Hdd жесткий диск

HDD from inside: Hard Drive Main parts

The goal of this article is to show you how a modern Hard Disk Drive or HDD built. What are its main parts, how do they look and what are these parts names and abbreviations. As an example we 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 Printed Circuit Board or PCB. PCB holds on place and wires electronic components of HDD. The black painted 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.

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

The Memory chip is DDR SDRAM memory type chip. Size of the memory defines size of the cache of HDD. This PCB has Samsung 32MB DDR memory chip which theoretically means HDD has 32MB 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 eats some memory to store some firmware modules and as far as we know only Hitachi/IBM drives show real cache size in data sheets for the other drives you can just guess how big is the real cache 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 reads content of the flash chip into the memory and starts the code. Without such code drive wouldn't even spin up. Sometimes there is no flash chip on PCB that means content of the flash located inside 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 theoretically should 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 and signals from such sensors help VCM controller tune up heads movements. Such drives should have at least two shock sensors.

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

Let's take a quick look on HDA

You can see motor and heads contacts which were hiding under the PCB. There is also small almost unnoticeable hole on HDA. This hole called Breath hole. You maybe heard old rumor which says that HDD has vacuum inside, well that is not true. HDD uses Breath hole to equalize pressure inside and outside HDA. From the inside Breath hole closed by Breath filter to make air clean 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 including ferromagnetic layer which actually stores all the data. As you can see part of the platter covered with the Dumper. Dumpers sometimes called as Separators located between platters, they reduce air fluctuations and acoustic noise. Usually dumpers made of aluminum or plastic. Aluminum dumpers better for cooling air inside HDA.

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 spindle and 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 work HDD may create some very small particles of metal and oil inside. To clean air immediately a drive uses Recirculation filter. This hi-tech filter permanently collects and absorbs even finest particles. 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.

HDDs use very strong Neodymium magnets. Such a magnet is so strong it could lift up to 1300 times its own weight, so don't put your fingers between magnet and steel or another magnet - it can develop great impact. You can see on this picture there is a HSA stopper on the magnet. HSA stoppers limit HSA movements, so heads wouldn't bang on the platters clamp and on the other side they wouldn't just fly off the platters. HSA stoppers may have different construction but there are always two of them and they always present on modern HDDs. On this drive the second HSA stopper 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 protection device - it will release HSA when drive un-parking (loading) heads normally and it should block HSA movements in the moment of impact if drive was dropped. Basically it protects (should, at least) 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 milled from piece of aluminum called the Arm. Heads Gimbal Assembly or HGA attached to the Arm. HGAs and Arms usually produced on different factories. Flexible orange widget called Flexible Printed 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 the breathing hole. On this drive contacts covered with thin layer of gold, for better conductivity.

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 sliders claimed as actual heads but a slider itself is not a head it's a wing which helps read and write elements fly under the platter's surface. Heads flying height on modern HDDs is about 5-10 nanometers. 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 heads and 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 good microscope.

As you can see slider's surface is not flat, it has aerodynamical grooves. These grooves help a slider fly on the certain height. Air under the slider forms Air Bearing Surface or ABS. ABS makes slider 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 or preamp. The preamp is a chip, which controls heads and amplifies signals from/to them.

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 weak signals 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's because HDD can work only with one "head" (pair of read an write elements) at a time. HDD sends control signals to the preamp and the preamp selects the head which HDD needs at the current 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 or magnetic 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. The heater can heat the gimbal - special joint which connects slider to HGA, the gimbal made from two stripes of different alloys with different thermal expansion. Once gimbal got heated it bents itself toward platter's surface and this action reduces flying height. After cooling down the gimbal straights 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

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 on the hub when spindle rotates.

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

Now you see how platters packet has room for heads - platters laying on spacer rings. You can see 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's see the breath filter closer.

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

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HDD Reviews | StorageReview.com - Storage Reviews

Consumer hard drive reviews include 2.5" HDDs with 5mm, 7mm or 9.5mm z-heights and 3.5" form factor hard drives. The consumer hard drive review category also includes solid state hybrid drive (SSHD) reviews which focus on hard drives united with flash storage for caching and better overall performance.

October 25th, 2017 by Adam Armstrong

Seagate has expanded its Guardian Series of HDDs with even higher capacity version. On the NAS front, Seagate has taken both its IronWolf and IronWolf Pro and expanded the capacity up to 12TB per drive. The IronWolf Pro is designed specifically for use in NAS devices and is aimed toward creative professionals, SOHO, and SME markets. While both drives share many of the same features, the Pro version supports up to 16 drive bays, has a higher mean time between failures (1.2 million hours), has rotational vibration sensors on all capacities, and is better optimized for multi-users (300TB/year).

Read more October 25th, 2017 by Lyle Smith

As data requirements continue to rapidly grow, so does the cost of managing storage through devices such as NAS solutions. This puts organizations in a tight spot, as their budgets don’t necessarily correlate with this massive growth, which is why new high-capacity releases like Seagate IronWolf 12TB is so attractive: it helps to lower the total cost of ownership and gives organizations the ability to and stay within and better manage their budgets. The company has also released a Pro version of the drive, reviewed here.

Read more October 5th, 2017 by Brian Beeler

Seagate has launched the latest update to their high-performance desktop 3.5" HDD line in the BarraCuda Pro family. Now available in capacities up to 12TB, the BarraCuda Pro is designed to meet the needs of professionals who want the high capacity that 3.5" hard drives offer, with as much performance as possible. To that end, the BarraCuda Pro features a 7,200 RPM spindle speed with 256MB cache, offering up to 250MB/s in sustained sequential transfer rates. Incidentally, 250MB/s is 30MB/s faster than the prior top capacity 10TB Pro drive. Seagate is also making sure they take care of their BarraCuda Pro owners with a five-year warranty and two years of Seagate Rescue data recovery included. 

Read more July 7th, 2017 by Lyle Smith

Toshiba continues to lend more of its focus to the NAS drive market with the release of its N300 line, 3.5-inch hard drives designed for consumer and business/office users looking for a 24x7 high-performing, high-capacity storage solution. Like all drives of this kind, the N300 is optimized for reliability and endurance (a maximum of 180TB/year workload factor), and supports multi-RAID configurations inside NAS devices with up to 8 bays. The N300 family features a 6Gbps SATA interface, comes in capacities of 4TB, 6TB and 8TB, spin at 7,200rpm, and features 1 million hours mean time between failures.

Read more July 7th, 2017 by Adam Armstrong

WD continues to expand the capacities of its popular Red brand of HDDs with the latest being 10TB. With this new bump up in capacity an 8-bay NAS can have a whopping 80TB of capacity without adding any expansion units. The HDDs come in 3.5” form factor making them a simple drop in replacement for lower capacity HDDs that users are looking to upgrade. As with the 8TB Red, WD is using its HelioSeal helium-technology and NASware 3.0.

Read more November 20th, 2016 by Lyle Smith

The new Seagate IronWolf HDD is designed for all types of NAS use cases, including those that leverage multi-RAID environments, with capacities spanning up to 10TB. Seagate has had a lot of success with their purpose-built drives in the past, such as the Seagate Enterprise, Seagate NAS, and Seagate SkyHawk Surveillance HDDs. And their new line is certainly specced to follow in their footsteps. Featuring multi-tier caching technology, this uniquely named drive is built to handle the constant vibration that is inherent in 24/7 NAS spindle drives and thrives under heavy user-workload rates in a high data-traffic network. 

Read more July 19th, 2016 by Adam Armstrong

Part of Seagate’s new “Guardian Series,” the BarraCuda Pro is the world’s highest capacity desktop hard disk drive (HDD) topping out at a whopping 10TB. The 3.5” HDD builds off of Seagate’s past innovation to being this ultra-high capacity HDD to market. The capacity isn’t the only selling point for this drive, with 7200 RPM Seagate is claiming high performance, up to 220MB/s max sustained transfer rate. The drive has decent endurance as well for a desktop HDD at 300TB per year or 820GB per day workload rate with 24x7 usage.

Read more June 1st, 2016 by Tucker Mindrum

Seagate’s new Mobile HDD provides 2TB of storage in a 7mm form factor. During a time when SSD innovation leads the market for this form factor, this drive holds unique appeal for users who want to upgrade their laptop storage without switching over. Although SSDs indisputably outperform HDDs, the Mobile HDD allows users to load up to 2TB of storage into their laptop at a fraction of the cost of an SSD.

Read more April 14th, 2016 by Tucker Mindrum

Western Digital has expanded their Red line to include an 8TB model, increasing the maximum capacity of 8-bay NAS units to 64TB so that SOHO users can get even more out of their initial server investment. WD is using their HelioSeal helium-technology to get the higher capacity much like the HGST Ultrastar Helium Drives. WD Reds still make use of NASware 3.0, which Western Digital originally released alongside the 6TB model to expand drive compatibility, allowing users to load Red drives into 8-bay servers (they were previously only recommended up to 5 bays). NASware 3.0 also improved the reliability and performance of Red drives, optimizing them for NAS environments in which downtime can be devastating.

Read more April 14th, 2016 by Tucker Mindrum

Seagate's new NAS 8TB HDD expands their NAS line of drives that is intended to more efficiently serve multi-drive use cases while maintaining the performance and price-point desired by SOHO users. The Seagate NAS HDD utilizes NASWorks firmware, which specifically hones drives for server functionality. In addition to enhancing host compatibility, NASWorks reduces HDD power consumption, which also reduces heat production. NAS environments, in which multiple drives may be operating simultaneously, greatly benefit from the energy efficiency of duty-specific drives. Seagate also constructed this line of HDDs with dual-plane balanced motors, which work to control the vibrations that disk drives produce. Reduced heat production paired with vibration control maximize drive performance and improve server reliability, which helps to maintain the 24/7 operability that is essential for remote access and virtualization.

Read more


Laptop and Desktop Hard Disk Drives, Tests, Software, Firmware, Tools, Data Recovery, HDD Repair


Home: latest software and reviews

An updated version of HDD Raw Copy Rool v1.10 has been released. The tool now displays volume letters associated with physical drives. Also, the tool now shows correct hard drive serial numbers.

This HDD Raw Copy tool can make an exact duplicate of a SATA, IDE, SAS, SCSI or SSD hard disk drive. Will also work with any USB and FIREWIRE external drive enclosures as well as SD, MMC, MemoryStick and CompactFlash media. The tool is free for home use.

New version of HDD LLF Low Level Format Tool 4.40 has been released. The tool now displays volume letters associated with physical drives. Also, serial number detection should now be finally fixed as well as inability to lock storage devices under certain circumstances.

This HDD Low Level Format utility is free for home use. It can erase and Low-Level Format a SATA, IDE, SAS, SCSI or SSD hard disk drive. Will also work with any USB and FIREWIRE external drive enclosures as well as SD, MMC, MemoryStick and CompactFlash media.

New version of HDD LLF Low Level Format Tool 4.30 has been released. Added support for Advanced Format drives. Also, hard drive serial number detection has been fixed.

This HDD Low Level Format utility is free for home use. It can erase and Low-Level Format a SATA, IDE, SAS, SCSI or SSD hard disk drive. Will also work with any USB and FIREWIRE external drive enclosures as well as SD, MMC, MemoryStick and CompactFlash media.

First version of Wipe My Disks v1.1 is out.

Wipe My Disks securely wipes all disks installed in your computer. It supports SATA, IDE, SAS, SCSI or SSD hard disk drives. Will also work with most external drive enclosures as well as SD, MMC, MemoryStick and CompactFlash media. The tool is freeware.

New version of HDD LLF Low Level Format Tool 4.25 has been released. Fixed "Timer - Unknown Error" issue on some platforms. Added error code explanations.

This HDD Low Level Format utility is free for home use. It can erase and Low-Level Format a SATA, IDE, SAS, SCSI or SSD hard disk drive. Will also work with any USB and FIREWIRE external drive enclosures as well as SD, MMC, MemoryStick and CompactFlash media.

New version of HDD LLF Low Level Format Tool 4.09 has been released. Fixed "Incorrect Function" issue when using program on laptops with certain SD card readers. Cosmetic and other minor fixes.

This HDD Low Level Format utility is free for home use. It can erase and Low-Level Format a SATA, IDE, SAS, SCSI or SSD hard disk drive. Will also work with any USB and FIREWIRE external drive enclosures as well as SD, MMC, MemoryStick and CompactFlash media.

First version of HDD Raw Copy Rool v1.01 is out.

This HDD Raw Copy tool can make an exact duplicate of a SATA, IDE, SAS, SCSI or SSD hard disk drive. Will also work with any USB and FIREWIRE external drive enclosures as well as SD, MMC, MemoryStick and CompactFlash media. The tool is free for home use.

New version of HDD LLF Low Level Format Tool 4.01 is out. Added support for Windows Vista and Windows 7 (both 32 and 64 bit). Added full support for AHCI devices. Speed of formatting has been singnificantly increased.

This HDD Low Level Format utility is free for home use. It can erase and Low-Level Format a SATA, IDE, SAS, SCSI or SSD hard disk drive. Will also work with any USB and FIREWIRE external drive enclosures as well as SD, MMC, MemoryStick and CompactFlash media.

New version of HDDSCAN is out. There is no changelog provided by the author, but it appears that the entire program has been rewritten from scratch. The program now has a new refreshed look :)

HDDScan is a freeware program for low-level HDD diagnostics, it supports IDE/SATA/SCSI hard disk drives, RAID arrays, external USB/Firewire hard disks, flash cards.

The program can scan the surface, view SMART attributes, adjust AAM, APM (Power Management), etc.

New version of HDDSCAN is out. Added SMART support and IDE Features control for some USB/FireWire hard drives. SMART attributes names are updated. Some bugs were fixed as well.

HDDScan is a freeware program for low-level HDD diagnostics, it supports IDE/SATA/SCSI hard disk drives, RAID arrays, external USB/Firewire hard disks, flash cards.

The program can scan the surface, view SMART attributes, adjust AAM, APM (Power Management), etc.

New version of HDDSCAN is out. There are a lot of improvements in the version 2.7. Now it is possible to pause the scanning, view defect lists and start/stop spindle on SCSI drives, control AAM, APM, SMART by using command line parameters. Also the possibility to send e-mails has been implemented. Some little issues have been fixed.

HDDScan is a freeware program for low-level HDD diagnostics, it supports IDE/SATA/SCSI hard disk drives, RAID arrays, external USB/Firewire hard disks, flash cards.

The program can scan the surface, view SMART attributes, adjust AAM, APM (Power Management), etc.

New version of HDD LLF Low Level Format Tool 2.36 is out. "Seek Error" is fixed, also improved compatibility with some USB devices.

This freeware Low Level Format utility will erase, Low-Level Format and re-certify a SATA, IDE or SCSI hard disk drive with any size of up to 281 474 976 710 655 bytes. Will work with USB and FIREWIRE external drive enclosures. Low-level formatting of Flash Cards is supported too. Low Level Format Tool will clear partitions, MBR, and every bit of user data. The program utilizes Ultra-DMA transfers when possible.

New version of HDD Wipe Tool 2.35 is out. "Seek Error" is fixed, also improved compatibility with some USB devices.

This freeware HDD Wipe utility will erase and re-certify a SATA, IDE or SCSI hard disk drive with any size of up to 281 474 976 710 655 bytes. Will work with USB and FIREWIRE external drive enclosures. Low-level erasing of Flash Cards is supported too. HDD Wipe Tool will clear partitions, MBR, and every bit of user data. The program utilizes Ultra-DMA transfers when possible.

New version of HDDSCAN is out. In this version 2.6 nice speed graphs are added along with other bugfixes and additions. SMART attributes now will be automatically saved into smart.txt.

HDDScan is a freeware program for low-level HDD diagnostics, it supports IDE/SATA/SCSI hard disk drives, RAID arrays, external USB/Firewire hard disks, flash cards.

The program can scan the surface, view SMART attributes, adjust AAM, APM (Power Management), etc.


Timeline: 50 Years of Hard Drives

Over the past five decades, hard drives have come a long way. Travel through time with us as we chronicle 50 milestones in hard-drive development--from product firsts to new technologies, and everything in between.

Photograph: Courtesy of Hitachi GST

1956: IBM ships the first hard drive in the RAMAC 305 system. The drive holds 5MB of data at $10,000 a megabyte. The system is as big as two refrigerators and uses 50 24-inch platters. (For the full story and interviews with key players, read "The Hard Drive Turns 50.")

1961: IBM invents heads for disk drives that "fly" on a cushion of air or on "air bearings."

1963: IBM comes up with the first removable hard drive, the 1311, which has six 14-inch platters and holds 2.6MB.

1966: IBM introduces the first drive using a wound-coil ferrite recording head.

1970: General Digital Corporation (renamed Western Digital in 1971) is founded in California.

Photograph: Courtesy of Hitachi GST

1973: IBM announces the 3340, the first modern "Winchester" hard drive, which has a sealed assembly, lubricated spindles, and low-mass heads.

1978: First RAID (Redundant Arrays of Independent Disks) technology patent is filed. (Read "How to Buy a Hard Drive: Key Features" for a description of this technology.)

1979: A group headed by Al Shugart founds disk-drive manufacturer Seagate Technology.

Photograph: Courtesy of Hitachi GST1979: IBM's 3370 uses seven 14-inch platters to store 571MB, the first drive to use thin-film heads.

1979: IBM's 62 PC, "Piccolo," uses six 8-inch platters to store 64MB.

Photograph: Courtesy of Seagate Technology

1979: Seagate introduces the ST-506 drive and interface, which is then used in all early microcomputer implementations.

1980: IBM introduces the first gigabyte hard drive. It is the size of a refrigerator, weighs about 550 pounds, and costs $40,000.

1980: Seagate releases the first 5.25-inch hard disk.

1981: Shugart Associates joins NCR to develop an intelligent disk drive interface called the Shugart Associates Systems Interface (SASI), a predecessor to SCSI (Small Computer System Interface).

1982: Western Digital announces the first single-chip Winchester hard drive controller (WD1010).

1983: Rodime releases the first 3.5-inch hard drive; the RO352 includes two platters and stores 10MB.

1984: Western Digital makes the first Winchester hard drive controller card for the IBM PC/AT--and sets an industry standard.

1985: Control Data, Compaq Computer, and Western Digital collaborate to develop the 40-pin IDE interface. IDE stands for Intelligent Drive Electronics, more commonly known as Integrated Drive Electronics.

1985: Imprimis integrates the first hard drive controller into a drive.

1985: Quantum introduces the Plus Hardcard, which allows the addition of a hard drive without an available bay or a separate controller card.

1985: Western Digital produces the first ESDI (Enhanced Small Device Interface) controller board, which allows larger capacity and faster hard drives to be used in PCs.

1986: The official SCSI spec is released; Apple Computer's Mac Plus is one of the first computers to use it.

1988: Prairie Tek releases the 220, the first 2.5-inch hard drive designed for the burgeoning notebook computer market; it uses two platters to store 20MB.

1988: Connor introduces the first 1-inch-high 3.5-inch hard drive, which is still the common form factor. Before this, hard drives were either full height or half-height.

1988: Western Digital buys the disk-drive assets of Tandon Corporation with an eye to manufacturing IDE drives.

1990: Western Digital introduces its first 3.5-inch Caviar IDE hard drive.

Photograph: Courtesy of Hitachi GST

1991: IBM introduces the 0663 Corsair, the first disk drive with thin film magnetoresistive (MR) heads. It has eight 3.5-inch platters and stores 1GB. (The MR head was first introduced on an IBM tape drive in 1984.)

1991: Integral Peripherals' 1820 Mustang uses one 1.8-inch platter to store 21MB.

1992: Seagate comes out with the first shock-sensing 2.5-inch hard drive.

1992: Seagate is first to market with a 7200-revolutions-per-minute hard drive, the 2.1GB Barracuda.

1992: Hewlett-Packard's C3013A Kitty Hawk drive uses two 1.3-inch platters to store 2.1GB.

1994: Western Digital develops Enhanced IDE, an improved hard drive interface that breaks the 528MB-throughput barrier. EIDE also allows for attachment of optical and tape drives.

1996: IBM stores 1 billion bits per square inch on a platter.

1996: Seagate introduces its Cheetah family, the first 10,000-rpm hard drives.

1997: IBM introduces the first drive using giant magneto resistive (GMR) heads, the 16.8GB Deskstar 16GP Titan, which stores 16.8GB on five 3.5-inch platters.

Photograph: Courtesy of Hitachi GST

1998: IBM announces its Microdrive, the smallest hard drive to date. It fits 340MB on a single 1-inch platter.

2000: Maxtor buys competitor Quantum's hard drive business. At the time, Quantum is the number-two drive maker, behind Seagate; this acquisition makes Maxtor the world's largest hard drive manufacturer.

2000: Seagate produces the first 15,000-rpm hard drive, the Cheetah X15.

2002: Seagate scores another first with the Barracuda ATA V Serial ATA hard drive.

2002: A demonstration by Seagate yields a perpendicular magnetic recording areal density of 100 gigabits per square inch.

2002: Among its many 2002 technology accomplishments, Seagate successfully demos Heat-Assisted Magnetic Recording. HAMR records magnetically using laser-thermal assistance and ultimately aims to increase areal density by more than 100 times over 2002 levels.

2003: IBM sells its Data Storage Division to Hitachi, thus ending its involvement in developing and marketing disk drive technology.

2003: Western Digital introduces the first 10,000-rpm SATA hard drive, the 37GB Raptor, which is designed for the enterprise, but which gamers quickly learn is a hot desktop performer in dual-drive RAID setups.

2004: The first 0.85-inch hard drive, Toshiba's MK2001MTN, debuts. It stores 2GB on a single platter.

Photograph: Courtesy of Toshiba Storage Device Division

2005: Toshiba introduces its MK4007 GAL, which stores 40GB on one 1.8-inch platter, fielding the first hard drive using perpendicular magnetic recording.

2006: Seagate completes the acquisition of Maxtor, further narrowing the field of hard drive manufacturers.

Photograph: Courtesy of Seagate Technology

2006: Seagate's Momentus 5400.3 notebook hard drive is the first 2.5-inch model to use perpendicular magnetic recording, which boosts its capacity up to 160GB.

2006: Seagate releases the Barracuda 7200.10, at 750GB the largest hard drive to date.

Photograph: Courtesy of Western Digital

2006: Western Digital launches its 10,000-rpm Raptor X SATA hard drive, boosting its capacity to 150GB and placing a flashy transparent window that allows specially designed computer cases to showcase its inner workings.

2006: Cornice and Seagate each announce a 1-inch hard drive that holds 12GB. The drives are slated to ship in the third quarter of 2006.

Rex Farrance is PC World's senior technical editor. To comment on this article and other PCWorld content, visit our Facebook page or our Twitter feed.


Hard Disk Sentinel - HDD health and temperature monitoring


In the news:

12 Feb 2018

Hard Disk Sentinel 5.01.13 released with AMD Ryzen RAID support


If the status of your HDD, SSD (NVMe M.2 SSD) or Intel RAID status missing, download this version first!

11 Oct 2017

How to: monitor Network Attached Storage (NAS) status

9 Mar 2017

Hard Disk Sentinel 5.01 version released


Monitor, diagnose, repair hard disks, SSDs, SSHDs (hybrid drives), NVMe SSDs, RAID arrays and external RAID boxes, industrial (micro) SD cards, tape drives, pendrives to avoid disk failure and data loss.

Hard Disk Sentinel

Hard Disk Sentinel (HDSentinel) is a multi-OS SSD and HDD monitoring and analysis software. Its goal is to find, test, diagnose and repair hard disk drive problems, report and display SSD and HDD health, performance degradations and failures. Hard Disk Sentinel gives complete textual description, tips and displays/reports the most comprehensive information about the hard disks and solid state disks inside the computer and in external enclosures (USB hard disks / e-SATA hard disks). Many different alerts and report options are available to ensure maximum safety of your valuable data.

No need to use separate tools to verify internal hard disks, external hard disks, SSDs, hybrid disk drives (SSHD), disks in RAID arrays as these are all included in a single software. In addition, since version 4.71.7, Hard Disk Sentinel Pro detects and displays status and S.M.A.R.T. information about LTO tape drives and appropriate industrial (micro) SD cards too.

Hard Disk Sentinel monitors hard disk drive / HDD status including health, temperature and all S.M.A.R.T. (Self-Monitoring, Analysis and Reporting Technology) values for all hard disks. Also it measures the disk transfer speed in real time which can be used as a benchmark or to detect possible hard disk failures, performance degradations.

Proven invaluable on our backup server

Read the success story provided by Pan Pacific Products (PDF).

HDSentinel is the perfect data protection solution: it can be effectively used to prevent HDD failure and SSD / HDD data loss because it has the most sensitive disk health rating system which is extremely sensitive to disk problems. This way even a small HDD problem can't be missed. The Professional version has scheduled and automatic (on-problem) disk backup options to prevent data loss caused by not only failure but by malware or accidental delete also.

How does Hard Disk Sentinel work?

Hard Disk Sentinel runs in the background and verifies SSD / HDD health status by inspecting the SMART status of the disk(s). If an error is found or unexpected behaviour is detected, it warns the user about the current situation and also can perform appropriate actions (for example, start an automatic backup).

Usually, hard disk health status may slowly decline, from day to day. The SMART monitoring technology can predict HDD failure by examining the critical values of the disk drive. Compared to other software, Hard Disk Sentinel detects and reports every disk problem. It is much more sensitive to disk failures and can display better and more detailed information about hard disk expected life and the problems found (if any). This is a more sophisticated way to predict failures than the "traditional" method: checking S.M.A.R.T. attribute thresholds and values only. For more information, please read how hard disk S.M.A.R.T. works and why Hard Disk Sentinel is different.

The software displays the current hard disk temperature and logs maximum and average HDD temperatures. This may be used to check the maximum temperature under high hard disk load. For the importance of the hard disk operating temperature, see the Frequently Asked Questions. See the list of Features of Hard Disk Sentinel Professional or our products for hard disk monitoring.

Do I need Hard Disk Sentinel?

If you are using a computer equipped with at least one hard disk or solid state disk and you want to ensure that your data will be available any time, then the answer is YES. Hard Disk Sentinel is especially designed to you if

  • you are using multiple hard disks / SSDs / hybrid drives (SSHD) in your computer (IDE / Serial ATA (S-ATA, e-SATA) / NVMe / SCSI / SAS / USB hard disks) or in an external enclosure (check the hardware compatibility pages for the list of compatible hardware)
  • you are using a mobile / removable rack or enclosure with hard disk inside
  • you are using notebook computer
  • you are using server or desktop computers with high disk load
  • you want to maximize system stability, HDD performance and overall integrity, receive HDD alert on high temperature or low health
  • you do not want to lose your sensitive and valuable data, do not want to pay for HDD recovery

It is much better to avoid HDD failure than use HDD recovery. Be alerted and prevent HDD data loss with HDSentinel ! Be your HDD life healthy.

Select which hard disk monitoring product will suit my needs

Download Hard Disk Sentinel software and try yourself.



HDDScan Free HDD Test Diagnostics Software with RAID and USB Flash support

Capabilities and Requirements:

Supported storage devices:
  • IDE (ATA) and SATA HDD.
  • External USB drives and all major USB boxes (see Appendix A).
  • FireWire or IEEE 1394 HDD (see Appendix A).
  • RAID volumes made of ATA (IDE) / SATA / SCSI HDDs (surface tests only).
  • USB Flash (pen drives) – surface tests only.
  • SATA / ATA SSD – solid state drives.
Storage device tests:
  • Verification in linear mode – helps to determine if your drive needs data rescue, has recoverable errors or in its perfect shape.
  • Reading in linear mode – simpler, but faster disk check.
  • Erasing in linear mode.
  • Reading in Butterfly mode (synthetic random read).
  • Reading and analyzing SMART parameters from ATA/SATA/USB/FireWire HDD.
  • Reading and analyzing Log Pages from SCSI HDD.
  • SMART tests running on ATA/SATA/USB/FireWire HDD.
  • Temperature monitor for ATA/SATA/USB/FireWire/SCSI HDD.
Additional features:
  • Reading and analyzing identity information from ATA/SATA/USB/FireWire/SCSI HDD.
  • Changing AAM, APM, PM parameters on ATA/SATA/USB/FireWire HDD.
  • Reporting defect information on SCSI HDD.
  • Spindle start/stop function on ATA/SATA/USB/FireWire/SCSI HDD.
  • Reports can be saved in MHT format.
  • Reports can be printed.
  • Skins support.
  • Command line support.
  • SSD SMART and Identity reports.
  • Windows XP SP3, Windows Server 2003 (with restrictions), Windows Vista, Windows 7, Windows 8, Windows 10 (NEW).
  • The program shouldnt be run from a read-only device/media.

User interface

Main view

Main view

Control elements:
  • Select Drive drop box - contains a list of supported storage devices in a system. The list contains models and serial numbers of the devices. Icon defines possible storage type.
  • S.M.A.R.T. button generates S.M.A.R.T. attributes report.
  • TESTS button shows pop-up menu to select read and write tests.
  • TOOLS button shows pop-up menu to select available drives controls and features.
  • More button shows drop-down menu with program controls.
  • When you click on TEST button, the pop-up menu offers you one of the tests. If you select any test the Test selection dialog will be opened.
  • Test selection pop-up

  • When you click on TOOLS button, the pop-up menu would offer you to choose one of the following options.
  • Tools selection pop-up

  • DRIVE ID generates Identity information report.
  • FEATURES opens ATA or SCSI features control
  • S.M.A.R.T. TEST activates a dialog with Short, Extended and Conveyance S.M.A.R.T. tests.
  • TEMP MON starts temperature monitoring task.
  • COMMAND opens a dialog that can build command line for the program.

Test Selection Dialog

Test Selection pop-up

Control elements:
  • FIRST SECTOR determines first Logical Block Address (LBA) for testing.
  • SIZE a number of LBAs for this test.
  • BLOCK SIZE indicates Block Size for testing (in LBA sectors).
  • Previous button returns the program on the Main screen.
  • Next button adds the test into a tasks queue.
Tests capabilities and limitations:
  • Only one test at a time. Author wasnt able to get stable test results with two or more simultaneous tests.
  • Verify test may have restrictions on Block Size with 256, 16384 or 65536 sectors because of Windows limitations.
  • Verify test may work in unreliable way on USB/Flash devices.
  • In Verify mode device reads block of data into drives internal buffer only and checks for consistency, there is no data transfer through an interface connector/cable. The program measures operation time for each block. The program tests blocks one by one from minimum to maximum.
  • In Read mode device reads block of data and transfers it thorough interface to the host controller. The program reads block of data into a temporary buffer and measures time of operation for each block. The program tests blocks one by one from minimum to maximum.
  • In Erase mode the program prepares block of data field with special pattern and an LBA number. The program sends the block of data to the drive and the drive writes the block (All previous data in the block on the drive will be overwritten with the pattern and cannot be recovered after that!) The program measures operation time for each block. The program tests blocks one by one from minimum to maximum.
  • Butterfly Read mode is similar to Read mode difference only in blocks order. Blocks are tested by pairs. The first block in the first pair will be Block 0, the second block in the first pair will be Block N (where N is number of last block for testing). Next pair will be Block 1 and Block N-1. Test ends in the middle of the testing area. The program measures operation time.

Tasks Manager window

This window shows a tasks queue. All surface tests, S.M.A.R.T. tests and Temperature Monitor tasks will be displayed in the Tasks Manager Window.

Double clicking on a task line will open task information window (alternatively you can select Show Details option from the menu of the Tasks Manager).

Test information window

This window contains information about selected test. Test could be paused or stopped and report with results can be generated.

Graph Tab:

Displays testing speed for each block. Information is represented as a graph.

Graph Tab

Map Tab:

Displays response time for each block. Information is represented as a map.

Map Tab

You can select Block Processing Time in milliseconds. Every tested block that would have taken operation time longer than the Block Processing Time would be logged in the Report tab.

Report Tab:

Contains information about selected test and each tested block on a drive which responding time was longer than the Block Processing Time.

Report Tab

Identity information

Report contains information about physical and logical parameters of HDD. Report can be saved to an MHT file.

Identity information example

S.M.A.R.T. report

Report contains information about drives performance and health described in attributes. Green icon means attribute values are normal. Yellow icon marks important attributes which may indicate HDDs malfunction. Red icon indicates abnormal attribute values.

Report can be saved to an MHT file.

SMART report example

Temperature monitor

Monitor allows evaluating HDD's temperature. Temperature is indicated on the Task bar and in an information window.

Temperature monitors on the Task bar

For ATA/SATA/USB/FireWire drives the information widow displays two values. The second value is shown on the Task bar and represents temperature from HDA Temperature attribute.

The first value indicates temperature from Airflow Temperature attribute.

If the second value is not supported be the drive then the fist value will be shown on the Task bar.

Temperature monitor for ATA/SATA HDD

For SCSI drives the information window shows two values. The second value is shown on the Task bar and represents current temperature.

The first value indicates maximum allowed temperature for HDD.

Temperature monitor for SCSI HDD

S.M.A.R.T. tests

The program can run three types of tests

  1. Short test lasts about 1-2 minutes. The test inspects drives main electronics, scans small part of drives surface and checks sectors from the Pending-list (such sectors may have read errors). This test recommended for a quick drive testing.
  2. . Extended test could take 0.5-60 hours, depending of the size of the drive. The test inspects drives main electronics and scans the whole drives surface.
  3. Conveyance test usually lasts several minutes. The test inspects drives main electronics and logs that may have records which could indicate incorrect transportation or storing.

The SMART Test can be selected from the SMART tests dialog that can be called by pressing SMART TESTS button

SMART Tests Dialog

After selecting, the test will be added to the Tasks queue.

SMART Tests details window can show progress and completion status.

S.M.A.R.T. test information window


The program might be able change some parameters for ATA/SATA/USB/FireWire HDD:

  1. AAM this function changes drives acoustic. If this function enabled drives noise may be decreased by smoothing HSAs seek operations. HDD could lose some performance.
  2. APM this function allows power savings by temporary decreasing spindles rotation speed (including complete stop) when drive is in idle.
  3. PM this function allows setting spin-down timer. If drive is in idle spindle would be stopped after the time set in the timer. If any program requests HDD access the internal timer will be reset and spindle will continue to spin.
  4. The program can also start or stop spindle immediately. If any program requests HDD access drives spindle will spin up.

Features window for ATA/SATA HDD

For SCSI/SAS/FC drives the program can show defect-lists and start or stop the spindle.

Features window for SCSI HDD

Command Line Dialog

HDDScan can build a command line and save it to .cmd or .bat file. When you run such file the program starts in background mode, changes selected parameters and closes automatically.

Build a command line

Appendix A: USB and FireWire HDDs

If USB/FireWire HDD is supported by the program, tests, S.M.A.R.T. capabilities and additional features may be executed on the drive.

If USB/FireWire HDD is no supported by the program, only tests can be executed.

USB/FireWire HDDs supported by the program:

Storage device Controller chip
StarTeck IDECase35U2 Cypress CY7C68001
WD Passpopt Unknown
Iomega PB-10391 Unknown
Seagate ST9000U2 (PN: 9W3638-556) Cypress CY7C68300B
Seagate External Drive (PN: 9W286D) Cypress CY7C68300B
Seagate FreeAgentPro Oxford
Vantec CB-ISATAU2 (adapter) JMicron JM20337
Beyond Micro Mobile Disk 3.5" 120GB Prolific PL3507 (supported only USB)
Maxtor Personal Storage 3100 Prolific PL2507
Maxtor Personal Storage (USB2120NEP001) In-System ISD300A
SunPlus SPIF215A
Toshiba USB Mini Hard Drive Unknown
USB Teac HD-15 PUK-B-S Unknown
Transcend StoreJet 35 Ultra (TS1TSJ35U-EU) Unknown
AGEStar FUBCP JMicron JM20337
USB Teac HD-15 PUK-B-S Unknown
  Prolific 2571
All Drives That Support SAT Protocol Majority of Modern USB controllers

USB/FireWire HDDs which are probably supported by the program:

Storage device Controller chip
AGEStar IUB3A Cypress
AGEStar ICB3RA Cypress
AGEStar IUB3A4 Cypress
AGEStar IUB5A Cypress
AGEStar IUB5P Cypress
AGEStar IUB5S Cypress
AGEStar NUB3AR Cypress
AGEStar IBP2A2 Cypress
AGEStar SCB3AH JMicron JM2033x
AGEStar SCB3AHR JMicron JM2033x
AGEStar CCB3A JMicron JM2033x
AGEStar CCB3AT JMicron JM2033x
AGEStar IUB2A3 JMicron JM2033x
AGEStar SCBP JMicron JM2033x
AGEStar FUBCP JMicron JM2033x
Noontec SU25 Prolific PL2507
Transcend TS80GHDC2 Prolific PL2507
Transcend TS40GHDC2 Prolific PL2507
I-O Data HDP-U series Unknown
I-O Data HDC-U series Unknown
Enermax Vanguard EB206U-B Unknown
Thermaltake Max4 A2295 Unknown
Spire GigaPod SP222 Unknown
Cooler Master - RX-3SB Unknown
MegaDrive200 Unknown
RaidSonic Icy Box IB-250U Unknown
Logitech USB Unknown

USB/FireWire HDDs not supported by the program:

Storage device Controller chip
Matrix Genesis Logic GL811E
Pine Genesis Logic GL811E
Iomega LDHD250-U Cypress CY7C68300A
Iomega DHD160-U Prolific PL-2507 (modified firmware)
Iomega Prolific PL-3507 (modified firmware)
Maxtor Personal Storage 3200 Prolific PL-3507 (modified firmware)
Maxtor One-Touch Cypress CY7C68013
Seagate External Drive (PN-9W2063) Cypress CY7C68013
Seagate Pocket HDD Unknown
SympleTech SympleDrive 9000-40479-002 CY7C68300A
  Myson Century CS8818
  Myson Century CS8813

Appendix B: supported SSD drives

Support of any particular solid state drive depends mostly on its SSD controller.

Solid state drives, supported by HDDScan:

SSD Drive SSD Controller Chip
OCZ Vertex, Vertex Turbo, Agility, Solid 2 Indilinx IDX110M00
Super Talent STT_FTM28GX25H Indilinx IDX110M00
Corsair Extreme Series Indilinx IDX110M00
Kingston SSDNow M-Series Intel PC29AS21AA0 G1
Intel X25-M G2 Intel PC29AS21AA0 G2
OCZ Throttle JMicron JMF601
Corsair Performance Series Samsung S3C29RBB01
Samsung SSDs Samsung Controllers
Crucial and Micron SSDs Some Marvell Controllers

SSD drives, which are probably supported by HDDScan:

SSD Drive SSD Controller Chip
OCZ Vertex2, Agility2 SandForce SF1200
OCZ Vertex LE, Vertex 2 Pro SandForce SF1500
Corsair Force F100 Series SandForce SF1200
Xceed Lite Unknown
Phison-based SSDs Phison Controllers




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