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app:using_analogtest [2022/03/02 14:53] – [Drive Analog Characteristics] wordsmithing flanapp:using_analogtest [2022/03/02 15:02] – [What do all these graphs mean?] Added a bit more explanation. flan
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 === Noise === === Noise ===
  
-The *Noise* test in the lower left gives us a baseline for the density of noise that is generated by the drive when in "full panic" mode. Having a high noise level here **doesn't** mean that a drive is bad or will have trouble reading a disk. It is more the representation of the worst-case scenario of a drive trying to read a disk but it cannot find any data. Many drives have an automatic gain control function that tries to increase the sensitivity of the read head in order to lock in on the flux transitions on the disk. Unfortunately, the sensitivity can be turned up so much that the drive starts making up data that doesn't actually exist. The graph shows the number of "fake" transitions that the drive sends per rotation.+The Noise test in the lower left gives us a baseline for the density of noise that is generated by the drive when in "full panic" mode. Having a high noise level here **doesn't** mean that a drive is bad or will have trouble reading a disk. It is more the representation of the worst-case scenario of a drive trying to read a disk when it cannot find any data. Many drives have an automatic gain control function that tries to increase the sensitivity of the read head in order to lock in on the flux transitions on the disk. Unfortunately, the sensitivity can be turned up so much that the drive starts making up data that doesn't actually exist. The graph shows the number of "fake" transitions that the drive sends per rotation on a track that has been wiped of data.
  
 === Window Stability === === Window Stability ===
  
-The *Window Stability* graph at the top of the window is the analysis of what the drive can and cannot process reliably. The gray vertical lines show the results for individual tests at various flux frequencies long lines are high success rate, and short or no line means lower success rate. The gold line in the graph is a breakdown of the signal reliability along with factoring in things like spindle motor speed fluctuations and such. The most important thing you need to recognize in this graph is the durations which are covered with the gold line pinned to the top which is 100% reliability. The above graph shows that the signal is 100% stable from 3.75µs through to 19µs. If you aren't familiar with how data is stored on disks at a very low level, then that range of stability probably means absolutely nothing to you. And as an expert in this, I could give you the definitive answer of "well, it depends on what kind of disks you want to be imaging". Here is a quick table of some popular disk formats:+The Window Stability graph at the top of the window is the analysis of what the drive can and cannot process reliably. The gray vertical lines show the results for individual tests at various flux frequencies long lines are high success rate, and short or no line means lower success rate. The gold line in the graph is a breakdown of the signal reliability along with factoring in things like spindle motor speed fluctuations and such. The most important thing you need to recognize in this graph is the durations which are covered with the gold line pinned to the top which is 100% reliability. The above graph shows that the signal is 100% stable from 3.75µs through to 19µs. If you aren't familiar with how data is stored on disks at a very low level, then that range of stability probably means absolutely nothing to you. And as an expert in this, I could give you the definitive answer of "well, it depends on what kind of disks you want to be imaging". Here is a quick table of some popular disk formats:
  
 ^ Media ^ Encoding ^ Platform ^ 100% Stability Required ^ ^ Media ^ Encoding ^ Platform ^ 100% Stability Required ^
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 === First Injection Timing === === First Injection Timing ===
  
-The *First Injection Timing* graph is a bit more complex to explain and for the most part is irrelevant to most users. If you really want to know, there is some details about what it is showing in the last section of this page.+The First Injection Timing graph is a bit more complex to explain and for the most part is irrelevant to most users. If you really want to know, there is some details about what it is showing in the last section of this page.
  
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