1. A system, comprising:
a first memory configured to store first metadata to associate logical addresses with physical addresses;
a second memory having the physical addresses, wherein the second memory is configured to
store first data based on the physical addresses of the second memory, and
store portions of the first metadata i) in response to a status of a predetermined group of the physical addresses being changed, and ii) regardless of whether the system is being powered down; and
a recovery module configured to, in response to a determination that the system was powered down improperly, update the first metadata stored in the first memory based on the portions of the first metadata stored in the second memory,
wherein the first metadata includes a first lookup table to associate the logical addresses with the physical addresses of the second memory,
wherein the first metadata includes a second lookup table to associate the physical addresses of the second memory with the logical addresses,
wherein the predetermined group of the physical addresses is a wide erase block unit (WERU),
wherein the first metadata includes identifiers for a plurality of WERUs, and wherein the identifiers correspond to respective bins, and
wherein the first metadata includes an activity log to indicate when a first identifier for one of the plurality of WERUs is changed.
2. The system of claim 1, wherein the first memory includes volatile memory, and the second memory includes a flash memory module.
3. The system of claim 1, wherein the bins include a working bin, a partial bin, a valid bin, and a free bin.
4. The system of claim 1, wherein the second memory stores the portions of the first metadata when the first identifier is changed.
5. The system of claim 4, wherein the portions of the first metadata include portions of the second lookup table associated with the one of the plurality of WERUs.
6. The system of claim 5, wherein the recovery module updates the first lookup table based on (i) the portions of the second lookup table and (ii) the activity log.
7. The system of claim 6, wherein the recovery module retrieves the portions of the second lookup table and the activity log from the second memory when the system powers up.
8. A method for operating a device, the method comprising:
storing, in a first memory, first metadata that associates logical addresses with physical addresses, wherein the physical addresses are associated with a second memory;
storing, in the second memory, first data based on the physical addresses of the second memory;
storing portions of the first metadata in the second memory i) in response to a status of a predetermined group of the physical addresses being changed, and ii) regardless of whether the device is powered down;
in response to a determination that the device was powered down improperly, updating the first metadata stored in the first memory based on the portions of the first metadata stored in the second memory;
associating the logical address with the physical addresses of the second memory based on a first lookup table included in the first metadata;
associating the physical addresses of the second memory with the logical addresses based on a second lookup table included in the first metadata,
wherein the predetermined group of the physical addresses is a wide erase block unit (WERU), and
wherein the first metadata includes identifiers for a plurality of WERUs, and wherein the identifiers correspond to respective bins; and
indicating when a first identifier for one of the plurality of WERUs is changed using an activity log included in the first metadata.
9. The method of claim 8, further comprising storing the portions of the first metadata in the second memory when the first identifier is changed.
10. The method of claim 9, wherein the portions of the first metadata include portions of the second lookup table associated with the one of the plurality of WERUs.
11. The method of claim 10, further comprising updating the first lookup table based on the portions of the second lookup table and the activity log.
12. The method of claim 11, further comprising retrieving the portions of the second lookup table and the activity log from the second memory when the device powers up.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for scanning a semiconductor wafer, comprising the steps of:
scanning the wafer with a plurality of scan lines by creating a relative motion between a camera and the wafer,
acquiring images of regions on the wafer with the camera at a scanning speed in a direction of one scan line,
changing from a current scan line to a new scan line that is to be scanned next, by:
providing a deceleration of the relative motion in the scan line direction in the scan line until that relative motion comes to a standstill, and
providing acceleration in the opposite scan line direction until the scanning speed is reached, and
superimposing at least partially the acceleration and subsequent deceleration of a relative motion between the camera and wafer the until the new scan line is reached.
2. The method as defined in claim 1, wherein the decelerating and accelerating of the relative motion in the scan line direction and perpendicular thereto begin, at the earliest, after imaging of a last region of the current scan line that is to be imaged; and the scanning speed in the opposite scan line direction is reached, and the relative speed perpendicular to the scan lines goes to zero, at the latest upon reaching a region that is to be imaged next.
3. The method as defined in claim 1, wherein the decelerating and accelerating of the relative motion in the scan line direction and perpendicular thereto begin, at the earliest, after imaging of a last region of the current scan line that is to be imaged; or the scanning speed in the opposite scan line direction is reached, and the relative speed perpendicular to the scan lines goes to zero, at the latest upon reaching a region that is to be imaged next.
4. The method as defined in claim 1, wherein the deceleration in the scan line direction and the acceleration perpendicular to the scan lines begin simultaneously, and the acceleration in the scan line direction and the deceleration perpendicular to the scan lines are completed simultaneously.
5. The method as defined in claim 1, wherein the deceleration in the scan line direction begins even before imaging of a region that is the last to be imaged in the current scan line.
6. The method as defined in claim 1, wherein the scanning speed in the opposite scan line direction is reached only after a region to be imaged next in the new scan line is reached.
7. The method as defined in claim 1, wherein the greatest relative speed perpendicular to the scan lines is reached upon reaching a relative speed of zero in the scan line direction.
8. The method as defined in claim 1, wherein the acceleration values upon deceleration and acceleration in and perpendicular to the scan line direction are modified continuously.
9. The method as defined in claim 1, wherein regions on the wafer adjacent to one another in the scan line direction are imaged with the camera.
10. The method as defined in claim 9, wherein regions adjacent to one another on the wafer are imaged in such a way that their images partially overlap.
11. The method as defined in claim 1, wherein the wafer is completely scanned, and images of the entire surface of the wafer are acquired.
12. The method as defined in claim 11, wherein regions adjacent to one another on the wafer (1) are imaged in such a way that their images partially overlap.
13. The method as defined in claim 1, wherein the camera defines a rectangularly configured image field having a short side an the short side of the image field is oriented parallel to the scan line direction.
14. An apparatus for scanning a semiconductor wafer in plurality of scan lines comprising: a camera for on-the-fly acquisition of images of a plurality of regions on the wafer, means for generating a relative motion between the camera and the wafer thereby defining a scanning speed in a direction of the scan line, a control device with which, upon a changeover from a current scan line to a new scan line that is to be scanned next, a deceleration of the relative motion in the direction of the scan line is carried out until that relative motion comes to a standstill, and a subsequent acceleration in an opposite direction of the scan line is carried out until the scanning speed is reached, and the control device performs a superimposition on that relative motion with regard to acceleration and subsequent deceleration of a relative motion between camera and wafer perpendicular to the scan lines until the new scan line is reached.
15. The apparatus as defined in claim 14, wherein in the context of a rectangularly configured image field of the camera, a short side of the rectangle of the image field is oriented parallel to the scan line direction.
16. The apparatus as defined in claim 14, wherein a scanning stage is provided, on which the wafer (1) is placeable and securable and with which the relative motion with reference to a stationary camera is performable.
17. An apparatus for scanning a semiconductor wafer comprising: a camera for on-the-fly acquisition of images with an image field of a plurality of regions on the wafer, a plurality of scan lines are defined and the wafer is divided into that plurality of scan lines, means for scanning the wafer with a scanning speed in a scan line direction as a relative motion between the camera and the wafer, the image field of the camera has a rectangular configuration, and a short side of the rectangular configuration of the image field is oriented parallel to the scan line direction.