Storage devices used to store operating system, software, data, etc. Storage devices is also known as secondary memory or external memory. They are non-volatile memory. There are many storage devices such as floppy disk, hard drive, SSD, optical disc, USB, etc. This article will present the features of solid-state drive (SSD) and Compact Disc (CD).
1. SSD (Solid State Drive)
SSD consists of many memory chips, using flash memory to store data. This storage device has faster data access speed than HDD.
Internal flash memory in SSD
It is non-volatile memory that can be erased and reprogrammed. Flash memory includes NAND and NOR gates, which are logic gates.
Architecture of SSD
The important component is the Flash Controller and many Flash memory chips.
Types of connectors of SSD
SATA 3 includes 7 data pins and 15 power pins. According to the size, there are 3.5 inch, 2.5 inch types.
It is 1.8 inches in size. Micro SATA includes 7 data pins and (7+2) power pins. It usually has a SATA to Micro SATA converter.
It is a miniature connector of 2.5 inch SSD. mSATA also includes 7 data pins and 15 power pins.
M.2 SATA has 3 types: 2242, 2260 and 2280. They have default width is 22mm and variable length is 42mm, 60mm, 80mm respectively. They includes 6 pins + 19 pins + 5 pins.
It also known as M.2 PCIe. M.2 NVME includes 29 pins + 5 pins.
2. OD drive (Optical Disc Drive)
OD drive has function that read/write data of optical disc. Data of optical disc is read/written by converging of light rays. The optical drive composes of two parts: the mechanical part and the electrical circuit.
CD-ROM (Compact Disc Read-Only Memory) consists of a pre-pressed optical compact disc that contains data. It has a diameter of 120, 80 mm. CD-ROM has a storage capacity of 650-700MB.
Classification of compact disc
- CD Recordable (CD-R): data recorded in bit by bit, laser recorded. CD-R is recorded once, can continue recording if space is available.
- CD Rewritable (CD-RW): data can be erased, rewritten many times.
- DVD (Digital Versatile Disc or Digital Video Disc): an optical disc storage similar to a compact disc. But DVD has bigger data storage capacities as well as with higher quality of video and audio formats. Types of DVD are DVD-R, DVD-RW. Capable of storing over 4GB (theoretical 4.7GB, actual 4.3GB).