TEE COURSE GRADE 10

MODULE 7 - PC HARDWARE Memory and Storage Devices

LEARNING OBJECTIVES At the end of this lesson, students will be able to : 1. Meet the expectations of the Course Curriculum coded as: TFV.01E, TF2.01E, TF2.02E, TF2.03E, TF2.04E, IC1.02E, SPV.01E;2. Explain the function and interaction of the primary (RAM, ROM) and secondary storage devices (magnetic and optical); 3. Describe secondary storage devices: FDD, HD, CD-ROM, DVD;4. Use precise terminology in relation to all storage devices;5. Explain how data is stored on the surface of magnetic and optical disks; 6. Uninstall and re-install main and secondary storage devices: RAM, FDD, HD, CD-ROM;7. Use safe practices in the handling of computer hardware and electronic components.

Computer System ComponentsShort Review Communication Devices

Three levels of memory hierarchyPrinciple: the closer the memory is to the CPU, the faster it is.

Memory addressesMemory is a collection of cells, each with a unique physical/memory address Each cell can hold one byte or 8 bitsWith one by we can represent one character in ASCII CodeExample: A is 65 in ASCII code and 01000001 in binary representation

Application/ThinkingHow many bytes are in the phrase You are great! . 1113141So, this sentence will occupy __?__ cells in memory

Storage Capacity

Unit ------------kilobytemegabytegigabyteterabytepetabyteexabyteExact Number of bytes ------------------------210 bytes220 bytes230 bytes240 bytes250 bytes260 bytesApproximation ------------103 bytes106 bytes109 bytes1012 bytes1015 bytes1018 bytes

Application/ThinkingHow many megabytes (MB = 2 to the power of 20 bytes) are in a terabyte (1TB = 2 to the power of 40 bytes): 2 to the power of 102 to the power of 202 to the power of 402 to the power of 80

PRIMARY MEMORY: RAM AND ROM RAM (Random Access Memory) is volatile (temporary). Programs and data can be written to and erased from RAM as needed. This means that RAM does not retain its bit configuration when the power is turned off, but ROM does

ROM ( Read Only Memory) is nonvolatile (permanent). The contents in locations in ROM cannot be changed

It holds instructions that run the computer when it is first turned on (BIOS)

The CPU accesses each location in memory by using a unique number, called a memory address.

Memory types ROMROM: read-only memory (Pre-programmed)PROM: programmable ROMOnly written onceEPROM: erasable PROMUse ultraviolet light to erase dataEEPROM: electronically EPROMCan be erased using electronic impulses (higher voltages)

Secondary Storage DevicesStorage devices hold data, even when the computer is turned off.

The physical material that actually holds data is called a storage medium. The surface of a floppy disk is a storage medium.

The hardware that writes data to or reads data from a storage medium is called a storage device. A floppy disk drive is a storage device.

The two primary storage technologies are magnetic and optical.

Magnetic Storage DevicesDiskettes (floppy disks) (FDD)

Hard disks (HD)

High-capacity floppy disks (ZIP Disk)

USB flash drive

Magnetic tape

Optical Storage DevicesCompact Disk Read-Only Memory (CD-ROM)

Digital Video Disk Read-Only Memory (DVD-ROM)

CD-Recordable (CD-R)

CD-Rewritable (CD-RW)

PhotoCD

CLASSIFICATION- BIG PICTURE

Memory Types &Storage Devices

PrimarySecondaryVolatileRegistersCache (I, II, III)RAMSRAMDRAM SDRAMEDRAMEDOFLASH RAM Non-volatileROMPROMEPROMEEPROMMagnetic memoryTapeHD, Zip DiskFDD

Optical MemoryCD-ROM, CD-R, CD-RWDVD-ROM, DVD-RDVD- RW (Semiconductor chip). Main Memory(Devices)2ns5ms

Magnetic Storage Devices- How Magnetic Storage WorksA magnetic disk's medium contains iron particles, which can be polarizedgiven a magnetic chargein one of two directions (north or south).

Each particle's direction represents a 1 (on) or 0 (off), representing each bit of data that the CPU can recognize.

A disk drive uses read/write heads containing electromagnets to create magnetic charges on the medium.

As the mediumrotates, the headwrites the data.

Magnetic Storage Devices - DiskettesDiskette drives, also known as floppy disk drives, read and write to diskettes (called floppy disks or floppies).

In disks the areas to save data are organized as a set of concentric circles called Tracks. Floppy disks have 80 tracks. The disks are further divided into pie-slice Sectors.

300 rpm

Diskettes size: 3.5-inch.

Formatted Disk

3.5 inchfloppyand drive

Hard Disk DrivePurpose: Long-term, nonvolatile storage Large, inexpensive, slow level in the storage hierarchyDisk compositionA magnetic disk consist of a collection of platters (1to 20 per disk) that rotate on a spindle. Disk surface divided into tracks (1000 to 4800 per platter).Tracks are divided into sectors (64 per track), which are the smallest unit that can be read or written. Up to 10,000 rpm

Magnetic DisksA read/write head travels across a spinning magnetic disk, retrieving or recording data The organization of a magnetic disk

Optical Storage Devices How Optical Storage WorksAn optical disk is a high-capacity storage medium. An optical drive uses reflected light to read data.

To store data, the disk's metal surface is covered with tiny dents (pits) and flat spots (lands), which cause light to be reflected differently.

When an optical drive shines light into a pit, the light cannot be reflected back. This represents a bit value of 0 (off). A land reflects light back to its source, representing a bit value of 1 (on).

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Optical storage devicesCD-ROM: compact disc ROM (Read Only Memory)Capacity: 650MBCD-R: compact disc recordableCD-RW: compact disc rewritableDVD: digital versatile disc Capacity: 4.7GB 17GBDVD-RDVD-RW (2 versions: + (plus) and (dash)

DVD (Digital Versatile Disk)

Allows up to 17 gigabytes of storage (from 4.7 GB to 17 GB).Compatible with older CD-ROM technology.The four versions of the DVD:

lesson ReviewList four types of magnetic and four types of optical storage devices.

Identify two common uses for floppy disks.

Explain how data is stored on the surface of magnetic and optical disks.

List three variations on optical disk technology.

EVALUATION 1. Cache memory has the fastest speed: TF2. A TB has 1024 MB?T F3. EPROM is a volatile memory?TF4. SRAM needs to be refreshed?TF5. EEPROM use ultraviolet light to erase data?TF 6. A land reflects light back to its source,representing a bit value of 1 (on). TF7. A pit, does not reflect the light back and this represents a bit value of 0 (off). TF

EVALUATION SHORT TEST conted8. Define the following acronyms: SRAM ______________________________DRAM______________________________SDRAM______________________________EDRAM______________________________PROM______________________________EPROM ______________________________EEPROM ______________________________CD-ROM ______________________________HDD ______________________________FDD ______________________________DVD RW ______________________________CD-RW ______________________________

*A computer system is an interrelated combination of components performing specialized basic functions to provide end users with a powerful information processing tool. Key functions include:Input. The input devices of a computer system include keyboards, touch screens, pens, electronic "mice," optical scanners, and other peripheral hardware components that convert electronic data into electronic machine-readable form. Input may be direct entry (by the end user) or through telecommunications links.Processing. The central processing unit (CPU) is the main processing component of a computer system. A key component of the CPU is the arithmetic-logic unit (ALU), which performs the arithmetic and logic functions required in computer processing. Output. Output devices convert the electronic information produced by the computer system (binary or digital information) into human-intelligible form for presentation to end users. Output devices include video display units, printers, audio response units, and other peripheral hardware components specialized in this function.Storage. Storage devices store data and programs instructions needed for processing. A computer's primary storage or memory is used to hold key information needed to run the computer while secondary storage (such as magnetic disks and tape units) hold larger parts of programs used less frequently and the content files created by end users.Control. The control unit of the CPU interprets computer program instructions and transmits directions to the other components of the computer system.

*Like the CPU, memory is made of silicon chips containing circuits holding data represented by on or off electrical states, or bits. Eight bits together form a byte. Memory is usually measured in megabytes or gigabytes.A kilobyte is roughly 1,000 bytes. Specialized memories, such as cache memories, are typically measured in kilobytes. Often both primary memory and secondary storage capacities today contain megabytes, or millions of bytes,of space.Increasingly desktop computers come with gigabytes or billions of bytes of storage capacity on their hard disks or secondary storage. Although today terabytes of storage are found only in large computers such as mainframe computers, it shouldnt be long before we are accessing terabytes of storage on our desktop computers.In fact we are starting to hear of even larger quantities of storage. For example, there are operating systems that can access files that contain over one exabyte one quintillion bytes - of data, and there are databases that hold over an exabyte of data. An exabyte equals about one quintillion bytes.*