It is the first step to analyze page structure in binary data by professional data recovery software, therefore knowing how to analyze page structure via data recovery software is a basic skill to prepare for the use of the data-recovery-software Flash Doctor.

What is a sector?

In HDD, a reading and writing unit is a sector. A Sector is a manually devised section, which should have contained 512 bytes of user data. Actually, there is more than 512 bytes of information in a sector. The following figure is an example of a sector format.

The exact detail of how a sector is structured depending on the drive model and Manufacturers.  However, a sector usually includes the following elements:

•ID Information: Conventionally, it is the space in the left of each sector to identify the sector's number and location. This is used for locating a sector on the disk. And status information about the sector is also included in this area.  For example, usually a bit will be left to store the info whether the sector is defective and remapped. Meanwhile you can use data recovery software like Winhex or R-Studio.

•Synchronization Fields: These are used internally by the drive controller to guide the read process.

•Data: The actual user data in a sector.

•Gaps: One or more "spacers" added as necessary as to separate from other areas of the sector,  or  provide  time  for  the  controller  to  process  what  it  has  read  before  reading more bits.

What is a page?

Different from HDD, in flash chip the basic unit is page. Page is also a section manually divided, which is with different size and structure, such as 528 bytes, 2112 bytes, 4224 bytes etc. The following is an example of a page structure with 2112 bytes of page size. Likewise, we can view the pages in data recovery software.

Service information distributed evenly

Similarly, a page includes not only user data bytes but also some service information (service information is recorded in spare area).
As Shown in the above picture, the page contains totally 2048 bytes of user data (each unit with 512 bytes data) and 64 bytes of service information (4 units with 16 bytes each). Service information includes ID info, address Mark, ECC code etc (these info can be figured out by data recovery software). Moreover, the location of service information varies from controller to controller.  For example, service information may be distributed evenly within a page like the above picture, or sometimes it will locate at pager head or page tail, and to work out this info we have to make an analysis to the page structure via data recovery software.

Service information locates at page tail

Service information is distributed to head, middle and tail