HP Digital AlphaStation 255 Family - Adding Memory Modules

Installing System Options
4–5
Adding Memory Modules
The procedures for adding SIMMs to the AlphaStation 255 system are outlined below.
There are two memory banks in the system; each bank consists of four SIMMs. Four
SIMMs are required because the memory bus width is 132-bits (128 bits of data and 4 bits
of parity). Each SIMM in a bank supplies 33 bits of the 132-bit bus width. All SIMMs in
a bank must be identical.
To add memory modules (SIMMs), refer to Figure 4–3 as you perform the following steps:
1. Install the SIMM into the socket at an angle  . Ensure that the notch  is aligned
with the protrusion in the bottom of the connector. Rock the SIMM gently until it is
seated evenly into the bottom of the socket. Tip the SIMM upright  until both the
retaining clips  at the socket ends engage.
2. Repeat steps 1 and 2 for the remaining three modules.
2
4
1
3
Figure 4–3: Memory Installation