Mitsubishi Electric APRICOT FT4200, Owner'S Handbook Manual

Page: 89 / 124

T e c h n i c a l i n f o r m a t i o n
11/4
Memory
Server memory is located in two memory slot areas on the motherboard.
Fully loaded, these provide 2 Gbytes of common high-speed memory for the
server. Each group can hold 1,2, or 4 ECC Dual In-line Memory modules
(DIMMs.) All DIMMs in a bank must be the same. There are advantages in
fitting two or four DIMMs into any bank as two way and four way
interleave become available. Full details of the memory population rules can
be found with other relevant information in chapter 2.
Interleave scheme
Interleave BANK ONE BANK TWO
1 way Socket 2 Socket 1
2 way Socket 2+4 Socket 1+3
4 way Socket 2+4+6+8 Socket 1+3+5+7
Read perfomance
No. of
DIMMs in a
bank
Interleave Page miss
+Precharge
Page miss Page hit Page hit burst
data rate
four 4 : 1 14:1:1:1 11:1:1:1 8:1:1:1 194 Mb/s
two 2 : 1 14:2:2:2 11:2:2:2 8:2:2:2 152 Mb/s
one 1 : 1 14:4:4:4 11:4:4:4 8:4:4:4 107 Mb/s
The above is based upon 60ns DRAM and a system clock of 66 Mhz.
Write performance
No. of
DIMMs in a
bank
Interleave Page miss
+precharge
Page miss Page hit
four 4 : 1 10 7 7
two 2 : 1 11 8 8
one 1 : 1 16 13 13
The above is to memory of complete cache line.
Full details of the type of memory modules supported can be found in
section 1, chapter 2, which deals with memory upgrades and other related
topics.
The ECC function detects and corrects single-bit errors from DRAM
(Dynamic Random Access Memory) in real time, allowing your system to
function normally. It detects all double-bit errors but does not correct all of
them, it also detects all three-bit and four-bit adjacent errors in a DRAM
nibble but does not correct them. When one of these uncorrected errors
occurs, the ECC memory card generates an NMI (NonMaskable Interrupt)
and usually halts the system.