What is Hard Disk Drive

 Hard Disk Drive

 what is a hard disk drive a hard disk drive is a data storage device that uses magnetic storage to store and retrieve digital information using one are more rigid rapidly rotating discs put in the magnetic material the platters are padded with magnetic heads usually arranged on a moving actuator arm which read and write data on the platter surfaces data is accessed in a random access memory meaning that individual blocks of data can be stored or retrieved in any order and not only sequentially STDs are a type of non-volatile storage retaining store the data even when powered off introduced by IBM in 1956 H CDs became the dominant secondary storage device for general-purpose computers by the early 1960s more than 200 companies have produced as CDs historically though after extensive industry consolidation most current units are manufactured by Seagate Toshiba and Western Digital the primary characteristics of HDD are its capacity and performance capacity specified in unit four fixes corresponding to powers of thousand a 1tb drive has a capacity of 100 gigabytes where 1 GB is equal to 1 billion bytes the two most common form factors of hen CDs are 3.5 inch for 

 Hard Disk Drive

desktop computers and 2.5 which primarily for laptops HD DS are connected to systems by standard interface cables such as pata parallel ata SATA serial ata USB or SAS serial Attached SCSI cables SCSI pronounced scusi and sometimes colloquially known as scuzzy the small computer system interface let's look into the improvements of HDD characteristics over time let's look into how they all started in 1956 and how it has been developed to 2017 so the parameter is follows capacity when formatted it started with three point seven five megabytes and entered in 14 terabytes physical volume 68 cubic feet 1.9 cubic meter now which is just 2.1 cubic inches that is 34 cubic centimeters wait mmpumps around 910 kgs now it is just 2 point 2 ounces 62 grams average access time approximately 600 milliseconds now it is just to point to 10 milliseconds read/write depends on the lab price it was nine thousand two hundred US dollars per megabyte in 1961 now they just cost 0.32 u.s. dollars per gigabyte by 2015 data density two thousand bits per square inch now which is one point three terabytes per square inch in 2015 average lifespan two hundred hours mean time between failures back in 1956 now they are 2.5 million hours mean time between failures in 2017