Memory+and+Storage

Back Memory and Storage

ROM

Read-only memory (ROM) chips are located on the motherboard. ROM chips contain instructions that can be directly accessed by the CPU. Basic instructions for booting the computer and loading the operating system are stored in ROM. ROM chips retain their contents even when the computer is powered down. The contents cannot be erased or changed by normal means.



RAM

Random access memory (RAM) is the temporary storage for data and programs that are being accessed by the CPU. RAM is volatile memory, which means that the contents are erased when the computer is powered off. The more RAM in a computer, the more capacity the computer has to hold and process large programs and files, as well as enhance system performance.

The different types of RAM are:

 • Dynamic Random Access Memory **(DRAM)** is a memory chip that is used as main memory. DRAM must be constantly refreshed with pulses of electricity in order to maintain the data stored within a chip. •Static Random Access Memory **(SRAM)** is a memory chip that is used as cache memory. SRAM is much faster than DRAM and does

not have to be refreshed as often.

. •Fast Page Mode DRAM **(FPM Memory)** is memory that supports paging. Paging enables faster access to the data than regular

DRAM. Most 486 and Pentium systems from 1995 and earlier use FPM memory.

<span style="direction: ltr; font-family: Georgia,serif; font-size: 120%; language: en-US; line-height: 90%; margin-bottom: 0pt; margin-left: 0.12in; margin-top: 7.2pt; punctuationwrap: simple; text-indent: -0.12in; unicode-bidi: embed; vertical-align: baseline;">•Extended Data Out RAM **(EDO Memory)** is memory that overlaps consecutive data accesses. This speeds up the access time to

<span style="direction: ltr; font-family: Georgia,serif; font-size: 120%; language: en-US; line-height: 90%; margin-bottom: 0pt; margin-left: 0.12in; margin-top: 7.2pt; punctuationwrap: simple; text-indent: -0.12in; unicode-bidi: embed; vertical-align: baseline;">retrieve data from memory, because the CPU does not have to wait fro one data access cycle to end before another data access cycle

<span style="direction: ltr; font-family: Georgia,serif; font-size: 120%; language: en-US; line-height: 90%; margin-bottom: 0pt; margin-left: 0.12in; margin-top: 7.2pt; punctuationwrap: simple; text-indent: -0.12in; unicode-bidi: embed; vertical-align: baseline;">begins.

<span style="direction: ltr; font-family: Georgia,serif; font-size: 120%; language: en-US; line-height: 90%; margin-bottom: 0pt; margin-left: 0.12in; margin-top: 7.2pt; punctuationwrap: simple; text-indent: -0.12in; unicode-bidi: embed; vertical-align: baseline;">•Synchronous DRAM **(SDRAM)** is DRAM that operates in synchronization with the memory bus. The memory bus is the data path

<span style="direction: ltr; font-family: Georgia,serif; font-size: 120%; language: en-US; line-height: 90%; margin-bottom: 0pt; margin-left: 0.12in; margin-top: 7.2pt; punctuationwrap: simple; text-indent: -0.12in; unicode-bidi: embed; vertical-align: baseline;">between the CPU and the main memory.

<span style="direction: ltr; font-family: Georgia,serif; font-size: 120%; language: en-US; line-height: 90%; margin-bottom: 0pt; margin-left: 0.12in; margin-top: 7.2pt; punctuationwrap: simple; text-indent: -0.12in; unicode-bidi: embed; vertical-align: baseline;">•Double Data Rate SDRAM **(DDR SDRAM)** is memory that transfers data twice as fast a SDRAM. DDR SDRAM increases performance

<span style="direction: ltr; font-family: Georgia,serif; font-size: 120%; language: en-US; line-height: 90%; margin-bottom: 0pt; margin-left: 0.12in; margin-top: 7.2pt; punctuationwrap: simple; text-indent: -0.12in; unicode-bidi: embed; vertical-align: baseline;">by transferring data twice per cycle.

<span style="direction: ltr; font-family: Georgia,serif; font-size: 120%; language: en-US; line-height: 90%; margin-bottom: 0pt; margin-left: 0.12in; margin-top: 7.2pt; punctuationwrap: simple; text-indent: -0.12in; unicode-bidi: embed; vertical-align: baseline;">•Double Data Rate 2 SDRAM **(DDR2 SDRAM)** is faster than DDR SDRAM memory. DDR2 SDRAM improves performance over DDR

<span style="direction: ltr; font-family: Georgia,serif; font-size: 120%; language: en-US; line-height: 90%; margin-bottom: 0pt; margin-left: 0.12in; margin-top: 7.2pt; punctuationwrap: simple; text-indent: -0.12in; unicode-bidi: embed; vertical-align: baseline;">SDRAM by decreasing noise and crosstalk between the signal wires.

<span style="direction: ltr; font-family: Georgia,serif; font-size: 120%; language: en-US; line-height: 90%; margin-bottom: 0pt; margin-left: 0.12in; margin-top: 7.2pt; punctuationwrap: simple; text-indent: -0.12in; unicode-bidi: embed; vertical-align: baseline;">•RAMBus DRAM **(RDRAM)** is a memory chip that was developed to communicate at very high rates of speed. RDRAM chips are not

<span style="direction: ltr; font-family: Georgia,serif; font-size: 120%; language: en-US; line-height: 90%; margin-bottom: 0pt; margin-left: 0.12in; margin-top: 7.2pt; punctuationwrap: simple; text-indent: -0.12in; unicode-bidi: embed; vertical-align: baseline;">commonly used.



<span style="font-family: 'Comic Sans MS',cursive; font-size: 130%;">Memory Modules

<span style="font-family: Georgia,serif; font-size: 120%;">Early computers had RAM installed on the motherboard as individual chips. The individual memory chips, called dual inline package (DIP) chips, were difficult to install and often became loose on the motherboard. To solve this problem, designers soldered the memory chips on a special circuit board called a memory module.

<span style="direction: ltr; font-family: Georgia,serif; font-size: 120%; language: en-US; line-height: 90%; margin-bottom: 0pt; margin-left: 0.12in; margin-top: 7.2pt; punctuationwrap: simple; text-indent: -0.12in; unicode-bidi: embed; vertical-align: baseline;">The different types of memory modules are:

<span style="direction: ltr; font-family: Georgia,serif; font-size: 120%; language: en-US; line-height: 90%; margin-bottom: 0pt; margin-left: 0.12in; margin-top: 7.2pt; punctuationwrap: simple; text-indent: -0.12in; unicode-bidi: embed; vertical-align: baseline;">•Dual Inline Package (DIP) is an individual memory chip. A DIP had dual rows of pins used to attach it to the motherboard.

<span style="direction: ltr; font-family: Georgia,serif; font-size: 120%; language: en-US; line-height: 90%; margin-bottom: 0pt; margin-left: 0.12in; margin-top: 7.2pt; punctuationwrap: simple; text-indent: -0.12in; unicode-bidi: embed; vertical-align: baseline;">•Single Inline Memory Module (SIMM) is a small circuit board that holds several memory chips. SIMMs have 30-pin and 72-pin

<span style="direction: ltr; font-family: Georgia,serif; font-size: 120%; language: en-US; line-height: 90%; margin-bottom: 0pt; margin-left: 0.12in; margin-top: 7.2pt; punctuationwrap: simple; text-indent: -0.12in; unicode-bidi: embed; vertical-align: baseline;">configurations.

<span style="direction: ltr; font-family: Georgia,serif; font-size: 120%; language: en-US; line-height: 90%; margin-bottom: 0pt; margin-left: 0.12in; margin-top: 7.2pt; punctuationwrap: simple; text-indent: -0.12in; unicode-bidi: embed; vertical-align: baseline;">•Dual Inline Memory Module (DIMM) is a circuit board that holds SDRAM, DDR SDRAM, and DDR2 SDRAM chips. There are 168-pin

<span style="direction: ltr; font-family: Georgia,serif; font-size: 120%; language: en-US; line-height: 90%; margin-bottom: 0pt; margin-left: 0.12in; margin-top: 7.2pt; punctuationwrap: simple; text-indent: -0.12in; unicode-bidi: embed; vertical-align: baseline;">SDRAM DIMMs, 184-pin DDR DIMMs, and 240-pin DDR2 DIMMs.

<span style="direction: ltr; font-family: Georgia,serif; font-size: 120%; language: en-US; line-height: 90%; margin-bottom: 0pt; margin-left: 0.12in; margin-top: 7.2pt; punctuationwrap: simple; text-indent: -0.12in; unicode-bidi: embed; vertical-align: baseline;">•RAM Bus Inline Memory Module (RIMM) is a circuit board that holds RDRAM chips. A typical RIMM has a 184-pin configuration.

<span style="font-family: Georgia,serif; font-size: 120%;">The speed of memory has a direct impact on how much data a processor can process because faster memory improves the performance of the processor. As processor speed increases, memory speed must also increase. For example, single-channel memory is capable of transferring data at 64 bits. Dual-channel memory increases speed by using a second channel of memory, creating a data transfer rate of 128 bits.

<span style="font-family: 'Comic Sans MS',cursive; font-size: 130%;">Cache memory

<span style="font-family: Georgia,serif; font-size: 120%;">SRAM is used as cache memory to store the most frequently used data. SRAM provides the processor with faster access to the data than retrieving it from the slower DRAM, or main memory. The three types of cache memory are d

<span style="font-family: Georgia,serif; font-size: 120%;">Storage drives, read or write information to magnetic or optical storage media. The drive can be used to store data permanently or to retrieve information from a media disk. Storage drives can be installed inside the computer case, such as a hard drive. For portability, some storage drives can connect to the computer using a USB port, a FireWire port, or an SCSI port. These portable storage drives are sometimes referred to as removable drives and can be used on multiple computers. Here are some common types of storage drives:
 * <span style="font-family: 'Comic Sans MS',cursive; font-size: 130%;">Storage Devices **

<span style="font-family: 'Comic Sans MS',cursive; font-size: 120%;">Floppy Drive

<span style="font-family: Georgia,serif; font-size: 120%;">A floppy drive, or floppy disk drive, is a storage device that uses removable 3.5-inch floppy disks. These magnetic floppy disks can store 720 KB or 1.44 MB of data. In a computer, the floppy drive is usually configured as the A: drive. The floppy drive can be used to boot the computer if it contains a bootable floppy disk. A 5.25-inch floppy drive is older technology and is seldom used.



<span style="font-family: 'Comic Sans MS',cursive; font-size: 120%;">Hard Drive

<span style="font-family: Georgia,serif; font-size: 120%;">A hard drive, or hard disk drive, is a magnetic storage device that is installed inside the computer. The hard drive is used as permanent storage for data. In a Windows computer, the hard drive is usually configured as the C: drive and contains the operating system and applications. The hard drive is often configured as the first drive in the boot sequence. The storage capacity of a hard drive is measured in billions of bytes, or gigabytes (GB). The speed of a hard drive is measured in revolutions per minute (RPM). Multiple hard drives can be added to increase storage capacity.

<span style="font-family: 'Comic Sans MS',cursive; font-size: 120%;">Optical Drive

<span style="font-family: Georgia,serif; font-size: 120%;">An optical drive is a storage device that uses lasers to read data on the optical media. There are three types of optical drives: >
 * <span style="font-family: Georgia,serif; font-size: 120%;">Compact Disc (CD)

> > > > > <span style="font-family: Georgia,serif; font-size: 120%;">CD, DVD, and BD media can be pre-recorded (read-only), recordable (write once), or re-recordable (read and write multiple times). CDs have a data storage capacity of approximately 700 MB. DVDs have a data storage capacity of approximately 4.3 GB on a single-layer disc, and approximately 8.5 GB on a dual-layer disc. BDs have a storage capacity of 25 GB on a single-layer disc, and 50 GB on a dual-layer disc. > > > <span style="font-family: Georgia,serif; font-size: 120%;">There are several types of optical media: > > > > > > <span style="font-family: 'Comic Sans MS',cursive; font-size: 130%;">External Flash Drive > > <span style="font-family: Georgia,serif; font-size: 120%;">An external flash drive, also known as a thumb drive, is a removable storage device that connects to a USB port. An external flash drive uses the same type of non-volatile memory chips as solid state drives and does not require power to maintain the data. These drives can be accessed by the operating system in the same way that other types of drives are accessed. > > > <span style="font-family: 'Comic Sans MS',cursive; font-size: 120%;">﻿   <span style="font-family: 'Comic Sans MS',cursive; font-size: 120%;">Summary <span style="font-family: Georgia,serif; font-size: 120%;">Storage and memory play an important role in storing data in the computer. There are two types of memory: RAM and ROM. ROM memory includes instructions that are carried by the CPU. Also, it is permanent memory which means that data and information will not be deleted if the computer switches off. There are different types of ROM: ROM, PROM, EROM and EEROM. RAM on oppiste is a temprary memoy for storing data and programs. when the computer is switch off ,data will be erased .To add, to improve the the performance, more RAM .Storage devices are used to read and write information and it can store data permenantly. It includes different categories: Floppy hard, optical drive and flash drive. Also, it can be installed into the computer such as Floppy drive or connect to the computer using USP such as flash drive. It includes different categories: Floppy hard, optical drive and flash drive.
 * <span style="font-family: Georgia,serif; font-size: 120%;">Digital versatile Disc (DVD)
 * <span style="font-family: Georgia,serif; font-size: 120%;">Blu-ray Disc (BD)
 * <span style="font-family: Georgia,serif; font-size: 120%;">CD-ROM – CD read-only memory media that is pre-recorded.
 * <span style="font-family: Georgia,serif; font-size: 120%;">CD-R – CD recordable media that can be recorded one time.
 * <span style="font-family: Georgia,serif; font-size: 120%;">CD-RW – CD rewritable media that can be recorded, erased, and re-recorded.
 * <span style="font-family: Georgia,serif; font-size: 120%;">DVD-ROM – DVD read-only memory media that is pre-recorded.
 * <span style="font-family: Georgia,serif; font-size: 120%;">DVD-RAM – DVD random access memory media that can be recorded, erased, and re-recorded.
 * <span style="font-family: Georgia,serif; font-size: 120%;">DVD+/-R – DVD recordable media that can be recorded one time.
 * <span style="font-family: Georgia,serif; font-size: 120%;">DVD+/-RW – DVD rewritable media that can be recorded, erased, and re-recorded.
 * <span style="font-family: Georgia,serif; font-size: 120%;">BD-ROM – BD read-only media that is pre-recorded with movies, games, or software.
 * <span style="font-family: Georgia,serif; font-size: 120%;">BD-R – BD recordable media that can record HD video and PC data storage one time.
 * <span style="font-family: Georgia,serif; font-size: 120%;">BD-RE – BD rewritable format for HD video recording and PC data storage.

<span style="font-family: Georgia,serif; font-size: 120%;">Resources

<span style="font-family: Georgia,serif; font-size: 120%;">Cisco Networking Academic Program website