Transcript Identifying Security Risks

Using and Configuring
Storage Devices
Guide to Operating Systems
Third Edition
Objectives
After reading this chapter and completing the
exercises you will be able to:
• Understand basic disk drive interface technologies
• Compare the different types of CD-ROM and DVD
storage
• Explain the differences between a storage area network
(SAN) and network attached storage (NAS)
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Objectives (continued)
• Discuss various removable storage options
• Describe tape drive options and their advantages and
disadvantages
• Briefly discuss storage management options in
different operating systems
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Disk Storage Options
• Briefly discuss various storage technologies
• Most computers arrive with;
– 3.5-inch floppy drive
– high-density floppy or Zip disk
– hard drive
– CD-ROM or DVD drive
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Hard Drive Interfaces
• Integrated Drive Electronics (IDE)
– most popular hard drive interface
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Hard Drive Interfaces
(continued)
• Master
– the first or main drive
• Slave
– secondary storage device
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Hard Drive Interfaces
(continued)
• Three 40-pin header connectors
• Enhanced IDE (EIDE)
– transfer speeds as high as 22 megabits per
second
• Small Computer System Interface (SCSI)
– fast interface
– 8 to 16 devices
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Hard Drive Interfaces
(continued)
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Hard Drive Interfaces
(continued)
• Platters, heads, tracks, and sectors per track
vary widely from hard disk to hard disk
• EIDE and SCSI provide ways for the controllers
to communicate with the disk
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Hard Drive Interfaces
(continued)
• Disk geometry
– information about the hard disk
– configuration
• Storage capacity
– few megabytes to several gigabytes
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Basic and Dynamic Disks
• Basic disk
– physical hard drive
– primary partitions, extended partitions, or logical
drives
• Dynamic Disks
– volumes that span multiple disks
– fault tolerant disks
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RAID Arrays
• Redundant Array of Inexpensive Drives (RAID)
• RAID arrays
– increased reliability
– increased storage capacity
– increased speed
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RAID Arrays (continued)
• Different levels of RAID focus on different
purposes
• RAID is implemented as a combination of
hardware and software
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CD-ROM and DVD
• Optical rather than magnetic technology
– compact disc-read only memory (CD-ROM)
– digital versatile disc (DVD)
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Compact Disk (CD)
Technology
• Use a big “spiral” that starts at the inside of the
disk and winds itself to the outside of the disc
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Compact Disk (CD)
Technology (continued)
• Rotated by a precision motor that keeps the
disc speed constant
• Cyclic Redundancy Check (CRC)
– bits encoded in it as other disks do
– error correction bits encoded on the disc
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Digital Video
Disc (DVD) Technology
• Works like the CD-ROM
• Two sides with up to two layers per side
• Laser light is reflected
• DVD has a spiral that moves from the middle
of the disk to the outside like a conventional
CD-ROM, but also has a second layer
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Recordable and
Rewritable CD and DVD
• CD-R and DVD-R
– record data once on the media, and then it can be
read many times
– R stands for recordable
• CD-RW and DVD-RW can
– write on the media thousands of times
– RW stands for rewritable
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Recordable and
Rewritable CD and DVD
(continued)
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CD-ROM and DVD-ROM
Interfaces
• Connected using a hard disk interface
• EIDE interface with SCSI as a close second
• Drivers for CD-ROM and DVD-ROM built in
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Connecting Drives
• Connect as hard disks
– EIDE or SCSI
– USB
– FireWire
• Make sure you have the drivers
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Network Storage
• Storage Area Networks (SANs) for
– backups
– disaster recovery
– availability of data
• SANs connect servers and storage systems
without sending data over the corporate
network
• Use Fibre Channel fabric
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Network Storage
(continued)
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Network Storage
(continued)
• Network Attached Storage (NAS) for
– directly attach to a local area network
– work with multiple operating systems
– use LAN rather than a Fibre Channel
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Network Storage
(continued)
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Removable Disks and
Mobile Storage
• Removable disks are hard disks with a twist
• The first group of drives are those that use flexible
magnetic disks such as Zip disks
• The second group consists of drives that use hard
platters such as Castlewood’s ORB drives
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Removable
Large-Capacity Floppy
Drives
• The Zip drive is addressed like a hard disk
– storage capacity of 100 or 750 MB
– external and internal varieties with printer port,
SCSI, EIDE, or USB connections
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Removable Rigid Cartridges
• Castlewood Systems, Inc. makes the ORB 2.2
GB and the ORB 5.7 GB drives
• The ORB drives come in
– EIDE, SCSI, USB, and FireWire models
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Mini USB Drives
• Mini or thumb drives
– use USB port
– Plug and Play
– 64 MB to 1 GB
• Table 6-2 shows storage devices and
capacities
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Mini USB Drives (continued)
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Tape drives
• Used to back up large volumes of data
• Popular for long term storage
• Tape media capacities:
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DAT Drives
• Digital Audio Tape drives
– use 4-mm tapes
– digital data storage (DDS) tapes
– DDS-4 capacity 20 Gb (40 Gb compressed)
– backward compatible with other DDS tapes
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DLT and SDLT Drives
• Digital Linear Tape drives
– use half-inch wide tapes
– 128 to 208 tracks
– DLT-III tapes are 10 GB (20 GB compressed)
– used in automated tape backup systems
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DLT and SDLT Drives
(continued)
• Super Digital Linear Tape drives
– magnetic and optical recording methods
– 160 Gb (320 Gb compressed)
– up to 640 Mb (1.28 Tb compressed)
– 1.2 Tb (2.4 Tb compressed) to be released in 2006
or 2007
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AIT and S-AIT Drives
• Advanced Intelligent Tape or Super Advanced
Intelligent Tape drives
• erasable memory chip in cartridge
• 35/90 Gb to 500 Gb/1.3 TB
• good for 500,000 hours of operation
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LTO Drives
• Linear Tape Open drives
• high-end server market
• 100 Gb cartridge with 16 Mbps transfer rate
• 1.6 Tb with 320 Mbps transfer rate planned for
future
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Windows Removable
Storage Options
• Introduced in Windows 2000
• Tracks tapes, CD-ROMs, DVD-ROMs, optical
disks
• Figure 6-6 shows the Removable Storage
section under Computer Management in
Windows 2000
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Windows Removable
Storage Options (continued)
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Storage Management Tools
• OS tools and commands to manage storage
devices
• See the Hands-on Projects for step-by-step
instructions
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Windows 2000/XP/Server
2003
• Use Windows Disk Management snap-in
tool
– view and manage hard disks
– see Figure 6-7
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Windows 2000/XP/Server
2003 (continued)
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UNIX/Linux
• Managing, formatting, and partitioning
disks
– fdisk
– format
– sfdisk
– cfdisk
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UNIX/Linux (continued)
• Mount a file system
– mount
– User Mount Tool
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UNIX/Linux (continued)
• GNOME-based Hardware Browser
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NetWare 6.x
• Novell Storage Services (NSS)
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Mac OS X
• Disk Utility
– repair the disk using the First Aid option
– erase the contents
– partition and format the disk
– set up RAID
– restore a disk image or volume
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Mac OS X (continued)
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Summary
• Conceptual overview of how operating systems
interface with storage devices
• Storage technologies such as hard disk drives,
RAID arrays, CD-ROMs, and DVD drives
• Removable storage devices such as Zip disk
and ORB drivers
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Summary (continued)
• Storage are networks (SANS) and network
attached storage (NAS)
• Tape drive options such as DAT, DLT SDLT AIT,
S-AIT, and LTO drives
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Summary (continued)
• Storage management tools
– disk management
– disk defragmenter
– event viewer
– Performance Logs and Alerts
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