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اولين ابزار ذخيره سازي اطالعات بصورت مغناطيسي در سال به بازار ST506 تحت استاندارد Seagate توسط شرکت 1978

به خود ESDIعرضه کرد. اين استاندارد بالفاصله ويرايش و عنوان گرفت.

:ويژگي هاي اين دو استانداردبورد کنترلر ابزار از آن جدا بوده و بصورت يک کارت در اسالتها نصب مي ◦

شود. پين )سيم( برقرار مي 34 و 20ارتباط ابزار با بورد کنترلر از طريق دو کابل ◦

شودهر بورد کنترلر حداکثر دو ابزار را پشتيباني مي کند.◦ظرفيت اين گونه ابزارها و سرعت خواندن و نوشتن آن پايين است◦وابستگي مستقيم به اطالعات حافظه باياس مادربورد◦زمانهاي دستيابي بسيارباال◦استفاده از موتورهاي پله اي براي حرکت◦

استاندارد جديد 1986سال IDE )Integrated Drive

Electronics( که اسم واقعيتر آنATA )AT Attachment(

است به بازار عرضه شد. تکنولوژي غالب بوده و در عرضه شد که AT 16Bit – XT 8Bit – MCA 16Bitسه نسخه

موجود است. در مادربوردها ATامروزه فقط :ويژگيها

بورد اينترفيس يا کنترلر بر روي خود ابزار است◦ 40ارتباط ابزار يا کنترلر ابزار با مادربورد از طريق يک کابل ◦

رشته80رشته يا جديدا هر اينترفيس از دو ابزار پشتيباني مي کند.◦وابستگي مستقيم به اطالعات حافظه باياس مادربورد◦

ATA-1: 1986-96 مگابايت در ثانيه8.33 – سرعت ATA-2 قابليت اتصال ابزارهاي ديگر را دارد. ظرفيت باالي:

137GB)EIDE(ATA-3 استفاده از قابليت :S.M.A.R.T. ATA-4 داراي قابليت :ATA Packet Interface )UDMA/33(ATA-5 رشته 40رشته( و 80مگابايت)66: حداکثر سرعت

(UDMA/66سيم. )ATA-6 براي :P4و PIII مگابايت سرعت 100بود و تا

(144PB( )UDMA/100دارد)ATA-7 براي : P4 مگابايت سرعت دارد. 133 طراحي شد و تا

(UDMA/133)

( محدوديتهاي ظرفيت درايوهاCHS - LBA مربوط به باياس ) سيلندر، 1024 – 13و استاندارد است. مثال در باياس وقفه

سکتور پشتيباني مي کند. در حالي که 63 هد و 256سکتور پشتيباني 255هد و 16سيلندر، 65536استاندارد از

مي کند بايت( به 264 به بعد تا 98 گيگابايت )8.4حذف مانع ظرفيت

استاندارد 98 شرکت فونيکس در سال EDDکمک تکنولوژيشد.

انتقال سريعتر اطالعات: به کمکPIO 4 تا 0 مدهاي- مدهاي انتقالDMA دونوع :DMA و Bus Mastering DMA استانداردATA Packet Interface براي پشتيباني از :

،ZIP ، درايو CD/DVDابزارهاي مختلف مانند درايوهاي و ...LS120 ، ديسکهايJazدرايوهاي

براي 2002يک استاندارد براي انتقال سرعت باالست که در سال سريال، درايوها و کارتهاي داخلي به وجود آمدند.ATAسيستمهاي با

رشته رسيم دارد.7، تعداد 80 و 40به جاي مگابايت در ثانيه600 و 300-150داراي سه مد انتقال تفاوتهاي آن باATA:

عدم نياز به جامپر براي انتخاب مستر و اسليو◦ متر بوده است(0.5متر) قبلي کمتر از 1حداکثر طول کابل ◦ پين) اختياري( به صورت استاندارد صنعتي15 يا 4کانکتور برق ◦

توجه به نوع کابل توجه به نوع وسيله وMaster يا Slave بودن

آن)ست کردن آن( رشته اي است از حالت 80اگر کابلCSاستفاده نکنيد دقت در نصب کابلها و توجه محل نصب آنها سيم قرمز کابلIDEبه سمت کابل برق باشد تنظيم شناساييIDE ها بصورت Auto توصيه مي

شود.

تعريف هارد: يکي از مهمترين قطعات براي نگهداري اطالعاتبصورت دائم است.

: يک هارد ازبورد کنترلر◦هدهاي خواندن و نوشتن◦بازوي هدها◦موتور چرخاننده بازوها◦صفحات دايره هاي که اطالعات بر روي آنها نوشته مي شود.◦بدنه فلزي◦کاور◦

25.سال از عمر آنها مي گذرد مگابايت بوده اما امروز مرز 30 تا10ظرفيتهاي اوليه در حدود

ترابايت را ردکرده گيگا رسيده است1 کيلو به 85سرعت انتقال از سنت به کمتر از يک سنت به ازاي يک مگابايت150قيمت از

Information is recorded in a circular fashion in what are called trackstracks.

A cylindercylinder is a vertical stack of tracks on multiple platters..

Tracks are divided into sectorssectors. A clustercluster is the smallest unit that DOS uses to store

information )also called an Allocation Unit(.

: فرمت کردنفيزيکي◦منطقي◦

پارتيشن بندي◦Fat 16 گيگابايت2 : حداکثر ◦Fat 32 ترابايت 2 : حداکثر ◦NTFSاندازه فضا و فضاي براي ذخيره سازي فايلها :

( امروزه اغلب 2.5 و 3.5صفحات هارد ديسک )صفحه هستند2اينچ هدهاي خواندن و نوشتن)مکانيزم حرکت )سرعت –عدم حساسيت به گرما- دقت در موقعيت – عدم لرزش

موتور پله اي – حرکت با مقدار ثابت - توقف در وسط گام ميسر نيست.- در چاپگر – فالپي و.... کاربرد ◦دارد.

حرکت حلقه صوتي: براي سرعتهاي باال و چگالي فشرده – بر اساس نيروي الکترومغناطيس کار مي کند. ◦وجود فيدبک از محل هد

)مکانيزم سروو )مجزا - مخفي – اختصاصيپارک اتومات هدها

فيلترهاي هواموتورهاي اسپيندل بوردهاي منطقي: براي کنترل موتور اسپيندل – سيستم حرکت هدها و خواندن و نوشتن و

مديريت اطالعات.کابلها و کانکتورها : کانکتور برق – کانکتور رابط اطالعات

1. Low level formatting )LLF(◦ This is the "true" formatting process for the disk.◦ It creates the physical structures )tracks, sectors,

control information( on the hard disk. ◦ Normally, this step begins with the hard disk platters

"clean", containing no information.2. Partitioning

◦ This process divides the disk into logical "pieces" that become different hard disk volumes )drive letters(.

◦ This is an operating system function.3. High level formatting )HLF(

◦ This final step is also an operating-system-level command.

◦ It defines the logical structures on the partition and places at the start of the disk any necessary operating system files.

event that happens when the surface of the read/write head or particles on its surface come into contact with the surface of the hard-disk platter, causing the loss of some or all of the data on the disk

– قابليت اعتمادMTBF 800000 تا 300000 بين ساعت است.

SMARTدادن اخطار قبل از يروز بحران : بازدهي: زمان جستجوي اطالعات بر حسب ميلي و زمان

انتقال از يک سيلندر به سيلندر ديگر است. نرخ انتقال اطالعات

* دور در 512نرخ انتقال: )سکتور در هر ترک * ثانيه(60دقيقه (بخش بر )

زمان دسترسي متوسط : زماني که به يک سکتور دستپيدا کنيم و برابر نصف زمان چرخش ديسک است.

Small Computer System Interfaceمستقل از مادربوردداشتن آداپتور ميزبانپشتيباني اسکازي از چند دستگاهسرعت انتقال باالقابليت پشتيباني از ابزارهاي مختلفاتصال ابزراهاي خارج از کيس

The primary disk used for mass storage is the hard disk drive.

Hard disks differ by technology, interface, speed, and capacity.

Most are capable of at least 5,000 revolutions per minute )RPM(.

The first PC hard disks ◦ a capacity of 10 megabytes ◦ $100 per MB

Modern hard disks ◦ 100 gigabytes ◦ Less than 1 cent per MB! ◦ improvement of 1,000,000% in just under 20 years,

or around 67% cumulative improvement per year.

Bits on disk - dark stripes are 0 bits and bright stripes are 1 bits

speed rotational

1

2

1latency average

speed rotational sectors ofnumber

1

2

1timetransfer

Removable hard drives◦ Hot swap

Disk Arrays◦ RAID )redundant array of inexpensive disk(

Mirrored array )fault-tolerant( Striped array

AT AttachmentAT Attachment◦ a disk drive implementation that integrates the

controller on the disk drive itself. ATA and IDE are the same thing, with an interface

that is 16 bits wide to match the old AT bus. The specification calls for a single channel, shared

by two devices that are configured as mastermaster and slaveslave.

ATA includes support for PIO modes 0, 1 and 2 ATA includes support for single word DMA modes 0, 1

and 2, and multiword DMA mode 0.

The only practical difference is that the PC will assign drive letters to the master drive before the slave drive, so that if you have a master and slave on the primary IDE channel and each has only one regular, primary partition, the master will be "C:" and the slave "D:". This means that the master drive )on the primary channel( is the one that is booted, and not the slave.

A newer version of the IDE mass storage device interface standard developed by Western Digital Corporation. ◦ It supports data rates of between 4 and 16.6 MBps,

about three to four times faster than the old IDE standard.

It can support mass storage devices of up to 8.4 gigabytes, whereas the old standard was limited to 528 MB. Because of its lower cost, enhanced EIDE has replaced SCSI in many areas.

EIDE is sometimes referred to as Fast ATA or Fast IDE, which is essentially the same standard, developed and promoted by Seagate Technologies. It is also sometimes called ATA-2.

ATA-2: Supports faster PIO modes )3 and 4( and multiword DMA modes )1 and 2(. Also supports logical block addressing )LBA( and block transfers.

ATA-2 is marketed as Fast ATA and Enhanced IDE )EIDE(.

PIO Mode 3 11.1 MB/s PIO Mode 4 16.6 MB/s DMA Multiword 1 13.3 MB/s DMA Multiword 2 16.6 MB/s

The newest version of the AT Attachment )ATA( standard, which supports burst mode data transfer rates of 33.3 MBps.

To take advantage of these high speeds, your computer must also be equipped with Ultra DMA, a protocol that supports faster data transfer rates to and from hard disk drives.

UDMA is a more advanced technology which provides for even faster throughput, up to 33.3 MB/s in UDMA mode 2 and 66.7 MB/s in UDMA mode 4, twice to four times that of EIDE, for much lower prices than SCSI. Many new computers come with large UDMA drives and UDMA interfaces, and it's possible to add a UDMA interface card )such as the Promise Ultra33 or Ultra66( to an existing system to boost speed, even on older non-UDMA drives.

Logical Block AddressingLogical Block Addressing A method used with SCSI and IDE disk drives to

translate the cylinder, head, and sector specifications of the drive into addresses that can be used by an enhanced BIOS.

LBA is used with drive's that are larger than 528 MB, and require an enhance BIOS that can handle LBA.

Logical Block Addressing )LBA( is used to Logical Block Addressing )LBA( is used to allow DOS and Windows to use drives over allow DOS and Windows to use drives over 504MB.504MB.

Small Computer Systems Small Computer Systems InterfaceInterface, a standard developed by the American National Standards Institute )ANSI(.

It specifies a universal, parallel, system-level interface for connecting up to eight devices )including the controller( on a single shared cable )called a SCSI bus(.

A SCSI device can install on any SCSI bus, whether on a Mac, PC, or any computer with a SCSI adapter.

SCSI-1: Uses an 8-bit bus, and supports data rates of 4 MBps SCSI-2: Same as SCSI-1, but uses a 50-pin connector instead of a

25-pin connector, and supports multiple devices. This is what most people mean when they refer to plain SCSI.

Wide SCSI: Uses a wider cable )168 cable lines to 68 pins( to support 16-bit transfers.

Fast SCSI: Uses an 8-bit bus, but doubles the clock rate to support data rates of 10 MBps.

Fast Wide SCSI: Uses a 16-bit bus and supports data rates of 20 MBps.

Ultra SCSI: Uses an 8-bit bus, and supports data rates of 20 MBps.

SCSI-3: Uses a 16-bit bus and supports data rates of 40 MBps. Also called Ultra Wide SCSI.

Ultra2 SCSI: Uses an 8-bit bus and supports data rates of 40 MBps.

Wide Ultra2 SCSI: Uses a 16-bit bus and supports data rates of 80 MBps.

Ultra320 SCSI : maximum throughput of 320MB/s using 80 MHz bus signaling

Remember that the SCSI specification allows devices other than a hard drive to be connected to the same cable, both internally and externally

The host adapter and every device must have a SCSI ID number between 0 and 7.

Usually, the host adapter is factory set at 7, the highest priority ID.

The cable must be terminated at both ends )the host adapter probably is self-terminating, and is commonly placed at one end. Make sure the termination is enabled. If the adapter is in the middle, you will need terminators at both ends.(

1. Low level formatting )LLF(◦ This is the "true" formatting process for the disk.◦ It creates the physical structures )tracks, sectors,

control information( on the hard disk. ◦ Normally, this step begins with the hard disk platters

"clean", containing no information.2. Partitioning

◦ This process divides the disk into logical "pieces" that become different hard disk volumes )drive letters(.

◦ This is an operating system function.3. High level formatting )HLF(

◦ This final step is also an operating-system-level command.

◦ It defines the logical structures on the partition and places at the start of the disk any necessary operating system files.

Redundant Arrays of Inexpensive Disks◦ use of multiple hard disk drives in an array that

behaves in most respects like a single large increased capacity, performance and reliability

◦ but they come with real costs.Nothing in life is free.◦

Self-Monitoring Analysis and Reporting Technology