第七课-文件存储技术.pptVIP

* 总结－测验 TDMS文件仅保存通道或通道组级别的属性。 对 错 * 总结－测验答案 TDMS文件仅保存通道或通道组级别的属性。 对 错 强化练习 文件存储技术 * 练习位置：Exercise/Exercise 7.4 Core 1.6 Core 2.6 ASCII (American Standard Code for Information Interchange) TDM (Technical Data Management) In LabVIEW, three of the most common techniques for storing data are: ASCII file format direct binary storage TDMS file format Arrow size is to indicate increasing file size. Point out high-level VIs and low-level VIs on palette. Key concept as it will apply to many areas, such as DAQ, TCP/IP, etc. Explain the concept of disk streaming here. Emphasize opening and closing outside of the loop. Core 1 6-1 Exercise time: 10 minutes Alternately, you can sequentially access the file one item at a time by repeatedly calling the Read from Binary File VI with the default count of 1. You can check for the End of File error after calling the Read from Binary File VI or calculate the number of reads necessary to reach the end of the file by using the Get File Size VI. Core 2 6-1 Would the generated bitmap file still be correct if you swapped the BITMAPFILEHEADER VI and the BITMAPINFOHEADER VI? Why? No. The bmp file format is strictly defined and swapping the file header and the info header would result in an invalid file format. It wasn’t necessary to specify the byte-order in the Write to Binary File functions. Why not? Both headers and the data are unsigned 8-bit integers. Setting the byte order only applies to data formats larger 8-bits such as 16-bit integers and 32-bit integers. Another idea for discussion: Did anyone run the VI more than once? Did you notice the Drawing Pad remembered your last drawing? How is the VI doing this? Did you open the Drawing Pad VI and look at the block diagram? Answer: Uninitialized shift register. If time permits, get students to talk through how they might change the VI so the drawing pad starts out with a blank picture. All the information in the TDMS_Index file is also contained in the TDMS file. This is why