Micro SD

Introduction

Micro SD, known as Micro Secure Digital, is a small memory card that is a variant of the Secure Digital (SD) card. It was developed and introduced by the SD Card Association (SD Association) to provide expandable storage solutions for portable devices.

Interface Test Methods

Read and Write Test

Open a terminal and type lsblk to find the SD card device, take /dev/mmcblk1 as an example.

NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
mmcblk1 179:0 0 116.5G 0 disk
|-mmcblk1p1 179:1 0 16M 0 part /config
|-mmcblk1p2 179:2 0 300M 0 part /boot/efi
|-mmcblk1p3 179:3 0 116.2G 0 part /

• Read test

dd if=/dev/mmcblk0 of=/dev/null bs=4M count=100

This command will read 100 blocks of data with a block size of 4MB from the Micro SD card and write them to the /dev/null device to be discarded. During this process, the command line will output the read and write speeds.

• Write test

dd if=/dev/zero of=/dev/mmcblk0 bs=4M count=100