Since the invention of the floppy disk drive, various standardized form factors have been used in computing systems. Standardized form factors and interface allow a variety of peripherals and upgrades thereto with no impact to the physical size of a computer system. Drives may slot into a drive bay of the corresponding size.
Compared to flash drives in same form factor, maximum rotating disk drive capacity is much smaller,[ citation needed ] with 100 TB available in 2018 [update] , [1] and 32 TB for 2.5-inch. [2]
Form factor (inch) | Status | Dimensions (Dimension in inches unless otherwise noted) | Largest capacity | Platters (max.) | Capacity per platter (GB) | ||
---|---|---|---|---|---|---|---|
Length | Width | Height | |||||
3.5 | Current | 5.75 | 4.0 | 0.72 [3] or 26.11 mm [4] or 19.99 mm [5] | 30 TB (November 2023) [6] | 10 [7] (June 2022) [8] | 2.6TB |
2.5 | Current | 4.0 | 2.75 | 5, [9] 7, 9.5, [lower-alpha 1] 12.5, 15 or 19 [10] (all mm) | 5 TB [11] (October 2016, no improvement since.) | 5 [12] | 1,000 |
1.8 | Obsolete | 78.5 mm, [lower-alpha 2] 71 mm [lower-alpha 3] | 54 mm | 5 mm [13] or 8 mm | 320 GB [14] (2009) | 2 | 220 [15] |
8 | Obsolete | 14.5 | 9.5 | 4.625 | 2.0 GB (1989) [16] [17] | Unknown. Minimum, 12 | Unknown. Minimum, 0.16 |
5.25 (FH) | Obsolete | 8.0 | 5.75 | 3.25 | 47 GB [18] (1998) | 14 | 3.36 |
5.25 (HH) | Obsolete | 8.0 | 5.75 | 1.625 | 19.3 GB [19] (1998) | 4 [lower-alpha 4] | 4.83 |
1.3 | Obsolete | 50.8 mm [20] | 36.5 mm [20] | 10.5 mm [20] | 40 GB [21] (2007) | 1 | 40 |
1 (CFII/ZIF/IDE-Flex, "Microdrive") | Obsolete | 42.8 mm | 36.4 mm | 5 mm | 20 GB (2006) | 1 | 20 |
0.85 | Obsolete | 32 mm | 24 mm | 5 mm | 8 GB [22] [23] (2004) | 1 | 8 |
IBM's first hard drive, the IBM 350, used a stack of fifty 24-inch platters and was of a size comparable to two large refrigerators. In 1962, IBM introduced its model 1311 disk, which used six 14-inch (nominal size) platters in a removable pack and was roughly the size of a washing machine. This became a standard platter size and drive form-factor for many years, used also by other manufacturers. The IBM 2314 used platters of the same size in an eleven-high pack and introduced the "drive in a drawer" layout, although the "drawer" was not the complete drive.
Later drives were designed to fit entirely into a chassis that would mount in a 19-inch rack. Digital's RK05 and RL01 were early examples using single 14-inch platters in removable packs, the entire drive fitting in a 10.5-inch-high rack space (six rack units). In the mid-to-late 1980s the similarly sized Fujitsu Eagle, which used (coincidentally) 10.5-inch platters, was a popular product.
Such large platters were never used with microprocessor-based systems. With increasing sales of microcomputers having built in floppy-disk drives (FDDs), HDDs that would fit to the FDD mountings became desirable. Thus HDD Form factors, initially followed those of 8-inch, 5.25-inch, and 3.5-inch floppy disk drives. Because there were no smaller floppy disk drives, smaller HDD form factors developed from product offerings or industry standards.
As of 2023 [update] , 2.5-inch and 3.5-inch hard disks are the most popular sizes.
By 2009, all manufacturers had discontinued the development of new products for the 1.3-inch, 1-inch and 0.85-inch form factors due to falling prices of flash memory, which has no moving parts.[ citation needed ]
While these sizes are customarily described by an approximately correct figure in inches, actual sizes have long been specified in millimeters. The older 3.5-inch form factor uses UNC threads, while 2.5-inch drives use metric M3 threads.
A hard disk drive (HDD), hard disk, hard drive, or fixed disk, is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating platters coated with magnetic material. The platters are paired with magnetic heads, usually arranged on a moving actuator arm, which read and write data to the platter surfaces. Data is accessed in a random-access manner, meaning that individual blocks of data can be stored and retrieved in any order. HDDs are a type of non-volatile storage, retaining stored data when powered off. Modern HDDs are typically in the form of a small rectangular box.
SATA is a computer bus interface that connects host bus adapters to mass storage devices such as hard disk drives, optical drives, and solid-state drives. Serial ATA succeeded the earlier Parallel ATA (PATA) standard to become the predominant interface for storage devices.
CompactFlash (CF) is a flash memory mass storage device used mainly in portable electronic devices. The format was specified and the devices were first manufactured by SanDisk in 1994.
Seagate Technology Holdings plc is an American data storage company. It was incorporated in 1978 as Shugart Technology and commenced business in 1979. Since 2010, the company has been incorporated in Dublin, Ireland, with operational headquarters in Fremont, California, United States.
Self-Monitoring, Analysis, and Reporting Technology is a monitoring system included in computer hard disk drives (HDDs) and solid-state drives (SSDs). Its primary function is to detect and report various indicators of drive reliability with the intent of anticipating imminent hardware failures.
A disk enclosure is a specialized casing designed to hold and power hard disk drives or solid state drives while providing a mechanism to allow them to communicate to one or more separate computers.
A drive bay is a standard-sized area for adding hardware to a computer. Most drive bays are fixed to the inside of a case, but some can be removed.
The Western Digital Raptor is a discontinued series of high performance hard disk drives produced by Western Digital first marketed in 2003. The drive occupies a niche in the enthusiast, workstation and small-server market. Traditionally, the majority of servers used hard drives featuring a SCSI interface because of their advantages in both performance and reliability over consumer-level ATA drives.
The Microdrive is a type of miniature, 1-inch hard disks produced by IBM and Hitachi. These rotational media storage devices were designed to fit in CompactFlash (CF) Type II slots.
Perpendicular recording, also known as conventional magnetic recording (CMR), is a technology for data recording on magnetic media, particularly hard disks. It was first proven advantageous in 1976 by Shun-ichi Iwasaki, then professor of the Tohoku University in Japan, and first commercially implemented in 2005. The first industry-standard demonstration showing unprecedented advantage of PMR over longitudinal magnetic recording (LMR) at nanoscale dimensions was made in 1998 at IBM Almaden Research Center in collaboration with researchers of Data Storage Systems Center (DSSC) – a National Science Foundation (NSF) Engineering Research Center (ERCs) at Carnegie Mellon University (CMU).
Small form factor is a term used for desktop computers and for some of its components, chassis and motherboard, to indicate that they are designed in accordance with one of several standardized computer form factors intended to minimize the volume and footprint of a desktop computer compared to the standard ATX form factor.
In computing, a hybrid drive is a logical or physical storage device that combines a faster storage medium such as solid-state drive (SSD) with a higher-capacity hard disk drive (HDD). The intent is adding some of the speed of SSDs to the cost-effective storage capacity of traditional HDDs. The purpose of the SSD in a hybrid drive is to act as a cache for the data stored on the HDD, improving the overall performance by keeping copies of the most frequently used data on the faster SSD drive.
Heat-assisted magnetic recording (HAMR) is a magnetic storage technology for greatly increasing the amount of data that can be stored on a magnetic device such as a hard disk drive by temporarily heating the disk material during writing, which makes it much more receptive to magnetic effects and allows writing to much smaller regions.
HGST, Inc. was a manufacturer of hard disk drives, solid-state drives, and external storage products and services.
Travelstar was a brand of 2.5-inch hard disk drive (HDD) that was introduced by IBM in 1994 with the announcement of the Travelstar LP. At 12.5 mm high with two platters, they were available in 360, 540 and 720 MB capacities. Initial models were industry-leading for small form factor HDDs in terms of areal density, data transfer rates and shock tolerance (500g).
A hard disk drive failure occurs when a hard disk drive malfunctions and the stored information cannot be accessed with a properly configured computer.
In 1953, IBM recognized the immediate application for what it termed a "Random Access File" having high capacity and rapid random access at a relatively low cost. After considering technologies such as wire matrices, rod arrays, drums, drum arrays, etc., the engineers at IBM's San Jose California laboratory invented the hard disk drive. The disk drive created a new level in the computer data hierarchy, then termed Random Access Storage but today known as secondary storage, less expensive and slower than main memory but faster and more expensive than tape drives.
A solid-state drive (SSD) is a solid-state storage device that uses integrated circuit assemblies to store data persistently, typically using flash memory, and functions as secondary storage in the hierarchy of computer storage. It is also sometimes called a semiconductor storage device, a solid-state device, or a solid-state disk, even though SSDs lack the physical spinning disks and movable read-write heads used in hard disk drives (HDDs) and floppy disks. SSD also has rich internal parallelism for data processing.
The Seagate Barracuda is a series of hard disk drives and later solid state drives produced by Seagate Technology that was first introduced in 1993.
Higher performance in hard disk drives comes from devices which have better performance characteristics. These performance characteristics can be grouped into two categories: access time and data transfer time .
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