Word F/V Identify device information 0 General configuration bit-significant information: F 15 0 = ATA device 1 = ATAPI device F 14 Obsolete F 13 Obsolete F 12 Obsolete F 11 Obsolete F 10 Obsolete F 9 Obsolete F 8 Obsolete F 7 1 = removable media device F 6 1 = not removable controller and/or device F 5 Obsolete F 4 Obsolete F 3 Obsolete F 2 Obsolete F 1 Obsolete F 0 Reserved 1 F Number of logical cylinders 2 R Reserved 3 F Number of logical heads 4 X Obsolete 5 X Obsolete 6 F Number of logical sectors per logical track 7-9 X Vendor specific 10-19 F Serial number (20 ASCII characters) 20 X Obsolete 21 X Obsolete 22 F Number of vendor-specific bytes available on READ/WRITE LONG commands 23-26 F Firmware revision (8 ASCII characters) 27-46 F Model number (40 ASCII characters) 47 X 15-8 Vendor specific R 7-0 00h = Reserved F 01h-FFh = Maximum number of sectors that can be transferred per interrupt on READ/WRITE MULTIPLE commands 48 R Reserved
Table 1—If you like to write code that parses data, then writing ATA hard drive code will keep you happy (and busy) for days. The data in Photo 3 was culled from this table of words spoken by the little Hitachi DK211A-54. F represents a fixed value, V represents a variable value, X represents a vendor-specific value, and R represents a reserved value.