RC 7 Succeeding

8/4/2019 RC 7 Succeeding

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Marlene A. CalisteCSE111L/RC7: HARD DRIVES PART 1BSIT, CSE111L/IT41P1-COMTECH LAB, S 1-5

History of Hard disk Drives

IBM in 1953 recognized the immediate application for what it termed a "Random Access File"having high capacity, rapid random access at a relatively low cost. After considering several

alternative technologies such as wire matrices, rod arrays, drums, drum arrays, etc., theengineers at IBM San Jose invented the disk drive. The disk drive created a new level inthe computer data hierarchy , then termed Random Access Storage but today known as secondarystorage , less expensive and slower than main memory (then typically drums ) but faster and moreexpensive than tape drives .

The commercial usage of hard disk drives began in 1956 with the shipment of an IBM 305RAMAC system including IBM Model 350 disk storage .Compared to modern disk drives, early hard disk drives were large, sensitive and cumbersomedevices, more suited to use in the protected environment of a data center than in factories,offices or homes where they are found today. Disk media diameter was nominally 14 or 8 inchesand were typically mounted in standalone boxes (resembling washing machines or even pizzaovens) or large equipment rack enclosures. Individual drives often required high-current ac powerdue to the large motors they required to turn the large disks. Hard disk drives were not commonlyused with microcomputers until after 1980, when Seagate Technology introduced the ST-506 , thefirst 5.25-inch hard disk drive.

The capacity of hard drives has grown exponentially over time. With early personal computers, adrive with a 20 megabyte capacity was considered large. During the mid-1990s the typical harddisk drive for a PC had a capacity of about 1 GB. As of July 2010, desktop hard disk drivestypically have a capacity of 500 to 1000 gigabytes , while the largest-capacity drives are3 terabytes.

1950s 1970s

The IBM 350 Disk File, invented by Reynold Johnson , was introduced in 1956 with the IBM 305RAMAC computer. This drive had fifty 24 inch platters, with a total capacity of five millioncharacters.A single head assembly having two heads was used for access to all the platters,making the average access time very slow (just under 1 second).

The IBM 1301 Disk Storage Unit, announced in 1961, introduced the usage of a head for eachdata surface with the heads having self acting air bearings (flying heads).Also in 1961, Bryant Computer Products introduced its 4000 series disk drives. These massiveunits stood 52 inches (1.3 m) tall, 70 inches (1.8 m) wide, and had up to 26 platters, each 39inches (0.99 m) in diameter, rotating at up to 1200 rpm. Access times were from 50 to 205 ms.

The drive's total capacity, depending on the number of platters installed, was up to 205,377,600bytes, or 196 MiB.

The first disk drive to use removable media was the IBM 1311 drive, which used the IBM 1316disk pack to store two million characters.In 1973, IBM introduced the IBM 3340 "Winchester" disk drive, the first significant commercial useof low mass and low load heads with lubricated media. All modern disk drives now use this

technology and/or derivatives thereof. Project head Kenneth Haughton named it afterthe Winchester 30-30 rifle because it was planned to have two 30 MB spindles; however, theactual product shipped with two spindles for data modules of either 35 MB or 70 MB. [10]Also in 1973, Control Data Corporation introduced the first of its series of SMD disk drives usingconventional disk pack technology. The SMD family became the predominant disk drive in theminicomputer market into the 1980s.

1980s, the PC era

As the 1980s began, hard disk drives were a rare and very expensive additional feature onpersonal computers (PCs); however by the late '80s, hard disk drives were standard on all but thecheapest PC.Most hard disk drives in the early 1980s were sold to PC end users as an add on subsystem, not

under the drive manufacturer's name but by Systems Integrators such as the Corvus Disk

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http://en.wikipedia.org/wiki/Computer_data_storagehttp://en.wikipedia.org/wiki/Computer_data_storage#Secondary_storagehttp://en.wikipedia.org/wiki/Computer_data_storage#Secondary_storagehttp://en.wikipedia.org/wiki/Computer_data_storage#Primary_storagehttp://en.wikipedia.org/wiki/Drum_memoryhttp://en.wikipedia.org/wiki/Computer_data_storage#Tertiary_storagehttp://en.wikipedia.org/wiki/Hard_disk_drivehttp://en.wikipedia.org/wiki/IBM_305_RAMAChttp://en.wikipedia.org/wiki/IBM_305_RAMAChttp://en.wikipedia.org/wiki/IBM_magnetic_disk_drives#IBM_350http://en.wikipedia.org/wiki/Washing_machinehttp://en.wikipedia.org/wiki/Seagate_Technologyhttp://en.wikipedia.org/wiki/ST-506http://en.wikipedia.org/wiki/Gigabytehttp://en.wikipedia.org/wiki/Terabytehttp://en.wikipedia.org/wiki/IBM_magnetic_disk_drives#IBM_350http://en.wikipedia.org/wiki/Reynold_B._Johnsonhttp://en.wikipedia.org/wiki/IBM_305_RAMAChttp://en.wikipedia.org/wiki/IBM_305_RAMAChttp://en.wikipedia.org/wiki/IBM_magnetic_disk_drives#IBM_1301http://en.wikipedia.org/wiki/IBM_magnetic_disk_drives#IBM_1311http://en.wikipedia.org/wiki/IBM_magnetic_disk_drives#IBM_3340http://en.wikipedia.org/w/index.php?title=Kenneth_Haughton&action=edit&redlink=1http://en.wikipedia.org/wiki/Winchester_30-30_riflehttp://en.wikipedia.org/wiki/History_of_hard_disk_drives#cite_note-9http://en.wikipedia.org/wiki/Control_Data_Corporationhttp://en.wikipedia.org/wiki/Storage_Module_Devicehttp://en.wikipedia.org/wiki/System_integratorhttp://en.wikipedia.org/wiki/Corvus_Systemshttp://en.wikipedia.org/wiki/Computer_data_storagehttp://en.wikipedia.org/wiki/Computer_data_storage#Secondary_storagehttp://en.wikipedia.org/wiki/Computer_data_storage#Secondary_storagehttp://en.wikipedia.org/wiki/Computer_data_storage#Primary_storagehttp://en.wikipedia.org/wiki/Drum_memoryhttp://en.wikipedia.org/wiki/Computer_data_storage#Tertiary_storagehttp://en.wikipedia.org/wiki/Hard_disk_drivehttp://en.wikipedia.org/wiki/IBM_305_RAMAChttp://en.wikipedia.org/wiki/IBM_305_RAMAChttp://en.wikipedia.org/wiki/IBM_magnetic_disk_drives#IBM_350http://en.wikipedia.org/wiki/Washing_machinehttp://en.wikipedia.org/wiki/Seagate_Technologyhttp://en.wikipedia.org/wiki/ST-506http://en.wikipedia.org/wiki/Gigabytehttp://en.wikipedia.org/wiki/Terabytehttp://en.wikipedia.org/wiki/IBM_magnetic_disk_drives#IBM_350http://en.wikipedia.org/wiki/Reynold_B._Johnsonhttp://en.wikipedia.org/wiki/IBM_305_RAMAChttp://en.wikipedia.org/wiki/IBM_305_RAMAChttp://en.wikipedia.org/wiki/IBM_magnetic_disk_drives#IBM_1301http://en.wikipedia.org/wiki/IBM_magnetic_disk_drives#IBM_1311http://en.wikipedia.org/wiki/IBM_magnetic_disk_drives#IBM_3340http://en.wikipedia.org/w/index.php?title=Kenneth_Haughton&action=edit&redlink=1http://en.wikipedia.org/wiki/Winchester_30-30_riflehttp://en.wikipedia.org/wiki/History_of_hard_disk_drives#cite_note-9http://en.wikipedia.org/wiki/Control_Data_Corporationhttp://en.wikipedia.org/wiki/Storage_Module_Devicehttp://en.wikipedia.org/wiki/System_integratorhttp://en.wikipedia.org/wiki/Corvus_Systems


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Marlene A. CalisteCSE111L/RC7: HARD DRIVES PART1BSIT, CSE111L/IT41P1-COMTECH LAB, S 1-5

System or the systems manufacturer such as the Apple ProFile . The IBM PC/XT in 1983 includedan internal standard 10MB hard disk drive, and soon thereafter internal hard disk drivesproliferated on personal computers.External hard disk drives remained popular for much longer on the Apple Macintosh . Every Mac

made between 1986 and 1998 has a SCSI port on the back, making external expansion easy;also, "toaster" Compact Macs did not have easily accessible hard drive bays (or, in the case of the Mac Plus , any hard drive bay at all), so on those models, external SCSI disks were the onlyreasonable option.

Timeline

1956 - IBM 350 , first commercial disk drive, 5 million characters 1961 - IBM 1301 Disk Storage Unit introduced with one head per surface and aerodynamic

flying heads, 28 million characters per module 1962 - IBM 1311 introduced removable disk packs containing 6 disks, storing 2 million

characters per pack

1964 - IBM 2311 with 7.25 megabytes per disk pack 1964 - IBM 2310 removable cartridge disk drive with 1.02 MB on one disk 1965 - IBM 2314 with 11 disks and 29 MB per disk pack 1968 - Memorex is first to ship an IBM-plug-compatible disk drive 1970 - IBM 3330 Merlin, introduced error correction, 100 MB per disk pack 1973 - IBM 3340 Winchester introduced removable sealed disk packs that included head

and arm assembly, 35 or 70 MB per pack 1973 - CDC SMD announced and shipped, 40 MB disk pack 1979 - IBM 3370 introduced thin film heads, 571 MB, non-removable 1980 - The world's first gigabyte-capacity disk drive, the IBM 3380, was the size of a

refrigerator, weighed 550 pounds (about 250 kg), and had a price tag of $40,000, 2.52 GB

1980 - ST-506 first 5 1/4 inch drive released with capacity of 5 megabytes, cost $1500 1986 - Standardization of SCSI 1989 - Jimmy Zhu and H. Neal Bertram from UCSD proposed exchange decoupled granular

microstructure for thin film disk storage media, still used today. 1991 - 2.5-inch 100 megabyte hard drive 1991 - PRML Technology (Digital Read Channel with 'Partial Response Maximum

Likelihood' algorithm) 1992 - first 1.3-inch hard disk drive - HP Kittyhawk 1993 - IBM 3390 model 9, the last Single Large Expensive Disk drive announced by IBM 1994 - IBM introduces Laser Textured Landing Zones (LZT) 1996 - IBM introduces GMR (Giant MR) Technology for read sensors 1998 - UltraDMA/33 and ATAPI standardized 1999 - IBM releases the Microdrive in 170 MB and 340 MB capacities 2002 - 137 GB addressing space barrier broken 2003 - Serial ATA introduced 2003 - IBM sells disk drive division to Hitachi 2005 - First 500 GB hard drive shipping (Hitachi GST) 2005 - Serial ATA 3Gbps standardized 2005 - Seagate introduces Tunnel MagnetoResistive Read Sensor (TMR) and Thermal

Spacing Control 2005 - Introduction of faster SAS ( Serial Attached SCSI ) 2005 - First Perpendicular recording HDD shipped: Toshiba 1.8-inch 40/80 GB 2006 - First 750 GB hard drive ( Seagate )

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http://en.wikipedia.org/wiki/Corvus_Systemshttp://en.wikipedia.org/wiki/Apple_ProFilehttp://en.wikipedia.org/wiki/IBM_PC/XThttp://en.wikipedia.org/wiki/Apple_Macintoshhttp://en.wikipedia.org/wiki/SCSIhttp://en.wikipedia.org/wiki/Compact_Macintoshhttp://en.wikipedia.org/wiki/Drive_bayhttp://en.wikipedia.org/wiki/Mac_Plushttp://en.wikipedia.org/wiki/IBM_magnetic_disk_drives#IBM_350http://en.wikipedia.org/wiki/IBM_magnetic_disk_drives#IBM_2310http://en.wikipedia.org/wiki/Memorexhttp://en.wikipedia.org/wiki/Storage_Module_Devicehttp://en.wikipedia.org/wiki/Thin_film_headhttp://en.wikipedia.org/wiki/ST-506http://en.wikipedia.org/wiki/Partial_Response_Maximum_Likelihoodhttp://en.wikipedia.org/wiki/HP_Kittyhawk_microdrivehttp://en.wikipedia.org/wiki/Microdrivehttp://en.wikipedia.org/wiki/Serial_ATAhttp://en.wikipedia.org/wiki/IBMhttp://en.wikipedia.org/wiki/Serial_Attached_SCSIhttp://en.wikipedia.org/wiki/Perpendicular_recordinghttp://en.wikipedia.org/wiki/Toshibahttp://en.wikipedia.org/wiki/Seagate_Technologyhttp://en.wikipedia.org/wiki/Corvus_Systemshttp://en.wikipedia.org/wiki/Apple_ProFilehttp://en.wikipedia.org/wiki/IBM_PC/XThttp://en.wikipedia.org/wiki/Apple_Macintoshhttp://en.wikipedia.org/wiki/SCSIhttp://en.wikipedia.org/wiki/Compact_Macintoshhttp://en.wikipedia.org/wiki/Drive_bayhttp://en.wikipedia.org/wiki/Mac_Plushttp://en.wikipedia.org/wiki/IBM_magnetic_disk_drives#IBM_350http://en.wikipedia.org/wiki/IBM_magnetic_disk_drives#IBM_2310http://en.wikipedia.org/wiki/Memorexhttp://en.wikipedia.org/wiki/Storage_Module_Devicehttp://en.wikipedia.org/wiki/Thin_film_headhttp://en.wikipedia.org/wiki/ST-506http://en.wikipedia.org/wiki/Partial_Response_Maximum_Likelihoodhttp://en.wikipedia.org/wiki/HP_Kittyhawk_microdrivehttp://en.wikipedia.org/wiki/Microdrivehttp://en.wikipedia.org/wiki/Serial_ATAhttp://en.wikipedia.org/wiki/IBMhttp://en.wikipedia.org/wiki/Serial_Attached_SCSIhttp://en.wikipedia.org/wiki/Perpendicular_recordinghttp://en.wikipedia.org/wiki/Toshibahttp://en.wikipedia.org/wiki/Seagate_Technology


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2006 - First 200 GB 2.5" hard drive utilizing Perpendicular recording ( Toshiba ) 2006 - Fujitsu develops heat-assisted magnetic recording ( HAMR) that could one day

achieve one terabit per square inch densities. [12]

2007 - First 1 terabyte hard drive ( Hitachi GST ) 2008 - First 1.5 terabyte hard drive ( Seagate ) 2009 - First 2.0 terabyte hard drive ] (Western Digital ) 2010 - First 3.0 terabyte hard drive ( Seagate , Western Digital ) 2010 - First Hard Drive Manufactured by using the Advanced Format of 4 KiB a block

instead of 512 bytes a block 2011 - First 4.0 terabyte hard drive prototype (denied by Samsung)

Manufacturing history

The technological resources and know-how required for modern drive development andproduction mean that as of 2011, virtually all of the world's HDDs are manufactured by just fivelarge companies: Seagate , Western Digital , Toshiba , Samsung [20] and HGST [21] ; the latter two maybe acquired in 2011 resulting in only three manufacturers of HDDs.Dozens of former HDD manufacturers have gone out of business, merged, or closed their HDDdivisions; as capacities and demand for products increased, profits became hard to find, and themarket underwent significant consolidation in the late 1980s and late 1990s. The first notablecasualty of the business in the PC era was Computer Memories Inc. or CMI; after an incident withfaulty 20MB AT disks in 1985, [22] CMI's reputation never recovered, and they exited the HDDbusiness in 1987. Another notable failure was MiniScribe , which went bankrupt in 1990 after itwas found that they had engaged in accounting fraud and inflated sales numbers for severalyears. Many other smaller companies (like Kalok , Microscience , LaPine, Areal, Priam, andPrairieTek) also did not survive the shakeout , and had disappeared by 1993; Micropolis was ableto hold on until 1997, and JTS, a relative latecomer to the scene, lasted only a few years and wasgone by 1999, after attempting to manufacture HDDs in India. Their claim to fame was creating anew 3 form factor drive for use in laptops. Quantum and Integral also invested in the 3 formfactor; but eventually ceased support as this form factor failed to catch on. Rodime was also animportant manufacturer during the 1980s, but stopped making disks in the early 1990s amid theshakeout and now concentrates on technology licensing; they hold a number of patents related to3.5-inch form factor HDDs.

The following is the genealogy of the current HDD companies: 1967: Hitachi enters the HDD business. 1967: Toshiba enters the HDD business. 1979: Seagate Technology founded. 1988: Western Digital , then a well-known controller designer, enters the HDD business by

acquiring Tandon Corporation 's disk manufacturing division. 1988: Samsung enters the worldwide HDD market, previously having manufactured

Comport disk drives for the Korean market. 1989: Seagate Technology purchases Control Data 's HDD business. 1990: Maxtor purchases MiniScribe out of bankruptcy, making it the core of its low-end

HDDs. 1994: Quantum purchases DEC's storage division, giving it a high-end disk range to go

with its more consumer-oriented ProDrive range. 1996: Seagate acquires Conner Peripherals in a merger.

http://en.wikipedia.org/wiki/Perpendicular_recordinghttp://en.wikipedia.org/wiki/Toshibahttp://en.wikipedia.org/wiki/Fujitsuhttp://en.wikipedia.org/wiki/HAMRhttp://en.wikipedia.org/wiki/History_of_hard_disk_drives#cite_note-11http://en.wikipedia.org/wiki/Hitachi_GSThttp://en.wikipedia.org/wiki/Seagate_Technologyhttp://en.wikipedia.org/wiki/History_of_hard_disk_drives#cite_note-14http://en.wikipedia.org/wiki/Western_Digitalhttp://en.wikipedia.org/wiki/Seagate_Technologyhttp://en.wikipedia.org/wiki/Western_Digitalhttp://en.wikipedia.org/wiki/Advanced_Formathttp://en.wikipedia.org/wiki/Seagate_Technologyhttp://en.wikipedia.org/wiki/Western_Digitalhttp://en.wikipedia.org/wiki/Western_Digitalhttp://en.wikipedia.org/wiki/Toshibahttp://en.wikipedia.org/wiki/Toshibahttp://en.wikipedia.org/wiki/Samsunghttp://en.wikipedia.org/wiki/Samsunghttp://en.wikipedia.org/wiki/History_of_hard_disk_drives#cite_note-SamsungAcq-19http://en.wikipedia.org/wiki/History_of_hard_disk_drives#cite_note-SamsungAcq-19http://en.wikipedia.org/wiki/HGSThttp://en.wikipedia.org/wiki/HGSThttp://en.wikipedia.org/wiki/HGSThttp://en.wikipedia.org/wiki/History_of_hard_disk_drives#cite_note-HGSTAcq-20http://en.wikipedia.org/wiki/HGSThttp://en.wikipedia.org/wiki/History_of_hard_disk_drives#cite_note-HGSTAcq-20http://en.wikipedia.org/wiki/Consolidation_(business)http://en.wikipedia.org/wiki/Consolidation_(business)http://en.wikipedia.org/wiki/Computer_Memories_Inc.http://en.wikipedia.org/wiki/History_of_hard_disk_drives#cite_note-21http://en.wikipedia.org/wiki/MiniScribehttp://en.wikipedia.org/wiki/Kalokhttp://en.wikipedia.org/w/index.php?title=Microscience_International_Corporation&action=edit&redlink=1http://en.wikipedia.org/wiki/Shakeouthttp://en.wikipedia.org/wiki/Shakeouthttp://en.wikipedia.org/wiki/Micropolis_Corporationhttp://en.wikipedia.org/wiki/JT_Storagehttp://en.wikipedia.org/wiki/Rodimehttp://museum.ipsj.or.jp/en/computer/device/magnetic_disk/0017.htmlhttp://sdd.toshiba.com/main.aspx?Path=Company/Heritagehttp://en.wikipedia.org/wiki/Seagate_Technologyhttp://en.wikipedia.org/wiki/Western_Digitalhttp://en.wikipedia.org/wiki/Tandon_Corporationhttp://en.wikipedia.org/wiki/Tandon_Corporationhttp://en.wikipedia.org/wiki/Seagate_Technologyhttp://en.wikipedia.org/wiki/Control_Data_Corporationhttp://en.wikipedia.org/wiki/Control_Data_Corporationhttp://en.wikipedia.org/wiki/MiniScribehttp://en.wikipedia.org/wiki/Quantum_Corporationhttp://en.wikipedia.org/wiki/Digital_Equipment_Corporationhttp://en.wikipedia.org/wiki/Digital_Equipment_Corporationhttp://en.wikipedia.org/wiki/Conner_Peripheralshttp://en.wikipedia.org/wiki/Conner_Peripheralshttp://en.wikipedia.org/wiki/Perpendicular_recordinghttp://en.wikipedia.org/wiki/Toshibahttp://en.wikipedia.org/wiki/Fujitsuhttp://en.wikipedia.org/wiki/HAMRhttp://en.wikipedia.org/wiki/History_of_hard_disk_drives#cite_note-11http://en.wikipedia.org/wiki/Hitachi_GSThttp://en.wikipedia.org/wiki/Seagate_Technologyhttp://en.wikipedia.org/wiki/History_of_hard_disk_drives#cite_note-14http://en.wikipedia.org/wiki/Western_Digitalhttp://en.wikipedia.org/wiki/Seagate_Technologyhttp://en.wikipedia.org/wiki/Western_Digitalhttp://en.wikipedia.org/wiki/Advanced_Formathttp://en.wikipedia.org/wiki/Seagate_Technologyhttp://en.wikipedia.org/wiki/Western_Digitalhttp://en.wikipedia.org/wiki/Toshibahttp://en.wikipedia.org/wiki/Samsunghttp://en.wikipedia.org/wiki/History_of_hard_disk_drives#cite_note-SamsungAcq-19http://en.wikipedia.org/wiki/HGSThttp://en.wikipedia.org/wiki/History_of_hard_disk_drives#cite_note-HGSTAcq-20http://en.wikipedia.org/wiki/Consolidation_(business)http://en.wikipedia.org/wiki/Computer_Memories_Inc.http://en.wikipedia.org/wiki/History_of_hard_disk_drives#cite_note-21http://en.wikipedia.org/wiki/MiniScribehttp://en.wikipedia.org/wiki/Kalokhttp://en.wikipedia.org/w/index.php?title=Microscience_International_Corporation&action=edit&redlink=1http://en.wikipedia.org/wiki/Shakeouthttp://en.wikipedia.org/wiki/Micropolis_Corporationhttp://en.wikipedia.org/wiki/JT_Storagehttp://en.wikipedia.org/wiki/Rodimehttp://museum.ipsj.or.jp/en/computer/device/magnetic_disk/0017.htmlhttp://sdd.toshiba.com/main.aspx?Path=Company/Heritagehttp://en.wikipedia.org/wiki/Seagate_Technologyhttp://en.wikipedia.org/wiki/Western_Digitalhttp://en.wikipedia.org/wiki/Tandon_Corporationhttp://en.wikipedia.org/wiki/Seagate_Technologyhttp://en.wikipedia.org/wiki/Control_Data_Corporationhttp://en.wikipedia.org/wiki/MiniScribehttp://en.wikipedia.org/wiki/Quantum_Corporationhttp://en.wikipedia.org/wiki/Digital_Equipment_Corporationhttp://en.wikipedia.org/wiki/Conner_Peripherals


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2000: Maxtor acquires Quantum's HDD business; Quantum remains in the tape business. 2003: Hitachi acquires the majority of IBM's disk division, renaming it Hitachi Global

Storage Technologies (HGST). 2006: Seagate acquires Maxtor . 2009: Toshiba acquires Fujitsu 's HDD division. 2011: Western Digital proposes acquiring Hitachi 's HDD division. 2011: Seagate proposes acquiring Samsung 's HDD division.

Hard Disk Form FactorsMost hard disks are designed to be installed on the inside of the PC, and are produced in one of adozen or so standard sizes and shapes. These standards are called hard disk form factors andrefer primarily to its external dimensions. The reason for standardizing on form factors iscompatibility. Without these standards, hard disks would have to be custom-made to fit differentPCs. By agreeing on standards shapes and sizes for hard disks--as well as standard interfaces of course--it is possible for any of the thousands of PC makers to purchase units from any hard disk

manufacturer and know that there won't be problems with fit or form during installation.

Over the life of the PC there have only been a few different hard disk form factors. Since changinga form factor standard requires coordination from the makers of other components (such as themakers of system cases ) there is resistance in the industry to change the standard sizes unlessthere is a compelling reason to do so. (For example, when laptop PCs became popular new,smaller drives were created to save space and power, important goals in the world of mobilecomputing.)

Form factors are generally described by a single metric. For example, the most common formfactors today are "3.5-inch" and "2.5-inch". These numbers generally refer to the width of thedrive, but they can be both vague and misleading (nice, huh? :^) ) They usually were chosen forhistorical reasons and in typically were based on either the platter size of drives that use the formfactor, or the width of drives using that form factor. Obviously a single number cannot representboth, and in some cases, it represents neither! For example, 3.5" hard disks are generally 4" wideand use 3.74" platters. :^) (The name in this case comes from the fact that the drives fit in thesame space as a 3.5" floppy disk drive !) Much more about the relationship between form factorsand platters can be found in the discussion of platter size in the media section. You will also findthere a detailed description of the trend towards smaller platters in modern hard disks.

http://en.wikipedia.org/wiki/Hitachi_Global_Storage_Technologieshttp://en.wikipedia.org/wiki/Hitachi_Global_Storage_Technologieshttp://en.wikipedia.org/wiki/Seagate_Technologyhttp://en.wikipedia.org/wiki/Maxtorhttp://en.wikipedia.org/wiki/Toshibahttp://en.wikipedia.org/wiki/Fujitsuhttp://en.wikipedia.org/wiki/Western_Digitalhttp://en.wikipedia.org/wiki/Western_Digitalhttp://en.wikipedia.org/wiki/Hitachihttp://en.wikipedia.org/wiki/Seagate_Technologyhttp://en.wikipedia.org/wiki/Samsunghttp://en.wikipedia.org/wiki/Samsunghttp://www.pcguide.com/ref/hdd/op/form-c.htmlhttp://www.pcguide.com/ref/hdd/if/index.htmhttp://www.pcguide.com/ref/case/bays.htmhttp://www.pcguide.com/ref/fdd/media_Density.htmhttp://www.pcguide.com/ref/hdd/op/media_Size.htmhttp://en.wikipedia.org/wiki/Hitachi_Global_Storage_Technologieshttp://en.wikipedia.org/wiki/Hitachi_Global_Storage_Technologieshttp://en.wikipedia.org/wiki/Seagate_Technologyhttp://en.wikipedia.org/wiki/Maxtorhttp://en.wikipedia.org/wiki/Toshibahttp://en.wikipedia.org/wiki/Fujitsuhttp://en.wikipedia.org/wiki/Western_Digitalhttp://en.wikipedia.org/wiki/Hitachihttp://en.wikipedia.org/wiki/Seagate_Technologyhttp://en.wikipedia.org/wiki/Samsunghttp://www.pcguide.com/ref/hdd/op/form-c.htmlhttp://www.pcguide.com/ref/hdd/if/index.htmhttp://www.pcguide.com/ref/case/bays.htmhttp://www.pcguide.com/ref/fdd/media_Density.htmhttp://www.pcguide.com/ref/hdd/op/media_Size.htm


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The five most popular internal form factors for PC hard disks.Clockwise from the left: 5.25", 3.5", 2.5", PC Card andCompactFlash.

In this section I examine the major form factors that have been used for internal hard drives inPCs. This includes details on the dimensions of the form factor, especially the different heightsassociated with each. (Most form factors are actually a family of form factors, with different drivesvarying in the height dimension). In addition to the standard internal drive form factors, I brieflydiscuss external drives and also removable drive trays, which are sort of a "hybrid" of internal andexternal designs.

5.25" Form Factor

The 5.25" form factor is the oldest in the PC world. Used for the first hard disks on the original IBMPC/XT back in the early 1980s, this form factor has been used for most of the PC's life span, but isnow obsolete. The basis of the form factor is the 5.25" drive bay used in the first PCs for 5.25"floppy disk drives (themselves obsolete today). These bays still exist today in modern PCs, butare now used primarily for CD-ROM/DVD drives and similar devices, not hard disks. The 5.25"form factor was replaced by the 3.5" form factor for two main reason: first, 5.25" drivesare big and take up a lot of space; second, 3.5" drives offer better performance; see thediscussion in the section on platter sizes for an explanation . The use of 5.25" drives continued aslate as the mid-1990s for high-end drives used in servers and other applications where the largesize of the platters in these drive was needed to allow drives with high capacities to be created.

They mostly disappeared from consumer PC many years prior to that.

A 3.5" form factor hard disk piggybacked on a 5.25" form factorhard disk to contrast their dimensions. The 5.25" drive here is aQuantumBigfoot and is the same height as a regular 3.5" low profile drive.

5.25" drives generally use 5.12" platters and have a width of 5.75" and depth of 8.0". For manyyears they were found in only two different height profiles: full-height, meaning the same heightas the floppy drive on the original PC and the bay it used (3.25"); and half-height, which is of course half that number. In the 1990s, Quantum launched a new line of 5.25" drives namedtheBigfoot family, which reintroduced 5.25" drives to the consumer marketplace. These were soldas "economy" drives and due to the larger platter size, offered a lot of capacity--but due to slowerspindle speeds and a "value line" design, not much performance. They were popular with manyPC manufacturers but eventually were phased out. These drives used what had up to that point

been non-standard heights for 5.25" drives, typically 1" high or less. Quantum calls these

http://www.pcguide.com/ref/hdd/op/formIn525-c.htmlhttp://www.pcguide.com/ref/case/bays_Sizes.htmhttp://www.pcguide.com/ref/hdd/op/media_Size.htmhttp://www.pcguide.com/ref/hdd/op/media_Size.htmhttp://www.pcguide.com/ref/hdd/op/formIn525-c.htmlhttp://www.pcguide.com/ref/case/bays_Sizes.htmhttp://www.pcguide.com/ref/hdd/op/media_Size.htmhttp://www.pcguide.com/ref/hdd/op/media_Size.htm


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drives low-profile or ultra-low-profile. Here are the statistics and applications of the differentprofiles used in the 5.25" form factor:

Form FactorWidth(in)

Depth(in)

Height(in) Application

5.25" Full-Height 5.75 8.0 3.25

All drives in early 1980s; Large capacitydrives with many platters as late as themid-1990s

5.25" Half-Height 5.75 8.0 1.63 Early 1980s through early 1990s

5.25" Low-Profile 5.75 8.0 1.0 Quantum Bigfoot, mid-to-late 1990s

5.25" Ultra-

Low-Profile5.75 8.0 0.75 -

0.80Quantum Bigfoot, mid-to-late 1990s

Interestingly, despite the general trend to smaller drives, the drives that continued to use the5.25" form factor through the late 1980s and early 1990s were more often found as full-heightdevices than half-height ones. This may be due to the fact that their niche became applicationswhere a lot of storage was needed, so the ability to fit many more platters in that nice, roomy3.25" high package was attractive.

3.5" Form Factor

The 3.5" form factor is the standard in the PC world today, and has been for about the lastdecade. Drives of this size are found almost exclusively now in modern desktop PCs, and even inservers and larger machines. The only major market where other form factors hold sway over 3.5"is that for laptops and other portable devices, where the reduced size of 2.5" and smaller formfactors is important.

Like the 5.25" form factor before it, the 3.5" form factor is named not for any dimension of thedrives themselves, but rather for the fact that they were designed to fit into the same drivebay as 3.5" floppy disk drives. 3.5" form factor drives traditionally have used 3.74" platters withan overall drive width of 4.0" and depth of about 5.75". In recent years, 3.5" form factor driveswith platters smaller than 3.74"--in some cases much smaller--have appeared on the market.Most 10,000 RPM spindle speed drives reduce the size of the platters to 3", and the new 15,000

RPM Seagate drive has platters just 2.5" in diameter. The shrinking media size is done forperformance reasons, but the 3.5" form factor is maintained for compatibility (these high-enddrives are designed to go into expensive servers, not laptops!) For this reason, it is no longer thecase that you can tell the size of a drive's platters by its form factor. See the discussion of plattersize for more details .

3.5" form factor drives come in two general profiles: the larger is the so-called half-height drive,which is 1.63" in height. This name is kind of funny, since it is "half" of a height that never existedfor 3.5" form factor drives. The name was derived from the fact that these drives are the sameheight as half-height 5.25" form factor drives, which are half the height of full-height 3.25" highdrives in that form factor. Half-height 3.5" form factor drives are still used today, but only inservers and other high-end platforms. The standard for 3.5" is 1" height, which is commonlycalled slimline or low-profile, but just as commonly given no name at all and assumed as the

http://www.pcguide.com/ref/hdd/op/formIn25-c.htmlhttp://www.pcguide.com/ref/case/bays_Sizes.htmhttp://www.pcguide.com/ref/case/bays_Sizes.htmhttp://www.pcguide.com/ref/hdd/op/spin_Speed.htmhttp://www.pcguide.com/ref/hdd/op/media_Size.htmhttp://www.pcguide.com/ref/hdd/op/media_Size.htmhttp://www.pcguide.com/ref/hdd/op/formIn525-c.htmlhttp://www.pcguide.com/ref/hdd/op/formIn25-c.htmlhttp://www.pcguide.com/ref/case/bays_Sizes.htmhttp://www.pcguide.com/ref/case/bays_Sizes.htmhttp://www.pcguide.com/ref/hdd/op/spin_Speed.htmhttp://www.pcguide.com/ref/hdd/op/media_Size.htmhttp://www.pcguide.com/ref/hdd/op/media_Size.htmhttp://www.pcguide.com/ref/hdd/op/formIn525-c.html


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default. The reason for the smaller size being the standard is that 1" is the height of a standard3.5" floppy disk drive and 3.5" drive bay. In addition, there are some drives that are reduced insize from the 1" standard, using for example 0.75" height. Here are the standard profiles for 3.5"form factor drives:

Form Factor Width(in)Depth(in)


3.5" Half-Height 4.0 5.75 1.63 High-end, high-capacity drives

3.5" Low-Profile 4.0 5.75 1.0

Industry standard, most common formfactor for PC hard disks

It is likely that the 3.5" form factor will continue to be the industry standard in PCs for years tocome, due to the enormous installed base of systems that use this size, and no real compelling

reason to change the form factor or the typical desktop machineUnlike its larger, older siblings, the 2.5" form factor actually is named for the platter size of drivesthat use it. The width of a 2.5" drive is 2.75", and depth is 3.94". These drives originally came in

just one height (0.75" or 19 mm). Since for any storage technology level there is a tradeoff between size and capacity, over time several different heights were created in this form factor asstandards for mobile PC users with different requirements. They are usually specified inmetric (mm) and to my knowledge have no fancy names:



2.5" 19 mmHeight 2.75 3.94 0.75

Highest-capacity 2.5" drives, used in full-featured laptop systems

2.5" 17 mmHeight 2.75 3.94 0.67

Mid-range capacity drives used in somelaptop systems

2.5" 12.5 mmHeight 2.75 3.94 0.49

Low-capacity drives used in smalllaptops (subnotebooks)

2.5" 9.5 mmHeight 2.75 3.94 0.37

Lowest-capacity drives used in verysmall laptops (mini-subnotebooks)

2.5" drives are pretty much entrenched as the standard for laptop machines. They are also usedoccasionally in industrial applications, where the smaller size and increased ruggedness of portable drives is important.

PC Card (PCMCIA) Form Factor

One of the most popular interfaces used in the notebook PC world is the PC Card interface, alsosometimes called PCMCIA after the group that created it in the late 1980s. This interface standardwas created to allow for easier expansion of notebook systems, which at that time had very fewoptions for adding hardware at all. For information on the PC Card interface as it relates to harddisks, see this page .

Despite the relatively small size of cards that adhere to the PC Card standard, hard disk engineershave managed to create hard disks to fit. There are actually three PC Card form factor sizes,defined by the PCMCIA in 1995. The width and depth of these devices is exactly the same as that

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of a credit card, which I am sure is not a coincidence! They are all 2.13" wide and 3.37" deep. Thethree sizes differ only in their height. Type I devices are 3.3 mm thick; Type II devices are 5.0 mmthick, and Type III devices are 10.5 mm thick. Originally, the intention was for solid state deviceslike memory, modems and the like to use the Type I and Type II devices, while the Type III

devices were for hard disks. Due to the extreme height limits of PC Cards, it is difficult to makehard disks that will fit into the allowed space, and most PC Card hard disks are Type III. However,advances in miniaturization have allowed some companies to now make hard disks that actuallyfit into the Type II PC Card form factor as well. Since most laptops can only accept either two TypeI/II cards or a single Type III, this is a significant advantage. Here's a summary table of thedifferent sizes:


Height(in/mm) Application

PC Card Type I 2.13 3.37 0.13 /3.3 Not used for hard disks (yet?)

PC Card Type II 2.13 3.37 0.20 /5.0Smaller-capacity expansion hard disksfor laptops and consumer electronics

PC Card Type III 2.13 3.37 0.41 /10.5Higher-capacity expansion hard disksfor laptops

The 2.13" width of this form factor puts a hard limit on the platter size of these drives--even 2.5"platters are too large. Most PC Card drives today use 1.8" platters. Interestingly, the first harddrive to use the PC Card form factor was probably the Hewlett PackardKittyhawk drive, with muchsmaller 1.3" platters. This drive is a good example of a technology being "ahead of its time". Itwas actually introduced way back in 1992, very early on for such miniaturized technology.Unfortunately, at the time the market may not have been big enough to provide HP with sufficientrevenues to keep making it. The Kittyhawk was used in early hand-helds and other small

consumer electronic devices (even printers!) for a while, but was eventually discontinued, and HPis no longer making hard disk drives of any sort. If this technology had been introduced five yearslater, it may have been a runaway success; certainly IBM is having great success with its slightly-smaller Microdrive .

A CompactFlash card (left) and a PC Card(right).

The quarter is included for size context. Neitherof these is a hard disk (though the SanDisk is asolid-state flash card "hard disk") but are the samesize andshape as hard drives of their respective form

http://www.pcguide.com/ref/hdd/op/media_Size.htmhttp://www.pcguide.com/ref/hdd/op/formPCCard-c.htmlhttp://www.pcguide.com/ref/hdd/op/formPCCard-c.htmlhttp://www.pcguide.com/ref/hdd/op/formCF-c.htmlhttp://www.pcguide.com/ref/hdd/op/media_Size.htmhttp://www.pcguide.com/ref/hdd/op/formPCCard-c.htmlhttp://www.pcguide.com/ref/hdd/op/formPCCard-c.htmlhttp://www.pcguide.com/ref/hdd/op/formCF-c.html


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factor.

Interestingly, with a couple of exceptions, most of the smaller PC Card hard disks are not made by

the bigger, well-known hard disk companies, but rather smaller niche companies. I am not surewhat the reason is for this. I suspect that there just may not be enough profit potential there forthe big names to bother with this market, which is small compared to the market for mainstreamPC drives.

CompactFlash Form Factor

In much the same way that the need for expansion capabilities in laptops led to the creation of the PCMCIA and PC Card devices, a consortium of electronics and computer industry companies in1995 formed the CompactFlash Association to promote a new form factor called, of course, CompactFlash (abbreviated CF or CF+). This form factor is similar to the PC Card formfactor , but amazingly enough, even smaller. CF cards are intended to be used not in laptop PCsbut smaller electronic devices such as hand-held computers, digital cameras and communicationsdevices (including cellular phones).

Unlike the PC Card standard, which is used for a wide variety of devices, CompactFlash isprimarily designed around permanent storage. The "flash" in "CompactFlash" is from the primarytechnology used in these cards: flash memory. Flash memory is really electrically-erasable read-only memory , typically used in regular PCs only for holding the motherboard's BIOS code. Theword "flash" refers to the ability to write and erase these ROMs electrically. Much the way youcan "flash" your motherboard BIOS to update it, these flash memory storage cards havecontrollers in them that do this as part of their normal operation. Unlike regular memory, flashmemory is of course non-volatile and retained when the power is removed.

The intention of the CompactFlash form factor was to allow consumer electronic devices to use

these CompactFlash cards for their equivalent of a hard disk. Since the flash memory is notvolatile, it does perform the same general function as a hard disk. Like PCMCIA devices, variantsof the form factor were developed, differing only in thickness; the thicker cards provide morespace to pack in additional flash memory chips for greater capacity. Here are the dimensions of the two types of CompactFlash cards:


Height(in/mm) Application

CF+ Type I 1.69 1.42 0.13 /3.3

Smaller-capacity flash cards for digitalcameras, hand-held computers andconsumer electronics; not used for

hard disks (yet)

CF+ Type II 1.69 1.42 0.20 /5.0

Larger-capacity flash cards and harddisks for digital cameras, hand-heldcomputers and consumer electronics

As you can see, the CF form factors are very small: so small that they were probably neverdesigned with the thought that anyone would make a true hard disk using them. The engineers atIBM however had a different idea! In 1999, while the makers of regular flash memory cards werestruggling to reach 64 MB capacity, IBM introduced the Microdrive, a true hard disk that fits intothe small confines of the CF form factor. The original Microdrive was available in either 170 MB or340 MB capacities, which is pretty impressive considering that the drive uses a single 1" platter...even more impressive is the new Microdrive released in 2000 with a whopping 1 GB capacity! TheMicrodrive uses the CF Type II format, which is 5.0 mm thick. No current hard disks are made for

http://www.compactflash.org/http://www.pcguide.com/ref/hdd/op/formPCCard-c.htmlhttp://www.pcguide.com/ref/hdd/op/formPCCard-c.htmlhttp://www.pcguide.com/ref/ram/types_ROM.htmhttp://www.pcguide.com/ref/ram/types_ROM.htmhttp://www.pcguide.com/ref/mbsys/bios/comp_Flash.htmhttp://www.pcguide.com/ref/hdd/op/formCF-c.htmlhttp://www.compactflash.org/http://www.pcguide.com/ref/hdd/op/formPCCard-c.htmlhttp://www.pcguide.com/ref/hdd/op/formPCCard-c.htmlhttp://www.pcguide.com/ref/ram/types_ROM.htmhttp://www.pcguide.com/ref/ram/types_ROM.htmhttp://www.pcguide.com/ref/mbsys/bios/comp_Flash.htmhttp://www.pcguide.com/ref/hdd/op/formCF-c.html


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the even smaller Type I size (only 3.3 mm thick) but I have heard rumors that at least onecompany is working on it, and I'd be surprised if IBM themselves didn't have something brewingin this regard also. Pretty cool.

IBM's amazing Microdrive.

Smaller drives generally have less performance than full-sized ones and the Microdrive is noexception; it certainly doesn't compete with the newest 2.5" or 3.5" form factor drives forperformance (though in many ways it is superior to flash memory chips). For its size it is certainlyno slouch, though: it has a 3,600 RPM spindle speed , and very decent maximum areal density of as much as 15.2 Gbits/in 2 . (The original generation actually used a faster 4,500 RPM spindle; thiswas probably lowered to reduce power consumption and heat, both very serious issues for thisform factor... however, the first Microdrives also had only one-third the areal density of the 1 GBmodel.) The extremely small size of the drive allows it to spin up to full speed in only half asecond, a fraction of the time required by most large drives. This lets the Microdrive power down

often when idle to save power, an essential feature for devices that use small batteries.

Form factor

Mainframe and minicomputer hard disks were of widely varying dimensions, typically in freestanding cabinets the size of washing machines (e.g. HP 7935 and DEC RP06 Disk Drives) ordesigned so that dimensions enabled placement in a 19" rack (e.g. Diablo Model 31 ). In1962, IBM introduced its model disk, which used 14 inch (nominal size) platters. This became astandard size for mainframe and minicomputer drives for many years, but such large platterswere never used with microprocessor-based systems.With increasing sales of microcomputers having built in floppy-disk drives (FDDs) , HDDs thatwould fit to the FDD mountings became desirable, and this led to the evolution of the markettowards drives with certain Form factors, initially derived from the sizes of 8-inch, 5.25-inch, and3.5-inch floppy disk drives. Smaller sizes than 3.5 inches have emerged as popular in themarketplace and/or been decided by various industry groups.

8 inch: 9.5 in 4.624 in 14.25 in (241.3 mm 117.5 mm 362 mm)In 1979, Shugart Associates ' SA1000 was the first form factor compatible HDD, having thesame dimensions and a compatible interface to the 8 FDD.

5.25 inch: 5.75 in 3.25 in 8 in (146.1 mm 82.55 mm 203 mm) This smaller form factor, first used in an HDD by Seagate in 1980, was the same size asfull-height 5 1 4-inch-diameter (130 mm) FDD, 3.25-inches high. This is twice as high as "half height"; i.e., 1.63 in (41.4 mm). Most desktop models of drives for optical 120 mm disks(DVD, CD) use the half height 5 dimension, but it fell out of fashion for HDDs.

http://www.pcguide.com/ref/hdd/op/spin_Speed.htmhttp://www.pcguide.com/ref/hdd/op/media_Density.htmhttp://en.wikipedia.org/wiki/HP_7935http://www.columbia.edu/acis/history/rp06.htmlhttp://en.wikipedia.org/wiki/19_inch_rackhttp://www.digibarn.com/stories/bill-pentz-story/docs/Diablo%2030%20PB%20197201xx.pdfhttp://en.wikipedia.org/wiki/IBMhttp://en.wikipedia.org/wiki/Floppy_diskhttp://en.wikipedia.org/wiki/Shugart_Associateshttp://en.wikipedia.org/wiki/CDhttp://www.pcguide.com/ref/hdd/op/spin_Speed.htmhttp://www.pcguide.com/ref/hdd/op/media_Density.htmhttp://en.wikipedia.org/wiki/HP_7935http://www.columbia.edu/acis/history/rp06.htmlhttp://en.wikipedia.org/wiki/19_inch_rackhttp://www.digibarn.com/stories/bill-pentz-story/docs/Diablo%2030%20PB%20197201xx.pdfhttp://en.wikipedia.org/wiki/IBMhttp://en.wikipedia.org/wiki/Floppy_diskhttp://en.wikipedia.org/wiki/Shugart_Associateshttp://en.wikipedia.org/wiki/CD


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The Quantum Bigfoot HDD was the last to use it in the late 1990s, with "low-profile"(25 mm) and "ultra-low-profile" (20 mm) high versions.

3.5 inch: 4 in 1 in 5.75 in (101.6 mm 25.4 mm 146 mm) = 376.77344 cm

This smaller form factor, first used in an HDD by Rodime in 1983, was the same size as the"half height" 3 FDD, i.e., 1.63 inches high. Today it has been largely superseded by 1-inch high "slimline" or "low-profile" versions of this form factor which is used by mostdesktop HDDs.

2.5 inch: 2.75 in 0.2750.59 in 3.945 in (69.85 mm 715 mm 100 mm) =48.895104.775 cm 3

This smaller form factor was introduced by PrairieTek in 1988; there is no correspondingFDD. It is widely used today for solid-state drives and for hard-disk drives in mobiledevices (laptops, music players, etc.) and as of 2008 replacing 3.5 inch enterprise-classdrives. It is also used in the Playstation 3 [50] and Xbox 360 video game consoles. Today, thedominant height of this form factor is 9.5 mm for laptop drives (usually having two plattersinside), but higher capacity drives have a height of 12.5 mm (usually having threeplatters). Enterprise-class drives can have a height up to 15 mm. Seagate has released a7mm drive aimed at entry level laptops and high end netbooks in December 2009.

1.8 inch: 54 mm 8 mm 71 mm = 30.672 cm This form factor, originally introduced by Integral Peripherals in 1993, has evolved into theATA-7 LIF with dimensions as stated. It was increasingly used in digital audioplayers and subnotebooks , but is rarely used today. An original variant exists for 25GBsized HDDs that fit directly into a PC card expansion slot. These became popular for theiruse in iPods and other HDD based MP3 players.

1 inch: 42.8 mm 5 mm 36.4 mm This form factor was introduced in 1999 as IBM's Microdrive to fit inside a CF Type II slot.

Samsung calls the same form factor "1.3 inch" drive in its product literature.0.85 inch: 24 mm 5 mm 32 mm

Toshiba announced this form factor in January 2004 [54] for use in mobile phones and similarapplications, including SD /MMC slot compatible HDDs optimized for video storageon 4G handsets. Toshiba currently sells a 4 GB (MK4001MTD) and 8 GB (MK8003MTD)version and holds the Guinness World Record for the smallest hard disk drive

3.5-inch and 2.5-inch hard disks currently dominate the market.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 is slightly more stableand resistant to damage from impact and/or dropping.

The inch-based nickname of all these form factors usually do not indicate any actual productdimension (which are specified in millimeters for more recent form factors), but just roughlyindicate a size relative to disk diameters, in the interest of historic continuity.

http://en.wikipedia.org/wiki/Quantum_Bigfoothttp://en.wikipedia.org/wiki/Rodimehttp://en.wikipedia.org/wiki/SSDhttp://en.wikipedia.org/wiki/Playstation_3http://en.wikipedia.org/wiki/Playstation_3http://en.wikipedia.org/wiki/Hard_disk_drive#cite_note-49http://en.wikipedia.org/wiki/Hard_disk_drive#cite_note-49http://en.wikipedia.org/wiki/Xbox_360http://en.wikipedia.org/wiki/Xbox_360http://en.wikipedia.org/wiki/Digital_audio_playerhttp://en.wikipedia.org/wiki/Digital_audio_playerhttp://en.wikipedia.org/wiki/Subnotebookhttp://en.wikipedia.org/wiki/PC_cardhttp://en.wikipedia.org/wiki/IBMhttp://en.wikipedia.org/wiki/Microdrivehttp://en.wikipedia.org/wiki/Compact_Flashhttp://en.wikipedia.org/wiki/Toshibahttp://en.wikipedia.org/wiki/Hard_disk_drive#cite_note-53http://en.wikipedia.org/wiki/Secure_Digital_cardhttp://en.wikipedia.org/wiki/MultiMediaCardhttp://en.wikipedia.org/wiki/4Ghttp://en.wikipedia.org/wiki/Guinness_World_Recordhttp://en.wikipedia.org/wiki/Flash_memoryhttp://en.wikipedia.org/wiki/Quantum_Bigfoothttp://en.wikipedia.org/wiki/Rodimehttp://en.wikipedia.org/wiki/SSDhttp://en.wikipedia.org/wiki/Playstation_3http://en.wikipedia.org/wiki/Hard_disk_drive#cite_note-49http://en.wikipedia.org/wiki/Xbox_360http://en.wikipedia.org/wiki/Digital_audio_playerhttp://en.wikipedia.org/wiki/Digital_audio_playerhttp://en.wikipedia.org/wiki/Subnotebookhttp://en.wikipedia.org/wiki/PC_cardhttp://en.wikipedia.org/wiki/IBMhttp://en.wikipedia.org/wiki/Microdrivehttp://en.wikipedia.org/wiki/Compact_Flashhttp://en.wikipedia.org/wiki/Toshibahttp://en.wikipedia.org/wiki/Hard_disk_drive#cite_note-53http://en.wikipedia.org/wiki/Secure_Digital_cardhttp://en.wikipedia.org/wiki/MultiMediaCardhttp://en.wikipedia.org/wiki/4Ghttp://en.wikipedia.org/wiki/Guinness_World_Recordhttp://en.wikipedia.org/wiki/Flash_memory


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.

Types of Hard Drive Connections

There are two categories of hard drive connections. The first type are power connections whichsupply device specific voltages to power the hard drive, both electronically and mechanically. The

second type are data connections, which serve to connect the hard drive to the motherboard's


5 full height 110 MB HDD,

2 (8.5 mm) 6495 MB HDD,US/UK pennies for comparison

A 2.5 inch SATA hard drive

from a Sony Vaio E series

laptop.

Six hard drives with 8, 5.25, 3.5,2.5, 1.8, and 1 disks, partiallydisassembled to show platters andread-write heads, with a rulershowing inches.
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chipset through a data bus. There are also hard drive planes which combine both for variousreasons.

Molex Connectors

The established power connector for PATA, Parallel ATA or EIDE, and some budget SCSI, SmallComputer System Interface, drives is the Molex connector. This connector was first pioneered bythe Molex corporation, and remained the standard for device power connectors until the adventof the SATA specification. These connectors provide two voltage rails, 12 Volt and 5 Volt, and twoground rails. These connectors are keyed to prevent improper insertion, and are virtually always atranslucent white color.

Parallel ATA Data Connector

PATA drives use a flat ribbon style connector to interface between the computer's motherboardand physical disk. This ribbon contains 80 wires, as of the current 2009 specification revision,which support up to two devices per cable. This interface is also used widely with most non-SATAoptical drives. The PATA ribbon cables are usually grey with one blue connector for themotherboard interface, one grey connector that provides secondary device connections, and oneblack connector for primary device connection. The ribbons may be up to 18 inches in length.

SATA Power Connector

The SATA, Serial ATA, power connector, is the successor to the Molex power connector ever sinceits release in 2003. The SATA power cable is a 15 pin connector that is built on a slim waferdesign to prevent improper installation. The SATA power connector does not, unlike the Molexconnector, rely on friction to stay securely attached. Rather, it has a quick release push lever tohold it in place and facilitate quick release. This was seen by the market as a welcomeimprovement, as Molex connectors were often difficult to remove from their sockets.

SATA Data Connector

The SATA data connector is also a wafer connector which calls for seven connective wires, threefor ground and four for data. Unlike Molex connectors, the SATA cables can only support onedevice per channel. However, these cables are much smaller in size and cylindrical in shape.

These connectors are also keyed for device damage prevention, and can be in lengths of up to3.3 feet. These connectors also have a push button lock-in holding system. The most commoncolors for these cables are red cords with black connectors.

Plane Connectors

Plane connectors are solid state connectors which combine the power and data interfaces intoone physical connector. This can be advantageous in an area with tight space, as it allows forcables to be more easily directed away from hot components. The most common applications forplane connectors is within enterprise server chassis and laptop computers. Both of thesecomputing solutions have very little free space available, and require hard drive maintenance tobe as streamlined as possible. Plane connectors require that a drive merely be pushed against itin the correct orientation to be operational.

Types of Hard Drive Cables

There are several types of hard drives, and they all require different data cables. To connect ahard drive to a computer, one must have the proper cables and plug the cables into theappropriate places.



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There are three main types of hard drive data cables: IDE/PATA, SATA and SCSI.IDE (Integrated Drive Electronics) drives, also known as PATA (Parallel AT Attachment) drives, arecommonly found in personal computers. However, manufacturers rarely install IDE/PATA drives innew personal computers as of early 2009: These drives usually are found only in older computers.

The IDE/PATA technology was designed in 1986 and has mostly been superseded by the SATAtechnology in new personal computers.SATA (Serial Advanced Technology Attachment) drives are also commonly found in personalcomputers; its technology was developed in 2003.SCSI (Small Computer System Interface) drives usually are found only in high-endserver/mainframe computers. Although the SCSI technology has existed since 1981, it has beenrevised numerous times since then; SCSI drives are still used today.

IDE/PATA Cable

IDE/PATA data cable.

An IDE/PATA hard drive cable is a ribbon cable containing 40 pins. Either one or two devices maybe connected to an IDE/PATA cable, and the devices need not be of the same type. For example,an IDE/PATA DVD-R drive may be connected along with an IDE/PATA hard drive on the samecable.

SATA Cable

SATA data cable.

A SATA hard drive cable has seven conductors and is smaller than an IDE/PATA cable. A SATAcable connects a single hard drive to a single connector on the SATA controller, which is usuallyfound on the computer's motherboard.

SCSI Cable

SCSI 50-pin cable - by Smial on Wikimedia, Creative Commons Attribution ShareAlike 2.0Germany.



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SCSI cables look similar to IDE/PATA cables in that both drives use ribbon cables. However, SCSIcables have more pins than IDE cables. Depending on the SCSI interface, a SCSI cable may have50 or 68 pins (IDE/PATA drives have 40). Like IDE, multiple SCSI devices can be connected to asingle channel through "daisy chaining." Depending on the SCSI interface, as many as 7 or 15

devices may be connected to a single SCSI channel.

Form Factor Comparison

For ease of comparison, the summary table below lists all of the standard internal hard disk formfactors with their dimensions, typical platter sizes found in hard disks that use the form factor,and common applications:

FormFactor Profile

PlatterSize(in)

Width(in)

Depth(in)


5.25"

Full-Height 5.12 5.75 8.0 3.25

All drives in early1980s; Large capacitydrives with manyplatters as late as themid-1990s

Half-Height 5.12 5.75 8.0 1.63

Early 1980s throughearly 1990s

Low-Profile 5.12 5.75 8.0 1.0

Quantum Bigfoot, mid-to-late 1990s

Ultra-

Low-Profile 5.12 5.75 8.00.75 -0.80

Quantum Bigfoot, mid-to-late 1990s

3.5"

Half-Height

2.5,3.0,3.74

4.0 5.75 1.63 High-end, high-capacitydrives

Low-Profile

2.5,3.0,3.74

4.0 5.75 1.0Industry standard,most common formfactor for PC hard disks

2.5"19 mmHeight 2.5 2.75 3.94 0.75

Highest-capacity 2.5"drives, used in full-featured laptopsystems

17 mmHeight 2.5 2.75 3.94 0.67

Mid-range capacitydrives used in somelaptop systems

12.5 mmHeight 2.5 2.75 3.94 0.49

Low-capacity drivesused in small laptops(subnotebooks)

9.5 mmHeight

2.5 2.75 3.94 0.37 Lowest-capacity drivesused in very smalllaptops (mini-

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subnotebooks)

PC Card

Type I 1.8 2.13 3.37 0.13 Not used for hard disks(yet?)

Type II 1.8 2.13 3.37 0.20

Smaller-capacityexpansion hard disksfor laptops andconsumer electronics

Type III 1.8 2.13 3.37 0.41Higher-capacityexpansion hard disksfor laptops

CompactFlash

Type I1.0 1.69 1.42 0.13

Smaller-capacity flashcards for digitalcameras, hand-held

computers andconsumer electronics;not used for hard disks(yet)

Type II 1.0 1.69 1.42 0.20

Larger-capacity flashcards and hard disksfor digital cameras,hand-held computersand consumerelectronics

Internal Parts of Computer Hard DriveHard drives store the operating system, application, and much of the user data. Hard drives areone of the computer components that suffer from mechanical failures due to wear on the parts.

These failures affect the internal portions of the hard drive.

The Platters

The platters are the discs of the hard drive where the computer information gets stored. Bothsides of the platters store data.



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Read/Write Heads

The read/write heads write data to the hard disk platters and retrieve information from them. Theread/write heads work in a manner similar to the needle on record players or the laser on CDs andDVDs.

Arm Assembly

The arms contain the read/write heads. The hard drive controller moves the arms to the correctposition on the disk. The arm assembly is comprised of the head sliders, head arms, sliders andactuator.

The Spindle

The platters of a hard drive rest on the spindle. The spindle of the hard drive serves the samefunction as the spindle on a record player---it causes the disks to rotate.

The Spindle Motor

The spindle motor causes the spindle to spin and allows the arm actuators to move the arms tothe correct position on the hard disk drive.

HDD from inside: Main parts

The goal of this article is to show you how a modern Hard Disk Drive or HDD built. What are itsmain parts, how do they look and what are these parts names and abbreviations. As an examplewe are going to disassemble 3.5" SATA drive.

To make it more fun we going to tear to pieces pretty new 1TB Seagate ST31000333AS drive.Let's take a look on our "Guinea pig".

The fancy piece of green woven glass and copper with SATA and power connectors called PrintedCircuit Board or PCB. PCB holds on place and wires electronic components of HDD. The blackpainted aluminum case with all stuff inside called Head and Disk Assembly or HDA. The case itself called Base.

Now let's remove PCB and see electronic components on the other side.



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The heart of PCB is the biggest chip in the middle called Micro Controller Unit or MCU. On modernHDDs MCU usually consists of Central Processor Unit or CPU which makes all calculations andRead/Write channel - special unit which converts analog signals from heads into digitalinformation during read process and encodes digital information into analog signals when driveneeds to write. MCU also has IO ports to control everything on PCB and transmit data throughSATA interface.

The Memory chip is DDR SDRAM memory type chip. Size of the memory defines size of the cacheof HDD. This PCB has Samsung 32MB DDR memory chip which theoretically means HDD has32MB cache (and you can find such information in data sheet on this HDD) but it's not quite true.Because memory logically divided on buffer or cache memory and firmware memory. CPU eatssome memory to store some firmware modules and as far as we know only Hitachi/IBM drivesshow real cache size in data sheets for the other drives you can just guess how big is the realcache size.

Next chip is Voice Coil Motor controller or VCM controller. This fellow is the most power

consumption chip on PCB. It controls spindle motor rotation and heads movements. The core of VCM controller can stand working temperature of 100C/212F.

Flash chip stores part of the drive's firmware. When you apply power on a drive, MCU chip readscontent of the flash chip into the memory and starts the code. Without such code drive wouldn'teven spin up. Sometimes there is no flash chip on PCB that means content of the flash locatedinside MCU.

Shock sensor can detect excessive shock applied on a drive and send signal to VCM controller.VCM controller immediately parks heads and sometimes spins down the drive. It theoreticallyshould protect the driver from further damage but practically it doesn't, so don't drop you drive -it wouldn't survive. On some drives shock sensors used for detection even light vibrations andsignals from such sensors help VCM controller tune up heads movements. Such drives shouldhave at least two shock sensors.

Another protection device called Transient Voltage Suppression diode or TVS diode. It protectsPCB from power surges from external power supply. When TVS diode detects power surge it friesitself and creates short circuit between power connector and ground. There are two TVS diodeson this PCB for 5V and 12V protection.

Let's take a quick look on HDA



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You can see motor and heads contacts which were hiding under the PCB. There is also smallalmost unnoticeable hole on HDA. This hole called Breath hole. You maybe heard old rumor whichsays that HDD has vacuum inside, well that is not true. HDD uses Breath hole to equalizepressure inside and outside HDA. From the inside Breath hole closed by Breath filter to make airclean and dry.

Now it is time to take a look under the hood. We are going to remove the drive's lid.

The lid itself is nothing interesting. Just a piece of steel with rubber cord for dust protection.Finally we are going to see HDA from inside.

Precious information stored on platters, you can see top platter on the picture. Platters made of polished aluminum or glass and covered with several layers of different compounds includingferromagnetic layer which actually stores all the data. As you can see part of the platter coveredwith the Dumper. Dumpers sometimes called as Separators located between platters, they reduceair fluctuations and acoustic noise. Usually dumpers made of aluminum or plastic. Aluminumdumpers better for cooling air inside HDA.



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Next picture shows platters and dumpers from the side

Heads mounted on Head Stack Assembly or HSA. This drive has parking area closer to the spindleand if power is not applied on a drive, HSA normally parked like on the picture.

HDD is a precision mechanism and in order to work it requires very clean air inside. During workHDD may create some very small particles of metal and oil inside. To clean air immediately adrive uses Recirculation filter. This hi-tech filter permanently collects and absorbs even finestparticles. The filter located on the way of air motion created by platters rotation.

Now we are going to remove top magnet to see what is under.



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HDDs use very strong Neodymium magnets. Such a magnet is so strong it could lift up to 1300times its own weight, so don't put your fingers between magnet and steel or another magnet - itcan develop great impact. You can see on this picture there is a HSA stopper on the magnet. HSAstoppers limit HSA movements, so heads wouldn't bang on the platters clamp and on the otherside they wouldn't just fly off the platters. HSA stoppers may have different construction but thereare always two of them and they always present on modern HDDs. On this drive the second HSAstopper located on HDA under the top magnet.

And here is what you may see under the top magnet.

There is the other HSA stopper. And you also can the second magnet. The Voice coil is a part of HSA, Voice coil and the magnets form Voice Coil Motor or VCM. VCM and HSA form the Actuator -a device which moves the heads. Tricky black plastic thingy called Actuator latch is a protectiondevice - it will release HSA when drive un-parking (loading) heads normally and it should blockHSA movements in the moment of impact if drive was dropped. Basically it protects (should, atleast) heads from unwanted movements when HSA is in parking area.

On the next step we going to take out HSA

HSA has precision bearing to make movements nice and smooth. The biggest part of HSA milledfrom piece of aluminum called the Arm. Heads Gimbal Assembly or HGA attached to the Arm.



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HGAs and Arms usually produced on different factories. Flexible orange widget called FlexiblePrinted Circuit or FPC joins HSA and plate with heads contacts.

Let's take closer look on each part of HSA.

Voice coil connected to FPC

Here is the bearing

On the next picture you can see HSA contacts

The gasket makes connection airtight. The only way for air to go inside HDA is through thebreathing hole. On this drive contacts covered with thin layer of gold, for better conductivity.



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This is the classic definition of the arm. Sometimes by the arm imply the whole metal piece of HSA.

The black small things at the end of HGAs called Sliders. In many sources you can find that slidersclaimed as actual heads but a slider itself is not a head it's a wing which helps read and writeelements fly under the platter's surface. Heads flying height on modern HDDs is about 5-10nanometers. For example: an average human's hair is about 25000 nanometers in diameter. If any particle goes under the slider it could immediately overheat (because of friction) the headsand kill them that's why clean air inside HDA is so important. The actual read and write elements

located at the end of the slider and they are so small that can only be seen under a goodmicroscope.



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As you can see slider's surface is not flat, it has aerodynamical grooves. These grooves help aslider fly on the certain height. Air under the slider forms Air Bearing Surface or ABS. ABS makesslider fly almost parallel to the platter's surface.

Here is another picture of the slider

You can clearly see heads contacts.

There is very important part of HSA which we haven't discussed yet. It called the preamplifier orpreamp. The preamp is a chip, which controls heads and amplifies signals from/to them.



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The reason why the preamp located inside HDA is simple - signals from heads are very weak and

on modern HDDs have more than 1GHz frequency, if take the preamp out of HDA such weaksignals wouldn't survive, they will disappear on the way to PCB.

The preamp has much more tracks going to the heads (right side) than to the HDA (left side), it'sbecause HDD can work only with one "head" (pair of read an write elements) at a time. HDDsends control signals to the preamp and the preamp selects the head which HDD needs at thecurrent moment. This HDD has six contacts per "head", why so many? One contact is for ground,other two for read and write elements. Other two for microactuators - special piezoelectric ormagnetic devices which can move or rotate slider, it helps tune up heads position under a track.And finally the last contact is for a heater. The heater can help adjust heads flying height. Theheater can heat the gimbal - special joint which connects slider to HGA, the gimbal made fromtwo stripes of different alloys with different thermal expansion. Once gimbal got heated it bentsitself toward platter's surface and this action reduces flying height. After cooling down the gimbalstraights itself.

Enough about heads, let's continue disassembling. We going to remove top dumper.

That's how it looks

And next picture shows HDA without the top dumper and HSA



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Now the top platter is not covered, you also can see the bottom magnet

Let's move further and remove the platters clamp

The platters clamp squeezing platters into the platters packet, so they wouldn't move.

Platters sitting on the spindle hub, the platters clamp creates enough friction to hold platters onthe hub when spindle rotates.

Now when nothing holding platters on the hub we are going to remove the top platter and nextpicture shows what we may see under.



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Now you see how platters packet has room for heads - platters laying on spacer rings. You cansee the second platter and the second dumper.

The spacer ring is a precision detail made of non-magnetic alloy or polymer. Let's take it out.

Finally we are going to shake out the rest of the stuff from HDA and see the base

That's how the breath filter looks. And the breath hole located right under the breath filter. Let'ssee the breath filter closer.



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Because air from outside definitely has dust the breath filter has several layers of filtration andit's much thicker than recirculation filter, it also may have some silica gel inside to reduce airmoisture.

References

http://www.ehow.com/facts_5192626_internal-parts-computer-hard-drive.htmlhttp://hddscan.com/doc/HDD_from_inside.htmlhttp://www.webopedia.com/DidYouKnow/Hardware_Software/2002/InsideHardDrive.asphttp://www.ehow.com/about_5070595_types-hard-drive-cables.htmlhttp://www.ehow.com/about_5426236_types-hard-drive-connections.htmlhttp://en.wikipedia.org/wiki/History_of_hard_disk_driveshttp://www.pcguide.com/ref/hdd/op/form.htmhttp://en.wikipedia.org/wiki/Hard_disk_drivehttp://www.pcguide.com/ref/hdd/op/form.htmhttp://www.pcguide.com/ref/hdd/op/form.htmhttp://www.pcguide.com/ref/hdd/op/form.htm

25/08/2011 21 20 49 HARDWARE & SOFTWARE INTERFACING
http://www.ehow.com/facts_5192626_internal-parts-computer-hard-drive.htmlhttp://hddscan.com/doc/HDD_from_inside.htmlhttp://www.webopedia.com/DidYouKnow/Hardware_Software/2002/InsideHardDrive.asphttp://www.ehow.com/about_5070595_types-hard-drive-cables.htmlhttp://www.ehow.com/about_5426236_types-hard-drive-connections.htmlhttp://en.wikipedia.org/wiki/History_of_hard_disk_driveshttp://www.pcguide.com/ref/hdd/op/form.htmhttp://en.wikipedia.org/wiki/Hard_disk_drivehttp://www.pcguide.com/ref/hdd/op/form.htmhttp://www.pcguide.com/ref/hdd/op/form.htmhttp://www.pcguide.com/ref/hdd/op/form.htmhttp://www.ehow.com/facts_5192626_internal-parts-computer-hard-drive.htmlhttp://hddscan.com/doc/HDD_from_inside.htmlhttp://www.webopedia.com/DidYouKnow/Hardware_Software/2002/InsideHardDrive.asphttp://www.ehow.com/about_5070595_types-hard-drive-cables.htmlhttp://www.ehow.com/about_5426236_types-hard-drive-connections.htmlhttp://en.wikipedia.org/wiki/History_of_hard_disk_driveshttp://www.pcguide.com/ref/hdd/op/form.htmhttp://en.wikipedia.org/wiki/Hard_disk_drivehttp://www.pcguide.com/ref/hdd/op/form.htmhttp://www.pcguide.com/ref/hdd/op/form.htmhttp://www.pcguide.com/ref/hdd/op/form.htm

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