB

The low-profile vertically mounted 4 MB SIMMs are easier to install in
the NeXTcube than the horizontally mounted 4 MB SIMMs because of the
small height clearance above the SIMM slots.  It is possible to install
the horizontally  mounted 4 MB SIMMs, but you will be required to slide
the CPU board and the center tower in simultaneously. 

Parity (9-bit) SIMMs can be used in both 68030 and 68040 NeXT machines,
but should not be mixed with non-parity SIMMs. Only 68040 boards with
ROM levels of 2.2 (v63) and higher can use the parity memory to detect
parity errors.     

[One user adds the following unverified claims:]

It is OK to mix parity and non-parity memory, but the system will not
boot unattended. Cubes with early boot ROMs will not work with 4 Mb
parity ram, unless at least 3 banks are used.  The system gives an
exception error on power up. The fix is to get a new boot rom from Next.
You can pay $30, or you may be able to squawk and get one for free.  I
have found Next to be pretty responsive, once I find the right person.

[Jimmie Quan, NeXT Hardware Service, adds:]

The correct version is v66 which was the last or final rev for this series
of 040 boards. This version also fixed the problem in the second paragraph. 

NeXTdimension boards (i860):

Number SIMM slots: 8
SIMM group size: 4
SIMM type: 72-pin
SIMM access rating: 80 ns
SIMM capacity: 1, 4, 8 MB (256Kx32, 1Mx32, 2Mx32)
Maximum RAM: 64 MB (32 MB official NeXT)

NeXT didn't officially bless the use of 8 MB SIMMs, but they seem to
fit and work.

NeXTstations (68040-25MHz) serial numbers below ABB 002 6300:

Number SIMM slots: 8
SIMM group size: 4
SIMM type: 30-pin
SIMM access rating: 100 ns
SIMM capacity: 1, 4 MB (1x8/1x9, 4x8/4x9)
Maximum RAM: 32 MB

Faster SIMMS (70/80 ns) don't make the memory system work any
faster than the 100 ns units. 

NeXTstation Color (68040-25MHz):  

Number SIMM slots: 8
SIMM group size: 2
SIMM type: 72-pin
SIMM access rating: 80 ns
SIMM capacity: 1, 4 MB (256Kx32/256Kx36, 1Mx32/1Mx36)
Maximum RAM: 32 MB

NeXTcube Turbo (68040-33MHz),
NeXTstation Turbo (68040-33MHz),
NeXTstation Color Turbo (68040-33MHz),
NeXTstations (68040-25MHz) serial numbers above ABB 002 6300:

Number SIMM slots: 4
SIMM group size: 2
SIMM type: 72-pin
SIMM access rating: 70/100 ns
SIMM capacity: 1, 4 ,8, 16, 32 MB (256Kx32/256Kx36, 1Mx32/1Mx36)
Maximum RAM: 128 MB

For maximum performance use 70 ns SIMMs: SIMMs rated at 80 or 100 ns will
be detected upon powerup and the memory system clock slowed to 100 ns.  

NeXT manufacturing introduced the new 25 MHz NeXTstation CPU board
into  production in late June '92. To verify which SIMM type your machine
uses, check the system's memory configuration. You can do this by using
the ROM monitor�s print memory configuration command m. Start with
your machine powered down. Press the Power key to power on. As soon as the
message �Testing system...� disappears, press
command-command-tilde (~ on the numeric keyboard). Under these
circumstances, this will access the ROM monitor. In the ROM monitor,
type m and press return. Turbo-designed boards�including new 25 MHz
NeXTstations and all Turbo systems�will return messages reporting
the memory configuration contained in four sockets (sockets 0 -3); old
25 MHz boards will return messages for more than four sockets (usually
8).   You can tell a Turbo-designed board, and the accompanying 72 pin, 70
nanosecond SIMMs, by the fact it only reports information for only four

[John Graves, Hardware Engineering, NeXT Computer, Inc. adds]

The memory system has programmable memory timing such that the number
of processor clocks needed to access a given amount of data can be
tailored to the speed of the memory installed. 70 ns memory is just
enough faster than 80 ns memory to allow the cpu to access the data with
fewer clock cycles. This improves memory system performance.

"70 ns" memory is faster than "80 ns" memory in many parameters other
than just RAS access time. The faster CAS access time in particular
allows the memory system to respond quicker to burst (16 bytes) bus


Subject: N2. What is the NeXT SIMM tool?

The tool came with 68040 upgrade kits for NeXTcubes.

It really makes removing SIMMs easy.  It looks like a dental tool: about
six inches long with a 1/2" long head offset at 90 degrees.  To remove
SIMMs, you slip the head into the hole on one side of the SIMM, rest the
head on the SIMM socket next to the SIMM you are pulling, and pivot the
tool back, using the simple fulcrum to gently pry the SIMM up about 1/8"
from the socket on that side.  Repeat on the other side, and the SIMM can be
then removed by hand.     


Subject: N3. Where can I purchase memory for a NeXT?

This list contains only a few vendors; prices listed may change and are
provided as examples only.

There is significant day-to-day fluctuation in prices, especially
since the destruction of a factory in Japan in July that manufactured
resin used in chips.  Prices are currently very high. 

First Tech Stratum Technologies
Austin, TX
512-258-3689 (fax)

[Prices current as of 16-Nov-94]

30 Pin SIMMs
1x8-70ns     1 Mb SIMM		$  36
4x8-70ns     4 Mb SIMM		$ 127

1x9-70ns     1 Mb SIMM		$  39.50
4x9-70ns     4 Mb SIMM		$ 141

72 Pin SIMMs
1x32-70ns	 4 Mb SIMM	$ 148
2x32-70ns	 8 Mb SIMM	$ 294
4x32-70ns	16 Mb SIMM	$ 479 (non-composite)
4x32-70ns	16 Mb SIMM	$ 504 (composite)

1x36-70ns	 4 Mb SIMM	$ 166
2x36-70ns	 8 Mb SIMM	$ 334
4x36-70ns	16 Mb SIMM	$ 549 (non-composite)
4x36-70ns	16 Mb SIMM	$ 567 (composite)

Lifetime Warranty.

Marco International

800-621-4668 (Within US/Canada)
800 447 8448 (CT Office)

[Prices current as of 21-Jul-94]

30 Pin SIMMs
1x8-70ns	 1 Mb SIMM	$  38.50
4x8-70ns	 4 Mb SIMM	$ 129
1x9-70ns	 1 Mb SIMM	$  40.50
4x9-70ns	 4 Mb SIMM	$ 157

72 Pin SIMMs
1x32-70ns	 4 Mb SIMM	$ 148
1x36-70ns	 4 Mb SIMM	$ 171
2x32-70ns	 8 Mb SIMM	$ 295
2x36-70ns	 8 Mb SIMM	$ 345
4x32-70ns	16 Mb SIMM	$ 585 (non-composite)
4x36-70ns	16 Mb SIMM	$ 645 (composite)
8x32-70ns	32 Mb SIMM	$1250
8x36-70ns	32 Mb SIMM	$1410

Lifetime Warranty, toll-free support, 24hr RMA.
"NeXT certified".

Chip Merchant
9541 Ridgehaven Court
San Diego, CA 92123
(800) 426-6375

South Coast Electronics
Tustin, CA
(800) 289-8801


(617) 837-8877


Editor: [email protected]
Nathan Janette
Systems Manager, Axel T. Br�nger Lab

Internet:	[email protected]