Bài giảng Computer - Chapter 07

Chapter Overview ROM and RAMMemory Mapping 1Defining Memory Memory is the area within a computer where information is stored while being worked on. Information is stored by using 0s and 1s as switches.When strung together, these switches can represent large numbers and code values. 2Nonvolatile and Volatile Memory Computer memory includes two major classes. Nonvolatile: computer retains data when the power is shut offVolatile: computer loses data when the power is shut off3Read-Only Memory (ROM) Is nonvolatile memory, generally installed during manufacturingProtects the information required to start and run the computerHolds instructions for performing the power-on self test (POST) and basic input/output system (BIOS) informationRequires attention only if it needs to be replaced or upgraded 4Random Access Memory (RAM) Is volatile memoryIncludes two common forms Dynamic RAM (DRAM)Synchronous DRAM (SDRAM) Uses two methods to ensure data integrity ParityError-correction encoding (ECC) 5RAM Packaging 6Memory Configuration 8-bit data bus requires memory in 8-bit chunks.16-bit data bus requires memory in 16-bit chunks.32-bit data bus requires memory in 32-bit chunks. 7Installing SIMMs Check the memory module voltage.Use electrostatic discharge (ESD) protection and handle single inline memory modules (SIMMs) carefully.Insert the SIMM at a 45-degree angle and click it into place. (The notch in the SIMM prevents improper installation.) 8Cache Memory 9Hexadecimal Code 10Memory Allocation 11Shadow RAM 12Determining Usable Memory MEM.COM Display13Chapter Summary The two basic computer memory types are ROM (nonvolatile) and RAM (volatile).RAM is packaged in a variety of designs.Installing SIMMs requires ESD protection and careful handling.Cache memory enhances performance.Hexadecimal code simplifies binary code notation.Memory allocation has been simplified under Microsoft Windows. 14