Technical FAQ’s

USB Flash Drive Data Recovery Technical FAQ’s

• What is NAND memory? Introduced by Toshiba in 1989, NAND flash memory is a type of non-volatile storage technology that does not require power to retain data.
• What is Thermoset? Thermoset is a petroleum hydrocarbon solid from the process of resin Thermosetting where the final product once cured leaves an hard exterior plastic coating. This is the typical covering encapsulating the monolith device.
• What is Wear Leveling? Since NAND Flash Memory has a very finite amount of read and write cycles, common USB Flash Drive Controllers employ wear leveling algorithms so the same memory cells are not repeatedly written to over and over.
• What is ECC? Error Correcting Code. Modern day Flash drives write ECC data at the end of a typical 512 byte sector to allow for errors which are correctable.
• How is a Flash Memory Chip Organized? Typical USB Flash Drive NAND memory has data arranged as a hierarchy of Banks, Blocks, Pages, Sectors, Bytes, Bits
• What is an IC? Integrated Circuit.
• What is an oscilloscope? In general, an oscilloscope is a device that measures voltage over time. This is extremely helpful in diagnosing problems with AC and DC circuits. It gives a graphical representation of voltage versus time on a screen for viewing.
• Why is hot air soldering used for usb flash drive data recovery? Hot air rework stations supply precise, digitally controlled consistent air to precise locations for a precise amount of time. The hot air re-work stations provide removal and placement of very small discrete SMT (surface mount technology) components limiting the potential for damage.
• Can I take the NAND memory off of the broken PCB and replace it on a known good working PCB? In theory this could work; however, it would be very rare that this would work. If the controllers matched and the pcb was an exact match, the controller algorithms programmed into the controller to manipulate the data are almost always different from device to device. Only in very rare circumstances would swapping the NAND memory between circuit boards work.
• What is TSOP48? The actual enclosure that encapsulates the silicon substrate of the NAND IC itself is called a package. In semiconductor electronics, packages come in all different shapes and forms. In the case of NAND memory IC’s one of the most popular package is the TSOP48. This is a 48 pin Thin Small Outline Package.
• How are USB Flash drives made? Many manufacturers use slightly different process but for the most part, the internal components are all the same. Most parts are assembled using robotics in mass production facilities in China. Typically one end has a standard USB plug which fits into a computer or other device that can interface with it. A plastic or similar light material is used as the exterior casing to protect the internal components. The internals consist of a small PCB (printed circuit board), controller, oscillator, various small components and most importantly the NAND memory chip that contains the users data. See Anatomy of a Flash Drive to learn more.
• In terms of usb flash memory, what is a bank?
• In terms of usb flash memory, what is a block? A block is a unit of NAND flash memory that is a made up of a number of pages. NAND flash memory is erased by blocks at a time while data written to a NAND flash memory is written by pages.
• In terms of usb flash memory, what is a page? A page is a basic unit of flash memory. A USB flash drive uses a page as the minimum unit used to access data on the NAND memory chip. Page size is determined by the technical specifications from the manufacturer. A typical page size is 8576.
• In terms of usb flash memory, what is a sector? Sectors are generally 512 bytes of data similar to a hard disk drive; however, NAND memory allows for ECC bytes and other service related information stored at the end of the sector making a typical sector 528 bytes but only 512 will be seen to the user as a logical usable sector.
• In terms of usb flash memory, what is a byte? Generally, a byte is 8 bits of data.
• In terms of usb flash memory, what is a bit? A bit is generally a single binary digit of the value either zero or one. This is the smallest basic unit of which all digital electronics and computers use for operations.
• What is XOR encryption? More and more USB flash drive manufacturers are employing XOR encryption in how they store the data on the NAND memory chip. This is also called exclusive or which is often seen as XOR. Data is encrypted based on a set pattern of “one or the other but not both.” This refers to the bit if a comparison is made and at least one of bits is in the true state. So essentially the encryption algorithm operates on the existing data flipping the state of the data based on its current value following a pattern.
• What is BGA 224 NAND? BGA 224 made primarily by Toshiba is NAND memory that comes in a surface mount BGA (Ball Grid Array) package with 224 pads (connection points). It is similar in physical dimensions to the typical LGA found in many usb flash drives.