Lecture 5: Primary Memory (Introduction To Computers) PDF
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Uploaded by ScenicNourishment
Mohamed Almojtaba
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Summary
This document presents a lecture on primary memory, a fundamental component of computer systems. It explores the different types of primary memory like RAM and ROM, along with their roles and functions. The lecture also touches on memory hierarchy, cache memory, and error correction methods, to give a broad overview of the subject. The focus is on computer science.
Full Transcript
Lecture 5 Primary Memory Mohamed Almojtaba What is Memory? Memory is used to: Store data; Store commands (instructions); Store system settings; Computer Memory Three categories of memory devices: Primary Memory; Secondary Memory; Archival Storage Devices; What is Primary M...
Lecture 5 Primary Memory Mohamed Almojtaba What is Memory? Memory is used to: Store data; Store commands (instructions); Store system settings; Computer Memory Three categories of memory devices: Primary Memory; Secondary Memory; Archival Storage Devices; What is Primary Memory? Also called system memory. Essential for computer to operate. Stores data and commands to be used by the CPU. Stores basic system settings. Two main types: RAM ROM RAM vs. ROM RAM ROM Random Access Memory Read Only Memory Stores data and instructions Stores basic system settings Volatile Non-volatile Examples: Example: RAM chips BIOS CMOS The Primary Memory Hierarchy Cache: The papers in Notes in your locker, your hand are the next car, or at home, are ones you will use! too far away! RAM: The book on your desk is much Retrieving Data from closer! Secondary Storage RAM on the Motherboard Static RAM (SRAM) Dynamic RAM (DRAM) Very fast; Slow; Expensive; Cheaper; Does not need to be refreshed; Needs constant refreshing; Used as Cache; Used as RAM; SIMMs, DIMMs and RIMMs On Chip, Coast Card, or inside CPU; Different Types of DRAM SIMM Single Inline Memory Module DIMM Dual Inline Memory Module RIMM Rambus Inline Memory Module Installing a SIMM Chip Installing a DIMM Chip Installing a RIMM Chip Older Types of RAM Conventional RAM Fast Page Memory (FPM) Extended Data Out (EDO) RAM Burst EDO (BEDO) RAM Newer Types of RAM Sychronous DRAM (SDRAM) Synced with system clock Double Data Rate (DDR) SDRAM Most popular today 184-pin DIMMs 200-pin SODIMMs Rambus DRAM (RDRAM) Not as common Faster system bus RIMMs Cache Memory Very fast SRAM Used to store the very next command or data needed by the CPU Three Types: L1 L2 L3 Error Correction Method used to: Detect integrity of data stored in RAM Ensure memory is complete Prevent data corruption or loss Non-Error Correcting Memory: Used in older systems to speed up memory; Types of Error Correction Parity: Older; Cannot correct data corruption; Error Correcting Code (ECC): Newer; Most widely used; Can correct data corruption; How Parity Works System Memory Conventional Memory: First 1 MB of memory; Used to run programs and store system drivers; High Memory (Hi-Mem): About 64 KB of memory just above the 1 MB point; Extended and Expanded Memory: Anything above 1 MB; Systems must run in ‘Protected Mode’ to use; Anything above 1 MB Reserved for device drivers and system functions Available to the user for any software
