As the storage capacity of micro SD memory cards has greatly increased, now up to 200 GB, they can be used as a tiny, rugged media choice to store backup files. A micro SD memory card is designed to be small, for use in mobile consumer devices, including digital cameras, video camcorders, smartphones, and tablet PCs.
For mobile devices, the memory card is normally formatted with FAT32 file format, providing greater compatibility between operating systems when transferring files between a mobile device and a notebook PC or desktop computer. But FAT32 is an older file system that was replaced in Windows by the more robust NTFS file format.
FAT32 vs NTFS File System Comparison
The primary advantage of FAT32 file format is compatibility across different operating systems. But it has several disadvantages.
With FAT32, the maximum file size is 4 GB. This can be a problem if you are storing large video files. The maximum volume size is 2 TB. FAT32 is not as reliable or fault-tolerant as NTFS. It does not support file security permissions, file compression or file encryption. It is less secure since all users have access to all files. NTFS does not have these disadvantages. It keeps a journal for auto-repair of file problems.
Format Micro SD Memory Card With NTFS
For using a micro SD memory card to backup files on a computer, format the device using NTFS. In Windows 7, right click on the micro SD device name in the Control Panel. Choose Format from the drop-down menu. A Format pop-up window will appear.
Choose NTFS for the file system. For allocation unit size, choose 8 KB for an 8 GB memory card, 16 KB for 16 GB and 32 KB for 32 GB or larger. Enter a Volume Label for the device. Choose Quick Format, then Start.
Warning: Be certain you are formatting the correct device. Backup any files on the device before you format.
SDHC vs SDXC Memory Card
Secure Digital High Capacity (SDHC) memory cards include storage capacities up to 32 GB. That is the maximum size supported by older card readers. For 32 GB and larger storage, SDXC (extended capacity) memory cards are used. Check your card reader specs to see if it supports both SDHC and SDXC memory cards.
USB Micro SD Memory Card Reader
If needed, you can buy an external USB memory card reader, for under $20, that supports SDHC and SDXC memory cards. Support for UHS-I is also needed for the newest high speed memory cards.
Note: I use a TekRepublic USB 3.0 Card Reader, Model #TUC-310.
Advantages of Using Micro SD Memory Card
A micro SD memory card has no moving parts to break. A hard disk drive has a motor and moving parts that wear out and can break and cause a disk crash. A hard disk is susceptible to water, temperature, impact, shock, vibration, and magnetic fields. A hard disk provides cheaper storage and much more storage, but it will not survive harsh conditions.
• Waterproof, up to 72 hours in 1 meter of water
• Temperature proof, -13 F to 185 F
• Shock and vibration proof, up to 500 Gs of shock
• X-ray proof, immune to airport X-rays
• Magnet proof, up to 5,000 Gauss of static magnetic field
• Impact proof, withstands drops up to 5 meters and being run over by 5-ton truck
Field Test: I kept a Sandisk SDHC memory card, loaded with backup files, in a hidden location in my car for 2 years. Winter temperatures dropped to -10 F or below. Summer temperatures inside the car reached 120 F or more. When I tested the memory card in my PC, after 2 years of harsh temperatures and vibration in the car, it worked fine.
Data Transfer Speed and Backup Time
The effective speed of USB 2.0 (Hi-Speed USB) is 35 MB/sec. USB 3.0 is about 10 X faster, up to 400 MB/sec. The data transfer speed of a micro SD memory card is designated by speed class. Class 4 is 4 MB/sec. Class 10 is 10 MB/sec or faster. Slower speed memory cards are cheaper but are not a good choice for a large backup of many GB, because it will take longer.
Newer micro SD memory cards, designed for 4K Ultra HD video recording, are faster, but more expensive, designated as Ultra High-Speed interface I (UHS-I), with speed class U1 (10 MB/sec) or U3 (30 MB/sec). Sandisk Extreme 32 GB micro SDHC supports UHS-I, at U3 speed, and is rated at 60 MB/sec read and 40 MB/sec write speed. Cost under $20.
Tip: To measure data transfer speed, use speed test benchmark software like Crystal Disk Mark or FlashBench.
To achieve maximum speed, you will need a USB 3.0 (SuperSpeed) port and a memory card reader that supports USB 3.0 and UHS-I. Otherwise, the data transfer speed will be slower and the backup will take longer.
Sandisk Ultra and Ultra Plus memory cards are also available, at Class 10 speeds and lower prices. They are designed for slower Full HD video speed. Sandisk Extreme is a better choice for faster backups.
Rugged Data Backup
Data backup to a micro SD memory card allows the user to keep a local copy of important and confidential files on a tiny removable memory card. The memory card can be easily stored in a fireproof safe or at an offsite location as protection from onsite risks of data loss due to fire, flood, earthquake, explosion, storm damage or theft. The tiny memory card is about the size of a fingernail and is rugged and can be easily hidden in a secret location.
These memory cards are not fast, like a solid state disk (SSD), but they are ideal for rugged storage of videos, music, and photos, and for backup of data files. To refresh data and maintain a full charge on the flash memory used in these devices, it is a good practice to scan all the files every 3 months. This can be done by scanning with an antivirus program or doing a file verify operation with a utility program like TeraCopy.
To reduce the risk of losing the tiny micro SD memory card, use a storage wallet or carrying case.