SCSI Toolbox :: Newsletter - May 2007
IN THIS EDITION
Coming soon – Record command sequences and play them back!
Upgrade your old SCSItoolbox32 to the SCSItoolbox Suite today!
What are the White and BlueGreen arrows on the BAM Performance Monitors display?
Ask Dr. SCSI - "My disk drive is not reporting any errors, but ..."
Coming soon – Record command sequences and play them back!
The newest feature in the SCSIToolbox Suite is an enhancement to the BAM/STB application pair which allows you to capture a command sequence sent to any device from any application, and then later play that identical command sequence back to any device using the STB CDB Sequencer.
The command sequence can be generated by any application. As an example, let’s say that you have a third party application that initializes a drive for a specific use – such as prepping a drive to be used in an A/V application. You want to be able to reproduce the drive setting process without having to keep multiple copies of the A/V application loaded on your development machines.
Simply start BAM, select the drive, and begin the capture. Now run your application that preps the drive. Stop the BAM capture, and use the new File->Save to CDB Seq. File choice to save all data pertaining to the capture.
Bring this file over to your STB test computer. Within STB go to the Scripts & Sequences->CDB Sequencer choice. Use the Load BAM File button to load in your capture file. The Command History window will now show the CDB sequence that you captured with BAM. Select all, then click the Execute button – voila – the sequence of commands is issued to your device!
Perhaps you have an application that is causing errors – use BAM to capture the I/O then send the same CDB’s to a drive, using all the SCSIToolbox features to examine the results of each I/O and gather detailed error information. Issue all the commands as a sequence with one button-click, or send each command individually.
The more you think about it, the more uses you will discover for capturing I/O activity and playing it back.
Upgrade your old SCSItoolbox32 to the SCSItoolbox Suite today!
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What are the White and BlueGreen arrows on the BAM Performance Monitors display?
The White indicator shows the current average value achieved during the BAM capture. The Blue/Green indicator shows the highest value seen during the capture. In the example below we see highest Transfer rate during the capture was around 65 MB/s, with an average Transfer rate of 8 Mb/s.
Ask Dr. SCSI - “My disk drive is not reporting any errors, but it seems to be slower than it used to be. Is there a way to measure it’s performance?"
Q. “My disk drive is not reporting any errors, but it seems to be slower than it used to be. Is there a way to measure it’s performance?
A. “Good question – I couldn’t have asked a better one myself. Disk drive health is not a binary system – good or bad. It is linear, more like the Sears catalog of old, with a Good/Better/Best continuum. In other words, a drive may complete commands without failure but it may do so in a good or a poor way.”
In a best-case situation the drive would execute the command in the shortest time possible. A “good-but-not-best” case would be where the drive executes the command, but due to error correction methods it takes slightly longer to complete. There may be several levels of “good-but-not-best”, each level taking more time to complete than the level before. Finally there is the worst case, where the drive spends considerable time trying to execute the command but finally failing.
To make matters more interesting a disk drive may have all the above, where data retrieval from one area of the drive may complete in the fastest possible time but transfers from another area are as slow as can be without actual failure.
In the world of data transfer, time is the enemy. The faster a command executes the better.
Read Full Article here with screenshots
