--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/sd-card.rst	Sat Feb 17 19:24:27 2024 +0200
@@ -0,0 +1,53 @@
+
+==========
+ SD cards
+==========
+.. contents::
+   :local:
+
+Standards
+=========
+
+======= =========== ====== ======= =============== ==================
+Acronym Capacity    FS     Spec    Compatibility   Name
+======= =========== ====== ======= =============== ==================
+SD      128MB-2GB   FAT16          SD, SDHC, SDXC
+SDHC    4-32 GB     FAT32  SDA 2.0 SDHC, SDXC      High Capacity
+SDXC    64GB-2TB    exFAT  SDA 3.0 SDXC            Extended Capacity
+======= =========== ====== ======= =============== ==================
+
+Ultra High Speed, Phase I (UHS-I):
+* 50MB/s (UHS-50)
+* 104MB/s (UHS-104)
+
+Ultra High Speed Phase II (UHS-II):
+* 156MB/s
+* 312MB/s
+
+Speed
+=====
+
+SD Speed Class:
+
+====== =========
+Class  Min Speed
+====== =========
+2      2MB/s
+4      4MB/s
+6      6MB/s
+8      8MB/s
+10     10MB/s
+====== =========
+
+UHS Speed Class:
+
+====== =========
+Class  Min Speed
+====== =========
+1      10MB/s
+3      30MB/s
+====== =========
+
+https://support-in.wd.com/app/answers/detailweb/a_id/36273/~/specifications-and-compatibility-for-sd%2Fsdhc%2Fsdxc-memory-cards
+  Specifications and Compatibility for SD/SDHC/SDXC Memory Cards.
+