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1993-01-27
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NeXT-FAQ.memory: NeXT memory.
*** Subject: R1. What type of memory may be installed in a NeXT?
[See also NeXTanswers' hardware.620, and "Announcing
NeXTstation Turbo and NeXTcube Turbo" in
92_spring_bulletin]
Remember, RAM replacement voids the warranty on the
older products, but is "allowed" for the Turbo
and newer 25-MHz systems.
NeXT Computer (68030-25MHz/68040-25MHz), NeXTcube (68040-25MHz):
Cubes have 16 SIMM slots. SIMMs must be installed in
groups of 4 in these machines.
Use low-profile 30-pin 1 or 4 MB SIMMs with 100 ns minimum
access time. 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.]
NeXTdimension boards (i860):
These boards have 8 SIMM slots. SIMMs must be installed in
groups of four on the NeXTdimension board.
Use 72-pin 1, 4, or 8 MB SIMMs with 80 ns or faster access
time. The SIMMs are organized 256Kx32 or 1Mx32 for
non-parity systems, and 256Kx36 and 1Mx36 for parity.
NeXTstation (68040-25MHz) and NeXTstation Color
(68040-25MHz) (older styles):
NeXT manufacturing introduced the new 25 MHz
NeXTstation CPU board into production in late June. 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 sockets.
Older NeXTstations have 8 SIMM slots. SIMMs must be installed
in groups of 4 in these machines. Use 30-pin 1 or 4 MB SIMMs
with 100 ns minimum access time.
Older NeXTstation Colors have 8 SIMM slots. SIMMs must be
installed in groups of two. Use 72-pin 1 or 4 MB SIMMs with
80 ns or faster access time. The SIMMs are organized
256Kx32 or 1Mx32 for non-parity systems, and 256Kx36 and
1Mx36 for parity.
NeXTcube Turbo (68040-33MHz), NeXTstation Turbo
(68040-33MHz), NeXTstation Color Turbo
(68040-33MHz), newer NeXTstations (68040-25MHz), and
newer NeXTstation Color (68040-25MHz):
These systems have only 4 SIMM slots, but they can take
double-sided SIMMs. SIMMs must be installed in groups of
two in these machines.
Use 72-pin 4, 8, 16, or 32 MB SIMMs with 100 ns minimum
access time. For maximum performance use 70 ns SIMMs.
[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 transfers.
*** Subject: R2. 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: R3. Where can I purchase memory for a NeXT?
This list does not necessarily contain all vendors.
Suggestions for additional vendors welcome!
South Coast Electronics
Tustin, CA
(800) 289-8801
714-669-9503
Contact: Jim
[Prices current as of 11-Aug-92]
Standard SIMMs (NeXTcubes, NeXTstations)
1x8-80ns 1 Mb SIMM $ 38/43(PO Price)
4x8-80ns 4 Mb SIMM $131/151
72 Pin SIMMs (for Turbos, NeXTstation Color, NeXTdimension)
8 MB Kit (non parity) $293/338
16 MB Kit (non parity) $576/665
32 MB Kit (non parity) $1152/1329
8 MB Kit (parity) $329/380
16 MB Kit (parity) $647/747
32 MB Kit (parity) $1295/1494
MC/Visa same as cash, Purchase Orders more.
Impediment
(617) 837-8877
Contact: Alex
[Prices current as of 11-Aug-92]
Standard SIMMs (NeXTcubes, NeXTstations)
1x8-80ns 1 Mb SIMM $ *
4x8-80ns 4 Mb SIMM $ *
72 Pin SIMMs (for Turbos, NeXTstation Color, NeXTdimension)
1x32-80ns 4 Mb SIMM $ *
1x32-70ns 4 Mb SIMM $ *
2x32-80ns 8 Mb SIMM $ *
2x32-70ns 8 Mb SIMM $ *
* Refused to give pricing! Also has parity SIMMs.
Stratum Technologies
Austin, TX
800-533-1744
512-258-3570
Contact: Ted, Mike
[Prices current as of 21-Sep-92]
Standard SIMMs (NeXTcubes, NeXTstations)
1x8-80ns 1 Mb SIMM $ 27.50
4x8-80ns 4 Mb SIMM $ 98
72 Pin SIMMs (for Turbos, NeXTstation Color, NeXTdimension, newer NeXTstations)
1x32-80ns 4 Mb SIMM N/A
1x32-70ns 4 Mb SIMM $101
2x32-80ns 8 Mb SIMM N/A
2x32-70ns 8 Mb SIMM $218
"16 MB SIMMs to be announced within days."
Marco International
800-621-4668 (Within US/Canada)
303-449-9191
Contact: Lisa
[Prices current as of 21-Sep-92]
Standard SIMMs (NeXTcubes, NeXTstations)
1x8-80ns 1 Mb SIMM $ 26
4x8-80ns 4 Mb SIMM $ 99
72 Pin SIMMs (for Turbos, NeXTstation Color, NeXTdimension)
1x32-80ns 4 Mb SIMM $118
1x32-70ns 4 Mb SIMM $118
2x32-80ns 8 Mb SIMM $220
2x32-70ns 8 Mb SIMM $220
4x36-70ns 16 Mb SIMM $480
Parity also available.
Lifetime Warranty, 24hr RMA.
---
Editor:
Nathan Janette nathan@laplace.csb.yale.edu