Figure 7.2 SIPP
SIPPs have a row of pins along one side. These pins are easily broken, and care should be taken to avoid damaging them during installation.
SIMMs (single inline memory modules) quickly replaced SIPPs, because they are easier to install. They are similar to SIPPs with one exception-they require no pins; 30-pin SIMMs have 30 contacts in a single row along the lower edge (see Figure 7.3). A 30-pin SIMM can have as few as two, or as many as nine, individual DRAM chips. While SIMM modules can have pin counts as high as 200, in PCs, 30- and 72-pin versions are the most common.
Figure 7.3 30-pin SIMM
Avoid touching the contacts on SIMMs, and use proper handling to reduce the risk of damage from electrostatic discharge (ESD).