Western Digital (250-0100/1/2/3/4) Drive Parameters Faxback Doc. # 2896 Hard Disk Upgrade Kits Catalog #/Model # Recommended Parameters Total Sectors ────────────────────────────────────────────────────────────────────────── 250-0100 Caviar AC1210 989 x 12 x 35 * 415,380 250-0101 Caviar AC2340 1010 x 12 x 55 * 666,600 250-0102 Caviar AC2420 989 x 15 x 56 * 830,760 250-0103 Caviar AC2540 1048 x 16 x 63 * 1,056,384 250-0104 Caviar AC31000 2100 x 16 x 63 * 2,116,800 * (Cylinders x Heads x Sector/Track) Drive Cylinders Heads Sectors/Track Total Sectors ────────────────────────────────────────────────────────────────────────── 212 MByte 989 12 35 415,380 (212.7 Mbyte) 987 12 35 414,540 (212.2 Mbyte) 987 10 42 414,540 (212.2 Mbyte) 882 10 47 414,540 (212.2 Mbyte) 735 12 47 414,540 (212.2 Mbyte) 658 14 45 414,540 (212.2 Mbyte) ────────────────────────────────────────────────────────────────────────── 340 MByte 1010 12 55 666,600 (341.3 Mbyte) 1013 14 47 666,554 (341.3 Mbyte) 807 14 59 666,582 (341.3 Mbyte) 952 14 50 666,400 (341.2 Mbyte) ────────────────────────────────────────────────────────────────────────── 420 MByte 989 15 56 830,760 (425.3 Mbyte) 989 14 60 830,760 (425.3 Mbyte) 1023 14 58 830,676 (425.3 Mbyte) 944 16 55 830,720 (425.3 Mbyte) ────────────────────────────────────────────────────────────────────────── 540 MByte *1048 16 63 1,056,384 (540.8 Mbyte) 1024 16 63 1,032,192 (528.5 Mbyte) ────────────────────────────────────────────────────────────────────────── 1 Gigabyte **2100 16 63 CMOS 1033 Mbytes CHKDSK 1083.7 Mbytes ────────────────────────────────────────────────────────────────────────── *See Note 1 **See Note 2 Note 1: At this time, the DOS/BIOS system limitation for maximum allowable usable drive size is 528 Mbytes (1024 cylinders). Many systems with AUTO setup options for drive type selection make use of the Identify Drive command to automatically determine the number of cylinders, heads, and sectors per track. The AC2540 returns default parameters of 1048 cylinders. Most systems will correctly truncate the AC2540 from 1048 to 1024 cylinders to achieve the maximum usable disk space under DOS (528 Mbytes). However, there are some systems that will incorrectly truncate to only 24 cylinders, allocating only 12 Mbytes of usable disk space. Systems that have AUTO drive type options usually also have USER DEFINED drive type options. If the AUTO drive type does not work, the USER DEFINED drive type option can be used to manually specify 1024 cylinders, 16 heads, and 63 sectors per track. If the AUTO drive type option does not work and your system does not have a USER DEFINED option in the system setup, Western Digital can provide you with the WDX utility to change the size the AC2540 reports to the host system from 540 Mbytes to 528 Mbytes. You may need to partition your drive(s) to overcome certain limitations of your MS DOS version. Partitioning allows you to divide your disk to multiple partitions, which function as separate disk drives. Use the MS-DOS FDISK.COM utility to display a series of menus that help you partition your hard disk for MS DOS. Note 2: The Western Digital one Gigabyte IDE Hard Drive comes with special Ontrack Disk Management Software. This Software includes a driver to allow 32 bit access from Windows 3.1. This software also allows for creation of partitions of up to 2 Gigabytes. (ALL/jlc-08/08/94)