A C - 2 4 2 0 WESTERN DIGITAL NO MORE PRODUCED Native| Translation ------+-----+-----+----- Form 3.5"/SLIMLINE Cylinders 2720| 989| | Capacity form/unform 425/ MB Heads 4| 15| | Seek time / track 13.0/ 4.0 ms Sector/track | 56| | Controller IDE / AT Precompensation Cache/Buffer 128 KB STATIC RAM Landing Zone Data transfer rate 3.000 MB/S int Bytes/Sector 512 5.740 MB/S ext Recording method RLL 1/7 operating | non-operating -------------+-------------- Supply voltage 5/12 V Temperature *C 5 55 | -40 60 Power: sleep 0.3 W Humidity % 8 80 | 5 80 standby 0.4 W Altitude km -0.305 3.048| -0.305 12.192 idle 2.1 W Shock g 10 | 70 seek W Rotation RPM 3314 read/write 3.1 W Acoustic dBA 39 spin-up 15.0 W ECC Bit 176,REED SOLOMON MTBF h 250000 Warranty Month 36 Lift/Lock/Park YES Certificates CSA,FCC,IEC950,TUV,UL1950 ********************************************************************** L A Y O U T ********************************************************************** WESTERN WDAC1210/AC2420 TECHNICAL REFERENCE MANUAL +---------------------------------------------------------+ | |XX I | |XX N | |XX T | |XX E | |XX R | |*X F J2 | |XX A | |XX C | |XX E | |XX | |XX1 | |6-5 J8 | || | ++LED |2-1 ++ |XX J1 | |XX Power +---------------------------------------------------------+ J2 J8 J1 +39------------------------------------1++5-3-1++-------+ |o o o o o o o o o o o o o o o o o o o o||o o o||O O O O| |o o o o o o o o o o o o o o o o o o o||o o o||4 3 2 1| --+40------------------------------------2++6-4-2+++-+-+-++---- | | | +12V (Pin 20 keyed) | | +- GND | +--- GND +----- +5V ********************************************************************** J U M P E R S ********************************************************************** WESTERN WDAC1210/AC2420 TECHNICAL REFERENCE MANUAL Jumper setting ============== J8 Master/Slave/Cable Select Configuration ------------------------------------------- +5-3-1+ Single Drive +5-3-1+ Master Drive |o o o| Configuration |X o o| Configuration |o o o| |X o o| (Dual Drives) +6-4-2+ +6-4-2+ +5-3-1+ Slave Drive +5-3-1+ Cable Select |o X o| Configuration |o o X| Configuration |o X o| (Dual Drives) |o o X| (Dual Drives) +6-4-2+ +6-4-2+ The Caviar can be assigned as either a single, master, or slave drive. Dual Installations ------------------ Dual installations require a master/slave drive configuration, where one drive is designated as the promary (master) drive and the other is designated as the secondary (slave) drive. The Caviar drive is compatible in dual installations with other intelligent drives that supports a master/slave configuration. If your installation requires the use of an adapter card, it is useful to know that you may also be able to connect your floppy drive(s) to the adapter card. Single Drive Mode ----------------- If you are installing the Caviar drive as the only intelligent drive in the system, you do not need install jumpers on the J8 connector. This is considered a standard single drive installation, and no jumpers are required. Note that even with no jumper installed, the Caviar checks the DRIVE ACTIVE/SLAVE PRESENT (DASP) signal to de- termine if a slave intelligent drive is present. If you have a dual installation (two intelligent drives), you must designate one of the drives as the master and the other as the slave drive. The jumper pins on the J8 connector need to be configured for the dual installation. Master Drive Mode ----------------- To designate the drive as the master, place a jumper shunt on pins 5-6. With the Caviar configured as the master drive, the Caviar assumes that a slave drive is present. The jumper on pins 5-6 is optional if the slave drive follows the same protocol (Common Access Method AT Bus Attachment) as the Caviar. Slave Drive Mode ---------------- To designate the drive as the slave, place a jumper shunt on pins 3-4. When the Caviar is configured as the slave drive, the Caviar delays spin up for three seconds after powerup reset. This feature prevents overloading of the power supply during power-up. Cable Select (CSEL) ------------------- Caviar also supports the CSEL signal on the drive cable as a drive address selection. Place a jumper shunt on pins 1-2 to enable this option. When enabled, the drive address is 0 (Master) if CSEL is low or 1 (Slave) if CSEL is high. Do not install the CSEL jumper shunt when installing the Caviar drive in systems that do not support the CSEL feature. ********************************************************************** I N S T A L L ********************************************************************** WESTERN WDAC1210/AC2420 TECHNICAL REFERENCE MANUAL Notes of Installation ===================== Orientation ----------- The Caviar can be mounted in many different ways depending upon the physical design of your system. Determining Your Configuration ------------------------------ You can configure the Caviar in one of two ways: 1. The drive is cabled directly to a 40-pin connector on the mother- board, or 2. The drive is cabled to an adapter card mounted in one of the expansion slots in the computer. Both configurations use a 40-pin host interface cable. If you are using the Caiar drive as one of two hard disk drives in the computer (dual installation), you may use either configuration. In dual installations, you must use a 40-pin host interface cable with three connectors and daisy-chain the two drives to the mother- board or adapter card. Mounting the Drive ------------------ For dual installations, it is usually easier to completely install one intelligent drive in the lower position first. The order of intelligent drives is unimportant if you are using to Western Digital drives. As explained previously, one must be jumpered as the master drive and the other as the slave drive. When installation is complete he drives are daisy-chained together. Cabling and Installation Steps ------------------------------ Make sure your interface cable is no longer than 18 inches to minimize the noise which is induced on the data and control buses. Also, if you are connecting two drives together, you need a daisy- chain cable that has three 40-pin connectors. Caution: You may damage the Caviar drive if the interface cable is not connected properly. To prevent incorrect connection, use a cable that has keyed connectors at both the drive and host ends. Pin 20 has been removed from J2 connector. The female connector on the interface cable shoul have a plug position 20 to prevent incorrect connection. Make sure that pin 1 on the cable is connected to pin 1 on the connectors. Mounting Screws --------------- Mount the caviar drive bay using four 6-32 screws. Be sure to use the correct size screws. Do not install the screws past six threads (3/16 inch). Screws that are too long will damage the Caviar drive. Power Connectors and Cables --------------------------- Power Connector: 4-pin MOLEX P/N 15-24-4041 or equivalent Mating Connector: Body AMP 1-480424-0 or equivalent Pins AMP 60619-4 or equivalent Power Cable Wire Gauge 18 AWG Buffer RAM ---------- A 128-Kbyte (optional 256-Kbyte) static RAM buffer enhances data throughput by buffering sector data between the Caviar and the AT system bus. The buffer is accessed by two channels, each having a separate 16-bit address and byte-count register. The channels operate simultaneously, accepting read and write operations from two data paths. Universal Translation --------------------- The Caviar implements linear address translation. The translation mode and translated drive configuration are selected by using the Set Drive Parameters command to issue head and sector/track counts to the translator. Caviar supports universal translation, therefore, any valid combination of cylinder, head and SPT can be assigned to the drive, as long as the total number of sectors is not greater than the physical limits. The product of the cylinder, head and sectors/track counts must be equal to or less than the maximum number of sectors available to the user. The maximum number of sectors per drive are: AC1210 - 415,380 AC2420 - 830,760 Each sector consists of 512 bytes. The minimum values for any translation parameter is one. The maximum value for any translation parameter is as follows: Sectors/Track - 255 Heads - 16 Cylinders/Drive - 2048 ********************************************************************** F E A T U R E S ********************************************************************** WESTERN WDAC1210/AC2420 TECHNICAL REFERENCE MANUAL Zoned Recording --------------- The AC1210, and AC2420 drives employ Zoned Recording to in- crease the data density on the outer tracks of the drive. The outer- most tracks contain 71% more sectors than the innermost tracks, thereby increasing the total capacity of the drive. Advanced Defect Management -------------------------- The Caviar is preformatted (low-level) at the factory and comes with a full complement of defect management functions. Extensively tested during the manufacturing process, media defects found during intelligent burn in are mapped out with Western Digital's high performance defect management technique. No modifications are required before installation. Embedded Servo Control ---------------------- The Caviar festures an embedded servo concept as the means of providing sampled position feedback information to the head position servo system. Servo bursts are located along a radial path from the disk center,ensuring that head positioning data occurs at constant intervals. This high sampling rate supports the high frequency servo bandwidth required for fast access times as well as highly accurate head positioning. The embedded servo concept provides the means of generating accurate feedback information without requiring a full data surface as would a dedicated servo control concept. Seek Time --------- Average Seek Sub-13 Milliseconds Track-to-Track Seek 4 Milliseconds Maximum Seek 26 Milliseconds Index Pulse Period 18 Milliseconds Average Latency 9 Milliseconds Voice Coil Assembly ------------------- The voice coil assembly consists of an upper and lower magnetic plate, a flat rotary coil, a bidirectional crash stop and a pivot bearing. The pivot assembly fits in the actuator block bore. Defect Management ----------------- Every Caviar undergoes factory-level intelligent burn in, which thoroughly tests for and maps out defective sectors on the media before the drive leaves the manufacturing facility. Following the factory tests, a primary defect list is created. The list contains the sector cylinder and head numbers for all defects. The purpose of the sector/track map is to manage the reallocation of spare sectors and tracks after they have been assigned. Defects managed at the factory are sector slipped. Grown defects that can occur in the field are handled by realocation to spare sectors on the inner cylinders of the drive. Format Characteristics ---------------------- In order to be compatible with existing industry standard defect management utility programs, the Caviar supports logical format. When the host issues the Format Track command, the Caviar performs a logical version of this command in response to the host's interleave table request for good and bad sector marking or assign/unassign the sector to/from an alternate sector. If the host issues the Format Track Command during normal operating modes, the data fields of the specified track are filled with a data pattern of all zeros. The interleave table identifies any bad sectors on a given track. The interleave table must contain all appropriate number of bytes of data. There are two bytes per sector for each entry in the interleave table. The first byte marks the sector as good or bad. ********************************************************************** G E N E R A L ********************************************************************** WESTERN ALLGEMEINES QUESTION -------- Which hard drive specification is most important to overall system performance ? - Host Transfer Rate - Drive RPM (revolutions per minute) - Disk Transfer Rate (Media Rate) - Seek Time - Cache Size - PC Data Handling - All of the above Answer ------ The correct answer is actually a combination of "all of the above," keeping in mind most of the above specifications are interrelated when it comes to optimizing system performance. The pie chart illustrates the relative influence of factors affecting drive performance during a typical random I/O operation (reading and writing to a hard drive). The major determinate of hard drive performance is mechanical factors which are one hundred times slower than the high-speed electronics contained in a drive. Factors Affecting Hard Drive Performance (In their relative order of importance) MECHANICAL LATENCIES Mechanical Latencies include both Seek Time and Rotational Latency. The seek time is a measure (in milliseconds) of how fast the hard drive can move its read/write heads to a desired location. Rotational latency is a measure of the average time (also in milliseconds) the read/write heads must wait for the target sector on the disk to pass under them once the read/write heads are moved to the desired target track. Mechanical latencies are the main hindrance to higher performance in modern Enhanced IDE (EIDE) hard drives. The time delays of mechanical latencies are one hundred times higher than electronic (non-mechanical) latencies associated with the transferring of data. Therefore, reducing mechanical latencies (a lowering of seek time and rotational latency) should be the top consideration in improving hard drive performance. RPM --- This is the rotational speed of the media (disk), also referred to as the spindle speed. Hard drives only spin at one constant speed. Typical speeds are 3600 to 3880, 4500, and 5200 to 5400 revolutions per minute. The slower the RPM, the higher the Mechanical Latencies. Disk RPM is a critical component of hard drive performance because it directly impacts the rotational latency and the Disk Transfer Rate explained below. DISK TRANSFER RATE ------------------ The Disk Transfer Rate (sometimes called media rate) is the speed at which data is transferred to and from the disk media (actual disk platter) and is a function of the recording frequency. Typical units are bits per second (BPS), or bytes per second. Modern hard disks have an increasing range of Disk Transfer Rates from the inner diameter to the outer diameter of the disk. This is called a "zoned" recording technique. The key media recording parameters relating to density per platter are Tracks Per Inch (TPI) and Bits Per Inch (BPI). A track is a circular ring around the disk. TPI is the number of these tracks that can fit in a given area (inch). BPI defines how many bits can be written onto one inch of a track on a disk surface. To greatly simplify, the Disk Transfer Rate (the rate at which data is read and written to the disk) is dependent upon the speed of the disk (RPM) and the density of the data on the disk (BPI). Even most modern, high-speed, 5000 RPM hard drives are generally limited to a maximum Disk Transfer Rate of approximately 9 to 10 MB per second. This specification is critical to performance and must be weighed carefully against such electronic latencies as Mode 3 PIO and Mode 4 PIO host transfer rates explained below. PC DATA HANDLING ---------------- After the data moves down the IDE cable from the drive to the host interface, there are several factors that can affect drive performance over which the hard drive has no control. PC Data Handling is independent from the hard drive and very dependent upon the CPU type and speed, the BIOS overhead (how the system issues commands to the hard drive), speed and size of the system RAM and RAM cache, CPU-to-memory speed, and storage subsystem performance. PC Data Handling is also affected by the caching methods of such software applications as SMARTDRIVE, 32-bit disk access operating system drivers, etc. HOST TRANSFER RATE ------------------ The speed at which the host computer can transfer data across the IDE or EIDE interface. Processor Input/Output (PIO) modes and Direct Memory Access (DMA) modes are defined in the ATA-2 industry specification as follows: Mode 3 PIO 11.1 MB/sec Mode 4 PIO 16.6 MB/sec Mode 1 DMA 13.3 MB/sec Mode 2 DMA 16.6 MB/sec Modern host computer systems usually support most of the above modes. Faster Host Transfer Rates in the future will use multi-word DMA modes as the industry will not support any future PIO mode standards beyond mode 4. The computer system manufacturer is responsible for implementing a Host Transfer Rate that is high enough to ensure that the host computer is not the performance bottleneck. Implementing increasingly higher Host Transfer Rates without corresponding increases in Disk Transfer Rates on the hard drive will not result in increased drive performance. Cache Buffer Size - Is Bigger Always Better ? A Cache Buffer is similar to a water glass. When you are writing to a hard drive, the host computer fills the glass and the disk media empties it. If you are reading data from a hard drive, the disk media fills the glass and the host computer empties it. The reason that a bigger cache buffer is not always better (or faster) is because the host computer (with Mode 4 PIO or Mode 2 DMA capabilities) can empty or fill the glass much faster than the hard drive can empty or fill it. When the host system can transfer data in or out of the cache buffer faster than the media rate, a larger buffer size becomes irrelevant because the host system is always "waiting" for the hard drive. Western Digital hard drives are designed with cache buffer sizes that are matched to the Disk Transfer Rate capabilities of the drive and the Host Transfer Rates of modern computer systems. All of our drives are benchmarked with various cache buffer sizes to verify that the most cost-effective and performance-effective cache size is implemented. Confusion Over Mode 4 and Mode 2 DMA ------------------------------------ The Enhanced IDE program created the long-range road map for performance enhancements which included faster disk and host transfers, Mode 3, Mode 4, Mode 2 DMA, etc. Currently, computer systems and hard drive controller silicon have most of the elements needed to implement Mode 4 PIO or Mode 2 DMA (a 16.6 MB/sec Host Transfer Rate). However, to take advantage of these performance modes, physical drive architecture must also make some performance improvements in the area of Mechanical Latencies and Disk Transfer Rate (media rate) as defined earlier. Some competitors, in their eagerness to supply a new feature, are prematurely marketing Mode 4 and Mode 2 DMA. While their drive controller silicon supports these modes (which is very easy and inexpensive to implement), spindle speeds (RPM), rotational latency, bit density, and other factors have not yet been improved (these being very difficult and costly). The result is hard drives which have the electronic capability to do Mode 4 and Mode 2 DMA transfer rates, but can't take advantage of these modes due to the slower Disk Transfer Rate of the drive. Western Digital will not be implementing Mode 4 or Mode 2 DMA on older drive products as the host systems into which these drives are designed are not electrically capable of these data transfers, nor are the Disk Transfer Rates on these drives beyond current Mode 3 capabilities. As next generation systems are introduced, they will be paired with next generation drives. Those drives will require and offer true Mode 4 / Mode 2 DMA capability from a total drive architecture standpoint. ==================================================================== AC2540/2635/2700/2850/21000/31000/31200/31600 Windows 95 Operating System Addendum ------------------------------------ The information in this addendum supersedes that supplied in Windows 95 section on pages 35 and 36 of this manual. Please refer to thos addendum for Windows 95 questions. Although Windows 95 is capable of recognizing the full capacity of hard drives larger than 528 MB in systems with a translating BIOS, some restrictions apply to systems without a translating BIOS. For Systems With a Translating BIOS ----------------------------------- Enter your CMOS setup and select a drive type that will recognize the full capacity of your drive. This is usually done by selecting the auto config drive tape. The boot partition can be set up to be as large as the full capacity of your hard drive. For Systems Without a Translating BIOS -------------------------------------- Enter your CMOS setup and select a user defined drive type. Enter these parameters: cylinders = 1024, heads = 16, sectors = 63. Your system's total disk space will be limited to a maximum of 528MB. If you want your system to utilize more than 528 MB of disk space, you must use Ontrack's Disk Manager software (or a similar third- party installation software). Installing Windows 95 on a Hard Drive with Ontrack Disk Manager Already Installed --------------------------------------------------------------- The Windows 95 installation program will analyze your computer system and install seamlessly with Ontrack Disk Manager. Computer Systems with Windows 95 Already Installed -------------------------------------------------- If you are installing a Western Digital hard drive and Ontrack Disk Manager on a computer system with Windows 95 already installed, you must install Ontrack Disk Manager as described here. Enter your CMOS setup and select a user defined drive type. Enter these parameters for drives with capacities over 528MB: Cylinders = 1024, Heads = 16, Sectors = 63. Save these changes and reboot your computer. 1. Select the Start icon from the Windows 95 main screen. DO NOT open an MS-DOS menu from Win 95 to install Ontrack Disk Manager. 2. Choose the Shut Down option. 3. Select Resatrt Computer in DOS mode. When your computer restarts, you should be at the DOS prompt. 4. Install Ontrack Disk Manager. Windows 95 will noe recognize the full capacity of your hard drive and run in 32-bit disk access mode for optimum performance.