CompuServe Messages

Your statement that AB-Tools is 2 to 3 times faster than Quarterback Tools 2.0 had me a bit puzzled, since I don't recall it being nearly that much faster. So I did some checking… When all options to check data blocks are off, their speeds are very similar (Quarterback Tools is still slightly slower, but as I mentioned before, it is doing more integrity checks). When the option to read data blocks is turned on, Quarterback is indeed slower. However, because of the times turned in by AB-Tools I am very suspicious of their data block checking. On a six-megabyte partition of mostly small files (my SYS: partition), it took AB-Tools 10 seconds to scan without checking data blocks, and 16 seconds to scan with checking. This means that it read approximately six megabytes of data in six seconds! While this speed is possible if you are simply doing a disk scan (like when you turn on the "check for bad blocks" option in Quarterback Tools–that also takes about six seconds), when Quarterback Tools is checking data blocks in files it does a file-by-file analysis of the data blocks as it reads them. This is the correct thing to do, but it means that the hard drive head seeks all over the drive as it analyzes the data blocks (just as if you were opening and reading every file one-by-one from AmigaDOS). Note that I had the bad block check in Quarterback Tools turned off for this comparison, since AB-Tools doesn't seem to have a corresponding feature (this feature finds and maps out bad blocks on a drive). However, their "check" for data blocks seems to be nothing more than a drive scan, with no real checking involved. As such it is more like our bad block check, only without mapping out the bad blocks it finds. In fact, turning off Quarterback Tools' data block check, but turning _on_ its bad-block check gives scan times very similar to AB-Tools' times (16 seconds for AB-Tools vs. 21 seconds for Quarterback Tools). Note that generally we recommend you have _either_ data block checking or bad block checking turned on, but not necessarily both, since there is quite a bit of overlap in what they do (they both read all the data on a disk, the differ in the order they read it and what they do if they find a bad block).