what is hard disk. what is partition in hard disk. what is raid in hard disk?

Question

i have interest in computer. i am doing networking and hardware diploma. i want to gain more knowledge by anybody who interested in this field . please help me, you provided me more knowledge about operation system. hardware, networking. i will be very thankful

Answer 1

A hard disk is part of a unit, often called a "disk drive," "hard drive," or "hard disk drive," that stores and provides relatively quick access to large amounts of data on an electromagnetically charged surface or set of surfaces. Today's computers typically come with a hard disk that contains several billion bytes (gigabytes) of storage.
A hard disk is really a set of stacked "disks," each of which, like phonograph records, has data recorded electromagnetically in concentric circles or "tracks" on the disk. A "head" (something like a phonograph arm but in a relatively fixed position) records (writes) or reads the information on the tracks. Two heads, one on each side of a disk, read or write the data as the disk spins. Each read or write operation requires that data be located, which is an operation called a "seek." (Data already in a disk cache, however, will be located more quickly.)

A hard disk/drive unit comes with a set rotation speed varying from 4500 to 7200 rpm. Disk access time is measured in milliseconds. Although the physical location can be identified with cylinder, track, and sector locations, these are actually mapped to a logical block address (LBA) that works with the larger address range on today's hard disks.



A hard disk partition is a defined storage space on a hard drive.

Most operating systems allow users to divide a hard disk into multiple partitions, in effect maaking one physical hard disk into several smaller logical hard disks.

Reasons to Use Hard Disk Partitions
A user may decide to split a hard disk into multiple partitions in order to organize his data more effectively. On Microsoft Windows machines, it is common to store the OS and applications on one hard disk partition and user data on another hard disk partition. When a problem occurs with Microsoft Windows, the OS partition can be completely formatted and reinstalled without affecting the data partition.

A user may decide to split a hard disk into multiple partitions because smaller partitions often have smaller cluster sizes. A cluster size is the smallest chunk of data which a partition can store. A large partition might have a cluster size of 16KB. This mens that a file with one character in it will occupy 16KB of space on the disk. In a smaller partition, that file might only require 4KB to store. This is a useful strategy if you are storing a large number of small files.

A user may have to split a large hard disk into multiple partitions if the hard disk is larger than the partition size supported by the operating system.

Creating Hard Disk Partitions
Most operating system use the `fdisk` command to create hard disk partitions. Many ooperating systems also have graphical tools which accomplish the same task.

Hard Disk Partitions and File Systems
You don't actually store data in hard disk partitions.

You store file systems in hard disk partitions and then you store data in these file systems.

Some operating systems blur the lines between partitions and filesystems.

The Partition Table
Partition information is stored in the partition table, a reserved area at the beginning of a hard disk.

Extended Partitions
A standard partition table is only able to store information about four partitions. At one time this meant that a hard disk could have a maximum of four partitions.

To work around this limitation, extended partitions were created.

An extended partition stores information about other partitions. By using an extended partition, you can create many more than four partitions on your hard disk.

The four standard partitions are often called the primary partitions.

Partitions configured into an extended partition are often referred to as logical partitions.

Partition Types
When a partition is created, a special byte of data is written to record what type of partition it is.

Because one hard disk may be shared by multiple operating systems, operating systems tend to agree on the meaning of these values.

The table below lists some of the partition types in use.

Partition Number Partition Type
00 Empty
01 DOS 12-bit FAT
02 XENIX root
03 XENIX usr
04 DOS 16-bit FAT <=32M
05 DOS Extended Partition
06 DOS 16-bit FAT >=32
07 OS/2 HPFS, WinNT NTFS
08 AIX
09 AIX bootable
0a OS/2 Boot Manager
0b Win95 FAT32
0c Win95 FAT32 (LBA)
0e Win95 FAT16 (LBA)
0f Win95 Extended (LBA)
35 OS/2 JFS
39 Plan 9
40 Venix 80286
51 Novell
52 Microport
63 Unix System V, Mach, GNU HURD
64 Novell Netware 286
65 Novell Netware 386
75 PIC/IX
80 MINIX until 1.4a
81 MINUX, Linux
82 Solaris X86, Linux swap
83 Linux native
85 Linux extended
93 Amoeba
94 Amoeba BBT
a5 FreeBSD, NetBSD, BSD/386, 386BSD
a6 OpenBSD
a7 NEXTSTEP
b7 BSDI BSD/386 filesystem
b8 BSDI BSD/386 swap
be Solaris 8 bootable
bf Solaris x86
c7 Syrinx
db CP/M
e1 DOS access
e3 DOS R/O
eb BeOS BFS
fb VMWare filesystem
fc VMWare swap
f2 DOS secondary
ff Xenix Bad Block Table



RAID (redundant array of independent disks; originally redundant array of inexpensive disks) is a way of storing the same data in different places (thus, redundantly) on multiple hard disks. By placing data on multiple disks, I/O (input/output) operations can overlap in a balanced way, improving performance. Since multiple disks increases the mean time between failures (MTBF), storing data redundantly also increases fault tolerance.
A RAID appears to the operating system to be a single logical hard disk. RAID employs the technique of disk striping, which involves partitioning each drive's storage space into units ranging from a sector (512 bytes) up to several megabytes. The stripes of all the disks are interleaved and addressed in order.

In a single-user system where large records, such as medical or other scientific images, are stored, the stripes are typically set up to be small (perhaps 512 bytes) so that a single record spans all disks and can be accessed quickly by reading all disks at the same time.

In a multi-user system, better performance requires establishing a stripe wide enough to hold the typical or maximum size record. This allows overlapped disk I/O across drives.

There are at least nine types of RAID plus a non-redundant array (RAID-0):

RAID-0: This technique has striping but no redundancy of data. It offers the best performance but no fault-tolerance.
RAID-1: This type is also known as disk mirroring and consists of at least two drives that duplicate the storage of data. There is no striping. Read performance is improved since either disk can be read at the same time. Write performance is the same as for single disk storage. RAID-1 provides the best performance and the best fault-tolerance in a multi-user system.
RAID-2: This type uses striping across disks with some disks storing error checking and correcting (ECC) information. It has no advantage over RAID-3.
RAID-3: This type uses striping and dedicates one drive to storing parity information. The embedded error checking (ECC) information is used to detect errors. Data recovery is accomplished by calculating the exclusive OR (XOR) of the information recorded on the other drives. Since an I/O operation addresses all drives at the same time, RAID-3 cannot overlap I/O. For this reason, RAID-3 is best for single-user systems with long record applications.
RAID-4: This type uses large stripes, which means you can read records from any single drive. This allows you to take advantage of overlapped I/O for read operations. Since all write operations have to update the parity drive, no I/O overlapping is possible. RAID-4 offers no advantage over RAID-5.
RAID-5: This type includes a rotating parity array, thus addressing the write limitation in RAID-4. Thus, all read and write operations can be overlapped. RAID-5 stores parity information but not redundant data (but parity information can be used to reconstruct data). RAID-5 requires at least three and usually five disks for the array. It's best for multi-user systems in which performance is not critical or which do few write operations.
RAID-6: This type is similar to RAID-5 but includes a second parity scheme that is distributed across different drives and thus offers extremely high fault- and drive-failure tolerance.
RAID-7: This type includes a real-time embedded operating system as a controller, caching via a high-speed bus, and other characteristics of a stand-alone computer. One vendor offers this system.
RAID-10: Combining RAID-0 and RAID-1 is often referred to as RAID-10, which offers higher performance than RAID-1 but at much higher cost. There are two subtypes: In RAID-0+1, data is organized as stripes across multiple disks, and then the striped disk sets are mirrored. In RAID-1+0, the data is mirrored and the mirrors are striped.
RAID-50 (or RAID-5+0): This type consists of a series of RAID-5 groups and striped in RAID-0 fashion to improve RAID-5 performance without reducing data protection.
RAID-53 (or RAID-5+3): This type uses striping (in RAID-0 style) for RAID-3's virtual disk blocks. This offers higher performance than RAID-3 but at much higher cost.
RAID-S (also known as Parity RAID): This is an alternate, proprietary method for striped parity RAID from EMC Symmetrix that is no longer in use on current equipment. It appears to be similar to RAID-5 with some performance enhancements as well as the enhancements that come from having a high-speed disk cache on the disk array.

Answer 2

A hard disk is the place or device where the computer stores all information. Its a non volatile memory i.e. data is still there after you turn off and switch on again the computer.
A partition is a logical marked area on the Hard Disk itself. It helps in organizing the files and also to keep different types of filesystems on same Hard Disk device.
Raid is a logical scheme of connecting many hard disks together and getting a good performance. Raid can be a special hardware device that lets you connect many hardisks to the system or it can be Software Raid that just enables the operating system to manage multiple disks using normal cables.

you can search for more on the wikipedia on these topics

Answer 3

Hard Disk : Storage space inside the computer. Imagine a house.

Partition: Splits up the hard disk into different section. Imagine the rooms in the house.

Raid (array of independent disks): Using many hard disk as 1 storage area. Imagine if u own 2 or more houses side by side. But it's still under your home.

Hope it's clear.

Answer 4

Hard Disk is A Secondary Storage device ranging from 2.1 GB to 180 GBs
Partition enables the user to have multiple sections on the same HDD with the size distributed as per settings
Raid is a software tool by VIA Inc that connects both HDD and MotherBoard with other secondary and tertiary devices in the CPU.

Answer 5

RAID is redundant array of inexpensive or independent disk. It is a category of disk drive that employ two or more drive in combination for fault tolerance.
I.e if one disk fail then also data is not lost because copy of it is made on other disk.
They are used for server and not preferred for personal computer as performance is also to be taken into account.
There are different levels of raid from 0 to 7 for more information you can use google search.

partition means we are dividing the hard disk into different section.There needs to be one primary partition which is generally c. Partition contain information about files and folders on that partition only.This partition are only logical it does not mean that hard disk is cut into two three pieces. It helps in organizing of data more conveniently. The only drawback of partition is that it uses extra space to store information about partition. Still benefit of partition are worth creating it.

Hard disk is one of reliable medium to store and retrieve data. There are different types of hard disk like SATA and ATA . serial ATA are more faster compared to parallel ATA.

Answer 6

A hard disk drive (HDD, also known as hard disk, hard drive, or the now-near-obsolete terms fixed disk, fixed drive, fixed disk drive, hard file) is a digitally encoded non-volatile storage device which stores data on the magnetic surfaces of hard disk platters.

http://en.wikipedia.org/wiki/Hard_disk

In computer engineering, hard disk drive partitioning is the creation of logical divisions upon a hard disk that allows one to apply operating system-specific logical formatting. In layman's terms, partitioning a hard drive makes it appear to be more than one hard drive, especially in how each partition is formatted for different operating systems, and in how files are copied from one partition to another.

http://en.wikipedia.org/wiki/Partition_%28computing%29

Answer 7

a partition is a general term which means some part of the hard disk. all these things you are going to study in your diploma
don't ask for taste before eating.
Ahard disk is a mass storage device inside your computer(CPU)

Answer 8

hard disk is like a cd which stores data but much greater than cd. partition of a hard disk(we can say make drive of harddisk)is just to save our data in a significant manner.that is like why we make boxes in an almirah . raid in hard disk is that someone stole your data from hard disk.

ihave also done computer hardware andnetworking diploma from jetking institute ludhiana

please mail me at [e-mail]

Answer 9

hard disk is the disk inside the mein drive mostly the c: drive partition is whan the pc makes another virtul drive inside the drive i dont know what raid