\pard\tx520\tx1060\tx1600\tx2120\tx2660\tx3200\tx3720\tx4260\tx4800\tx5320\f1\b0\i0\ul0\fs28\fc0 Q: What type of memory can my NeXT Computer use?\
Q: Can I install my own memory?\
Q: Should I purchase Parity Memory?\
\
A: All NeXTcube and NeXTstation products use industry standard SIMM style memory. New products support both non-parity SIMMs and parity SIMMs. Specifications are given below. Please note the following about adding RAM to your system before purchasing third party memory products: \
\
\pard\tx500\tx1060\tx1600\tx2120\tx2660\tx3200\tx3720\tx4260\tx4800\tx5320\b\fi-540\li540\fc0 1. NeXT does not support the addition of third party memory.\
2. We cannot answer if a given manufacturer's memory product will work in your system.\
3. Incorrect installation, incorrect parts or faulty parts can damage your CPU board.\
4. Many SIMMs will work, few will fit. Low profile SIMMs (i.e. no taller than .9 inches) are required in Cube based products.\
5. You cannot mix page and nibble mode memory within a bank.\
6. An 040 system with mixed parity and non-parity memory installed cannot boot automatically, you must boot from the monitor (all memory will be treated as non-parity).\
7. The information presented here is subject to change without notice.\
\pard\tx1260\tx1600\tx2120\tx2660\tx3200\tx3720\tx4260\tx4800\tx5320\fi-1260\li1260\fc0 1Mx8 One by eight SIMM, Literally One Megabit Chips arranged to form an 8 bit word (byte). This is one Megabyte (
\pard\tx1140\tx2300\tx3440\tx4600\tx5760\tx6900\tx8060\tx9200\tx10360\tx11520\fc0 one million
\pard\tx1260\tx1600\tx2120\tx2660\tx3200\tx3720\tx4260\tx4800\tx5320\fi-1260\li1260\fc0 base-two 8 bit addresses, or 8MBits).\
4Mx8 Four by eight SIMM, same as above but using Four Megabit Chips. This is four Megabytes (four million base-two 8 bit addresses, or 32 MBits).\
1Mx9 Same as 1Mx8 above, but with an additional bit per byte for parity. This is one Megabyte (one million base-two 8 bit addresses, or 8MBits) + Parity (one million base-two parity bits, one for each 8 bit address).\
4Mx9 Same as 4Mx8 above, but with an additional bit per byte for parity. This is four Megabytes (four million base-two 8 bit address, or 32 MBits) + Parity (four million base-two parity bits, one for each 8 bit address).\
256Kx32 256 by thirty-two SIMM, Literally One Megabit Chips arranged to form a 32 bit word. This is one Megabyte (256 thousand base-two 32 bit addresses).\
1Mx32 One by thirty-two SIMM, Literally Four Megabit Chips arranged to form a 32 bit word. This is four Megabytes (one
\pard\tx1140\tx2300\tx3440\tx4600\tx5760\tx6900\tx8060\tx9200\tx10360\tx11520\fc0 million base-two
\pard\tx1260\tx1600\tx2120\tx2660\tx3200\tx3720\tx4260\tx4800\tx5320\fi-1260\li1260\fc0 32 bit addresses).\
256Kx36 Same as the 256Kx32 above, but with 4 additional bits per 32 bit word for parity.\
1Mx36 Same as the 1Mx32 above, but with 4 additional bits per 32 bit word for parity.\
bank 4 contiguous SIMM slots in a NeXTstation or NeXTcube; 2 contiguous SIMM slots in a NeXTstation color or NeXTdimension board.\
M Mega, one-
\pard\tx1140\tx2300\tx3440\tx4600\tx5760\tx6900\tx8060\tx9200\tx10360\tx11520\fc0 million base-two
\pard\tx720\tx1060\tx1600\tx2120\tx2660\tx3200\tx3720\tx4260\tx4800\tx5320\fc0 The new 040 and based products (NeXTStation, NeXTcube 040) and NeXTdimension can use Parity memory. Parity memory provides an additional bit of information for each 8 bit byte of useable memory. This additional bit is used as a check value, to see if there is a problem with the first 8 bits in the word.\
\
\i Caveats:
\f2\i0\fs24 \
\pard\tx180\tx360\tx2120\tx2660\tx3200\tx3720\tx4260\tx4800\tx5320\f1\fs28\fi-720\li720\fc0 • This is an error detection scheme, not an error correction scheme. Your system may still crash, but chances are it will be easier to pinpoint the problem if it is a memory fault.\
• There is a speed penalty for accessing parity memory, since for each access a parity check sum must be computed. This translates into slower overall performance.\
• Parity memory is implemented by an additional memory chip on the SIMM. This is an additional hardware cost.\
• Parity is supported if only and if ALL SIMMs installed are parity SIMMs (
• Parity checking is currently not implemented on the NeXTdimension color product, although this product will function normally using parity style SIMMs.\
• 040 Systems with mixed parity and non-parity memory WILL NOT BOOT AUTOMATICALLY. You will see a "System Test Failed" message (you can boot in verbose mode from the monitor by typing "b" at the NeXT> prompt).\
\
\b\fs36 Memory information for Cube based products
The following chart illustrates possible valid memory configurations for NeXTcube based products: NeXTcube, NeXTserver and the NeXT Computer (030 based system).\
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\f2\b\fs24 Chart #1: Memory Configurations, cube based products\
\pard\tx520\tx1060\tx1600\tx2120\tx2660\tx3200\tx3720\tx4260\tx4800\tx5320\fc0 Horizontal axis--number of 4MB SIMMs\
Vertical axis--number of 1MB SIMMs\
x = a configuration below the minimum required memory size\
\
0 4 8 12 16\
0 x 16MB 32MB 48MB 64MB\
4 x 20MB 36MB 52MB\
8 8MB 24MB 40MB\
12 12MB 28MB\
16 16MB\
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\pard\tx1140\tx2300\tx3440\tx4600\tx5760\tx6900\tx8060\tx9200\tx10360\tx11520\f1\fs28\fc0 Parity memory specifications for NeXTcube, NeXTcube Server:\
1Mx9 100ns Low Profile SIMMs\
4Mx9 100ns Low Profile SIMMs\
\b0 \
The NeXTcube has 16 SIMM slots that can accommodate up to 64MB (Megabytes) of memory using Sixteen 4Mx9 SIMMs. The minimum configuration is 8MB using 8 1Mx9 SIMMs. See chart #1 for possible combinations.\
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\pard\tx520\tx1060\tx1600\tx2120\tx2660\tx3200\tx3720\tx4260\tx4800\tx5320\b\fc0 Non-parity memory specifications for NeXTcube, NeXTcube Server, NeXT Computer (030 based system):\
\pard\tx520\tx1060\tx1600\tx2120\tx2660\tx3200\tx3720\tx4260\tx4800\tx5320\fc0 SIMMs. The specs are the same as those listed above for parity memory for the NeXTcube, however,
\b low profile parts are not required
\b0 .\
\
\b Non-parity memory specifications for NeXTstation:\
\pard\tx520\tx1060\tx1600\tx2120\tx2660\tx3200\tx3720\tx4260\tx4800\tx5320\fc0 SIMMs. The specs are the same as those listed above for parity memory for the NeXTcube, however,
\pard\tx520\tx1060\tx1600\tx2120\tx2660\tx3200\tx3720\tx4260\tx4800\tx5320\fc0 SIMMs. You can add parity memory to the NeXTdimension color in groups of 2 SIMMs of the same style. Please see chart #4 for possible configurations.
\i Note: The NeXTdimension color card can use parity style SIMMs, however at this time it does not actually implement parity checking.
\pard\tx520\tx1060\tx1600\tx2120\tx2660\tx3200\tx3720\tx4260\tx4800\tx5320\fc0 SIMMs. You can add non-parity memory to the NeXTdimension color in groups of 2 SIMMs of the same style. Please see chart #4 for possible configurations.\
