User manual MAXTOR MAXLINE II 250GB 01-02-2004

[. . . ] Maxtor MaXLine II 250/300GB Product Manual January 2, 2004 Part Number: 1904 © January 2, 2004 Maxtor Corporation. Printed in U. S. A. This publication could include technical inaccuracies or typographical errors. Changes are periodically made to the information herein ­ which will be incorporated in revised editions of the publication. Maxtor may make changes or improvements in the product(s) described in this publication at any time and without notice. [. . . ] In addition, the proposal from Maxtor that was incorporated into ATA/ ATAPI-6 defines a method for extending the maximum amount of data that can be transferred per command for ATA devices from 256 sectors (about 131 kilobytes) to 65, 536 sectors (about 33 megabytes). This new method is particularly useful for applications that use extremely large files, such as those for A/V or multimedia. The following sections will describe issues surrounding the 137-gigabyte barrier and the solution for breaking it. Maxtor MaXLine II 250/300GB A-1 Breaking the 137GB Storage Barrier A. 1. 1 History Many of the "barriers" in the past resulted from BIOS and operating system issues caused by failure to anticipate the remarkable increases in device storage capacity by the people who designed hard disk structures, access routines, and operating systems many years ago. They thought, "Who will ever have xxx much storage?" In some cases, the barriers were caused by hardware or software bugs not found until hard disks had grown in size beyond a certain point where the bugs would occur. Past barriers often frustrated people trying to add a new hard disk to an older system when they discovered that not all of the designed capacity of the hard disk was accessible. This inability to access the entire drive is referred to as a "capacity barrier" and it has been seen and overcome many times in the computer and disk drive industry. The 137-gigabyte barrier is the result of the original design specification for the ATA interface that provided only 28 bits of address for data. This specification means a hard disk can have a maximum of 268, 435, 456 sectors of 512 bytes of data which puts the ATA interface maximum at 137. 4 gigabytes. Maxtor MaXLine II 250/300GB A-2 Breaking the 137GB Storage Barrier 10, 000, 000 1, 000, 000 100, 000 Win2000 WinME 137GB WinXP 10, 000 Win98 33GB Win95(osr2) 8GB Win95A Win 3. x 128MB 32MB 16MB 4GB 2GB 1, 000 DOS 5. x 100 4. x 528MB 3. x 10 10MB 1980 10 megabytes:early 16 megabytes: 32 megabytes: 128 megabytes: 528 megabytes: 2. 1 gigabytes: 4. 2 gigabytes: 8. 4 gigabytes: 32 gigabytes: 1985 1990 1995 2000 2005 PC/XT limit FAT 12 limit DOS 3. x limit DOS 4. x limit Early ATA BIOSs without BIOS extensions DOS file system partition limit CMOS extended CHS addressing limit (not widely experienced) BIOS/Int13 24-bit addressing limit BIOS limit Maxtor MaXLine II 250/300GB A-3 Breaking the 137GB Storage Barrier A. 1. 2 Solving the 137 Gigabyte Capacity Barrier As described earlier, the issue causing the 137-gigabyte barrier is the 28bit addressing method of the original ATA specification. A change to expand this method was required to provide more address bits for the interface, allowing significant growth for many years to come. A critical issue in expanding the addressing capability was maintaining compatibility with the existing installed base of products. A new ATA standard, ATA/ATAPI-6, has been in the works for some time, and the latest draft of this standard resolves this issue by increasing the maximum number of bits used for addressing from 28 to 48. This solution increases the maximum capacity of an ATA device to 144 petabytes while maintaining compatibility with current ATA products. A. 1. 3 How is the Extension Implemented? The 48-bit Address feature set provides a method to address devices with capacities up to approximately 144 petabytes by increasing the number of bits used to specify logical block addresses (LBAs) from 28 to 48. The feature set also provides a method to increase the number of sectors that can be transferred by a single command from 256 to 65, 536 by increasing the number of bits specifying sector count to 16 bits. New commands specific to this feature set have been defined so that devices can implement the new feature set in addition to previously defined commands. Devices implementing the 48-bit Address feature set commands will also implement commands that use 28-bit addressing in order to maintain interoperability with older system components. In addition, 8-bit and 48-bit commands may be intermixed. The 48-bit Address feature set operates in LBA addressing only. Support of the 48-bit Address feature set is indicated in the IDENTIFY DEVICE response data. In a device implementing the 48-bit Address feature set, the registers used for addressing are, in fact, a two-byte deep FIFO. Each time one of these registers is written, the new content written is placed into the "most recently written" location and the previous content of the register is moved to "previous content" location. A host may read the "previous content" of the registers by first setting a bit in the Device Control register to 1 and then reading the desired register. A. 1. 4 What Do the Drives Need to Meet the Spec? The challenge to drive manufacturers is to develop and implement new interface chips on drives that can accept and decode the new 48-bit addressing scheme. Many functions of decoding the commands sent to and from the drive are automated in the silicon of the drive interface ASIC, and this is where drive manufacturers must update their designs. [. . . ] Storage capacities of one or more terabytes is achieved by installing multiple hard drive in a RAID system. 1 TB = 1, 000, 000, 000, 000 bytes when referring to disk storage capacity. THIN FILM ­ A type of coating, used for disk surfaces. Thin film surfaces allow more bits to be stored per disk. [. . . ]