Tashkent University of Information Technology

A hard disk
(HDD) - hard disk, hard disk, or fixed 
disk is an electromechanical data storage device that 
stores and retrieves digital data using a magnetic storage 
device and one or more hard, rapidly rotating plates 
coated with magnetic material. The plates are coupled to 
magnetic heads, usually located on the movable arm of the 
drive, which read 
and write data on 
the surface of the 
plates. Data is 
accessed by the 
random 
access 
method, that is, 
individual 
data 
blocks can be 
stored 
and 

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retrieved in any order. Hard drives are a type of non-
volatile storage, keeping stored data even when the power 
is off. Modern hard drives usually have the shape of a small 
rectangular box. 
Hard drives, introduced by IBM in 1956, have been the 
dominant secondary storage device for general-purpose 
computers since the early 1960s. Hard drives have retained 
this position in the modern era of servers and personal 
computers, although personal computing devices 
manufactured in large volumes, such as cell phones and 
tablets, rely on flash storage devices. Historically, more 
than 224 companies have produced hard drives, although 
after extensive industry consolidation, most units are 
manufactured by Seagate, Toshiba and Western Digital. 
Hard drives dominate the volume of storage produced 
(exabytes per year) for servers, despite the fact that 
production is growing slowly (per exabytes shipped), 
sales revenue and single shipments are declining, since 
solid-state drives (SSDs) have a higher data transfer rate, 
higher storage density, slightly better reliability and much 
less latency and access time. 
 
A graphics card
- is an expansion card that generates a 
stream of output images to a display device (such as a 
computer monitor). They are often advertised as discrete 
or dedicated graphics cards, emphasizing the difference 

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between them and integrated graphics. Both are based on 
the graphics processor 
(GPU), which is the 
main 
component 
that 
performs 
calculations, 
but 
should 
not 
be 
confused with the 
graphics card as a 
whole, 
although 
"GPU" is often used as a 
metonymic abbreviation for graphics cards.