Hdd and SSD
The hard drive is an important component of a computer as it permanently stores all the data that is processed by the CPU. The hard drive is usually the slowest component in the computer but it can be faster if you select the right kind of hard drive.
There are different types of hard drives. The old hard drives were hard disk drives (HDD) which are still abundantly used because they are cheaper compared to other alternatives. The newer kind of hard drives are Solid State Drives (SSD) which are expensive but are a lot faster than HDD.
A hard drive fits inside a computer case and is firmly attached with the use of braces and screws to prevent it from being jarred as it spins. Typically it spins at 5,400 to 15,000 RPM. The disk moves at an accelerated rate, allowing data to be accessed immediately. Most hard drives operate on high speed interfaces using serial ATA (SATA) or serial attached technology. When the platters rotate, an arm with a read/write head extends across the platters. The arm writes new data to the platters and reads new data from them. Most hard drives use enhanced integrated drive electronics (EIDE) including cables and connectors to the motherboard. All data is stored magnetically, allowing information to be saved when power is shut off.
Hard drives need a read only memory (ROM) controller board to instruct the read/write heads how, when and where to move across the platters. Hard drives have disks stacked together and spin in unison. The read/write heads are controlled by an actuator, which magnetically reads from and writes to the platters. The read/write heads float on a film of air above the platters. Both sides of the platters are used to store data. Each side or surface of one disk is called a head, with each one divided into sectors and tracks. All tracks are the same distance from the center of the disk. Collectively they comprise one cylinder. Data is written to a disk starting at the furthest track. The read/write heads move inward to the next cylinder once the first cylinder is filled.
A hard drive is divided into one of more partitions, which can be further divided into logical drives or volumes. Usually a master boot record (MBR) is found at the beginning of the hard drive and contains a table of partition information. Each logical drive contains a boot record, a file allocation table (FAT) and a root directory for the FAT file system.
SSD
SSD is an advance storage that uses flash memory. Floating gate transistors record a charge to store the data. The gates are organized in grids and further, they are organized in blocks. SSD controller manages all the operations. There is no moving part, so SSDs are more durable and use less energy.
Short for solid-state drive, an SSD is a storage medium that uses non-volatile memory to hold and access data. Unlike a hard drive, an SSD has no moving parts, which gives it advantages, such as faster access time, noiseless operation, higher reliability, and lower power consumption. The picture shows an example of an SSD made by Crucial.
As the costs have come down, SSDs have become suitable replacements for a standard hard drive in both desktop and laptop computers. SSDs are also a great solution for netbooks, nettops, and other applications that don't require a lot of storage.
SSD Vs HDD
SSDs are 30% faster than an HDD are work silently. It also uses less power that means better battery life for laptops. Many SSDs come with SATA III ports, so you can easily replace an already installed HDD. SSDs can also be used over PCIe connection or M.2 port. Recent laptops generally use M.2 SSDs because they are smaller than SATA SSDs. NVMe is the newest SSD technology and is faster. Modern SSDs are really compact and be as small as a postage stamp. That’s why they have helped in making compact laptops.
SSDs are available from 128GB – 4TB capacities but are costly, so people generally prefer 256-512GB SSD storage as primary dive and additional HDD for more storage.
SSDs are faster than HDDs. An SSD will load data faster than a HDD will.
SSDs are less likely to break than HDDs because HDDs are comprised of moving parts. Empty list
SSDs are quieter than hard drives. A PC with a hard drive will be noisier than an SSD and may even send vibrations throughout your desk space if you use an external enclosure. Empty list
HDDs are cheaper than SSDs. You’ll get a better price per gigabyte (GB) with HDDs. So if budget or a large amount of files is your top concern, an HDD is worth considering.
In laptops, opting for an SSD can lead to longer battery life. Up to 45 minutes on average compared to HDD-equipped laptops.
Price
One of the main reasons HDDs have remained relevant has been their price per gigabyte. We’re currently seeing SSDs sell for under $100, or just $0.10 per GB, while HDDs are roughly $0.02-$0.03 per GB.
Therefore, HDDs are appealing to those looking for bulk storage. But their days seem numbered. Considering most people only need up to 500GB to meet their storage needs, HDDs are losing market share faster by the day. Many HDD vendors are now pushing HDDs for NAS applications and selling SSDs.
Advantages and Disadvantages of SSD and HDD
Hard drives are still around in budget and older systems, but SSDs are now the rule in mainstream systems and high-end laptops like the Apple MacBook Pro, which does not offer a hard drive even as a configurable option. Desktops and cheaper laptops, on the other hand, will continue to offer HDDs, at least for the next few years.
That said, both SSDs and hard drives do the same job: They boot your system, and store your applications and personal files. But each type of storage has its own unique traits. How do they differ, and why would you want to get one over the other?
Reliability
Unlike HDD drives, SSD disks do not have moving parts. So SSD reliability is higher. Moving parts in an HDD increase the risk of mechanical failure. The rapid motion of the platters and heads inside the hard disk drive make it susceptible to “head crash”. Head crashes can be caused by electronic failure, a sudden power failure, physical shock, wear and tear, corrosion, or poorly manufactured platters and heads. Another factor impacting reliability is the presence of magnets. HDDs use magnetic storage so are susceptible to damage or data corruption when in close proximity with powerful magnets. SSDs are not at risk for such magnetic distortion.
Data Transfer in an HDD vs SSD
In an HDD, data transfer is sequential. The physical read/write head "seeks" an appropriate point in the hard drive to execute the operation. This seek time can be significant. The transfer rate can also be influenced by file system fragmentation and the layout of the files. Finally, the mechanical nature of hard disks also introduces certain performance limitations.
In an SSD, data transfer is not sequential; it is random access so it is faster. There is consistent read performance because the physical location of data is irrelevant. SSDs have no read/write heads and thus no delays due to head motion (seeking).
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