Created the inquiry CDB structure and replaced some hardcoding.

Drive/Drive.hh

@@ -87,16 +87,16 @@ namespace Tape {
     void SCSI_inquiry(int fd) {
       unsigned char dataBuff[130];
       unsigned char senseBuff[256];
-      unsigned char cdb[6];
+      SCSI::Structures::inquiryCDB_t cdb; 
       memset(&cdb, 0, sizeof (cdb));
       memset(&dataBuff, 0, sizeof (dataBuff));
       /* Build command */
-      cdb[0] = SCSI::Commands::INQUIRY;
+      cdb.opCode = SCSI::Commands::INQUIRY;
 
       sg_io_hdr_t sgh;
       memset(&sgh, 0, sizeof (sgh));
       sgh.interface_id = 'S';
-      sgh.cmdp = cdb;
+      sgh.cmdp = (unsigned char *)&cdb;
       sgh.cmd_len = sizeof (cdb);
       sgh.sbp = senseBuff;
       sgh.mx_sb_len = 255;

SCSI/Structures.hh

@@ -29,8 +29,31 @@
 #include <arpa/inet.h>
 
 namespace SCSI {
+  /**
+   * Structures as defined in the SCSI specifications, and helper functions for them.
+   * SPC-4 (SCSI primary commands) can be found at:
+   * http://hackipedia.org/Hardware/SCSI/Primary%20Commands/SCSI%20Primary%20Commands%20-%204.pdf
+   * 
+   * and SSC-3 (SCSI stream commands, i.e. tape drives) at:
+   * http://hackipedia.org/Hardware/SCSI/Stream%20Commands/SCSI%20Stream%20Commands%20-%203.pdf
+   */
   namespace Structures {
 
+    /*
+     * Inquiry CDB as described in SPC-4.
+     */
+    typedef struct {
+      unsigned char opCode;
+      
+      unsigned char EVPD : 1;
+      unsigned char : 7;
+      
+      unsigned char pageCode;
+      
+      char allocationLength[2];
+      
+      unsigned char control;
+    } inquiryCDB_t;
     /*
      * Inquiry data as described in SPC-4.
      */