CHAPTER 10

CHAPTER 10

ADVANCED DISK DRIVE TECHNOLOG

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Chapter Overview

CD-ROM and DVD Drives Advanced Hard Disk Drives SCSI Drives

Advantages of CD-ROM and DVD Drives

Large storage capacities: up to 650 MB of data fit on a single 5-inch disk

Portability: the CD is a portable medium. Data cannot be changed: A CD is read only

hardiness: more strong than the standard floppy disk

Special capabilities: CD-ROMs are Audio-capable.

Low cost High speed

CD-ROM vs. Hard Disk Drives There is no physical contact between the CD-ROM and

the reading device. Storage tracks allow more data storage. Hard disks are less expensive and getting larger. Optical devices are used for archiving. Data is written to a CD-ROM by creating pits and lands

on the CD surface.

DVD: A Super CD-ROM Alternative

DVD-ROM: read only; holds up to 17 GB of data

DVD video: 4.7 GB; holds up to 135 minutes of video

DVD-R: recordable; holds up to 3.95 GB of data per side

DVD-RAM/RW: slow gaining acceptance because of incompatibilities

Connecting CD-ROM and DVD Drives

Adapter boards: Enhanced Integrated Drive Electronics (EIDE) or Small Computer System Interface (SCSI)

Sound cards with CD controller on board SCSI host adapter: operates at higher

data transfer rates EIDE connector

Audio Capability and Access Time CD-ROM ISO Yellow Book standardAny CD-ROM drive that meets the Yellow Book standard has the

ability to play back audio.

International Organization for Standardization (ISO) 9660 standard

Two important values: Data transfer rate: the long time standard for

transfer rate has been 150KB per second. A 2X CD-ROM operates at 300KB.

Mean access time : the time it takes the head to move over half the tracks, 200-400 ms.

Note : Check the table on page 227

Installing CD-ROM and DVD Drives

Controller Cards

Select the controller card before buying the CD-ROM.

Use a secondary Integrated Device Electronics (IDE) controller on the motherboard.

Ensure a proper connection.

Installing an Internal Drive Mount an internal drive in a computer with

an open bay for a 5.25-inch disk drive. Have the necessary tools and parts on

hand. Connect two cables: one flat ribbon cable

for data and one power cable. Check the documentation to connect the

DVD drive correctly. For SCSI drives, set the correct SCSI ID

and properly terminate the chain.

Software Setup

Multimedia Multimedia presents graphics, data, sound,

and video in an integrated way. The Microsoft Multimedia PC Marketing

Council, now the Multimedia PC Working Group, generates standards for multimedia computers.

The current standard, MPC Level 3 (MPC3), sets several minimum requirements.

Video-capture software provides the interface for importing, exporting, and editing video formats.

Limitations of Early Hard Disk Drives

The ST-506 interface developed by Seagate Technologies is now out of date

The IDE/ATA standard is limited to 528 MB and supports hard disk drives only.

EIDE Improvements

Supports up to four hard disk drives–two on each controller

Provides faster data transfer rates Supports CD-ROM, tape, and Zip drives

The 528-MB Limit

EIDE–Four Major Upgrades

Logical block addressing (LBA): is a means of addressing the physical sectors on a hard disk drive in a linear fashion.

Logical block addressing (LBA) is a common scheme used for specifying the location of blocks of data stored on computer storage devices

Use of IRQ15 and I/O address 170h

Overcoming the 528-MB difficulty

Before LBA: capacity = cylinders heads sectors per track (limit 528 MB)

After LBA: cylinders = capacity / (heads sectors per track)

Other Methods of Overcoming the 528-MB Barrier

Enhanced CHS translation: this standard allows drives to be manufactured a little faster and more easily than LBA

Fast ATA: it is a technique used by Seagate technologies or others to compete with EIDE

Logical CHS and physical CHS: LCHS is a value used by the O.S to determine the size of the HDD.

PCHS is a value used within the device to determine its size.

Direct memory access (DMA) transfer Is a transfer method. DMA bypasses the CPU to transfer data directly into

memory.

Breaking the 8.4-GB Barrier

Upgrade the system basic input/output system (BIOS).

Install a hard disk drive with interrupt 13h support.: Breaks through the 528 MB barrier through the use of a Logical Block Address (LBA). By modifying the BIOS to translate the information that is received into a 28-bit LBA, and instructing the BIOS to load the LBA driver from the hard disk,

Installing EIDE Drives

Other Drive Settings

Multiple block reads: ATA standard requires each drive to activate its IRQ every time it sends one sector of data , multiple block reads speed up the process by reading several sectors of data at a time.

32-bit disk access : enabling 32 file access allows later versions of windows to talk directly to the ROM BIOS.

SCSI-1, SCSI-2, and Fast SCSI-2 SCSI (Small Computer System Interface) is a set of

standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, and electrical and optical interfaces. SCSI is most commonly used for hard disks and tape drives, but it can connect a wide range of other devices, including scanners, and optical drives (CD, DVD, etc.).

SCSI-1 supported up to seven devices on a chain. SCSI-2 could address optical drives, tape drives, and

scanners. Fast SCSI-2 doubled the transfer rate from 5 MB per

second to 10 MB per second.

SCSI-3 High performance Plug and Play installation Simple expansion Advanced management tools SCAM (SCSI configured auto-magically) support :

meaning that the user does not have to worry about setting the ID numbers for them, because they will configure themselves, using an open ID position on the SCSI chain.

Connect/disconnect command: This command allows a SCSI device handling a large amount of data or performing complex operations to separate from the host adapter's bus while performing the task, allowing other devices free access until it is finished.

Tag command queuing : SCSI devices with this feature can reorder how blocks of data are moved on the bus to speed transfer

SCSI and Ultra DMA/IDE Comparison

Noise and SCSI Any electrical signal other than data is noise. Any noise spread through either the electrical power

cables or the data cable is called a common-mode noise. Single-ended devices are exposed to common-mode

noise. A single-ended device communicates through only one

wire per bit of information. This one wire is measured, or referenced, against the common ground provided by the metal frame

Differential-ended devices reject common-mode noise. These products use two wires per bit of data—one wire

for the data and one for the inverse of the data. The inverse signal takes the place of the ground wire in the single-ended cable

Troubleshooting a Device Conflict

Load only device drivers for the SCSI device. Use the F8 key to determine which driver

conflicts. Try the /? option with the device driver

executable. Look in the device documentation. Find the latest drivers. If no solution works, choose between the

devices or go to a multiple boot configuration.

Costs and Benefits of SCSI

SCSI costs more than IDE. The cost may be justified in certain

high-end environments.

Setting Up a SCSI Subsystem 1. Install the host adapter.2. Set the SCSI IDs, termination, and cabling.3. Power up one device at a time and check for

problems.4. Load the operating system, drivers, and SCSI

software.

A SCSI host adapter is a device used to connect one or more other SCSI devices to a computer bus

Setting SCSI IDs The host adapter is typically set to 7. There is no authorization order. The host adapter manufacturer may preset the ID. The logical unit number (LUN) is used to support more than

one device per ID.

Termination Termination prevents signal reflection. Newer SCSI devices use active termination; older SCSI devices

use passive termination. Termination is typically built in, but some devices require

manual termination. Both ends of the chain must be terminated, and devices in

between must not be terminated. Most new SCSI devices set termination automatically.

Chapter Summary CD-ROMs provide durable, removable

storage for archiving. Newer CD-ROM technology provides

multimedia support. DVD is an extension of CD-ROM technology. DVD can be used to store multiple formats. EIDE and Ultra DMA/IDE drives solve earlier

drive problems. SCSI drives offer performance and

reliability benefits.