硬盘技术及处理培训.ppt

硬盘技术及处理培训 12/May/04,2,硬盘培训(目录),IDE硬盘的简要历史.硬盘的基本组件.硬盘处理防范措施.硬盘的安装问题.WD硬盘的型号识别.WD 手持测试仪器.术语解释.附录(更多有用的详细信息).,3,从简要的历史看桌面电脑硬盘IDE硬盘,1980年末，发明了IDE接口.IDE是(Integrated Drive and Electronics)的缩写.它整合了控制器和驱动器使得主板端成为了一个简单的总线接口.从 老的34和 20芯电缆(从老的ST506接口)合并成了一个单40芯的电缆，以至于现在的80列电缆结构.,4,5,容量得到了巨大的突破.,Caviar,20MB Technical Specs.物理参数:Cylinders=782Heads=2Sectors/track=27Sectors/drive=42,228数据密度:Bits/inch(BPI)=22KbTracks/inch(TPI)=1021,1989,Caviar,200 GB(200,000 MB!)Technical Specs.物理参数:Cylinders=74,686Heads=6Sectors/track=506 945 Sectors/drive=390,721,968 数据密度:Bits/inch(BPI)=660KbTracks/inch(TPI)=76,000,2002,6,硬盘的基本部件,7,基本的部件,旋转马达(1).这个马达以恒定的转度转动，比如：5400 或 7200 rpm等等.中轴/励磁部分(2).读写臂的支点，读写臂在其周围移动。读写磁头(3).数据读写的动作就发生在这里。悬臂(4).保持读写磁头离开跌片，同时也固定了信号线和磁头的位置。记录碟片(5).典型的铝材做为盘基，上面镀以磁粉，在读写磁头下面以恒定转速旋转。挠性电缆电路(6).这条缆线使得信号线连接到了磁头和其放大器之间，然后连接到控制电路板.音圈马达（VCM）磁铁(7).当电流流经音圈马达的时候，带动悬臂上的读写磁头向不同正反方向移动，这是将磁头放置到指定的轨道所必需的。,8,硬盘的机械机构(HDA Head Disk Assembly),悬臂(4),电路板(底下),中轴/励磁部分(2),音圈马达磁铁(7),9,the direction of thecurrent flow determinesthe direction of the magnetic field(N,S),the currentflowing throughthe coil createsa magneticfield.,current carrying wire,coil,Magneticcore material,direction ofmagnetic fieldinside corematerial,magnetic field extends outside thecore material dueto the air gap.,N,S,magnetic material whichcan be altered by an external magnetic field.,The goal is tomagnetize a smallarea of the material,BASIC MAGNETICS,10,写数据到磁盘里,As the media rotates underneath,the r/w head produces short pulsed magnetic fields.These fields travels down into the magnetic layer of the disk.The magnetic particles in the media align themselves with the direction of the magnetic field.,11,从磁盘里读取数据,Magnetic fields from the disk will flow past the MR Element.This causes the RESISTANCE of the GMR Element to rapidly change.This is sensed by the disk drives electronics to be recovered.,12,Servo“Wedge”-Special NON-DATAarea used to position head properly on track,ECC*Field,DATA(512 bytes),one sector,How is data formatted on the drive?,Index(special servo mark that indicates the start.,*Error Correcting Code-A complex mathematical number that can be used to restore certain data errors.Also includes ID field information.,13,The HSA(Head Stack Assembly is moved by applying a current to the wires wound around a loop at its back end.This coil forms an electromagnet.The amount of current used is calculated by the drive electronics.The magnetic field generated reacts with the voice coil magnet,allowing extremely accurate positioning.By varying the current,very precise acceleration and deceleration can also be programmed,increasing performance.,Disk,Disk,HSA(Head Stack Assembly),HSA(Head Stack Assembly),COIL,COIL,VCM(Voice Coil Magnet),VCM(Voice Coil Magnet),14,What if an Error is Detected?,Basic ECC-Error Correcting Code,ECC is used to check AND CORRECT data read errors.The correctioninformation can be used to fix minor data errors.The length of the ECCdata,the pattern of the error,and the design of the polynomial all play a significant part.Today,errors of 45 consecutive Bytes or more can usually be corrected.,Read from Disk,CorrectionInformation,(BYTE 1/X)+(BYTE 2/X+.+(BYTE 512/X),15,See Appendix 2.for more details on Heads,Media and Recording principles!,16,硬盘操作,17,多数有缺陷的硬盘返回来后，多多少少都有一些是由于误操作损坏的。小心操作硬盘是必需的，特别是在安装硬盘的时候!,18,硬盘的处理磁头/盘片 飞行高度 vs.污染物,今天硬盘磁头与盘片之间的飞行高度为1.2 to 1.8 MILLIONTHS(.0000012 to.0000018 英寸 或 1.2 to 1.8 微英寸).,Head Fly Height.0000012-.0000018inches,19,冲击和振动,Hard Table Surface,硬盘非常容易受到伤害的时候是在安装（操作）的时候.比如：静电，野蛮的操作(冲击和振动)从1.75英寸高跌落到桌面上，可以产生200 G的冲击，很可能导致磁头击打碟片而对硬盘产生伤害。不要将硬盘相互堆叠起来！,典型的硬盘冲击规格:Non-Operating Shock=250 G Operating Shock=20 G,1.75 inches,被损坏的角落,20,此时硬盘突然被摔下,刚开始磁头受到向上的冲击力,(4)碟片因此永远受损,而且磁头上也沾到了破碎的颗粒,从而扩大碟片的破碎表面,没电时磁头拍打碟片情况,21,硬盘处理检测(目测),如果伺服封条破裂，空气和尘埃进入盘体从而导致硬盘毁坏。避免静电的伤害，在将硬盘装入静电袋之前，确保自己本身跟地面有良好接触。,角落破损,外壳受损,标签受损,针断,电路板/静电 损坏,22,硬盘的处理,总要 拿硬盘的侧面,永远不要 抓到硬盘的电路板,The drive casting is very durable for handling.,Applying pressure to the PCBmay cause ESD problems or youmay bend the PCB just enoughto break a solder connection.,BOTTOM,Caviar,TOP,23,有噪音的硬盘,高的噪音:,在距离正常距离远的地方还是能听到噪音的话，这个硬盘值得怀疑。这种声音典型的是有马达中的轴承引起.“Dents”on one or more motor ball bearings(or the housing)set up high pitched vibrations and almost ALWAYS results from ashock to the drive.,Caviar,24,硬盘处理硬盘拆封时,处理守则,请不要随意摔下硬盘,或放桌边 请不要堆叠硬盘或在硬盘上放置东西 请把硬盘保持在防静电袋里,直到预备装机前的一刻 请用合适的防静电袋 请在同一个时间,只能处理一个硬盘 请不要用刀割破防静电袋,这会造成电路板的损坏,25,26,硬盘安装,27,Hard Drive Installation Issues,硬件问题-安装-电缆连接软件问题BIOS 问题操作系统问题数据卫士工具缺陷管理CMOS 设置,28,Caviar,确保用4个螺丝锁紧硬盘。4个螺丝要正常的接地。,硬盘可以平放或者垂直安装。不要靠近太发热的地方。,硬盘的安装,29,冷却和通风,当前的硬盘需要正确的冷却和通风硬盘旋转更快经常不止只有1个碟片硬盘的寻道时间更快所有的这些因素会产生更多的热量!所有的EIDE 硬盘都有最高温度的限制:用一个温度传感器在测试硬盘温度Typically 5 C to 55 C(41 F to 131 F)OPERATINGTypically-40 C to 65 C(-40 F to 149 F)OFF,30,基本IDE概念,最大的数据线长不超过 18”（0.46M）第二个接头距离末端不应该大于 6”。如果只有个硬盘连接，应该将它连接到顶头那端。,31,两条数据线的连接头都一样,UATA-33 EIDE Cable,UATA-66/100 EIDE Cable,UATA-66(或以上)需要一条 80 conductor cable.连接头与原来 40 针的数据线相同.另外为了保护讯号,其余40针都是接地.蓝色接口一定要连接在主板上.,蓝色接口一定要连接在主板上.,32,BIOS 的障碍,As Hard Drive sizes grew from 528MB to over 137GB,severalchanges were necessary to the way BIOSs“look”at the drive.,528MB to 2.1GB,2.1GB to 8.4GB,Greater than 137GB,8.4GB to 137G,33,To handle todays larger drives,new BIOS functions were added.Basically,the size of the LBA Table was increased to 28 bits,which only works up to 137G.,28 Bit LBA Table=228,or 137.4 GB,X 512 Bytes/Sector=,137,438,953,472,BIOS Barriers(cont),Moving forward,the 48-Bit Address Feature Set in ATA-6 extends the addressable capacity of IDE devices to 144 Petabytes.,48 Bit LBA Table=248,X 512 Bytes/Sector=,281,474,976,710,656 SECTORS,or 144 PB,See Appendix 3.for details on 48 bit addressing!,34,Windows OS Limitations for drives 137G,35,WD硬盘一般检测工具,36,S.M.A.R.T.,Self Monitoring Analysis and Reporting Technology,硬盘持续监控内部的主要功能参数,保持记录,以作为预测硬盘何时功能会下降甚至于不能工作.很多譬如像error rates 及 spin-up retries都会被监控.,37,Data Lifeguard-a WD Exclusive,内藏软件,所以WD 的硬盘可自我检测.每隔8小时检测一次.如能提早发现,大部分的问题都能够修复譬如数据修复.硬盘读写时,不会进行检测,38,WD 软件工具,EZ-Install分区,格式化 and copies hard drives.DLGDIAG Drive Diagnostic测试硬盘的机械零件,电子及碟片的损坏.寻找及矫正一些小错误.(write“0”to all sectors).UATA 66/100 managementManages UATA 66/100 functions on the drive.,Western Digital Data Lifeguard 软件工具,包含以下功能:,The latest revisions of these programs(and other WD utilities)are always available at http:/OF CHARGE,39,Mysteries of the(CMOS)SETUP Menu:See Appendix 4.Includes PIO vs.DMAdata flow,Block transfers and more.,PressFor CMOS Setup,40,41,WD Drive Model Numbers,decoded,WD,1200,BB,22,CA,A0,-,Capacity4 Characters max.Last character is the decimal,i.e.120.0,RPM/bufferA=5400/2MBB=7200/2MBJ=7200/8MBL=7200/2MB,FDB,Interface B=ATA/100,Customer ID00=Generic22=OEM,Customer Config Code(CCC)Defines productlevel revision.,Family IdentifierCA=40G/platter DA=60G/platterEtc.,42,Quick Tester,Western Digital Quick Tester,Quick Tester Overview,Hand-held tester for IDE/EIDE drives No PC required,only standard PC power supply Optimized to issue most comprehensive IDE test algorithms and utilize enhanced SMART features of todays EIDE hard disk drives Microprocessor based User-friendly“two button”design with guided messages displayed on a 16 character by 2 line LCD display Tester size is about 4.5”x6”x1.25”Optimized for WD drives but will work with IDE drives from any hard drive manufacturer,See Appendix 5.for more details on the Quick Tester!,45,46,S.M.A.R.T.(contd.),Off-line Data Collection:a multi-zone error rate is computedfrom data collected during off-line scans and reported viaSMART.Self test:the Host may request either a short(2 minutes)or a full test of the drive.It includes a ConveyanceSelf Test,which can detect handling damage.“Selective Self Test”,available starting with XL60,allows Host to specify ranges of LBAs for testing.Error logging:error events and supporting data are recorded by the drive and accessible by the Host.,47,Average Access Time?,Avg.Access Time=Latency+Seek Time+Transfer Time+Controller Overhead,1/3,1/3,1/3,requestedsector,disk rotation,Seek Time:Time required to move the heads a desired distance.Typically specified at 1/3 the of the diameter of the platter.Latency:Amount of time the drive must wait before data is under the read/write head.,cont,DISK,This is the amount of time it typically takes to read orwrite the requested data.,48,Transfer Time:Amount of time required to transfer data to or from a disk.Controller Overhead:How long it takes the drive to decode a command from the HOST.,Hostsendscommand,disk drive registers,Cache,Disk Drive,DISK,Disk Electronics,Transfer Time,Controller Overhead,(Average Access Time,contd.),49,MTBF,Mean Time Between Failure.This is calculated as the average number of hours a field population of drives will work before a failure occurs.Based on mathematical calculations,NOT actual experience.The Western Digital MTBF specification is 500,000 hours.If a drive is operated for 24 hours/day for 365 days/year,it would take an average of 58 years before this disk drive would fail.The modern replacement for MTBF is AFR.Annual failure rate=failures per yr./Drives mfg.Per yr.Much more meaningful measure of reliability.Based on REAL data.Today,AFR is less than 1%.,50,Confusion exists as to what the TRUE size of large drives REALLY is,Method 1-1000 Byte Blocks-i.e.MB or GBDrive capacity is calculated in terms of the ACTUAL number of bytes available-(Max LBA)x(512)A MB is 1,000,000 Bytes-A GB is 1,000,000,000 BytesMethod 2-1024 Byte Blocks-i.e.Mb or GbSince computers are DIGITAL devices,a thousand Bytes actually should be defined as 210 or 1024 bytesA Mb is 220 or 1,048,576 bytes-A Gb is 230 or 1,073,741,824 bytesDrive capacity should therefore be calculated in terms of 2x(Max LBA)x(512)/1024,DRIVE SIZE,Method 2 will ALWAYS yield a SMALLER DRIVE SIZE,ALL Hard Drive Manufacturers today define capacity in terms of Method 1(i.e.1000 Byte Blocks),51,Appendices,Appendix 1.IDE Implementation Guide.Appendix 2.Heads,Media and Drive Geometry.Appendix 3.48 Bit Addressing for drives 137G.Appendix 4.Transfer modes,setup considerations.Appendix 5.The Quick Tester.Specs and features.,52,Question&Answer,53,Q1.头发与碟片/磁头比较,谁比较宽?,54,头发,55,Q2.请说出一个处置硬盘不当的做法?,56,硬盘处理硬盘拆封时,处理守则,请不要随意摔下硬盘,或放桌边 请不要堆叠硬盘或在硬盘上放置东西 请把硬盘保持在防静电袋里,直到预备装机前的一刻 请用合适的防静电袋 请在同一个时间,只能处理一个硬盘 请不要用刀割破防静电袋,这会造成电路板的损坏,57,The End.Thank You.,Western Digital,