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There Has Been Good Amount of Instances Of Provoking Me To Do This Due To Lack of time i was not able to do this ,I finally got down to do this.Here Is the article .I think Its The First Time a Registered Dealer Is Doing This ,I Might Be Wrong Here Too .There Has Been Communication And Misunderstanding That i Keep Spamming on the forum "Only Few Members Think So " Which I know From My Heart I Do Not I Just Try To Act As a Normal Member But Due To the Dealer Tag i am Mostly Misunderstood To Few Post I Reply . ,So I Though I Will Share With You Some of My Knowledge on different Subjects And Make You Aware That even Dealers On The Best Forum In India Have Little Brain .This Is Dedicated To all The Dealers On This Forum Who due To Lack Of Time Cannot Spend Much Time On Activities Like This .Regards And Greetings To KMD ,Rahul And All Others ...
What Is a HDD :Well HDD Is a Computer Part In which Using Using a Disc Platter Assembly The Information is coded On The Media On the Platter By the head ,the head send out signals and the info is recorded on the media ,The media is megnatic in nature .We all use hdd of different sizes and performance levels and Interfaces .
Parts of the HDD :
How It works
HDD Damage :
There Has Been Good Amount of Instances Of Provoking Me To Do This Due To Lack of time i was not able to do this ,I finally got down to do this.Here Is the article .I think Its The First Time a Registered Dealer Is Doing This ,I Might Be Wrong Here Too .There Has Been Communication And Misunderstanding That i Keep Spamming on the forum "Only Few Members Think So " Which I know From My Heart I Do Not I Just Try To Act As a Normal Member But Due To the Dealer Tag i am Mostly Misunderstood To Few Post I Reply . ,So I Though I Will Share With You Some of My Knowledge on different Subjects And Make You Aware That even Dealers On The Best Forum In India Have Little Brain .This Is Dedicated To all The Dealers On This Forum Who due To Lack Of Time Cannot Spend Much Time On Activities Like This .Regards And Greetings To KMD ,Rahul And All Others ...
What Is a HDD :Well HDD Is a Computer Part In which Using Using a Disc Platter Assembly The Information is coded On The Media On the Platter By the head ,the head send out signals and the info is recorded on the media ,The media is megnatic in nature .We all use hdd of different sizes and performance levels and Interfaces .
Parts of the HDD :
- MHA Assembly :Metal Head Asembly ,This is Also Know As head and platter assembly ,This is the Part that Contains The Motor ,The Platters ,the Head And The entire Iron Cage With The Top Cover Thats Air Sealed "Actually Air does Flow into the HDD Chamber ,More About This Later On ".
- PCB Plate :This is Called The Printed Circuit Board ,this Contains The Main Processor ,The EPROM ,RAM And The Motor And Spindle Controller .This Also Has a Protection Circuit for Protection of surges In The 12 And 5 Volt Electrical Line .
- PCB Plate
arts of The PCB Plate
- Main Processor :This Processor is made my many different electronic Manufacturers Like ST Micro And All ,Mostly they Are Specifically Made Processor For Different HDD Manufacturers And Are any Models even For One HDD Manufacturer .This Processor contains The Software code that Makes the HDD Work I Mean Its The code Or The Operating systems That starts As Soon As the PCB And The HDD Recieves Power ,If You Find That Your HDD Is Totally Dead That Might be due To the Fact That the Crystal That Gives Clock Signal to The Main Processor is Dead ,Try To check That With a Scope or a Multimeter With Frequency Measurement .
- EPROM :This Contains The code That Is In Addition To the Microcontroller "Main Processor " Code ,Some HDD Microcontrollers Do Not Have Enough Space For The Code ,So The HDD Manufacturers Put Additional Code Int the Serial Or Parallel EPROM On The PCB . Once the Microcontroller Processes All Its Firmware akka operating code It Send a Jump Instruction To The EPROM And The EPROM starts Executing Its Code .The Probability Of the EPROM Code Getting Damaged In The PCB is Very Very High ,You Could Take Out This EPROM And Program It With the Same Firmware Version Or Alternatively You Could Connect the PCb to The Serial Port on the Computer and then program the same ,Yes The PCB also Has a Serial Port ,More About That Later On.
- Ram :this IC Is Also There On The PCB and Its As RAm In Our Desktop Computers ,This Could also Get Damaged And Could Require Replacement .This Also Can Be checked And Replaced If Found Defective ,A Defective RAm Ic Will process everything with erros in the pcb .
- Spindle Contor Controller :This Ic controls the Speed of the Spindle Motor In The HDD ,a Defective Spindle Motor Is a Rather common Issue ,Most Commonly this Chip just blows away Due To The Fact That the Spindle Motor Gets a Coil Short Circuit .
- Preamp Control Chip :This Ic Is Present In Some Drives And In Some Its In The Spindle Motor Controller or The Main Microcontroller .The Purpose of This Is To Send The signal To The Ic Called The Preamp Control IC inside The Head And Platter Assembly Unit ,The Preamp Ic Amplifies That And Send To The Head And Visa Versa .Damage To This Is Also Very Common ,But Prior to Replacement of This You Should Make sure That the Preamp Ic Is Still Working Or If The Preamp ic Is Gine This IC Replaced Will Become Toast again .
- Protection Components And Parts :These Parts Helps To Keep The Voltage of The PCB At Acceptable Levels for The different IC And Some Of The Parts Are Used For Protection Too .
- MHA Assembly arts of The MHA Assembly
- Motor :The Platters Are Mounted On This .This Makes The Drive Spin ,This Is a Stepper Motor And Controlled By The Stepper Motor controller From The PCB .Common Issues Are that the the Coils Of the Motor Can Get Short circuit And the Same Needs Replacement ,But This Requires a Clean Room Environment And specialized Tools To Take The Platter Out And Then The Motor Out And The Replace The Same .Best Way Is to Test The Coils of The Motor By a Multimeter or a Mircometer .
- Platter :This is The Actual Megnatic Round Plate That Spins And has a Megnatic coating ,All the Info is Stored And Read By the Head on This ,Common Issues With This Are When a Head suffers a bang with the platter due to shock or any other issue .This Creates a permanent bad sector into the surface or damages the surface .Once this Item Suffers damage ,No person or data recovery company can recover the data.All Platters Have Servo information Written Into Them,This is Done By Servo Writers that The HDD Manufacturers Have .If the Servo information is lost on the platter the head does not come to know where it is positioned And The Drive Becomes Junk .
- Head And Preamp :The Long Needle Type Thing In The HDD Has a small Item in The End of It Now Thats the Head ,There is also a Ic that is connected In This This Is Called the Premplifier ,This Preamplifier Amplifies the Weak signals When the Head Reads and also send the signals to the head for writing on the media .More Power is Required To Write Then To Read the Megnatic Media on the Platter .
- Other Parts :Other Parts Are the Area where The Head Rests when The Drive Spins Down ,Mostly It Rests on the Platter Itself "There is Dedicated space Into The Platter for This " .There Are Also Air Filters Inside The MHA Assembly .Air Is Required for The Heads To Float on The Platter ,Thats The Reason All HDD Have a Small Hole On The Top Cover With Instructions "Do Not Cover This Hole " .
How It works
- The HDD starting Process :As Soon As We Switch On the HDD the HDD Main IC Or the Main Microcontroller starts executing the code inside it .This Ic Uses the Ram Ic for Temp Storage of the Code .Then The Microcontroller searches for External Code In The EPROM "If There Is Any" .If a EPROM is Found the Microcontroller passes the control of processing the firmware code to the EPROM ,the EPROM then starts Executing The Code inside It and USes The Mcrocontroller And The RAm Ic To support This .Now This is The Most Interesting Part Which thousands Of People Do not Know ,I would Say such Information is Highly classified But Here i Present It To TE Members.The EPROM Has a Head Map That Specifies That In The Perticular drive in action the main active head is what "Head 0 or 1 or 2 or 3 etc " .The The Control Is Passed To the Code Inside the Platter On The Mai Active Head ,Yes Mates the Platter Has The Code For The HDD Firmware Too .The code On the Platter Can Contain Two Parts the App Code and The Modules ,The App Code Akka application code Is something Like the Code in The Microcontroller And The EPROM .The Modules Are Small Collections of Data that Stores Critical HDD Information Like Glist And Plist ,The Smart Data Modules And Other Critical Modules .Once The Control Is In the Hands of The App Code It Reads the HDD Modules On The Platter and Then Passes This Information To The Executing Code ,Once This is Done The HDD Gets On Track And starts Working .So The Moral of the Fact Is That Is The HDD Cannot Read the App Code And The Modules On the Platter It Can Never Work
- More Info about Code On the Platter :Only 1 In thousands will Know That the HDD Has a Lot Of Information Other then your Data .There Are Sectors That Go n Reverse Means If The Sectors Starts From 0 Like 1,2,3,4,5 These Sectors Are Actually 0 and Minus Means -1,-2,-3 ,-4 etc .These Sectors Can Not Be Accessed By Any Software and Require Special Hardware And Techniques .Data That Make the HDD Run Are Stored On These Sectors .This Can Comprise Of Code Like ATA Code ,More Firmware And Modules .I Will Explain You all Of these In Great Depth Now .
- Firmware Code On These Sectors : Mostly the Micro controller Is Same In Many Many PCB's Plates So How Does The Manufacturer Make Different HD Family Different ,Well First If The MCU Is Same For Many Families It Uses The EPROM To Store More Firmware "Operating System" Code As Explained Earlier .And If The EPROM Is Not sufficient for Storing This ,Then The Manufacturer Uses The Space In These Reverse Sectors Of The Platter ,I Hope i Was Clear In This
- ATA Layer code :This Code in The Reverse Sectors Contains the code to Process ATA Commands ,This Layer In Mostly Present In Seagate and Few Other Drives .If This Layer Is Not Present in the Drive It Cannot Process The ATA Commands From the Motherboard IDE Port .
- Modules :One Of The Most difficult And The Most Interesting Sectors in the Reverse Sector Area Of The Platter .The Modules Are further Divided Into Into Many Type Like Essential Modules ,Unique Modules "That Are Unique To That HDD " ,Non Essential Modules ,Logs Etc .The Essential Modules are must for the drive operation .The Other Modules essential for operation are The Unique Modules .Lets Discuss Some Of the Ultra Essential Modules
- Glist Module :This is Called The Growing Bad Sector List ,This G List Can Get Filled By software Utilities Made To Remove Bad Sectors "Mark Them and Hide From the Operating system Like Windows" .The firmware Also From Time Automatically Keeps Adding Weak And Other Bad Sectors to the G-List .If the Glist Module Gets Full There Is No Way To Mark Bad Sectors ,Then Using specialized Hardware Either You Ned To empty the Glist Or You Ned To Move The Glist To the Plist "More About Plist Now " .
- Plist Module :This Is Called the Permanent Bad Sector And Defect Module List .This Contains The Sectors That Are Marked Bad at The Manufacturer Factory .There is No Way You Can Add More Defected And Recently Created Weak Sectors To This Module ,you Need special Hardware And Tools To Manuplate This Module .
- Smart Module :This Module Contains All the Smart Data That you see In Utilities Like everest ,Once when When I Had started a Massive Debate On E Forums About Temperatures I Was Virtually Killed By The Members and My Fellow Friends ,Well Not To Get Into That Temperature Debate Until I do Not Get To Actually Testing All HDD For Temp Rating .Coming To The Smart Module All The Things Like Bad Sector Count "From Glist " Etc Are Into This Module ,For HDD That Show Smart Errors When You Boot The HDD in The BIOS And Data Cannot Be recovered Can Be Made To Work By Manupalating The Values In This Module .
- Log Modules :These Modules Are Few In No And They Have Logs Stored By The HDD Disc Operating system Called The Firmware ,When you Do a Selfscan or Use The HDD Manufacturer software For Testing The HDD .
HDD Damage :
- Type of Damages :HDD Damages Are Classified Into Two Type Logical And Physical Damages ,Logical Damage Means The Damage is In the File system of the Data "Operating System Stored On the HDD ",Physical Damages Are Damages In the PCB ,The Head And Platter Assembly .Or Defective Or Weak Head Or Bad Area on Platter .Lets discuss About Both Of the Damages In Depth .
- Logical Damages :These Kind Of Damages Are Not Real Damages To The HDD And Are Damages To The File system Of The Operating system On The HDD .This Kind Of Damage Is Rather Common ,Many Software Packages Are There In The Market To do Recovery Of These Type Of Damages .But In My Experience Understanding About File system Organization And File Formats Is Also Very Important .
- Physical Damages :Lets Discuss More About This Type Of Damages ,I will divide The Same Into Parts ,Lets Discuss About all The Parts Now .
- Work In Progress ...
