Storage devices

The devices used for storage and retrieval of data for the later use are called storage devices. storage devices are commonly classified into two categoris.

1:- PRIMARY STORAGE

2:- SECONDARY STORAGE

Storage devices are the computer hardware used to remember/store data.

1:- PRIMARY STORAGE...

             

All data and programs used unit is called internal storage, because it usually occupies the same physical enclosures as the CPU.

The development of-semi-conductor silicon memory chips helped the computer to retain data and programs’ instruction. The instruction retained in the chips can initiate input/output operations and processing functions. Following clips are used as primary storage device.

RAM (Random Access Memory)

ROM (Read Only Memory)

2:- SECONDARY STORAGE....

secondary storage also called auxiliary storage or mass storage devics. it is used to store data and instructions for future use. these devices are available with high capacity as compare to primary storage devices. secondary storage devices are widely used to store large amount of data for future use.

1. Hard Drive Disk
2. Floppy Disk
3. Tape
4. Compact Disc (CD)
5. DVD and Blu-ray Discs
6. USB Flash Drive
7. Secure Digital Card (SD Card)
8. Solid State Drive (SSD)
9. Cloud Storage

PRIMARY STORAGE VS SECONDARY STORAGE DEVICES

TYPES OF PRIMARY STORAGE DEVICE :-

There are two main types of primary storage devices these are 

RAM

ROM

RAM (Random Access Memory)

 RAM (random access memory) is a hardware device that allows information to be stored and retrieved on a computer. RAM is usually associated with DRAM, which is a type of memory module. Because information is accessed randomly instead of sequentially like it is on a CD or hard drive, access times are much faster. However, unlike ROM, RAM is a volatile memory and requires power to keep the data accessible. If the computer is turned off, all data contained in RAM is lost.

Types of RAM

Over the evolution of the computer, there have been different variations of RAM. Some of the more common examples are DIMM, RIMM, SIMM, SO-DIMM, and SOO-RIMM.

ROM (Read Only Memory)

Read-only memory (ROM) is a type of storage medium that permanently stores data on personal computers (PCs) and other electronic devices. It contains the programming needed to start a PC, which is essential for boot-up; it performs major input/output tasks and holds programs or software instructions.

Because ROM is read-only, it cannot be changed; it is permanent and non-volatile, meaning it also holds its memory even when power is removed. By contrast, random access memory (RAM) is volatile; it is lost when power is removed.

There are numerous ROM chips located on the motherboard and a few on expansion boards. The chips are essential for the basic input/output system (BIOS), boot up, reading and writing to peripheral devices, basic data management and the software for basic processes for certain utilities.

Types of ROM

ROM may sometimes be called maskROM (MROM). MROM is a form of read-only memory that is static and programmed into an included circuit by the manufacturer. Solid-state ROM, the oldest type of ROM, is an example of maskROM. With the original ROM, since it was truly read-only, it had to be removed and physically replaced in order to change any of its contents.

However, new types of ROM have emerged that are still non-volatile, but can be reprogrammed; these types are categorized as programmable read-only memory (PROM). PROM can be used to update firmware, such as BIOS, through the utilization of installation software.

Types of PROM include:

• Ultraviolet-erasable ROM (UV-ROM) - ROM whose contents can be erased using ultraviolet light, and then reprogrammed.
• Erasable programmable ROM (EPROM) - A type of ROM that is programmed using high voltages and exposure to ultraviolet light for about 20 minutes.
• Electrically-erasable programmable ROM (EEPROM) - Often used in older computer chips and to control BIOS, EEPROM can be erased and reprogrammed several times while enabling the erase and writing of only one location at a time. Flash memory is an updated version of EEPROM that allows numerous memory locations to be changed at the same time.
  TYPES OF SECONDARY STORAGE DEVICES

• Hard Disk Drive

  A hard disk drive (also known as a hard drive, HD, or HDD) can be found installed in almost every desktop computer and laptop. It stores files for the operating system and software programs, as well as user documents, such as photographs, text files, and audio. The hard drive uses magnetic storage to record and retrieve digital information to and from one or more fast-spinning disks.

  2. Floppy Disk

  Also know as a diskette, floppy, or FD, the floppy disk is another type of storage medium that uses magnetic storage technology to store information. Floppy disks were once a common storage device for computers and lasted from the mid-1970's through to the start of the 21st century. The earliest floppies were 8-inch (203 mm) in size, but these were replaced by 5 ¹⁄₄-inch (133 mm) disk drives, and finally a ​3 ¹⁄₂ inch (90 mm) version.

  3. Tape

  In the past, magnetic tape was often used for digital data storage, because of its low cost and ability to store large amounts of data. The technology essentially consisted of a magnetically thin coated piece of plastic wrapped around wheels. Its relative slowness and unreliability compared to other data storage solutions has resulted in it now being largely abandoned as a media.

  4. Compact Disc (CD)

  The compact disc, known for short as a CD, is a form of optical storage, a technology which employs lasers and lights to read and write data. Initially compact discs were used purely for music audio, but in the late 1980's they began to be also used for computer data storage. Initially, the compact discs that were introduced were CD-ROM's (read only), but this was followed by CD-R's (writable compact discs) and CD-RW's (re-writable compact discs).

  
  

  5. DVD and Blu-ray Discs

  The DVD (digital versatile disc) and Blu-ray disc (BD) are formats of digital optical disc data storage which have superseded compact discs, mainly because of their much greater storage capacity. A Blu-ray disc, for example, can store 25 GB (gigabytes) of data on a single-layer disc and 50 GB on a dual-layer disc. In comparison, a standard CD is the same physical size, but only holds 700 MB (megabytes) of digital data.

  6. USB Flash Drive

  Also known as a thumb drive, pen drive, flash-drive, memory stick, jump drive, and USB stick, the USB flash drive is a flash memory data storage device that incorporates an integrated USB interface. Flash memory is generally more efficient and reliable than optical media, being smaller, faster, and possessing much greater storage capacity, as well as being more durable due to a lack of moving parts.

  7. Secure Digital Card (SD Card)

  A common type of memory card, SD cards are used in multiple electronic devices, including digital cameras and mobile phones. Although there are different sizes, classes, and capacities available, they all use a rectangular design with one side "chipped off" to prevent the card from being inserted into the camera or other device the wrong way.

  8. Solid State Drive (SSD)

  A solid state drive uses flash memory to store data and is sometimes used in devices such as netbooks, laptop, and desktop computers instead of a traditional hard disk drive. The advantages of an SSD over a HDD include a faster read/write speed, noiseless operation, greater reliability, and lower power consumption. The biggest downside is cost, with an SSD offering lower capacity than an equivalently priced HDD.

  9. Cloud Storage

  With users increasingly operating multiple devices in multiple places, many are turning to online and cloud computing solutions. Cloud computing basically involves accessing services over a network via a collection of remote servers. Although the idea of a "cloud of computers" may sound abstract to those unfamiliar with this metaphorical concept, in practice it can provide tremendous storage solutions for devices that are connected to the internet.