Wednesday, 15 April 2015


Been answering a support query recently, and mentioned to client that USB is outright bad in all respects [for data recovery use].

Well, pretty much so,
  • if one of the drives has a bad block, quite likely the USB converter will lock up on hitting that block;
  • with USB 2.0, speed is 15 MB/sec maximum, for all drives combined,
    • even if you have what appears to be different ports, they will be routed through a same root port or hub anyway;
  • devices advertised as USB 3.0 often work at 2.0 speeds, with no warning whatsoever;
  • power supply issues and limitations are difficult to control, 
    • especially so if hubs are involved;
  • any setup with daisy-chained hubs is unstable,
    • especially so with USB 3.0;

So, think twice before starting a recovery with a laptop-based all-USB setup.

Tuesday, 14 April 2015

RAID block size limiters

If you are doing a RAID Recovery and the software has the capability to limit the allowed block sizes for search (which is quite often actually, ReclaiMe Pro has it, Runtime has it, ZAR has it, and perhaps R-Studio has too), and if you happen to know the block size exactly, do not set the limiter to exact block size.

If you know the block size is 128 whatever units, set limits to 64 low and 256 high (of the same units, repeat, the same units). Otherwise, if the automatic detection gets you the value at one of the edges of the range, you do not know if it is because the value is correct, or because it hit the limit and was not able to further change the block size. The final block size must be inside the allowed range, not on the edge.