Pages: [1]   Go Down
Author Topic: Don't Format SD cards with OS utilities!  (Read 11543 times)
0 Members and 1 Guest are viewing this topic.
0
Offline Offline
Edison Member
*
Karma: 64
Posts: 1635
Arduino rocks
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Always format SD cards using SD Formatter https://www.sdcard.org/downloads/formatter_4/.

NEVER format SD card with OS utilities!

Here are some examples that show what can happen.  First is an extreme case for determining free space on an SD.  This type performance hit will also be true for seek.

Time to determine free space with a properly formatted card using the SdInfo sketch.  See http://forum.arduino.cc/index.php?topic=228128.msg1648437#msg1648437 for more details on code.

Time 0.302 seconds.
Quote
millis: 302
freeClusters: 63883
freeSpace: 2093.32 MB (MB = 1,000,000 bytes)

Same card formatted FAT32 with small clusters on Windows.
34.885 seconds.
Quote
millis: 34885
freeClusters: 4033302
freeSpace: 2065.05 MB (MB = 1,000,000 bytes)

Here are results running the SdFat bench sketch on this card.  Write takes about four times longer with FAT32 and small clusters.

Properly formatted card.
Quote
Type is FAT16
File size 5MB
Buffer size 100 bytes
Starting write test.  Please wait up to a minute
Write 358.47 KB/sec
Maximum latency: 58888 usec, Minimum Latency: 84 usec, Avg Latency: 273 usec

Starting read test.  Please wait up to a minute
Read 369.19 KB/sec
Maximum latency: 1912 usec, Minimum Latency: 84 usec, Avg Latency: 265 usec

Same card formatted FAT32 with small clusters on Windows.
Quote
Type is FAT32
File size 5MB
Buffer size 100 bytes
Starting write test.  Please wait up to a minute
Write 89.43 KB/sec
Maximum latency: 117636 usec, Minimum Latency: 84 usec, Avg Latency: 1113 usec

Starting read test.  Please wait up to a minute
Read 225.44 KB/sec
Maximum latency: 1920 usec, Minimum Latency: 80 usec, Avg Latency: 437 usec

These are extreme cases but I do often see this type problem so please use this formatter https://www.sdcard.org/downloads/formatter_4/.  It will always produce the optimum format for your card.
Logged

Central MN, USA
Offline Offline
Tesla Member
***
Karma: 73
Posts: 7197
Phi_prompt, phi_interfaces, phi-2 shields, phi-panels
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Karma Karma!
You saved my day!
Logged


Offline Offline
Newbie
*
Karma: 1
Posts: 8
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Wow, OS formatting really isn't very helpful!
Logged

Offline Offline
Newbie
*
Karma: 2
Posts: 10
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

relevant.... thanx for the info...  smiley
Logged

Central MN, USA
Offline Offline
Tesla Member
***
Karma: 73
Posts: 7197
Phi_prompt, phi_interfaces, phi-2 shields, phi-panels
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

This also helps with PC reading and writing the same SD card. I have a 32GB SD card that I put in my Dell venue 8 pro. I formatted it in NTFS and the performance of my Dell's video recording was bad. I then reformatted with the formatter and now the video recording is working fine. It's just the SD card performance issue.
Logged


Pages: [1]   Go Up
Jump to:  

Powered by SMF 1.1.19 | SMF © 2013, Simple Machines