Chapter 6 - Memory and Memory Management
OBJECTIVES:
Upon completing this chapter you will be able to perform tasks relating to:
INTRODUCTION
When deciding on the type of memory to purchase for a computer you have to consider memory speed, parity, error checking and correting and the type of memory banks are used for the memory.
Memory
Memory speed is measured in nanoseconds, this is the time to access data that is stored in memory. The range is 50 to 80 ns (nanoseconds).
Parity
Parity is a simple error-checking method where each data byte includes a ninth bit called the parity bit (even/odd = 1/0).
ECC (Error Checking and Correcting)
ECC is a enhanced memory checking that detects memory errors, but cannot correct the. It will halt the system and show an error message on the monitor.
Memory Banks
Memory Banks is banks that house/store the memory. (2) 30-pin, (2) 72-pin SIMMs (single inline memory modules). Present computers only need one DIMM (dual inline memory module)
TYPES OF MEMORY
There are various types of memory that is stored in a computer. They include ROM, RAM, DRAM, SRAM, VRAM, WRAM, SGRAM, and Memory Packages.
ROM (Read Only Memory) is non-volatile memory. When you turn off the computer the information is stored in the chip.
RAM (Random Access Memory) - is volatile memory. When you turn off the computer the information that was store in memory is erased. This type of memory is temporary. Examples of this type of memory include DRAM (Dynamic RAM), (Static RAM), Video RAM, Windows RAM, Synchronous Graphics RAM).
DRAM includeds DIMM, and SIMM. It is high density memory modules, stores data while programs are running. It has fast page mode DRAM and EDO (Extended Data Output) and Synchronous DRAM or SDRAM.
SRAM - is four times faster than DRAM and is used for speed critical functions like cache memory.
VRAM - is video RAM that is used for high performance video adapter cards.
WRAM is Windows RAM. It is single ported and sychronized with the system clock.
SGRAM is Synchronous Graphics RAM and synchronizes with the system clock.
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