mdg@uport.UUCP (Marc de Groot) (06/18/88)
This posting describes the meanings of those cryptic numbers that get printed out with an HD I/O error message. The three numbers are labeled status, estat, and drstat. They are the contents of three registers in the hard disk controller at the time of the error. They are displayed in hexadecimal, or base 16. In order to decode the error info, you need to know how to convert hexadecimal to binary. Ask your local guru; it is beyond the scope of this posting. Some of the registers have different names in the Western Digital reference material: - status is still called the status register. - estat is called the error register. - drstat is called the SDH byte (SDH stands for Sector, Drive, Head). The Status Register (status) ------------------------------------------------- | BSY | RDY | WF | SC | DRQ | CD | IDX | ERR | ------------------------------------------------- 7 6 5 4 3 2 1 0 BSY (Busy) When this bit is set to 1 the controller is executing a command. If this bit is set, bits 1, 4, 5, and 6 of the status register are valid, and all other bits (in all registers) may not be considered valid. RDY (Drive Ready) These bits reflect the states of the drive signals WF (Write Fault) of the same names. The drive signals are actual SC (Seek Complete) wires in the drive cable. IDX (Index) DRQ (Data Request) When this bit is set to a 1 the controller is waiting for one sector (512 bytes for Microport UNIX) to either be written to or read from the controller's sector buffer. CD (Corrected Data) If this bit is set after a read command, the sector in the sector buffer was corrected using the controller's error- correcting code feature. ERR (Error) If this bit is set, the last hard disk command resulted in an error. All HD I/O errors reported by the Microport hard disk driver will show this bit to be set. The Error Register (estat) ------------------------------------------------- | DNF | TK0 | AC | CC | INF | WP | ECC | BB | ------------------------------------------------- 7 6 5 4 3 2 1 0 DNF (Data Address Mark Not Found) This bit, when set, indicates that the Data Address Mark was not found in the sector header. TK0 (Track 0 Error) This bit is set when the drive cannot find track 0. AC (Aborted Command) This bit is set if the controller receives an invalid command, or if the Drive Not Ready, No Seek Complete, or Write Fault conditions are present on the drive. CC (Cartridge Changed) This bit is only used with removable media, and will never be seen with ST-506 fixed disks under Microport UNIX. INF (ID Not Found) When set, this bit indicates that the desired sector header ID field was not found. WP (Write Protected) This bit, like the CC bit, is only used with removable media and will never be seen with ST-506 fixed disks under Microport UNIX. ECC (Data ECC Error) This bit is set to 1 if a data error occurs which cannot be corrected with the error-correcting code feature. BB (Bad Block Detected) This bit indicates that a sector was read or written which has the bad block flag set in its sector header. The SDH Byte (drstat) ------------------------------------------------- | 1 | 0 | 1 | DRV | Head Select | ------------------------------------------------- 7 6 5 4 3 2 1 0 DRV (Drive Number) This bit is a zero for drive 0, and a one for drive 1. Head These bits give the head number on which the error occurred. Select ------------------------------------------------------------------------------ Hope this info helps. Please note that there will be a much-improved hard disk error-reporting routine in the next releases of our porducts. Marc de Groot Senior Engineer/Hard Disk Guru -- Marc de Groot (KG6KF) | UUCP: {hplabs, sun, ucbvax}!amdcad!uport!mdg Microport Systems, Inc. | uunet!uport!mdg 10 Victor Square | Scotts Valley, CA 95066 |
mp1@sdcc12.ucsd.EDU (Leroy Dorman) (06/23/88)
In article <358@uport.UUCP>, mdg@uport.UUCP (Marc de Groot) writes: > > This posting describes the meanings of those cryptic numbers > that get printed out with an HD I/O error message. > Isin't this not in the documentation? If not, why? If they are, where? Good docs is one of the keys to success . . . :-) ---------------------------------------------------- Eric Dorman "Hail, hail, fire and snow . ." University of California, San Diego Scripps Institution of Oceanography From- "And the children siolmd!eric@sdsioa.ucsd.edu shall lead." mp1@sdcc12.ucsd.edu Attn: eric dorman@mplvax.nosc.mil Attn: eric