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1.2 Packages

DIP (Dual In-line Package):

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CERDIP (CERamic Dual In-line Package).

PQFP (Plastic Quad Flat Package): surface mounted.
SQFP (Shrink Quad Flat Package): surface mounted, thermally enhanced.
MQFP (Metal Quad Flat Package).

PLCC (Plastic Leaded Chip Carrier).

PGA (Pin Grid Array):

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SPGA (Pin Grid Array).
CPGA (Ceramic Pin Grid Array).
PPGA (Plastic Pin Grid Array).

SEC module (Single Edge Contact): consists of a PCB containing the processor chip and the level 2 cache chips.

ZIF sockets (Zero Insertion Force) have a handle to fasten and loosen the chip to and from its socket.

BGA (Ball Grid Array):

The BGA system consists of balls on the chip package that fit into grips on the socket.
Two new systems are developed by and available from Aries Electronics, Inc.:

http://www.arieselec.com/

BallNest provides a four-fingered "nest" for each ball termination of the device to be socketed. On top of the BGA device a socket lid must be placed to hold it down. The BallLock system grips the balls of the BGA device, eliminating the need for a lid. A ZIF (Zero Insertion Force) version of the BGA socket is being worked on.

ZIP (Zigzag In-line Package):

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DRAM (Dynamic Random Access Memory):

• 4116 16 k x 1 (1980),
• 4164 64 k x 1 (1982),
• 41256 256 k x 1 (1984),
• 411000 1 M x 1 (1987, 1988).

SIMM (Single In-line Memory Module) (Wang): contains a complete RAM bank. Mac SIMMs are only 8 bits wide; they don't contain a parity bit. However, there are Personal Computers around in which parity checking can be disabled, that can operate with 8 bit SIMMs.

• 9-chip SIMM: 9 chips of 1 bit wide
• 8-chip SIMM: 8 chips of 1 bit wide (Mac)
• 3-chip SIMM: 2 chips of 4 bits wide and 1 chip of 1 bit wide or 3 chips of 3 bits wide
• 2-chip SIMM: 2 chips of 4 bits wide (Mac)

If the correct refresh is supplied, SIMMs with a different number of chips and different speed can be used together.

SIP (Single In-line Package): contains a complete RAM bank.

The orientation of SIMMs and SIPs is indicated by a hole. Starting from this indication the numbering of the pins starts with number 1. Apart from the pins there is no difference at all between SIMMs and SIPs.

The normal SIMMs and SIPs have 30 pads/pins. There are also 36 pin SIMMs and SIPs. The extra pins are used for speed detection by the motherboard.

There are also 72 pin SIMMs. These are 32 bits and 4 parity bits wide. 4 pins are assigned for speed detection. They are mostly used in 486 class and higher Personal Computers.
Capacity: 1, 2, 4, 8, 16, 32 Mbytes.

DIMM (Dual In-line Memory Module): 64 bit memory module.
They have 168 pads. They can only be found in the newer Pentium class Personal Computers.

Memory banks, consisting of 1, 2, or 4 sockets, should always be filled completely. The number of sockets in a bank depends on the width of the memory module and the width of the processor's address bus. For example, a bank in a 486 class motherboard (32 bit address bus) might need four 8 bit SIMMs, or a single 32 bit SIMM.

EDO RAM (Extended Data Output): faster access method.
This can only be found in the newer Pentium class Personal Computers.

SDRAM (Synchronous DRAM): clock synchronized with the processor busses.
This can only be found in the newer Pentium class Personal Computers.