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Setting up SD Card for Use with DWARF IIUpdated 6 months ago

This guide should help you to determine if the SD card installed in the Dwarf-II is usable, and what you need to do to correct that if it isn’t.

This article was written by Bob Nestor.

Please set up the SD card according to the following logic:

  1. Check if the SD card is recognized by DWARF II.
  2. When using the SD card on different computer systems, it needs to be reformatted to a DWARF-II compatible format.

Note: 

  • The SD card parameters for DWARF II are 64GB, the interface type is UHS-I, the transfer speed is 100MB/s, and the file format is exFAT.
  • Before using your SD card, make sure that DWARF II can correctly recognize the 64GB SD card provided.
  • DWARF II will generate a BadPixelMap based on the dark field captured, which is used to correct bad pixels. The BadPixelMap will exist internally in DWARF II, and even if the SD card is cleared, it will not be affected. The data on the SD card is only for the user's own post-processing use.

The simplest way to determine if the SD card you’ve inserted into the SD slot is supported is to try and take a photo with the Dwarf-II. If the message “Micro SD card not found” appears at the bottom of the device you’re using to control the Dwarf (Android or iPhone), then there’s either no card in the slot or the card that is in the slot isn’t in a unsupported format. The other function that will fail is any attempt to do an “Astro Dark” function. You won’t be able to invoke this function without a valid SD card; invoking “Astro Dark” will immediately revert to the “Astro” function.

Most SD cards found on the market today come prepared with a single Windows ExFAT partition that has been software formatted to accept files. This format is the most universal for SD cards and is widely supported in almost all other Operating Systems for reading and writing.

Windows, Mac OS X, Linux and BSD all support this format. However some cards may come in other formats, not be formatted at all or you may be trying to reuse an SD card that was set up for an entirely different use on another OS. If this is the case, then you’ll need to reformat the SD card into a Dwarf-II compatible format.

Beside the ExFAT disk format, the Dwarf-II also supports the NTFS format. This isn’t as widely used or supported by other Operating Systems for both reading and writing though. And in some ways it is a slightly less robust format than ExFAT. In fact, the development history of disk formats goes somewhat like FAT-12 -> FAT-16 -> FAT-32 -> NTFS -> ExFAT, so nowadays the ExFat format is the preferred format for SD cards on almost all Operating Systems.

In addition to the disk format, there is the disk partitioning to consider. In general an SD card is usually configured with only a single user partition using either MBR or GPT partitioning. For the Dwarf-II the MBR partitioning is supported for both ExFAT and NTFS disk formats. GPT partitioning also works but may be limited to NTFS disk file formats.

So probably the best choice of disk partition and disk file format for use with the Dwarf-II is to initialize your SD card to use MBR partitioning with an ExFAT file format.

Under Windows this is easily done with the disk reformat tools.

Under Mac OS X this is done using Disk Utility.

Under Linux and BSD this is done using command line tools such as “fdisk” and “newfs”. In fdisk the ExFAT format is type “12”, and the NTFS format is type “7”.


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