NET-103 (Chapter 5)

Foreign

A Foreign disk is a dynamic disk that was created in one system and moved to another system. When you first add the disk to a different system, the partition information for the disk must be updated to reflect all dynamic disks in the current system. Import the disk to make it available in the new system.

System Restore

A Microsoft feature that lets your revert a computer's state to a previous period in time.

RAID 10 (Stripe of Mirrors)

A RAID 10 volume stripes data across mirrored pairs and across multiple disks for data redundancy. If a single disk fails, its data can be recovered using the mirrored information stored on the remaining disks. If two disks in the same mirrored pair fail, all data will be lost because there is no redundancy in the striped sets. Provides fault tolerance for a single disk failure. Provides redundancy and performance. Uses 50% of the total raw capacity of the drives is due to mirroring. Requires a minimum of four disks.

RAID 5 (Striping with Distributed Parity)

A RAID 5 volume combines disk striping across multiple disks with parity for data redundancy. Parity information is stored on each disk. If a single disk fails, its data can be recovered using the parity information stored on the remaining disks. Striping with distributed parity: Provides fault tolerance for a single disk failure. Provides an increase in performance for read operations. Write operations are slower with RAID 5 than with other RAID configurations because of the time required to compute and write the parity information. Requires a minimum of three disks. Has an overhead of one disk in the set for parity information. (1 / n). A set with 3 disks has 33% overhead. A set with 4 disks has 25% overhead. A set with 5 disks has 20% overhead.

Storage Space

A Windows function that allows you to group physical disks into storage pools and create virtual disks from the available capacity.

Storage Spaces

A Windows technology that helps prevent drive failures by allowing you to group drives into a storage pool and make data backups.

Just a Bunch of Disks (JBOD)

A configuration that places multiple disks in a single logical storage unit.

Directory

A container in a volume that holds files or other directories.

Directory

A directory (also called a folder) is a container in a volume that holds files or other directories. It is used to logically sort and organize data to keep related files grouped together. Most operating systems use a hierarchal filing structure.

Redundant Array of Independent Disks (RAID)

A disk sub-system that combines multiple physical disks into a single logical storage unit.

File

A file is a one-dimensional stream of bits treated as a logical unit. Files are the most basic component that a file system uses to organize raw bits of data on the storage device itself. The file name is made up of the directory path plus the file name. An extension can also be added to the filename to identify the file type and the program used to create, view, and modify the file.

File

A file is a one-dimensional stream of bits treated as a logical unit. They are the most basic component that a file system uses to organize raw bits of data on the storage device itself. The filename is made up of the directory path plus the file name. An extension can also be added to the filename to identify the file type and the program used to create, view, and modify the file.

Solid State Drive (SSD)

A flash device with a large storage capacity comparable to a hard disk drive's.

SD card

A flash memory device is often used in digital cameras.

Hard Disk Drive (HDD)

A hard disk is a thick magnetic disk encased in a thicker protective shell. A hard disk consists of several aluminum platters, each of which requires a read/write head for each side. All of the read/write heads are attached to a single access arm to prevent them from moving independently. Each platter has circular tracks that cut through all of the platters in the drive to form cylinders. The spinning of the platters is referred to as revolutions per minute (RPM). The higher the revolutions per minute, the faster the data can be accessed. Standard hard drives are categorized as follow: 5400 rpm (inexpensive HDD) 7200 rpm (good quality HDD) 10,000 rpm (expensive HDD) Some of the advantages of hard disks are: They have lots of storage (starting at 16 GB up to several TB). They are significantly faster than floppy disks. The cost per MB is cheap. Some of the disadvantages of hard disks are: Many hard disks are internal devices, though you can get external enclosures. They are prone to failure. They are vulnerable to physical damage (e.g., when dropped). SCSI is a standard for transferring data between devices on internal and external computer buses. Though SCSI devices are most commonly used for tape storage devices and hard disks, they can also be used for devices such as CD-ROM drives, scanners, and printers.

Hard disk

A long-term storage device; a thick magnetic disk made of several aluminum platters in a protective shell.

File system

A means for organizing and storing data and information on a storage device.

Mean time before failure (MTBF)

A measurement of a hardware component's reliability generally stated in hours or thousands of hours.

Non-Volatile Memory Express (NVMe)

A memory storage device designed to allow access to non-volatile storage media through a PCI express (PCIe) bus.

Non-Volatile Memory Express (NVMe)

A memory storage device designed to allow access to non-volatile storage media through a PCI express (PCIe) bus. NVM Express is designed to work well with low latency and internal parallelism of solid-state storage devices. By allowing host hardware and software to utilize the level of parallelism possible in modern SSDs, NVM Express reduces I/O overhead and improves functionality. NVM Express devices come in three forms. The most common are standard-sized PCI Express expansion cards and a 2.5-inch form-factor devices that provide a four-lane PCI Express interface through the U.2 connector. There are also storage devices that use SATA Express and the M.2 specification, which support NVM Express as the logical device interface.

RAID 1 (Mirroring)

A mirrored volume stores data to two duplicate disks simultaneously. If one disk fails, data is present on the other disk, and the system switches immediately from the failed disk to the functioning disk. Mirroring: Provides fault tolerance for a single disk failure. Does not increase performance. Requires two disks. Has a 50% overhead. Data is written twice, meaning that half of the disk space is used to store the second copy of the data. Overhead is 1 / n where n is the number of disks. RAID 1 is the most expensive fault tolerant system.

Mount point

A mount point is an empty folder on an existing volume that points to another partition. Data saved to the folder is physically saved on the referenced partition.

Mount Point

A mount point is an empty folder on the existing volume that points to another partition. Data saved to the folder is physically saved on the referenced partition.

Partition

A partition is a logical division of a storage device associated with a hard disk drive. Multiple partitions can be assigned to a single device, in which case a drive letter is assigned to represent each partition. Multiple letters do not always mean that there are multiple devices, just multiple partitions. Some reasons why you may consider partitioning your hard drive are: Assigning the boot system to a different partition than application and data files can help many computers run more smoothly and minimize damage in a system crash. Storing the swap file on its own partition is sometimes necessary or useful. Creating a separate partition for your operating system can help it run properly. Some operating systems can't run on a large partition. Assigning log files to be stored on distinct partitions can help minimize the effects of a system crash due to excessively large log files. Assigning distinct operating systems to run on assigned partitions allows a dual boot system setup. Unallocated space is space on a partition that has not been assigned to a volume. You cannot store or read data in unallocated space

M.2

A popular solid state drive often used in portable electronics.

Disk Defragmenter

A program that optimizes the performance of your hard drive by joining fragments of files that are in different locations on your hard drive into a single location.

Windows Update

A program that updates your Windows operating system.

Logical Partition

A reserved block of space on a basic disk. Logical partitions can only be created within an extended partition. As long as free space exists in an extended partition, a new logical partition can be created. Logical partitions can be formatted with a file system directly.

Partition

A section of a hard disk separate from the rest. Partitions allow the operating system to manage the information in each section separately.

Volume

A single accessible storage area within a file system.

Unified Extensible Firmware Interface (UEFI)

A software program specification that connects firmware to the operating system. UEFI is eventually expected to replace BIOS.

Solid State Drive (SSD)

A solid state drive is a flash device with a storage capacity similar to a small hard drive. Solid state drives are used as replacements for hard disk drives for storing operating system, application, and data files. Some advantages of solid state drives: They are faster than hard drives. They have no moving parts. They have lower power consumption than hard drives (good for laptops). They are less susceptible to physical damage (from dropping) and immune from magnetic fields. They are smaller and lighter than hard drives The main disadvantage currently for solid state drives is cost. They are several times more expensive than comparable hard drives. However, their advantages make them a good choice, especially for portable devices. M.2 is a popular SSD for portable devices.

Spanned volume

A spanned volume has unallocated disk space on a different disk.

Extended File Allocation Table (ExFAT or FAT32)

A special file system designed to support large flash drives.

Optical disc

A storage device that records binary information through pits in a reflectively-coated disc. Optical discs use lasers for reading and writing information.

RAID 0 (Striping)

A stripe set breaks data into units and stores the units across a series of disks by reading and writing to all disks simultaneously. Striping: Provides an increase in performance. Does not provide fault tolerance. A failure of one disk in the set means all data is lost. Requires a minimum of two disks. Has no overhead because all disk space is available for storing data.

Volume

A volume is a single accessible storage area within a file system. A volume can encompass a single partition or span across multiple partitions depending on how it is configured and what operating system you are using. Volumes are identified by drive letters.

Active Partition

Active partition is the partition that your bootloader loads the operating system files from. You can boot an operating system only from a partition that's set to active. If your operating system files are in a partition that's not set to active, you can't boot the system.

TRIM

An SSD function that configures the operating system to communicate with an SSD device and tell it which blocks of data on the device are no longer required and can be deleted.

Integrated Drive Electronics (IDE)

An electronic interface allows communication between a motherboard's data paths or bus and a computer's hard disks.

Integrated Drive Electronics (IDE)

An electronic interface that allows communication between a motherboard's data pathos or bus and a computer's hard disks.

Extended volume

An extended volume has unallocated disk space on the same disk.

External Serial Advanced Technology Attachment (eSATA)

An extension to the SATA standard that enables SATA drives to attach externally. eSATA devices use a special SATA data cable with a locking clip to prevent the cable from being accidentally disconnected. Because power is not supplied through the SATA data cable, eSATA devices require an external power connector or power source. eSATA is typically faster than USB. eSATA has a rectangular connector.

Thin provisioning

An option that allows you to allocate larger storage spaces than the disk space available in the pool.

GUID Partition Table (GPT Partitions)

Are a new standard that are gradually replacing MBR partitions. GPT is associated with UEFI. GPT stands for GUID Partition Table. It's named for the fact that every partition on the drive has a globally unique identifier, or GUID. That means that each partition worldwide would have its own unique identifying number. A GPT disk: Can be basic or dynamic. Supports up to 128 partitions depending on space allocated for the partition table. There is no need for extended and logical partitions. Can support between 8 and 9.4 zettabytes depending on the sector size. Stores multiple copies of the partition table across the disk, so it's much more robust and can recover if the data is corrupted. Stores cyclic redundancy check (CRC) values to check that its data is intact. If the data is corrupted, GPT notices the problem and attempts to recover the damaged data from another location on the disk. MBR has no way of knowing if the data is corrupted. You would only see that there was a problem when the boot process failed or the partitions vanished. Includes a protective MBR. The protective MBR sees the GPT drive as a single partition that extends across the entire drive. If you try to manage a GPT disk with an old tool that can only read MBRs, it will see the GPT disk as a single partition that extends across the entire drive. The protective MBR makes sure that the old tools don't mistake the GPT drive for a non-partitioned drive and overwrite all your data. When implementing GPT partitioning, be aware of the following: You'll probably want to use GPT when setting up a drive. However, if you need compatibility with old systems, like the ability to boot Windows off a drive on a computer with a traditional BIOS, you'll need to use MBR. Windows can only boot from GPT on UEFI-based computers running 64-bit versions of Windows 7, 8.x, 10, and the corresponding server versions. All versions of Windows 7 and later can read GPT drives and use them for data, but they cannot boot from them without UEFI. Because Windows 7 does not support UEFI on 32-bit platforms, you cannot boot from a GPT partition on Windows 7. Linux has built-in support for GPT. Apple's Intel Macs no longer use Apple's APT, or Apple Partition Table, scheme but uses GPT instead.

Storage spaces

Are logical drives that display in File Explorer for storing data and other user files. Storage spaces are created by pooling space from multiple disk drives, or other storage devices, and then creating logical drives from the pooled space. A storage space appears to the user as one drive regardless of the number of disks or devices contributing space to the storage pool. The storage spaces feature is available only in Windows 8.x and 10; it is not included in Windows 7. Storage spaces are comprised of three components: Devices are the hard disks or other types of storage from which storage pools are created. You can use a variety of devices such as SATA drives and external drives to create storage pools. Pools of storage are created from the available disk space. A pool is a logical concept composed of the free space available on the specified storage devices. Storage spaces define logical units of space created from a pool. One or more storage spaces can be created from the pool. To the Windows system and the user, storage spaces appear as disks with typical drive letters (e.g., E: drive, F: drive).

Devices

Are the hard disks or other types of storage from which storage pools are created. You can use a variety of devices such as SATA drives and external drives to create storage pools.

Blu-ray Disc (BD)

Blu-ray Disc (BD) is a newer optical disc format that is capable of greater storage capacity than DVDs. Blu-ray was originally developed for high definition video (and expanded content on movie discs), but can also be used for data storage. Blu-ray uses a blue laser instead of the red laser used with CDs and DVDs. The blue laser light has a shorter wavelength, which allows data to be packed more tightly on the disc. A single layer Blu-ray disc holds 25 GB; a double layer disc holds up to 50 GB. Experimental 20 layer discs can hold up to 500 GB. Blu-ray discs can be read-only (BD-ROM), recordable (BD-R), or rewritable (BD-RE). A 1x Blu-ray drive reads data at 4.5 MBps. Most Blu-ray drives include a second read laser for reading CDs and DVDs. Without this additional laser, Blu-ray drives would not be able to read CDs or DVDs. Blu-ray is intended to eventually replace DVD. Blu-ray has become the accepted HD video standard as the last movie studio stopped distributing HD DVD movies.

Compact Disc Read-Only Memory (CD-ROM)

CD-ROMs are identical in appearance to audio CDs. Data are stored and retrieved in a very similar manner to audio CDs. CD-ROMs have lands and pits. They use reflective light to interpret the data on the disc. A standard CD-ROM can hold about 737 MB of data with error correction, or 847 MB total. The first CD-ROM drives transferred data at a rate of 150 kilobytes per second (kB/s). This 150 kB/s data rate is the same speed that's used by an audio CD player. However for PCs, this is a little too slow. Improvements in CD-ROM drive speeds are measured as multiples of this original speed. To calculate your CD-ROM drive's transfer rate, multiply its speed by 150 kB/s.

Digital Versatile Disc (DVD)

DVD (Digital Versatile Disc) is an optical media standard that can be used to store large amounts of different types of data (computer data, video, audio). Most DVD drives can read and write. Older drives or older DVD players might only support DVD-R. A DVD with a single side of data can hold about 4.7 GB. A DVD-ROM is read-only memory. DVD-RW is a rewritable DVD format. DVD-RW uses a crystal encoding on the bottom of the DVD disc. A DVD-RW DL employs two recordable dye layers, each capable of storing about 4.7 GB; the total disk capacity is 8.5 GB. Some DVDs can store data in two different layers on the same side. The outer layer is semi-transparent, allowing the laser to read data from the inner layer. Dual-layer discs can hold up to 8.5 GB of data. Dual-layer recordable discs cost more than single layer discs. Dual-layer DVDs are recorded using Opposite Track Path (OTP). Most newer drives can read both single and dual layer discs. However, older drives might not support dual layer discs. DVD speeds use a multiple of 1.35 MBps (1x = 1.35 MBps, 2x = 2.7 MBps, etc.) or 11 Mbps (1x = 11 Mbps, 2x = 22 Mbps, etc.).

Optical media

Discs that are easily portable and can store large amounts of data.

du command

Du will run through all the directories within a particular directory structure and tell you how much space is being consumed by the files in that directory.

Flash memory

Electronic non-volatile memory that is easy to erase and reprogram.

Basic Input/Output System (BIOS)

Firmware that initializes hardware at startup and provides runtime services to the operating system.

bootrec /fixboot command

Fixes the boot sector.

bootrec /fixmbr command

Fixes the master boot record.

Flash Devices

Flash memory cards store information using programmable, non-volatile flash memory. Some of the advantages of flash devices are: The memory is re-programmable. They can retain content without power. They are optimal for use in devices like cameras. They are highly portable. They have a larger capacity than CDs and DVDs. They have relatively fast memory access. Some of the disadvantages of flash devices are: Their storage capacity is not yet comparable to the capacity of modern hard disks. Different memory card formats require different readers. Common flash memory cards include: CompactFlash cards SD cards SSD cards MiniSD cards MicroSD cards xD cards Hybrid cards (combines SSD and HDD technology) Memory sticks

Formatting

Formatting is the process of preparing a partition to use a specific file system. Be aware of the following facts regarding formatting: When you format a disk, you identify the file system type and identify the cluster size used to store data. Reformatting removes the existing file system and replaces it with the new file system type. Reformatting a drive deletes all existing data. If your system or disk supports multiple operating systems, be sure to select a file system supported by all necessary operating systems. NTFS is not recommended for disks smaller than 10 MB. When using NTFS on removable devices, you must use Safely Remove Hardware before removing the flash device to prevent file corruption. If you run a Full Format, files are removed from the volume you scan and the system checks the hard disk for bad sectors. If you run a Quick Format, the system removes files from the partition, but does not scan the disk for bad sectors.

Hardware

Hardware RAID uses a special controller card that includes a RAID processor. Hardware RAID is the most expensive method but provides much better performance and is more reliable than other methods.

fsck command

Is a command that looks for errors in the file system.

Pool

Is a logical concept composed of the free space available on the specified storage devices.

File System

Is a means for organizing and storing data and information on a storage device.

SATA 2 (Second Generation)

It supported data transfers that were much faster, up to 3 Gbps (300 MBps). SATA 2 included other enhancements that were not included in SATA 1, such as native command queuing (NCQ) that increases the overall performance of the I/O bus. SATA2 includes the following enhancements: Xbox360 hard disk interface (called xSATA) Hot pluggable support, allowing drives to be added and removed while the system is running Improved connectors to reduce ESD, improved usability, and extended life when used with external devices Native Command Queuing (NCQ) for increased performance Port multiplier support, allowing multiple devices to be connected to a single SATA port

SATA 3 (Third Generation)

It supports data transfers up to 6 Gbps (600 MBps). This standard is mainly used for high performance hard disk drives as well as solid state flash drives. This standard also provides newer connectors for solid state devices and for thin optical devices. This standard mainly addresses solid state drives with SATA (hard disk drives are not capable with sending data at this rate). The standard includes new connectors for solid state devices and thin optical drives.

SATA 1 (First Generation)

It transferred data at about 1.5 Gbps (150 MBps), which really isn't a lot faster than the storage standards that it replaced.

df command

It will tell you how much disk space is being consumed on each of the files systems on your Linux system.

New Technology File System (NTFS)

Microsoft's default file system.

Operating System

Operating system RAID uses RAID features within the operating system. Like software RAID, the system CPU is used for RAID operations, but performance is typically better than software RAID because of integration with the operating system.

Optical Disc

Optical discs such as CDs, DVDs, and Blu-ray discs are a storage medium that uses lasers for both reading and writing information. Optical discs store information through pits in their reflective coating. As the disc spins, the optical drive sends laser optics to the disk and receives the stored information through the deflected output. Some of the advantages of optical discs are: They are great for music and video (they play in audio or video devices that aren't computers). They are portable and universal. They are cheap. You can buy discs that are recordable. They have a long shelf life and are relatively sturdy. Blu-ray discs can store a large amount of data (25 GB or more, depending upon the format). Some of the disadvantages of optical discs are: They are slower than hard disks. They have a small capacity (650 MB for CDs, 4.7 GB for DVDs). There are some compatibility issues between disc formats and readers.

Parity

Parity requires that you have at least three storage devices. It uses parity information to reconstruct data if one of the storage devices fails. Parity uses less space for redundancy than the mirror options, but performance is not as good as the mirror options if a device failure occurs. Parity requires only 50 percent more redundancy space than storage space.

Initialize

Prepare a new disk for use.

bootrec /rebuildbcd command

Rebuilds the entire boot configuration data.

Defragmentation

Reducing file fragments by grouping file pieces on a hard drive together.

Self-Monitoring, Analysis, and Reporting Technology (S.M.A.R.T.) errors

S.M.A.R.T. is a monitoring system that detects drive errors. If S.M.A.R.T. detects enough errors that a complete hard disk failure is imminent, a warning is displayed during system boot. S.M.A.R.T. is designed to warn you of disk failures before they actually happen.

Software

Software RAID uses a driver and the system CPU for controlling RAID operations. This is the slowest form of RAID. Some RAID controller cards support RAID configuration, but without the onboard RAID processor. These solutions are classified as software RAID (sometimes called fake RAID) even though you install a controller card to provide RAID capabilities. Many motherboards include built-in (onboard) support for RAID. RAID implemented in this way is typically software/driver RAID. Software RAID uses a driver and the system CPU to control RAID operations. This is the slowest form of RAID.

ExFAT

The Extended File Allocation Table (exFAT, sometimes called FAT64) file system is a special file system that is designed to support large flash drives. Using NTFS on flash drives is usually not a good idea due to its high overhead and risk of corruption if the device is not stopped properly prior to removal. However, many flash drives exceed the 32 GB limit discussed above. Microsoft introduced native exFAT support in Windows 7 to allow large removable flash storage devices to continue to use a FAT-type file system.

Failed

The Failed status shows for a volume that cannot be started, such as when the disk is damaged or the file system is corrupt. Make sure the disk is on and then try reactivating the volume. If that doesn't work, then you likely have data loss.

Formatting

The Formatting status is shown for volumes during the formatting process. After formatting is complete, the status for the volume changes to Healthy.

Healthy or Online

The Healthy or Online status indicates that the disk is turned on and can be accessed. The volume on the disk is valid and has no errors.

Initializing

The Initializing process shows while a disk is being converted from a basic disk to a dynamic disk. After the conversion, the status for the volume changes to Healthy.

Missing Offline

The Missing or Offline statuses show when a dynamic disk has failed, been removed, or turned off. If the disk is turned off, turn it back on, then reactivate the disk. If the disk no longer exists, then delete the disk from Disk Management.

No Media

The No Media status shows for an optical or removable media drive that does not contain a valid disc. This disk status only applies to CD-ROM, DVD-ROM, or removable disks.

Not Initialized Unknown

The Not Initialized or Unknown status indicates a disk without a valid master boot record or partition table (either missing or corrupt). To correct the problem, initialize the disk. If the partition table is invalid, use third party tools to try to recover the partition table.

Online (Errors)

The Online (Errors) status indicates that I/O errors have been detected on a dynamic disk. To correct the problem, try reactivating the disk.

Unallocated

The Unallocated status shows for portions of a disk that have not been assigned to a partition or a volume.

Unavailable

The Unavailable status indicates that errors have occurred on physical or dynamic disks.

Unreadable

The Unreadable status indicates a hardware failure, I/O errors, or other corruption but might also be caused by a delay in reading the disk in Disk Management. Try rescanning the disk to see if the status changes. If it doesn't, troubleshoot the hardware or disk problem.

Optical drive

The disc drive that reads and writes data from optical media.

Serial ATA (SATA)

The latest generation of standards for hard disk and other storage devices.

Extended Partition

The only partition on a hard drive that can contain more than one logical drive. In Windows, a hard drive can have only a single extended partition. Compare to the primary partition.

Formatting

The process of preparing a partition to use a specific file system.

Simple data Provisioning

This option simply adds space from the storage pool to the storage space. When you select the Simple option, all of the data in the storage space is lost if one of the drives fails.

Compact Disc-Rewritable

This type disc can be written, read many times, erased, and rewritten. These discs have a capacity of about 650 MB. It's like having a removable hard drive because you can insert the disc into the disc drive on one PC, add and/or delete data, eject it, insert it into the disc drive on another system, and have all your data immediately accessible. CD-RW drives can write to CD-RW discs, erase CD-RW discs, and read a CD-ROM disc. A CD-RW drive also has a speed rating. The speed rating includes three parameters, one parameter for a write speed, a rewrite speed, and a read speed. All of these are multiples of the original 150 kB/s 1x speed defined by the first CD-ROM drives. If you have an 8x4x32 CD-RW drive, it can write at 1,200 kB/s. It can rewrite to a CD-RW disc at 600 kB/s. It can read at 4,800 kB/s. The bottom surface of a CD-RW drive is coated with a photo reactive crystalline coating. A red laser causes a crystal to form which creates the reflective and non-reflective areas on the bottom of the CD-RW disc. A CD-RW drive has a second, high power write laser. When this laser hits the bottom of this photo reactive material on the bottom of the CD-RW disc, it causes crystals to form. This is called phase shifting or a phase shifting media. A crystal forming on the bottom of a CD-RW disc is like a land on a CD-ROM disk, because it reflects light.

Three-way mirror

Three-way mirror requires at least five storage devices. The data is written to three storage devices. This option provides redundancy for the data if two storage devices fail at one time.

Two-way mirror

Two-way mirror requires at least two storage devices. The data is written to two devices. Two-way mirror requires twice as much device space as the amount of storage allocated to the storage space. This option protects you from a single storage device failure.

Compact Disc (CD)

Were first developed to store digital music. Later the CD technology was adapted to store digital computer data. This was breakthrough technology because CDs were inexpensive to produce and could hold a large amount of data. When the first CD drives for PCs were introduced, PCs had 20 MB hard drives and 40 MB hard drives. Then you could add a CD drive to your PC and suddenly have 650 MB of storage. Users had no idea what to do with all that space. A CD can hold 74 to 80 minutes of audio. A CD is 120 millimeters in diameter and is also 1.2 millimeters thick.

-h option

Which formats the output in human readable form.

eSATAp (Power over eSATA or Power eSATA)

eSATAp combines the functionalities of an eSATA connector and a USB port. It sort of merges them together into a single connector. Because of this, you can plug an eSATA device or a USB device into an eSATAp port. An eSATAp port combines the four pins that are used by USB 2.0 with the seven pins that used by an eSATA port. It also adds two more pins that supply power at five and 12 volts. This allows SATA data, as well as device power, to be carried in a single cable. With that in mind, let's spend a few minutes reviewing the process for selecting and implementing a SATA device. The eSATAp (Power over eSATA or Power eSATA) standards are meant to replace eSATA. eSATAp combines the functionality of an eSATA and a USB port with a source of power in a single connector. Both SATA data and device power are integrated in a single cable. The eSATAp connector and port are neither an L-shaped or rectangular.