PC Hardware —

SIPPs

One of the first module forms of DRAM, the SIPP (single inline pin package) is a printed circuit board with individual DRAM chips mounted on it, shown in Figure 7.2. Physically, a SIPP module looks like a rectangular card with a single row of pins along one edge. The SIPP had a very short time in the sun, due to the fragile nature of these pins.

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Figure 7.2 SIPP

CAUTION
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 (30-pin)

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.

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Figure 7.3 30-pin SIMM

CAUTION
Avoid touching the contacts on SIMMs, and use proper handling to reduce the risk of damage from electrostatic discharge (ESD).