Big iron lessons, Part 2: Reliability and availability: What's the difference?

#define UPPER_LIMIT 100
#define TRUE 1
#define FALSE 0

extern void logMessage(char *msg);
extern unsigned int MMIORead(unsigned int addr);
extern void StartRecovery(void);
extern void ContinueOperation(void);
extern int RecoveryRequired;

int LimitTest(unsigned int val)
{
     if(val > UPPER_LIMIT)
     {
              logMessage("Limit Exceeded\n");
              return TRUE;
     }     
     else
     {
              return FALSE;
      }
 }
   
main()
{ 
      unsigned int IOValue = 0;
      
      IOValue = MMIORead(0xF0000100);
      
      if(RecoveryRequired || LimitTest(IOValue))
      {
               StartRecovery();
       }     
       else
       {
               ContinueOperation();
       }
}